Documenting my solar install
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SternWake
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Yes, Peukert basically says the faster the discharge rate, the less overall capacity a battery has to give.
The 20 hour rate on a hundred amp hour battery is measured with a 5 amp load, So a hundred amp hour battery, healthy and fully charged, can support 5 amps for 20 hours until the battery is considered 100% depleted at 10.5 volts. But this 10.5 volts is what the battery would eventually rebound to, well after the load is removed, so actual battery voltage during the end of that 20 hours might be in the low 9v range.
Loads over 5 amps reduce the overall usable battery capacity, and loads under 5 amps increase the capacity available over that 100 amp hour capacity measured at the 20 hour rate.
It's not just subtract the amp hours and that is what the battery has left, unless the load is the same load is what took 20 hours to take that battery to a rested 10.5v.
And some battery manufacturers move the fully discharged benchmark to 10V instead of the standard 10.5v.
The + 10% is a general figure. Some AGM's are as little as 103% and an old abused flooded battery can actually require up to 150% the energy removed from it to return to brimming full.
The important thing is that one is aware it takes a bunch more energy to fully recharge a battery than what was taken out, and that the battery monitor might not be taking this into account, or if it is, then not 100% accurately.
I view it as an informative tool, but not a perfect tool.
I like the amp hour from full screen after my peculiar battery has been sitting at high absorption and finish charge voltages for hours and was only accepting 1.6 amps at 15.3v.
I consider my % remaining screen to be a joke, as the battery is no where near the original capacity anymore and my guess as to how much capacity it has left could be wildly wrong.
Where as my AGM is full when it can no longer accept 0.6 amps at 14.7v, but this number will taper to 0.3 amps after 4 more hours at 14.7v
Flooded batteries need higher amperages, to be held at high voltages, when the battery is full or very nearly so.
The 20 hour rate on a hundred amp hour battery is measured with a 5 amp load, So a hundred amp hour battery, healthy and fully charged, can support 5 amps for 20 hours until the battery is considered 100% depleted at 10.5 volts. But this 10.5 volts is what the battery would eventually rebound to, well after the load is removed, so actual battery voltage during the end of that 20 hours might be in the low 9v range.
Loads over 5 amps reduce the overall usable battery capacity, and loads under 5 amps increase the capacity available over that 100 amp hour capacity measured at the 20 hour rate.
It's not just subtract the amp hours and that is what the battery has left, unless the load is the same load is what took 20 hours to take that battery to a rested 10.5v.
And some battery manufacturers move the fully discharged benchmark to 10V instead of the standard 10.5v.
The + 10% is a general figure. Some AGM's are as little as 103% and an old abused flooded battery can actually require up to 150% the energy removed from it to return to brimming full.
The important thing is that one is aware it takes a bunch more energy to fully recharge a battery than what was taken out, and that the battery monitor might not be taking this into account, or if it is, then not 100% accurately.
I view it as an informative tool, but not a perfect tool.
I like the amp hour from full screen after my peculiar battery has been sitting at high absorption and finish charge voltages for hours and was only accepting 1.6 amps at 15.3v.
I consider my % remaining screen to be a joke, as the battery is no where near the original capacity anymore and my guess as to how much capacity it has left could be wildly wrong.
Where as my AGM is full when it can no longer accept 0.6 amps at 14.7v, but this number will taper to 0.3 amps after 4 more hours at 14.7v
Flooded batteries need higher amperages, to be held at high voltages, when the battery is full or very nearly so.
Seraphim
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That explains yesterday's performance: I naively expected - at 7 amps - it would only take the battery several hours to recharge. Yet, after two hours there appeared to be no positive change in the battery's charge level. I'm going to have to reexamine my expectations of the system.
Seems like a sunnier day today. I think I'll pull the camper out into the sun and see what readings I'm getting. From reviews, just over 20 amps seemed average for the kit. But I figure results will vary due to location, panels, etc.
Seems like a sunnier day today. I think I'll pull the camper out into the sun and see what readings I'm getting. From reviews, just over 20 amps seemed average for the kit. But I figure results will vary due to location, panels, etc.
Seraphim
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Update:
Went out out and checked the system this morning. Whereas yesterday from 1 pm to 6 pm the battery level read 93%, this morning the level was up o 98%. So, at the very least, the system should keep the battery levels up when the camper is not in use, parked on the northern side of a large evergreen, during winter overcast skies. I dnt have to keep the unit plugged into shore power four months out of the year.
Probably should install a battery disconnect.
Addendum: checked the battery level this morning at 9:30 am, so the system probably had about 2 hours of morning, unshaded light to account for the raise in battery level. Just a thought.
Oh yeah - there was a warning light blinking - a COMI error. I reset the device and it disappeared. I'll keep an eye on it.
Or was it a CMO I error? Lol.
Went out out and checked the system this morning. Whereas yesterday from 1 pm to 6 pm the battery level read 93%, this morning the level was up o 98%. So, at the very least, the system should keep the battery levels up when the camper is not in use, parked on the northern side of a large evergreen, during winter overcast skies. I dnt have to keep the unit plugged into shore power four months out of the year.
Probably should install a battery disconnect.
Addendum: checked the battery level this morning at 9:30 am, so the system probably had about 2 hours of morning, unshaded light to account for the raise in battery level. Just a thought.
Oh yeah - there was a warning light blinking - a COMI error. I reset the device and it disappeared. I'll keep an eye on it.
Or was it a CMO I error? Lol.
Seraphim said:
Nice rig. The truck looks like a 1 ton. I bet there ain't many places you can drive it.
I been looking at dodge ram with cummins engine, Too expensive. Guess I'll have to stay with my little 4.6, F150.
correction
Let just say, I bet there ain't many places it won't go.
SternWake
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Please take note that the electrical crimpers you used yield a very poor crimp, both in terms of physical connection as well as electrical connection.
A shame because you used those nice crimps with the heat shrink insulation built in.
Monitor the connections for heating, and give that cheapo crimper to an enemy.
All connections introduce measurable resistance and possible failure points, so a goal should be minimizing the amount of connections and those that are necessary need to be done well with a good tool. Fuses also introduce resistance.
http://www.pbase.com/mainecruising/fuse_voltage_drop
So there is consequence to overfusing.
While you have a lot of solar for a little battery and the extra resistance should not be a deal breaker, it will increase over time and could be dangerous to the controller if a connector lets go.
One should avoid disconnecting the solar controller from the battery while the panels are generating. I try and do so only at night, and I only do so to reset my Blue Sky IPN pro remote battery monitor which gets its 12v power from the solar controller.
If your batteries are flooded, a good glass turkey baster style hydrometer should be used to verify that when the solar controller goes from absorption to float modes, that the Specific gravity was maxed out at 1.275 or higher( depends on battery) or nearly so.
This is the biggest issue with solar, and most charging sources which automatically reduce voltage when they believe the batteries are full. They are simply wrong most of the time, and the battery in most all cases needed more time at absorption voltages, and perhaps higher Absorption voltages too, and this neutered charging profile does so at the cost of battery performance and battery life.
Beware of blinking and soothing green lights. They are a marketer's best friend and the enemy of the engineer. They hydrometer is the best tool a flooded battery operator has and will often reveal shockingly low Specific gravity when both the solar controller has reverted to float and the battery monitor agrees.
AGM's are a bit more difficult, and amps hours out vs amps hours back in, as well as amps accepted by the battery at absorption voltages are ways to know when the AGM is in that 99%+ range.
Lifeline AGM battery has a "reconditioning" procedure that is similar to a flooded battery equalization charge, designed to restore capacity on chronically undercharged batteries. Lifeline's battery PDF is among the best manuals out there concerning battery charging, AGM or flooded.
http://www.lifelinebatteries.com/manual.pdf
But in the end batteries are only rented, and the effort to maximize their life might not be worth the extra effort to many. But awareness and suspicion and verification that they are possibly being chronically undercharged by charging sources, that love to display those soothing blinking or steady green full charge indicators, is the best way to insure the batteries can live upto their potential.
Of course a charge controller/source which allows one to actually fully charge a batteryvia adjustable Absorption voltage and duration is required, and most charging sources simply cannot do the job at which they claim to be proficient in doing especially before the sun gets too low to do the job and the next discharge cycle begins, which can happen often, if not daily, when a full time dweller.
Adjustable Absorption voltage and duration, validated with a hydrometer is the key. Ability to achieve equalization voltages is also a huge battery life extender, and is more important to do when batteries live their life undercharged.
I can reprogram my solar controller to do 16V, but I need at least 6.2 amps worth of sunlight to do so on a single group 31 flooded battery at 130 amp hours rating, and I have a MeanWell RSP-500-15 adjustable voltage switching power supply which will do 40.94 amps into a depleted battery, and can be dialed upto( and well past) 16 volts, but is a manual charger and must be monitored, or put on a timer when set to absorption voltages.
https://vanlivingforum.com/showthread.php?tid=10873&highlight=my+newest+electrical+toy
Note Equalization voltages should only be applied to a battery which has seen at least 2 hours at battery manufacturer recommended absorption voltage. The charging source should not just blow past 14.x and goto 15.5 or 16V as this is abusive to the battery. EQ sessions are abusive themselves, but less abusive than chronically undercharging them or never equalizing them. So begin an EQ after a regular 'full' charge, and stop when the Specific gravity, temperature compensated, no longer rises, or battery electrolyte temperature approaches 120F.
Battery manufacturers are all over the map as to recommendations as to how often to perform an EQ charge, but basically the deeper the cycles and the more chronically undercharged the batteries are each charge cycle, the more important and the more often an EQ should be performed, and it will be different for everybody, their batteries and their usage of said battery.
After an EQ session, the maximum SG reading is the goal one hopes to approach at the end of 2 hours at absorption voltage. If 2 hours at 14.8v gets within 0.005 of the maximum then rezero the battery monitor at that point. 2 hours at 14.4v might do it too, or come nowhere close. It depends on the battery, as well as the charging source, as generally higher initial amperages do not require the extended time at higher voltages to max out SG in my observsations and experience. The point is that one needs to verify the full charge indicators various charging sources use, and can't blindly believe their trimetric or other battery monitor or blinking green light of other charging sources.
I've found my batteries, past and present, love a morning blast of alternator amperage in the 40 to 60 amp range, even if for only 20 minutes, then letting the solar finish them off. Basically the earlier in the day that the batteries reach ABSV, the better chance they have of achieving maximum specific gravity. I have also set my 'Float' voltage up higher than Absorption voltage and use it as a 'Finishing' or 'topping' charge. But If I do not cycle the battery the night before, then I reduce absorption voltage and duration and reduce float voltage to 13.2v, as a non cycled battery does not need to spend 2 hours at 14.8 and the rest of the day at 15.3v, but my deeply cycled flooded group31 battery certainly and overwhelmingly does require this.
I've really been using this battery hard, and it has obviously lost capacity, but a year ago when I first got it, I was applying more standard Absv's and durations and SG had tanked into the red and performance was Horrid after 10 cycles to 75% SOC. The hydrometer and raising voltages and durations and EQ charges allowed me to get this petulant battery to perform properly. If I did not take the time to figure this out, this battery would have been recycled long ago.
Most all battery systems would benefit greatly by verifying that the charging source is doing the job it claims to be able to do. Mine was no where near. Most systems are likely similar. Not an issue if you get to plug in and recharge, or stop cycling the battery and give the solar a few days to shoehorn in everything into a battery, but when the next discharge cycle begins before sundown that night, then it is of utmost importance to get the battery to near as possible to 100% before that next discharge cycle begins.
The clock is ticking, and full time dwellers have a different set of charging requirements than those who part time or who get to plug into the grid and let a charging source have days to perform the task the full time dweller needs done in hours.
A shame because you used those nice crimps with the heat shrink insulation built in.
Monitor the connections for heating, and give that cheapo crimper to an enemy.
All connections introduce measurable resistance and possible failure points, so a goal should be minimizing the amount of connections and those that are necessary need to be done well with a good tool. Fuses also introduce resistance.
http://www.pbase.com/mainecruising/fuse_voltage_drop
So there is consequence to overfusing.
While you have a lot of solar for a little battery and the extra resistance should not be a deal breaker, it will increase over time and could be dangerous to the controller if a connector lets go.
One should avoid disconnecting the solar controller from the battery while the panels are generating. I try and do so only at night, and I only do so to reset my Blue Sky IPN pro remote battery monitor which gets its 12v power from the solar controller.
If your batteries are flooded, a good glass turkey baster style hydrometer should be used to verify that when the solar controller goes from absorption to float modes, that the Specific gravity was maxed out at 1.275 or higher( depends on battery) or nearly so.
This is the biggest issue with solar, and most charging sources which automatically reduce voltage when they believe the batteries are full. They are simply wrong most of the time, and the battery in most all cases needed more time at absorption voltages, and perhaps higher Absorption voltages too, and this neutered charging profile does so at the cost of battery performance and battery life.
Beware of blinking and soothing green lights. They are a marketer's best friend and the enemy of the engineer. They hydrometer is the best tool a flooded battery operator has and will often reveal shockingly low Specific gravity when both the solar controller has reverted to float and the battery monitor agrees.
AGM's are a bit more difficult, and amps hours out vs amps hours back in, as well as amps accepted by the battery at absorption voltages are ways to know when the AGM is in that 99%+ range.
Lifeline AGM battery has a "reconditioning" procedure that is similar to a flooded battery equalization charge, designed to restore capacity on chronically undercharged batteries. Lifeline's battery PDF is among the best manuals out there concerning battery charging, AGM or flooded.
http://www.lifelinebatteries.com/manual.pdf
But in the end batteries are only rented, and the effort to maximize their life might not be worth the extra effort to many. But awareness and suspicion and verification that they are possibly being chronically undercharged by charging sources, that love to display those soothing blinking or steady green full charge indicators, is the best way to insure the batteries can live upto their potential.
Of course a charge controller/source which allows one to actually fully charge a batteryvia adjustable Absorption voltage and duration is required, and most charging sources simply cannot do the job at which they claim to be proficient in doing especially before the sun gets too low to do the job and the next discharge cycle begins, which can happen often, if not daily, when a full time dweller.
Adjustable Absorption voltage and duration, validated with a hydrometer is the key. Ability to achieve equalization voltages is also a huge battery life extender, and is more important to do when batteries live their life undercharged.
I can reprogram my solar controller to do 16V, but I need at least 6.2 amps worth of sunlight to do so on a single group 31 flooded battery at 130 amp hours rating, and I have a MeanWell RSP-500-15 adjustable voltage switching power supply which will do 40.94 amps into a depleted battery, and can be dialed upto( and well past) 16 volts, but is a manual charger and must be monitored, or put on a timer when set to absorption voltages.
https://vanlivingforum.com/showthread.php?tid=10873&highlight=my+newest+electrical+toy
Note Equalization voltages should only be applied to a battery which has seen at least 2 hours at battery manufacturer recommended absorption voltage. The charging source should not just blow past 14.x and goto 15.5 or 16V as this is abusive to the battery. EQ sessions are abusive themselves, but less abusive than chronically undercharging them or never equalizing them. So begin an EQ after a regular 'full' charge, and stop when the Specific gravity, temperature compensated, no longer rises, or battery electrolyte temperature approaches 120F.
Battery manufacturers are all over the map as to recommendations as to how often to perform an EQ charge, but basically the deeper the cycles and the more chronically undercharged the batteries are each charge cycle, the more important and the more often an EQ should be performed, and it will be different for everybody, their batteries and their usage of said battery.
After an EQ session, the maximum SG reading is the goal one hopes to approach at the end of 2 hours at absorption voltage. If 2 hours at 14.8v gets within 0.005 of the maximum then rezero the battery monitor at that point. 2 hours at 14.4v might do it too, or come nowhere close. It depends on the battery, as well as the charging source, as generally higher initial amperages do not require the extended time at higher voltages to max out SG in my observsations and experience. The point is that one needs to verify the full charge indicators various charging sources use, and can't blindly believe their trimetric or other battery monitor or blinking green light of other charging sources.
I've found my batteries, past and present, love a morning blast of alternator amperage in the 40 to 60 amp range, even if for only 20 minutes, then letting the solar finish them off. Basically the earlier in the day that the batteries reach ABSV, the better chance they have of achieving maximum specific gravity. I have also set my 'Float' voltage up higher than Absorption voltage and use it as a 'Finishing' or 'topping' charge. But If I do not cycle the battery the night before, then I reduce absorption voltage and duration and reduce float voltage to 13.2v, as a non cycled battery does not need to spend 2 hours at 14.8 and the rest of the day at 15.3v, but my deeply cycled flooded group31 battery certainly and overwhelmingly does require this.
I've really been using this battery hard, and it has obviously lost capacity, but a year ago when I first got it, I was applying more standard Absv's and durations and SG had tanked into the red and performance was Horrid after 10 cycles to 75% SOC. The hydrometer and raising voltages and durations and EQ charges allowed me to get this petulant battery to perform properly. If I did not take the time to figure this out, this battery would have been recycled long ago.
Most all battery systems would benefit greatly by verifying that the charging source is doing the job it claims to be able to do. Mine was no where near. Most systems are likely similar. Not an issue if you get to plug in and recharge, or stop cycling the battery and give the solar a few days to shoehorn in everything into a battery, but when the next discharge cycle begins before sundown that night, then it is of utmost importance to get the battery to near as possible to 100% before that next discharge cycle begins.
The clock is ticking, and full time dwellers have a different set of charging requirements than those who part time or who get to plug into the grid and let a charging source have days to perform the task the full time dweller needs done in hours.
Seraphim
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Outstanding post Sternwake. Your time is really appreciated.
Have you considered writing a book? Lol
But you've just determined my agenda for tomorrow.
I did get the camper mounted in the truck, and took it to a nearby parking lot, free of shade. Still an overcast sky, but the average amperage increased to 9 to 12 amps. Tomorrow, the battery monitor should show 100%, and I can conduct the tests Sternwake recommended. Also want to check the battery manufacturer site and find the recommended charging voltages. The controller is programable in that aspect. In the morning I should also know if that CMO warning reappears. If it does, I'll contact REnogy about a replacement, and probably go ahead with an MPPT upgrade and pay the price difference. I hear Renogy is good about that. If the current comtroller is fine, I won't bother with an upgrade at the moment.
Also need to remove that negative wire fuse and solder the wire back together. A night time project, when the panel's aren't outputting.
I plan to download the PDF Sternwake mentioned and reading it tonight.
Who said retirement is boring?
* and of I UPGRADE the comtroller, might as well upgrade cable size to the batteries. I'll need to modify the venting system on the batteries as well, due to all the cables.
Have you considered writing a book? Lol
But you've just determined my agenda for tomorrow.
I did get the camper mounted in the truck, and took it to a nearby parking lot, free of shade. Still an overcast sky, but the average amperage increased to 9 to 12 amps. Tomorrow, the battery monitor should show 100%, and I can conduct the tests Sternwake recommended. Also want to check the battery manufacturer site and find the recommended charging voltages. The controller is programable in that aspect. In the morning I should also know if that CMO warning reappears. If it does, I'll contact REnogy about a replacement, and probably go ahead with an MPPT upgrade and pay the price difference. I hear Renogy is good about that. If the current comtroller is fine, I won't bother with an upgrade at the moment.
Also need to remove that negative wire fuse and solder the wire back together. A night time project, when the panel's aren't outputting.
I plan to download the PDF Sternwake mentioned and reading it tonight.
Who said retirement is boring?
* and of I UPGRADE the comtroller, might as well upgrade cable size to the batteries. I'll need to modify the venting system on the batteries as well, due to all the cables.
SternWake
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Note that large 12v batteries like the group 27/29 or 31 seem to require both higher voltages and durations to max out the specific gravity, compared to a pair of 6v golf cart batteries in series. This is one reason among some others why GC batteries excel in deep cycle applications.
If one can handle the extra height of a pair of flooded GC batteries, they are a lot of bang for the buck, and can handle more abuse, and take less extreme voltages and durations to actually revert to maximum specific gravity, making them a better mate for a charge controller which does not allow one to change voltage settings.
The battery manufacturer recommendations are a good starting point as to settings, but ultimately the hydrometer should have the final say. I found that 14.9v Absorption and 15.3v finishing/float got the battery much closer to max SG than the recommended 14.7absv and 15.3 'Finishing' charge USbattery recommended when on solar. But, when I make more use of the alternator or the MeanWell charging sources, that 14.7 and a higher amp rate to reach here is all that is required to achieve similar SG readings.
Dialing in the best solar settings is therefore not the same as when one is using other charging sources, and 'best' is a moving target too, and the hydrometer is the tool to determine that.
If one shives a git.
If one can handle the extra height of a pair of flooded GC batteries, they are a lot of bang for the buck, and can handle more abuse, and take less extreme voltages and durations to actually revert to maximum specific gravity, making them a better mate for a charge controller which does not allow one to change voltage settings.
The battery manufacturer recommendations are a good starting point as to settings, but ultimately the hydrometer should have the final say. I found that 14.9v Absorption and 15.3v finishing/float got the battery much closer to max SG than the recommended 14.7absv and 15.3 'Finishing' charge USbattery recommended when on solar. But, when I make more use of the alternator or the MeanWell charging sources, that 14.7 and a higher amp rate to reach here is all that is required to achieve similar SG readings.
Dialing in the best solar settings is therefore not the same as when one is using other charging sources, and 'best' is a moving target too, and the hydrometer is the tool to determine that.
If one shives a git.
Seraphim
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Currently we drive a lot, but intend to reduce that as diesel fuel hasn't really decreased in price, and we plan to spend more time in one place. So, with twin alternators, we never much worried about recharging. But we also couldn't spend more than four nights in one spot without charging somehow. We were hoping the panel's would extend that onsite time...
Not fond of genies....
And if I can extend battery life at the same time...
The original plan called for 400+ AH of GC batteries, but I needed to replace batteries on the road, so I took what I could get at Camping World. When these die, I figured I could add the sealed GC batteries - without the need for venting battery boxes, I have a lot more room available for actual battery...
Not fond of genies....
And if I can extend battery life at the same time...
The original plan called for 400+ AH of GC batteries, but I needed to replace batteries on the road, so I took what I could get at Camping World. When these die, I figured I could add the sealed GC batteries - without the need for venting battery boxes, I have a lot more room available for actual battery...
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Great looking setup!! Was that photo taken in the Klondike?
Bob
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There aren't many places left that your rig can get that dirty! Alaska and the Yukon are mainly those places!
Bob
Bob
SternWake
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Do note that newer batteries should not really be added in parallel to older batteries.
It wont go all fukushima on you insantly, but the new batteries will be constantly feeding the older batteries once any charging source is removed, and quickly age them.
AGM batteries and flooded batteries should not be left in parallel together. Some flooded batteries are sealed, but mostly when online, I will consider sealed batteries to be AGM, rather than flooded or gel.
There can also be issues with charging flooded and AGM batteries in parallel as AGM batteries have less internal resistance and will gobble more charging current at the same voltage and charge faster, and if the charging source holds high voltages for as long as the Flooded battery needs, it is possible to overcharge the AGMs.
Again not an instant self destruct scenario, but one that should be aware of, and avoided if possible.
That said I have one AGM and one Flooded, and I let the alternator feed them both together in parallel at 14.9v, but I get uneasy on long drives in hot weather, as AGMs aren't cheap, and 14.9 is high, So I do flip a switch and take the AGm out of the alternator charging loop.
Voltage regulators can be foolish devils.
Dashboard voltmeters with decimal places are worthwhile. Those analog gauges with a 11 on one end and a 19 on the other, and a needle that falls somewhere inbetween, are simply an insult, and mostly useless.
It wont go all fukushima on you insantly, but the new batteries will be constantly feeding the older batteries once any charging source is removed, and quickly age them.
AGM batteries and flooded batteries should not be left in parallel together. Some flooded batteries are sealed, but mostly when online, I will consider sealed batteries to be AGM, rather than flooded or gel.
There can also be issues with charging flooded and AGM batteries in parallel as AGM batteries have less internal resistance and will gobble more charging current at the same voltage and charge faster, and if the charging source holds high voltages for as long as the Flooded battery needs, it is possible to overcharge the AGMs.
Again not an instant self destruct scenario, but one that should be aware of, and avoided if possible.
That said I have one AGM and one Flooded, and I let the alternator feed them both together in parallel at 14.9v, but I get uneasy on long drives in hot weather, as AGMs aren't cheap, and 14.9 is high, So I do flip a switch and take the AGm out of the alternator charging loop.
Voltage regulators can be foolish devils.
Dashboard voltmeters with decimal places are worthwhile. Those analog gauges with a 11 on one end and a 19 on the other, and a needle that falls somewhere inbetween, are simply an insult, and mostly useless.
Seraphim
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Sternwake
It's interesting - haven't had the chance to get the hydrometer yet. The solar charger showed an MOS-I error again today ( that's the correct code this time lol) which disappeared when I rebooted the charger. But, according to the manual, I'll call Renogy tomorrow about the unit. If it needs replacing, I'll go ahead and upgrade to mppt for about another $100.
But when I checked the battery monitor, after operating the slide and lights a bit, the trimetric showed 98% of capacity remaining, while the SOC on the controller showed 51% and the battery charging, apparently at 13.8v 2.5A
The batteries had been on shore power for several months, and taken off for a couple of days with a .2 amp power draw, plus having a small charge from the panels. Don't see how the SOC could be down to 51%...
It's interesting - haven't had the chance to get the hydrometer yet. The solar charger showed an MOS-I error again today ( that's the correct code this time lol) which disappeared when I rebooted the charger. But, according to the manual, I'll call Renogy tomorrow about the unit. If it needs replacing, I'll go ahead and upgrade to mppt for about another $100.
But when I checked the battery monitor, after operating the slide and lights a bit, the trimetric showed 98% of capacity remaining, while the SOC on the controller showed 51% and the battery charging, apparently at 13.8v 2.5A
The batteries had been on shore power for several months, and taken off for a couple of days with a .2 amp power draw, plus having a small charge from the panels. Don't see how the SOC could be down to 51%...
SternWake
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The solar controller, if operating properly, likely considers the battery 100% charged after it holds the battery at absorption voltage for X amount of time, then reverts to float.
There is not some circuitry in the charge controller which actually senses the battery state of charge. I am not sure how the charge controller would even know how much the battery is being discharged to display anything other than the solar charging amps and flash a light when it thinks the batteries are full and can take no more, say such as after 2 hours at 14.8v and the 210 AH bank is taking less than 2.5 amps to hold 14.8v.
Do note 2.5 is just an off the top of my head ballpark figure. Each battery will differ and change as it ages.
The solar controller might see when the solar charging has nearly stopped, and later if had thought the battery was full, then it might post state of charge simply guessing by battery voltage, like 12.23v= 51%. But unless all the current that is discharging the batteries, goes through a shunt( like the trimetric) the solar controller simply has no way of counting current flowing out of the batteries. There are Hall Effect Sensors that can go around a cable, like a clamp on Ammeter, that can measure current flowing through a single wire, but the Shunted Ammeter/monitor is generally more accurate, especially at low currents. I am not aware of any solar controllers themselves having external shunts to monitor current flow out of the battery, they can only count solar current flowing through the controller into the battery.
Now the Solar controller itself can have an internal shunt, or HES to measure solar current passing through it, but discharging current cannot be measured by this method.
Do note that the Trimetric's shunt needs to have ALL current routed through it. Meaning all loads, all grounds go to one side(load) of the shunt, and the only connections that go directly to either battery (-), come from the other/battery side of the shunt.
If any single wire goes directly to either battery (-) and does not pass through the shunt, this current on this single wire can not be read by the shunt/monitor and since all grounds are common, even if a device is not operating, or hooked to the battery that is being monitored, some current will still find a path back to ground through this wire.
So getting the battery monitor to read alternator current requires pulling the main battery cable off the engine battery (-), and attaching it to the load side of the shunt. Note the Shunt has to be rated for 500 amps as starter current will flow through the shunt. 500 amp shunts only have resolution to 0.1 amp where as 100 amp shunts can have resolution down to 0.01a. So the 100 amp shunt is limited to scenarios where there is no alternator current feeding the batteries. Which is unacceptable to me as the alternator can accomplish in an hour of driving what can take the solar system all day.
Even a single thin wire going directly to either battery(-) will throw off readings as some current will find path back to ground bypassing the Shunt.
Since the well wired alternator is such a capable charging source on a depleted battery, not counting the current it makes is foolish, and the monitor has no chance of being anywhere near accurate.
There will be some more inaccuracy as the engine battery itself will be taking a portion of the charging current, and the monitor is reading this current and thinking all of it is flowing into just the house bank.
Not depleting the engine battery much, so that it only pulls a tiny fraction of the charging current, is a good strategy to combat this unavoidable inaccuracy.
My engine battery, when fully charged, right after starting the engine, takes about 30 amps from the alternator, and within 30 seconds this number has tapered to under 10 amps and within 2 minutes is down around 3 amps, and just keeps dropping.
But if my engine battery is depleted, then it will suck 62 amps from the alternator at idle, and higher rpms will allow currents in the 70 to 80 amp range, just into the single engine battery, and an hour later it will still be in the 15 to 20 amp range, and my monitor is displaying an amp hour from full and percentage remaining charge that are nowhere near accurate, for either battery
So you can see keeping the engine battery as full as possible greatly improves monitor accuracy.
But again, you have to take the monitor readings with a grain of salt, and use expectations and voltage and charging amps to see if it had an aneurysm. For example if it is claiming 100% charged, but the 210 AH of batteries are accepting 12 solar amps at 14.8v, then the batteries are still in the 75 to 85-% charged range maximum, and the monitor snuck out and smoked some crack when you were not looking.
But if the monitor is claiming 98% and the 2 batteries are taking only 3 amps to hold 14.8v, then you can have confidence in that 98% figure.
If any wire goes directly to either battery (-) that does not go through the shunt, then you cannot expect any accuracy from the monitor. Grounds are shared and even a small wire for something not even in use will allow a portion of current to bypass the shunt and being measured.
Not wiring the shunt correctly is pretty common, and it confuses the person watching the monitor, at some point, because they eventually notice that 2+2 does not equal 3.5, and this is where you might be now.
I hope the controller error code is easy to sort out. Many times controller issues are that the PV(-) ties into the chassis (-), before running through the controller. If someone has run a Solar panel frame (-) grounding wire, as most directions will say to do, then this wire cannot go into the controller, it needs to goto the chassis frame. The controller could very well still provide current if this frame grounding wire is hooked to PV(-) on controller, but it will confuse the living piss outta the controller, and it will not properly read PV current.
So double check this. You can't just tie the solar frame (-) to the pv(-) before the solar controller.
When I first installed my panel in 2007, everything was working properly, and then I was adding attachment points to hold my surfboards to the ceiling, and put a screw through my solar wiring, and it bridged this Solar Panel frame (-) ground, and the actual pv(-) wire. and my controller quit working, and I threw a fit, until I realized my ******* move with the screw and backed it out and full function was restored.
Grounding the solar panel frame is mainly for a lightning strike scenario. I later removed this dedicated ground wire I originally installed, when I added a unisolar 68 watt panel and ran 8 awg cable from the kyocera framed panel to replace the 12 awg I originally installed, as it would invite lightning into the van. But I now have a TV antenna and Wifi antenna in the solar panel frame and this is grounded, so if I were to get struck by lightning it would run down my coaxial cables. I'd be screwed either way, so I don't worry about it. If I were totally anal retentive about safety and lightning storms, I'd have a cable going from solar panel frame into a copper spike hammered into the earth next to the Van, but any strike would likely still fry everything in the van, and the copper spike would likely increase the chances that a lightning strike would hit.
I retasked this original Solar 3 wire 12 awg Ancor tinned and sheathed marine cable to make a new headlight harness, as I was losing 3+ volts through the original harness. Now I lose only 0.3v and the headlamps are Significantly brighter and fairly impressive for old sealed beam technology.
So check that the PV- and the Solar panel frame (-) are not tied together before the controller, and that no wires go directly to either battery (-) that do not first go through the 500 amp shunt. If you have a hundred amp shunt, then you cannot run alternator/starter current through it and can expect no accuracy from the monitor if allowing the alternator(s) to charge the house bank
There is not some circuitry in the charge controller which actually senses the battery state of charge. I am not sure how the charge controller would even know how much the battery is being discharged to display anything other than the solar charging amps and flash a light when it thinks the batteries are full and can take no more, say such as after 2 hours at 14.8v and the 210 AH bank is taking less than 2.5 amps to hold 14.8v.
Do note 2.5 is just an off the top of my head ballpark figure. Each battery will differ and change as it ages.
The solar controller might see when the solar charging has nearly stopped, and later if had thought the battery was full, then it might post state of charge simply guessing by battery voltage, like 12.23v= 51%. But unless all the current that is discharging the batteries, goes through a shunt( like the trimetric) the solar controller simply has no way of counting current flowing out of the batteries. There are Hall Effect Sensors that can go around a cable, like a clamp on Ammeter, that can measure current flowing through a single wire, but the Shunted Ammeter/monitor is generally more accurate, especially at low currents. I am not aware of any solar controllers themselves having external shunts to monitor current flow out of the battery, they can only count solar current flowing through the controller into the battery.
Now the Solar controller itself can have an internal shunt, or HES to measure solar current passing through it, but discharging current cannot be measured by this method.
Do note that the Trimetric's shunt needs to have ALL current routed through it. Meaning all loads, all grounds go to one side(load) of the shunt, and the only connections that go directly to either battery (-), come from the other/battery side of the shunt.
If any single wire goes directly to either battery (-) and does not pass through the shunt, this current on this single wire can not be read by the shunt/monitor and since all grounds are common, even if a device is not operating, or hooked to the battery that is being monitored, some current will still find a path back to ground through this wire.
So getting the battery monitor to read alternator current requires pulling the main battery cable off the engine battery (-), and attaching it to the load side of the shunt. Note the Shunt has to be rated for 500 amps as starter current will flow through the shunt. 500 amp shunts only have resolution to 0.1 amp where as 100 amp shunts can have resolution down to 0.01a. So the 100 amp shunt is limited to scenarios where there is no alternator current feeding the batteries. Which is unacceptable to me as the alternator can accomplish in an hour of driving what can take the solar system all day.
Even a single thin wire going directly to either battery(-) will throw off readings as some current will find path back to ground bypassing the Shunt.
Since the well wired alternator is such a capable charging source on a depleted battery, not counting the current it makes is foolish, and the monitor has no chance of being anywhere near accurate.
There will be some more inaccuracy as the engine battery itself will be taking a portion of the charging current, and the monitor is reading this current and thinking all of it is flowing into just the house bank.
Not depleting the engine battery much, so that it only pulls a tiny fraction of the charging current, is a good strategy to combat this unavoidable inaccuracy.
My engine battery, when fully charged, right after starting the engine, takes about 30 amps from the alternator, and within 30 seconds this number has tapered to under 10 amps and within 2 minutes is down around 3 amps, and just keeps dropping.
But if my engine battery is depleted, then it will suck 62 amps from the alternator at idle, and higher rpms will allow currents in the 70 to 80 amp range, just into the single engine battery, and an hour later it will still be in the 15 to 20 amp range, and my monitor is displaying an amp hour from full and percentage remaining charge that are nowhere near accurate, for either battery
So you can see keeping the engine battery as full as possible greatly improves monitor accuracy.
But again, you have to take the monitor readings with a grain of salt, and use expectations and voltage and charging amps to see if it had an aneurysm. For example if it is claiming 100% charged, but the 210 AH of batteries are accepting 12 solar amps at 14.8v, then the batteries are still in the 75 to 85-% charged range maximum, and the monitor snuck out and smoked some crack when you were not looking.
But if the monitor is claiming 98% and the 2 batteries are taking only 3 amps to hold 14.8v, then you can have confidence in that 98% figure.
If any wire goes directly to either battery (-) that does not go through the shunt, then you cannot expect any accuracy from the monitor. Grounds are shared and even a small wire for something not even in use will allow a portion of current to bypass the shunt and being measured.
Not wiring the shunt correctly is pretty common, and it confuses the person watching the monitor, at some point, because they eventually notice that 2+2 does not equal 3.5, and this is where you might be now.
I hope the controller error code is easy to sort out. Many times controller issues are that the PV(-) ties into the chassis (-), before running through the controller. If someone has run a Solar panel frame (-) grounding wire, as most directions will say to do, then this wire cannot go into the controller, it needs to goto the chassis frame. The controller could very well still provide current if this frame grounding wire is hooked to PV(-) on controller, but it will confuse the living piss outta the controller, and it will not properly read PV current.
So double check this. You can't just tie the solar frame (-) to the pv(-) before the solar controller.
When I first installed my panel in 2007, everything was working properly, and then I was adding attachment points to hold my surfboards to the ceiling, and put a screw through my solar wiring, and it bridged this Solar Panel frame (-) ground, and the actual pv(-) wire. and my controller quit working, and I threw a fit, until I realized my ******* move with the screw and backed it out and full function was restored.
Grounding the solar panel frame is mainly for a lightning strike scenario. I later removed this dedicated ground wire I originally installed, when I added a unisolar 68 watt panel and ran 8 awg cable from the kyocera framed panel to replace the 12 awg I originally installed, as it would invite lightning into the van. But I now have a TV antenna and Wifi antenna in the solar panel frame and this is grounded, so if I were to get struck by lightning it would run down my coaxial cables. I'd be screwed either way, so I don't worry about it. If I were totally anal retentive about safety and lightning storms, I'd have a cable going from solar panel frame into a copper spike hammered into the earth next to the Van, but any strike would likely still fry everything in the van, and the copper spike would likely increase the chances that a lightning strike would hit.
I retasked this original Solar 3 wire 12 awg Ancor tinned and sheathed marine cable to make a new headlight harness, as I was losing 3+ volts through the original harness. Now I lose only 0.3v and the headlamps are Significantly brighter and fairly impressive for old sealed beam technology.
So check that the PV- and the Solar panel frame (-) are not tied together before the controller, and that no wires go directly to either battery (-) that do not first go through the 500 amp shunt. If you have a hundred amp shunt, then you cannot run alternator/starter current through it and can expect no accuracy from the monitor if allowing the alternator(s) to charge the house bank
Seraphim
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Thanks Sternwake. Knew you'd have an answer.
The battery monitor shunt (500A) is wired only to the house battery. It monitors charge from shore power and the vehicle alternators, and current running from the battery to the fuse bank, off which everything in the unit runs.
The panel's are not grounded to the frame, both positive and negative go directly to the battery. No current from the panels cross the shunt.
The fault indicator, as best I can glean (the manual doesn't specify) is a short in the circuit that protects the charger from the panels - possibly from them being crosswired. Ahem. I think the controller will need replaced. I'll check tomorrow.
Glad I'm not the only one to make such errors...
The truck has a second alternator, setup to a snow plow rig which the truck doesn't have. I'm not sure how it's wired, but driving the vehicle seems to charge the batteries fairly quickly: no more than three or four hours driving when the batteries are at 60%. According to the battery monitor.
At fast idle, the monitor only reports about 8 amps going across the shunt. Then it drops to 5 as the idle steps down. 800 rpm idle, I think.
Also, when parked and not on shore power, I disconnect the house from the vehicle batteries, so the house electronics don't draw them down .
The battery monitor shunt (500A) is wired only to the house battery. It monitors charge from shore power and the vehicle alternators, and current running from the battery to the fuse bank, off which everything in the unit runs.
The panel's are not grounded to the frame, both positive and negative go directly to the battery. No current from the panels cross the shunt.
The fault indicator, as best I can glean (the manual doesn't specify) is a short in the circuit that protects the charger from the panels - possibly from them being crosswired. Ahem. I think the controller will need replaced. I'll check tomorrow.
Glad I'm not the only one to make such errors...
The truck has a second alternator, setup to a snow plow rig which the truck doesn't have. I'm not sure how it's wired, but driving the vehicle seems to charge the batteries fairly quickly: no more than three or four hours driving when the batteries are at 60%. According to the battery monitor.
At fast idle, the monitor only reports about 8 amps going across the shunt. Then it drops to 5 as the idle steps down. 800 rpm idle, I think.
Also, when parked and not on shore power, I disconnect the house from the vehicle batteries, so the house electronics don't draw them down .
SternWake
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You must move the engine battery ground to the load side of the shunt. Then from battery side of shunt. Run a new cable to engine battery from shunt.
If you do not. You can never expect the monitor to display any accuracy and you will just have a. Overpriced digital ammeter that only registers portions of the current flowing i. And out of battery.
If you do not. You can never expect the monitor to display any accuracy and you will just have a. Overpriced digital ammeter that only registers portions of the current flowing i. And out of battery.
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