SternWake
Well-known member
- Joined
- Nov 30, 2013
- Messages
- 3,874
- Reaction score
- 2
V,
You seem to be looking for some special magic energy bullett.
Perhaps my posts are be a little too 'the sky will fall' if the battery is undercharged chronically.
BUT,
When I first started doing this I was a wally world battery guy and thought the alternator was some magical battery charger. I also did not use much power, but the batteries were always failing quickly.
Even when they were warrantied it was still a pain in the ass.
I am hoping to prevent newbs from making the same mistakes I did when starting out, and today since solar is cheap it is much easier to do.
So, for a Newb who does not seek ideal, but who does not want to get all perturbed when their battery seems to be gasping for breathe on the floor.
Any lead acid battery wants to live its whole live at 100% full charge, or as close as possible to this.
It takes time when recharging, to get it fully charged, no matter how powerful the charging source might be. 80 to 100% is 3 to 3.5 hours, no less. Anybody thinking different is smoking crack and/or ignorant.
Is 95% good enough, yes, but the battery will get smaller faster. It is like a balloon that must be reinflated fully otherwise the skin gets less stretchy more crusty, and develops pin holes.
But if one can get to 95%, getting to 100% is hardly a big jump, perhaps another 1.5 hours when held at 14.x volts.
So why not try for it?
1 Automatic charging sources will flash a green light at 92 to 95% and give some false warm and fuzzies
2 Cheap unprogrammable solar charge controllers do the same
3 Vehicle voltage regulators are happy to prematurely drop voltage to a depleted battery.
All three of these charging sources do not know what a deeply cycled battery requires to keep it happiest. nor do they care.
1 So for automatic plug in charging sources, load battery until voltage drops below 12.6, restart charger, lather rinse repeat.
2 For solar, more wattage is always better, but make sure the controller allows one to set absorption voltage and its duration.
3 For the Vehicle voltage regulator, well, use fat copper between alternator and house battery so that when the battery is super depleted, one can send it high amperage to get it to 80% quickly. But if the VR chooses 13.7v, the charge rate will slow significantly, and not much can be done. So be it. Oh well.
1. Now in my personal system, I have give up on automatic plug in chargers. i have a modified 40 amp adjustable voltage power supply. I choose the target absorption voltage and boom, 40 amps delivered until it reaches it, and then it holds it as long as I decide to let it. My battery has no issues gobbling 40 amps charge current when depleted, That is not true for all batteries, but nor is it instant death to those that do not 'recommend' it.
meanwell rsp-500-15
2. I only have 198 watts of solar, but only 90AH of AGM battery. this is more than a 2 to 1 ratio, but it alone is not enough, on its own, to keep my AGM battery happiest, despite it mostly being able to return what i use overnight. I'd love another 100 watts. My solar controller can be programmed for absorption voltage AND its duration and or triggered by amperage. When amps taper to 0.4 at 14.4v, only then does it revert to float voltage, also programmable, at 13.6v.
Bluesky sb2512i with IPN proremote
Northstar AGM group27
3. My alternator Chrysler 50/120, has a fat cabling to the battery. Also a fat ground cable back to alternator casing. My voltage regulator is modified to allow me to choose any voltage between 12.8 and 15.3v.
50/120 means it is supposed to be able to deliver 50 amps at idle, 120 amps max. It is rare that it can do either.
Transpo 540hd is a Ford voltage regulator ( my van is a Dodge) but had a potentiometer inside for adjusting the voltage. I moved this potentiometer to my dashboard and twiddle voltage it to my heart's desire.
Those are my modifications which allow me to approach ideal, but even so, it requires time to fully recharge. I can't reduce this time, other than to insure it is at least at maximum charging pressure, Absorption voltage.
Any lead acid marine or deep cycle battery that is NOT overdischarged, will perform well as long as it is at least brought to and held at absorption voltage for an hour or two. Anything less will sacrifice longevity. how long at absorption voltage is required to be held depends on so many factors it would confuse matters in this post
Any lead acid battery that is held at absorption voltage until either specific gravity indicates full charge (wet/flooded), or whose amps at absorption voltage have tapered to 2 to 3 amps per 100Ah of capacity( wet flooded) or 0.5 amps for AGM, will be a very happy battery and be able to deliver the maximum amount of cycles over the longest period of time.
So once again I have outlined Ideal. Anything less is just that, but it is a matter of degree. One certainly does not have to aim for ideal. Ideal is expensive and time consuming and not worth it, for a newb. But overdischarging and under charging will have a newb stomping their feet petulantly, scratching their head, and blaming the battery when the fault lies in a mirror.
Now, on the overdischarging front, well the less deeply a battery is cycled, the less time it takes to fully recharge, and the more cycles it can deliver. How do you know how discharged a battery is? well, without getting too technical, look at battery voltage.
Voltage is electrical pressure, when the 12v battery cannot maintain more than 12.2v under a light electrical load, it is in the 50% range. Big loads will draw the voltage lower but it will rebound when removed. An extreme example is the starter motor, it can draw 160 amps perhaps more, and draw a fully charged battery to 10 volts. But if the engine were immediately shut down voltage would quickly rebound to 12.4, and then slowly rise back upto 12.6v or higher. When loads are removed from a battery, voltage will rebound to some degree.
In general, don't let battery fall below 12.2v under light loads and you will not fall below 50%. Aim to not fall below 50%. There are a thousand asterix's on the technical side of this paragraph.
Other methods to determine state of charge require a battery monitor which can measure and count amps both into and out of the battery. this requires a large Shunt on the negative battery cable and complicates wiring, and these are not 100% accurate and will drift over time, but are many fold better than relying on voltage alone for determining state of charge.
So even less technical......
fat copper good
recharge whenever possible, as long as possible, using whatever charging source possible
12.2v, do not go below this number when using house appliances.
replace battery when its capacity does not give you enough time to use house appliances as long as needed.
If battery replacement is required unacceptable early, recharge more, discharge less on next battery. if acceptable, carry on, nothing to see here.
Mo solar mo betta
You seem to be looking for some special magic energy bullett.
Perhaps my posts are be a little too 'the sky will fall' if the battery is undercharged chronically.
BUT,
When I first started doing this I was a wally world battery guy and thought the alternator was some magical battery charger. I also did not use much power, but the batteries were always failing quickly.
Even when they were warrantied it was still a pain in the ass.
I am hoping to prevent newbs from making the same mistakes I did when starting out, and today since solar is cheap it is much easier to do.
So, for a Newb who does not seek ideal, but who does not want to get all perturbed when their battery seems to be gasping for breathe on the floor.
Any lead acid battery wants to live its whole live at 100% full charge, or as close as possible to this.
It takes time when recharging, to get it fully charged, no matter how powerful the charging source might be. 80 to 100% is 3 to 3.5 hours, no less. Anybody thinking different is smoking crack and/or ignorant.
Is 95% good enough, yes, but the battery will get smaller faster. It is like a balloon that must be reinflated fully otherwise the skin gets less stretchy more crusty, and develops pin holes.
But if one can get to 95%, getting to 100% is hardly a big jump, perhaps another 1.5 hours when held at 14.x volts.
So why not try for it?
1 Automatic charging sources will flash a green light at 92 to 95% and give some false warm and fuzzies
2 Cheap unprogrammable solar charge controllers do the same
3 Vehicle voltage regulators are happy to prematurely drop voltage to a depleted battery.
All three of these charging sources do not know what a deeply cycled battery requires to keep it happiest. nor do they care.
1 So for automatic plug in charging sources, load battery until voltage drops below 12.6, restart charger, lather rinse repeat.
2 For solar, more wattage is always better, but make sure the controller allows one to set absorption voltage and its duration.
3 For the Vehicle voltage regulator, well, use fat copper between alternator and house battery so that when the battery is super depleted, one can send it high amperage to get it to 80% quickly. But if the VR chooses 13.7v, the charge rate will slow significantly, and not much can be done. So be it. Oh well.
1. Now in my personal system, I have give up on automatic plug in chargers. i have a modified 40 amp adjustable voltage power supply. I choose the target absorption voltage and boom, 40 amps delivered until it reaches it, and then it holds it as long as I decide to let it. My battery has no issues gobbling 40 amps charge current when depleted, That is not true for all batteries, but nor is it instant death to those that do not 'recommend' it.
meanwell rsp-500-15
2. I only have 198 watts of solar, but only 90AH of AGM battery. this is more than a 2 to 1 ratio, but it alone is not enough, on its own, to keep my AGM battery happiest, despite it mostly being able to return what i use overnight. I'd love another 100 watts. My solar controller can be programmed for absorption voltage AND its duration and or triggered by amperage. When amps taper to 0.4 at 14.4v, only then does it revert to float voltage, also programmable, at 13.6v.
Bluesky sb2512i with IPN proremote
Northstar AGM group27
3. My alternator Chrysler 50/120, has a fat cabling to the battery. Also a fat ground cable back to alternator casing. My voltage regulator is modified to allow me to choose any voltage between 12.8 and 15.3v.
50/120 means it is supposed to be able to deliver 50 amps at idle, 120 amps max. It is rare that it can do either.
Transpo 540hd is a Ford voltage regulator ( my van is a Dodge) but had a potentiometer inside for adjusting the voltage. I moved this potentiometer to my dashboard and twiddle voltage it to my heart's desire.
Those are my modifications which allow me to approach ideal, but even so, it requires time to fully recharge. I can't reduce this time, other than to insure it is at least at maximum charging pressure, Absorption voltage.
Any lead acid marine or deep cycle battery that is NOT overdischarged, will perform well as long as it is at least brought to and held at absorption voltage for an hour or two. Anything less will sacrifice longevity. how long at absorption voltage is required to be held depends on so many factors it would confuse matters in this post
Any lead acid battery that is held at absorption voltage until either specific gravity indicates full charge (wet/flooded), or whose amps at absorption voltage have tapered to 2 to 3 amps per 100Ah of capacity( wet flooded) or 0.5 amps for AGM, will be a very happy battery and be able to deliver the maximum amount of cycles over the longest period of time.
So once again I have outlined Ideal. Anything less is just that, but it is a matter of degree. One certainly does not have to aim for ideal. Ideal is expensive and time consuming and not worth it, for a newb. But overdischarging and under charging will have a newb stomping their feet petulantly, scratching their head, and blaming the battery when the fault lies in a mirror.
Now, on the overdischarging front, well the less deeply a battery is cycled, the less time it takes to fully recharge, and the more cycles it can deliver. How do you know how discharged a battery is? well, without getting too technical, look at battery voltage.
Voltage is electrical pressure, when the 12v battery cannot maintain more than 12.2v under a light electrical load, it is in the 50% range. Big loads will draw the voltage lower but it will rebound when removed. An extreme example is the starter motor, it can draw 160 amps perhaps more, and draw a fully charged battery to 10 volts. But if the engine were immediately shut down voltage would quickly rebound to 12.4, and then slowly rise back upto 12.6v or higher. When loads are removed from a battery, voltage will rebound to some degree.
In general, don't let battery fall below 12.2v under light loads and you will not fall below 50%. Aim to not fall below 50%. There are a thousand asterix's on the technical side of this paragraph.
Other methods to determine state of charge require a battery monitor which can measure and count amps both into and out of the battery. this requires a large Shunt on the negative battery cable and complicates wiring, and these are not 100% accurate and will drift over time, but are many fold better than relying on voltage alone for determining state of charge.
So even less technical......
fat copper good
recharge whenever possible, as long as possible, using whatever charging source possible
12.2v, do not go below this number when using house appliances.
replace battery when its capacity does not give you enough time to use house appliances as long as needed.
If battery replacement is required unacceptable early, recharge more, discharge less on next battery. if acceptable, carry on, nothing to see here.
Mo solar mo betta
