Charger comes on Wednesday 6/3/20
When do I give my battery bank it's first charge?
- Thread starter tera3yte
- Start date
After 3 years there will either be a loss of capacity or the AGM batteries will be dead.
However If there is say a 50% loss of capacity in the 3 stored batteries connecting them in parallel with 3 new AGM batteries will drag the new ones down to the level of the degraded batteries.
There is a lot of info on AGM shelf life online:
Re: Shelf life of lead acid deep cycle batteries
Post Sun Apr 22, 2018 5:31 pm
Most AGM deep cycle batteries have about a 3%/month self-discharge rate when stored at room temperature. Lower temp = lower discharge. Higher temp = higher discharge. After 3 years, its as pretty good bet they are fully discharged. Holding them in a discharged state will result in capacity loss. How much depends on several factors, including the chemical makeup of the battery. With sealed AGM batteries, the loss can be less than flooded lead acid.
Use a voltmeter to measure each battery. They are likely to read 0 volts, but note each one.
Next, try to recharge them with a quality "smart" charger driven from a generator or other steady AC source. If the charger won't start charging because the battery voltage is too low, connect a good 12V battery in parallel to the dead cells and charge until there is a measurable voltage on them, then disconnect the 12V auxiliary battery and proceed with charging until complete. Once a set is complete, set aside and charge the next set. Let all the charged cells rest for 24 hours.
Measure, and note, the voltage of each. A fully charged battery will measure around 12.8V.
If all take a charge, you can try to get an estimate of the battery capacity by running a discharge test.
Re: Shelf life of lead acid deep cycle batteries
Post Sun Apr 22, 2018 5:31 pm
Most AGM deep cycle batteries have about a 3%/month self-discharge rate when stored at room temperature. Lower temp = lower discharge. Higher temp = higher discharge. After 3 years, its as pretty good bet they are fully discharged. Holding them in a discharged state will result in capacity loss. How much depends on several factors, including the chemical makeup of the battery. With sealed AGM batteries, the loss can be less than flooded lead acid.
Use a voltmeter to measure each battery. They are likely to read 0 volts, but note each one.
Next, try to recharge them with a quality "smart" charger driven from a generator or other steady AC source. If the charger won't start charging because the battery voltage is too low, connect a good 12V battery in parallel to the dead cells and charge until there is a measurable voltage on them, then disconnect the 12V auxiliary battery and proceed with charging until complete. Once a set is complete, set aside and charge the next set. Let all the charged cells rest for 24 hours.
Measure, and note, the voltage of each. A fully charged battery will measure around 12.8V.
If all take a charge, you can try to get an estimate of the battery capacity by running a discharge test.
Silentpower
Over Rated
I've never been close to rich/well off/middle class etc. But I am resourceful. Because I have dedication to learning about the things I need. It doesn't take much work to find info on how to care for your equipment (even while being stored) and a motivating factor might be the inability to replace your hard earned investment.
Having said all that, put the batteries on a trickle charge with a charger designed for agm. A 'dumb' charger is better because you want to keep some current going in, but keep the voltage below 14.4, ideally 14.2v. If they've been kept cool they might come back to life. With lead acid it's a balance between plate corrosion which happens when kept 100% fully charged for long periods, and sulfation which builds during periods of semi charge (as in your case).
My resourcfulllness led to investigating where telecom and server companies take their scap batteries for disposal. Here in the UK, companies are under obligation to renew their electrical backup supplies every 3 years for insurance purposes so the batteries they dispose of are still good. I ran for 7 years on agm's that I bought for the weight of the lead.
Silentpower
Over Rated
SCC, is solar charge controller.
tbh, once a cell is beyond a certain point, they don't recover.
Silentpower
Over Rated
The idea of an equal battery Bank is all cells of same age and type, because what's known as internal resistance (IR) needs to be as close as possible. This is so the batteries in the bank charge and discharge at the same rate. Very important.
Tbh, if you've invested in 3 new ones, they really need matching to 3 more new ones because the ones in storage definitely wont match and the outcome will be a very short battery life time and wasted investment.
Sorry if I sound negative, I don't mean to come across like that..
So, I got my volt meter today....the new batteries measure 12.8v to 12.9v. I only have one of the old batteries here at home now. Guess what? It reads 12.5v! I'm hoping the other two give me results as good. I thinking that they are doing so well because I live in Maine and the storage unit in not climate controlled. The other two older ones are still in the storage unit.
So, advice please. Do I still need to put the old ones in the new bank if I can get them to match volts? Or are the cells too old to be able to mix? I have a 1,500 watt wind generator that I can put the old ones on but I was hoping to be able to use the windmill as an alternate charger for the solar bank.
So, advice please. Do I still need to put the old ones in the new bank if I can get them to match volts? Or are the cells too old to be able to mix? I have a 1,500 watt wind generator that I can put the old ones on but I was hoping to be able to use the windmill as an alternate charger for the solar bank.
Last edited:
hey, I got my volt meter and the one old battery I have at home reads 12.5v while the newer ones all read between 12.8v and 12.9v. How much damage would the three old batteries do to the new ones if I use them anyway? I'm really not feeling good about buying three more batteries at $179 a pop. Oh....and I haven't charged anything yet. I got an AGM charger that plugs into 110v. That's my next step.