Battery charger / converter questions (amps?)

[farok]

For the time being, I don't plan to install solar, and will be putting in two of the Costco 210 AH golf cart batteries to make a 12V-210AH battery bank. These are flooded lead acid batteries, not AGM or gel. I'm looking at the Iota 110V chargers since by swapping a $20 part, I can switch from charging FLA batteries to LiPO, which at some point down the road I would like to do. Three questions...

1. What size charger would make sense to charge the FLA batteries? I have seen that you want to charge them at about C/8, which would be only 25 amps. This seems low, but then again it's a smaller battery bank. Would a 30 amp or 45 amp charger work fine? Any issues I may run into with the larger amp rating charger?

2. If I don't get the batteries right away, can the charger/converter be plugged into the 12V house system without a battery to run 12V loads up to the converter's capacity? At this point it would be lights and a MaxxAir fan. I don't have a need to be off-grid for the time being, so if I can defer the cost of the batteries until I actually need them, that'd be a big help.

3. Are there other charge controllers that I should be looking at that will charge FLA as well as LiPO batteries?

Thanks for all the help!

Chris

[o1marc]

Rule of thumb says you want to charge the battery at 25% of it's ah capacity, a 100ah battery should be charged no faster than a 25amp charge. AGM batteries can be charged at full ah rating. Using a much stronger charge can overheat them and destroy them in 15 minutes. I'm sure that's what I did to my 8D when I left it on the 50amp start charge. I walked out and smelled the heavy odor of sulfur look all around but couldn't pinpoint where it came from. Called 911 and the FD showed up, as soon as he opened the door and step out of the truck he commented that he could smell it. They looked all around and couldn't determine what it was and just left. I determined later that it was the battery I killed.

[rffffffff]

I have four batteries on a 55 amp iota charger and it works fine. It does take quite a few hours to charge to full capacity from my worn out batteries but I think it’s sized about right. The problem with going with a smaller charger is that if you want to use it without batteries and have any kind of load 25 amps isn’t that much at 12 volts. I would go bigger on the charger if you’re going to have significant 12v loads. Probably a good idea to think about that side of things in the longer term and see if a smaller charger is going to swing it, and if not maybe buying additional batteries to be matched up better? I’m glad I have the 55 because I’m going to end up with a 860 amp hour bank and anything smaller would likely have to be replaced when I get the new batteries.

I don’t know how smart the chargers are, but I always thought that they wouldn’t kill the batteries if they were oversized but I have no real clue or experience

[john61ct]

Originally Posted by farok

Costco 210 AH golf cart batteries to make a 12V-210AH battery bank.

The Duracell / Deka ones are **much** higher quality, just as cheap.

Get at least 40A, higher if you might go bigger or AGM one day.



> If I don't get the batteries right away, can the charger/converter be plugged into the 12V house system without a battery to run 12V loads up to the converter's capacity?

Deends on the unit. A $20 lead batt can buffer if not.



> Are there other charge controllers that I should be looking at that will charge FLA as well as LiPO batteries?



Adjustable user-custom setpoint's all you need.

[john61ct]

Bigger amps is never a problem for the batt.

Ability to de-rate is good when the AC circuit is under powered.

[farok]

Thanks for the info! If the highest you want to go is 25% of it's amp hour capacity, then I should be good, as the bank would be 210 amp hours. The 45 amp charger would be comfortably below that. I don't plan to power much, so maybe the 30 amp charger would be fine if that's safer for the batteries. The most I plan to have on 12V without batteries includes some LED lights, and the MaxxAir fan. I'll have to check the power draw for the fan in particular. Eventually when I get the battery bank, I will have a water pump, and maybe a 12V fridge.

[farok]

What chargers are others using? It would be good for me to check specs on others I may not be aware of. I've not found any with customizable set points yet (but I've not looked too long, either). Thanks.

[john61ct]

Again, no such thing as too much current, just a higher investment into future proofing, good infrastructure like chargers should last longer than your next X number of banks, which are a consumable.

Both the Sterling Power ProCharge Ultra and ProMariner Pronautic P series will let you optimize setpoints for all types of bank chemistries.

[roach711]

I have two of those same batteries and charge them with a Progressive Dynamics 45 amp three stage converter/charger panel. The batteries are still going strong after 6 years of (admittedly) light use.

[john61ct]

Yes some PD lines give some manual voltage control, even come with battery temperature sensors/ compensation, very rare for RV "converters".

[farok]

Thanks, all! I looked at the Sterling / ProMariner charger and really like all the features that it offers. Sure the price is a bit more, but it seems like the available features are well worth it! If it's in the budget, that's where I'm leaning now.