thatswhatsup
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so for two t-105s i would need four panels I assume.
Starting with only batteries.....
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thatswhatsup said:
I have two T-125s (slightly higher AH rating) and three 100w Renogy panels. I run a 6 year-old laptop constantly and have no power issues unless I go 3 cloudy days in a row without driving (it also charges off the alternator). I don't use a generator or inverter.
SternWake
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I'd say a minimum of at least 250 watts for 232Ah of Trojan t-105, with the rare overnight discharges down to no lower than 65%., average at 75%+
More is better, you can certainly buy 100 watts to start with and add more as you can. They are only batteries, and only rented. The better you can recharge them to or near 100%, the longer the rental contract lasts, for the same price.
The lower the level of discharge, the more cycles they will endure, but when drained to 50%, keep in mind it might take solar well more than 1 day to recharge them fully, and only if you do not drain them overnight. Ideally when drained to 50%, one would want enough solar to get them to absorption voltage by 1PM, and this would likely be 500 watts for 232AH of capacity.
Throw in low winter sun angles, and shorter days and imperfect weather and, well, more is always better.
There is merit to the inexpensive 'learner battery' strategy. One might have a false confidence in a pair of t-105s resistance to abuse and kill them prematurely. Wally world will likely warranty the learner marine battery killed prematurely.
it ultimately comes down to cycles achieved per dollar spent. What is acceptable to one person might not be to another, but with more solar, even well more than needed 85% of the time, the numbers of cycles ultimately achieved before replacement becomes obviously necessary, could double or triple.
If it were initially a choice between 200 watts feeding one Wally world group 29, or 100 watts feeding two group T-105's, I'd go for the 200 watts initially and watch the voltmeter a little closer while you see how much battery capacity you actually require in your usage.
Lots of people go for lots of 'feel good' capacity and never/rarely actually need it, and then the few times they do need it, have way too little solar wattage to return the battery to full in the time allowed before the next discharge cycle begins, the result being partial state of charge cycling, which batteries do not take kindly to.
More is better, you can certainly buy 100 watts to start with and add more as you can. They are only batteries, and only rented. The better you can recharge them to or near 100%, the longer the rental contract lasts, for the same price.
The lower the level of discharge, the more cycles they will endure, but when drained to 50%, keep in mind it might take solar well more than 1 day to recharge them fully, and only if you do not drain them overnight. Ideally when drained to 50%, one would want enough solar to get them to absorption voltage by 1PM, and this would likely be 500 watts for 232AH of capacity.
Throw in low winter sun angles, and shorter days and imperfect weather and, well, more is always better.
There is merit to the inexpensive 'learner battery' strategy. One might have a false confidence in a pair of t-105s resistance to abuse and kill them prematurely. Wally world will likely warranty the learner marine battery killed prematurely.
it ultimately comes down to cycles achieved per dollar spent. What is acceptable to one person might not be to another, but with more solar, even well more than needed 85% of the time, the numbers of cycles ultimately achieved before replacement becomes obviously necessary, could double or triple.
If it were initially a choice between 200 watts feeding one Wally world group 29, or 100 watts feeding two group T-105's, I'd go for the 200 watts initially and watch the voltmeter a little closer while you see how much battery capacity you actually require in your usage.
Lots of people go for lots of 'feel good' capacity and never/rarely actually need it, and then the few times they do need it, have way too little solar wattage to return the battery to full in the time allowed before the next discharge cycle begins, the result being partial state of charge cycling, which batteries do not take kindly to.
WheelEstate USA
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I do agree that "marine" is a huge step down from a true deep cycle, but the plates are some beefier than a car battery and will take more abuse. For the beginner on a budget, the Wally marine holds up quite well for the $$.
To run a fridge (with my other 12V stuff) I think a couple 6V GCs and 200 W solar is a better choice.
To run a fridge (with my other 12V stuff) I think a couple 6V GCs and 200 W solar is a better choice.
Optimistic Paranoid
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Jay is right. A true starting battery, if discharged to 50% before recharging, is only good for 30 to 50 such cycles. A marine battery will go 300 to 400 cycles under such circumstances. True deep cycles will routinely give you a 1,000 or more cycles.
The best use for marine batteries is as a replacement for the starting battery for those people with very limited power needs who try to get by without a separate house battery. If all you're doing is recharging a cell phone and running some led house lights at night, you could get by very nicely on such a simple set up.
They are also popular with RVers who almost always camp with shore power, but need to do the OCCASIONAL overnight Walmart stop while enroute to another campground.
Regards
John
The best use for marine batteries is as a replacement for the starting battery for those people with very limited power needs who try to get by without a separate house battery. If all you're doing is recharging a cell phone and running some led house lights at night, you could get by very nicely on such a simple set up.
They are also popular with RVers who almost always camp with shore power, but need to do the OCCASIONAL overnight Walmart stop while enroute to another campground.
Regards
John
99% will just plug into cigarette plugs (power ports). A USB charger will convert 12 to 5 volt and charge phones tablets........ Almost everything that runs on 8 batteries (aaa, aa, a, c, d) can be wired directly (with a fusethatswhatsup said:
)My laptop cord converts 12 to 18 ..
Dewalt 18 volt charger plugs in a cigarette plug. Look at the wall wart for anything you want to power. They may be 12 volt already.
Do be careful 12 volt backwards will let the magic smoke out of a lot of things.
A multi-meter is a necessary tool.
The middle ground would be to get two of the Costco 6v golf cart batteries. They cost about $85 W/O the core charge. About half the cost of the T105's. Plan on killing them in a shorter period of time than you were expecting. But they will last much longer than a marine battery when mistreated. At least two 100w panels, three would be much better.
When the Costco g/c's die add at least another 100w panel and get a pair of the Trojan T105- RE (renewable energy) g/c's, heavier, more lead, more sophisticated plate design and double the warranty of the standard T105.
i suggest that you consider getting a hydrometer and use it often. The link below is a primer on the importance of temp compensation of hydrometer readings.
http://all-about-lead-acid-batterie...tery-hydrometer-temperature-correction-chart/
An option in panels: A single large high voltage grid tie 285w or larger panel can be bought for less than $300 these days. You would have to use a MPPT controler to bring the voltage down to 12v. A solar system with such a panel and two Costco g/c's with a MPPT controller would be a sweet beginner system. Such a system would be able to put 15-16 amps at 14.8 volts into the batteries when mounted flat on a roof in good conditions.
When the Costco g/c's die add at least another 100w panel and get a pair of the Trojan T105- RE (renewable energy) g/c's, heavier, more lead, more sophisticated plate design and double the warranty of the standard T105.
i suggest that you consider getting a hydrometer and use it often. The link below is a primer on the importance of temp compensation of hydrometer readings.
http://all-about-lead-acid-batterie...tery-hydrometer-temperature-correction-chart/
An option in panels: A single large high voltage grid tie 285w or larger panel can be bought for less than $300 these days. You would have to use a MPPT controler to bring the voltage down to 12v. A solar system with such a panel and two Costco g/c's with a MPPT controller would be a sweet beginner system. Such a system would be able to put 15-16 amps at 14.8 volts into the batteries when mounted flat on a roof in good conditions.
thatswhatsup
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29chico said:
I can get t-105s for 99 each... thats almost the cost of the costcos but id have to start off with at least a 200w kit and even that might not be enough right?
thatswhatsup
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A friend quoted that price, but I believe he has a country club / golf course connection where they buy in bulk. I'll confirm in case I misinterpreted or am confusing model numbers.
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Almost There said:
I'm a fan of the portable panels but not because it's hard to park a van with panels on top. It is true you have to watch for an opening in the forest so they aren't shaded but portable panels really don't help much.
Parking the van in the shade and moving the panels into the sun is a good reason for a portable panel. But the truth is few of us have a long enough cord to actually do that without voltage drop.
Bob
thatswhatsup
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akrvbob said:
Plus I could see portable panels being very inconvenient when looking to stealth boondock in urban areas.
That, plus seeing a video on how easy it is to mount flexible panels is making me reconsider.. again..
The reason I like panels on the roof is they're static, always there collecting sunlight. It doesn't matter whether I'm driving or if I sleep until noon, they're up there working without me having to get out and set something up. Anything I have to touch daily to make work is something I eliminate from my life. The panels on the roof I just wipe off occasionally. Yes, I do consider the angle of the sun when parking sometimes, but that's never been a complicated affair. If you're someone who regularly parks in the shade and you want to have enough cord to set your panels up elsewhere then it makes sense to do it that way. I move my van often enough that it makes no difference to me.
Almost There
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There are good reasons for going either way.
Me, I have never nor will I ever, stealth park in a city. I avoid cities like the plague anyways so that isn't a concern. When driving I will depend on the alternator to do its' job.
For 6 months of the year I tend to be in northern deep forest where parking in the sun would be a real pita...like parking in the middle of the logging road. The rest of the year I much prefer at least some trees around me as opposed to the open desert...didn't know this until I landed here in AZ.
I'd rather carry extra length of heavy cord and take my chances on a little bit of voltage drop than have to take into consideration the direction of the sun and how I'm parked to obtain my daily dose of electricity.
Now, aiming my lawn chair, that's a different matter entirely...
Me, I have never nor will I ever, stealth park in a city. I avoid cities like the plague anyways so that isn't a concern. When driving I will depend on the alternator to do its' job.
For 6 months of the year I tend to be in northern deep forest where parking in the sun would be a real pita...like parking in the middle of the logging road. The rest of the year I much prefer at least some trees around me as opposed to the open desert...didn't know this until I landed here in AZ.
I'd rather carry extra length of heavy cord and take my chances on a little bit of voltage drop than have to take into consideration the direction of the sun and how I'm parked to obtain my daily dose of electricity.
Now, aiming my lawn chair, that's a different matter entirely...
WheelEstate USA
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AT...Us desert rats are an unusual breed. I love forests, but can only sit and watch lumber grow for just so long.
The open desert views stimulate my mind. Raw, stark, rough, but a gem no less.
It's my home and to it I will always return.
Living this lifestyle gives us all the choice of locations we enjoy...doesn't get much better than that, huh?
The open desert views stimulate my mind. Raw, stark, rough, but a gem no less.
It's my home and to it I will always return.
Living this lifestyle gives us all the choice of locations we enjoy...doesn't get much better than that, huh?
thatswhatsup said:
Correct, with 200w of solar and watching the specific gravity with a hydrometer you would probably find yourself scrambling to find power outlets to plug a battery charger into on a somewhat regular basis.
Alternator charging WHILE driving to supplement solar charging is an option you might want to consider studying up on. Plenty of threads have been posted about it in this electrical forum. It may seem a bit daunting at first but it is actually fairly simple.
And here is another reason to research. I have had my TM2025-RV set at 230 amp hours when I really only have 115. So this morning when I thought I was 76% charged I was really 53% or dead, however you want to call it. Hoping the sun comes up fast.
SternWake
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Absolute faith in battery monitors, actual amp hour counting battery monitors is often misplaced. Far too many people act like a simple voltmeter is actually a battery monitor, when voltage tells only a small part of the story. Amps flowing at a certain voltage when charging reveal much much more
The % remaining screens are especially devious, as it requires the proper total capacity be programmed into it.
Also since the battery capacity is always declining at some rate, the programmed amp hour capacity is almost always wrong.
Many of these battery monitors do not account for Peukert. Peukert basically says that large loads reduce overall battery capacity available, and on lead acid batteries is a big factor.
I use the AH from full screen. The % remaining screen is quickly ignored with haste and derision scorn and contempt, even if sometimes it might be accurate, like the broken analog clock, twice a day.
Since my current battery is an AGM, I verify my battery monitor's accuracy by seeing how many amps at requires to maintain absorption voltage and if this agrees with the AH from Full screen.
When it reads 1Ah from full and the battery is still accepting 2 amps at 14.46 at 77f I know the monitor has drifted and the battery is more like 2Ah from full. Some other times it is the opposite and it will say 3 or 5AH from full but is accepting only 0.6 amps at 14.46, meaning it is likely 0.5Ah from full.
Sometimes by battery monitor gets confused by charging sources other than solar and just reverts to 0 from full and 100% when the battery is Nowhere near that ideal.
Occasionally rezeroing the battery monitor is required. They drift over time. When one has verified their batteries are full, with either a hydrometer or by measuring amps accepted at absorption voltage, then reset/rezero the monitor.
Battery temperature will also play a big role in battery capacity too, and effect its voltage readings under various loads and states of charge, but full is full, and the battery monitor should only read full when the batteries actually are, and this requires a human with ability to occasionally verify it and to rezero it then and there.
When a battery is chronically undercharged, getting it actually fully charged takes much much longer. One will need to hold absorption voltage for even longer, and 8 hours held at 14.8v might not be enough to maximize specific gravity, and yes the battery will be bubbling at a fairly good rate the whole time at absorption voltage.
Charging sources do not do understand this, they just spend their programmed time at absorption voltage, and flash the all's well green light which soothes the human watching it so well, while really mocking them. FAR too many people believe their blinking green lights on charging sources, when that green light should be viewed with large amounts of suspicion. If verified with a hydrometer, 90% of cases would reveal an undercharged battery, especially on a regularly cycled battery whose recharging requirements are far far different from the starting battery overdepleted once and unable to start the vehicle
So if an abused battery needs 8 hours at absorption voltage, and you only have 9 hours of daylight, and no other charging source, well your battery hates you and will give up prematurely.
This is where other charging sources, but especially a well wired alternator can compliment an Solar system to an incredible degree. An hour of driving at first light when the battery is most depleted, can get the battery to the point where the sun can then hold absorption voltage for the rest of the daylight hours, allowing the sulfates to possibly redissolve back into the electrolyte, restoring lost capacity and some degree of battery performance, as well as making future recharges to 100% faster and easier to obtain, to some degree.
Without additional charging sources, the best one can do is NOT discharge the battery at all overnight and then hope the next sunny day can hold absorption voltage for long enough to max out Specific gravity.
But often it simply cannot, and even higher voltages are required. Equalization charge time. Remove all loads from battery and bring an otherwise 'full' battery upto as high as 16 volts. Specific gravity might max out on all cells in 30 minutes, or it might take 8 hours.
Equalization requires a vigilant human to take specific gravity readings every 1/2 hour, or more often, and stop charging when battery temperature starts increasing rapidly or has approached 120F. When SG no longer rises, accounting for rising electrolyte temperature, end EQ charge. When battery temp approaches 120F, terminate. If one has a digital ammeter, and the amps required to maintain 15.5 to 16volts begins to rise again, so will the temperature, and quickly, terminate the EQ charge.
It should not take more than 5% of capacity, or 5 amps per 100Ah of battery capacity to get an already "full" battery upto 16 volts. if it requires more than this the battery needed more time at 14.4v to 14.8v before the EQ charge's 15.5 to 16 volts were initiated.
One does not want to just blast past 14.8v and climb upto 16v. The battery needs time to Absorb the current at 14.4 to 14.8v, and the amount of time required is always changing, and the happiest battery has the human who has an idea about this time requirement, and of course the charging tools required to maintain it for long enough.
Keep in mind also battery temperature and the proper absorption voltage recommendations are for 77F or 25C. A colder battery needs higher absorption voltages, a hotter battery requires lesser absorption voltages. Cold temp battery charging, one can easily undercharge them, yet that blinking green light will still try to soothe you, laughing at you while sulfating your battery.
The better one can return the battery to 100% each cycle, the less time will be required to perform equalization charges, and they will be required less frequently. One can easily double the life if a battery by performing an equalization charge when the battery's specific gravity is not responding to normal absorption voltages or durations.
Or one can just not worry about it and just replace the battery when it needs it, however soon that might be and however inconvenient it might be when that occurs, Just do not blame the battery. Batteries do not fail, they are murdered. Rarely do they live out their maximum expected cycle life. Those that do were recharged properly and promptly to an actual 100%, not just 95%, and also not overdischarged regularly.
The % remaining screens are especially devious, as it requires the proper total capacity be programmed into it.
Also since the battery capacity is always declining at some rate, the programmed amp hour capacity is almost always wrong.
Many of these battery monitors do not account for Peukert. Peukert basically says that large loads reduce overall battery capacity available, and on lead acid batteries is a big factor.
I use the AH from full screen. The % remaining screen is quickly ignored with haste and derision scorn and contempt, even if sometimes it might be accurate, like the broken analog clock, twice a day.
Since my current battery is an AGM, I verify my battery monitor's accuracy by seeing how many amps at requires to maintain absorption voltage and if this agrees with the AH from Full screen.
When it reads 1Ah from full and the battery is still accepting 2 amps at 14.46 at 77f I know the monitor has drifted and the battery is more like 2Ah from full. Some other times it is the opposite and it will say 3 or 5AH from full but is accepting only 0.6 amps at 14.46, meaning it is likely 0.5Ah from full.
Sometimes by battery monitor gets confused by charging sources other than solar and just reverts to 0 from full and 100% when the battery is Nowhere near that ideal.
Occasionally rezeroing the battery monitor is required. They drift over time. When one has verified their batteries are full, with either a hydrometer or by measuring amps accepted at absorption voltage, then reset/rezero the monitor.
Battery temperature will also play a big role in battery capacity too, and effect its voltage readings under various loads and states of charge, but full is full, and the battery monitor should only read full when the batteries actually are, and this requires a human with ability to occasionally verify it and to rezero it then and there.
When a battery is chronically undercharged, getting it actually fully charged takes much much longer. One will need to hold absorption voltage for even longer, and 8 hours held at 14.8v might not be enough to maximize specific gravity, and yes the battery will be bubbling at a fairly good rate the whole time at absorption voltage.
Charging sources do not do understand this, they just spend their programmed time at absorption voltage, and flash the all's well green light which soothes the human watching it so well, while really mocking them. FAR too many people believe their blinking green lights on charging sources, when that green light should be viewed with large amounts of suspicion. If verified with a hydrometer, 90% of cases would reveal an undercharged battery, especially on a regularly cycled battery whose recharging requirements are far far different from the starting battery overdepleted once and unable to start the vehicle
So if an abused battery needs 8 hours at absorption voltage, and you only have 9 hours of daylight, and no other charging source, well your battery hates you and will give up prematurely.
This is where other charging sources, but especially a well wired alternator can compliment an Solar system to an incredible degree. An hour of driving at first light when the battery is most depleted, can get the battery to the point where the sun can then hold absorption voltage for the rest of the daylight hours, allowing the sulfates to possibly redissolve back into the electrolyte, restoring lost capacity and some degree of battery performance, as well as making future recharges to 100% faster and easier to obtain, to some degree.
Without additional charging sources, the best one can do is NOT discharge the battery at all overnight and then hope the next sunny day can hold absorption voltage for long enough to max out Specific gravity.
But often it simply cannot, and even higher voltages are required. Equalization charge time. Remove all loads from battery and bring an otherwise 'full' battery upto as high as 16 volts. Specific gravity might max out on all cells in 30 minutes, or it might take 8 hours.
Equalization requires a vigilant human to take specific gravity readings every 1/2 hour, or more often, and stop charging when battery temperature starts increasing rapidly or has approached 120F. When SG no longer rises, accounting for rising electrolyte temperature, end EQ charge. When battery temp approaches 120F, terminate. If one has a digital ammeter, and the amps required to maintain 15.5 to 16volts begins to rise again, so will the temperature, and quickly, terminate the EQ charge.
It should not take more than 5% of capacity, or 5 amps per 100Ah of battery capacity to get an already "full" battery upto 16 volts. if it requires more than this the battery needed more time at 14.4v to 14.8v before the EQ charge's 15.5 to 16 volts were initiated.
One does not want to just blast past 14.8v and climb upto 16v. The battery needs time to Absorb the current at 14.4 to 14.8v, and the amount of time required is always changing, and the happiest battery has the human who has an idea about this time requirement, and of course the charging tools required to maintain it for long enough.
Keep in mind also battery temperature and the proper absorption voltage recommendations are for 77F or 25C. A colder battery needs higher absorption voltages, a hotter battery requires lesser absorption voltages. Cold temp battery charging, one can easily undercharge them, yet that blinking green light will still try to soothe you, laughing at you while sulfating your battery.
The better one can return the battery to 100% each cycle, the less time will be required to perform equalization charges, and they will be required less frequently. One can easily double the life if a battery by performing an equalization charge when the battery's specific gravity is not responding to normal absorption voltages or durations.
Or one can just not worry about it and just replace the battery when it needs it, however soon that might be and however inconvenient it might be when that occurs, Just do not blame the battery. Batteries do not fail, they are murdered. Rarely do they live out their maximum expected cycle life. Those that do were recharged properly and promptly to an actual 100%, not just 95%, and also not overdischarged regularly.
Whew to much info
I've been telling a year with no issues. Today was the second time I've run a generator. As I haven't been able to find charging specs on these advanced auto batteries have been charging at 13.5 and equalizing at 14.4. Have to fill water twice a month. If they die in 6 years instead of 11 I will still learn from them.
I've been telling a year with no issues. Today was the second time I've run a generator. As I haven't been able to find charging specs on these advanced auto batteries have been charging at 13.5 and equalizing at 14.4. Have to fill water twice a month. If they die in 6 years instead of 11 I will still learn from them.
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