Require 12v/24v battery charger to run from a generator

[sleepless]

Hi folks. I am currently using a 40A 12v/24v mppt charge controller (100V max, 500W/1000W max) to charge four 6V 225ah batteries tied series/parallell for 12V at 450ah. I have four 240W panels, but am currently only using two because it is a 12V system. The future plan is to run the batteries in series 24V when I can afford to get a good 24V inverter, and then connect the other two panels, but for now I'm stuck with the 12V inverter I have.

In the mean time, I'm looking for a battery charger to connect to my 120V/20A gas generator. There's a good chance that when I purchase the new inverter, it will include a charger, but that's still unclear at this point, and so I'd like to have the 24V option in the charger. So I need a 12V/24V charger. I'd like to be able to charge the battery bank, if half depleted, in the range of 8-12hrs, so I guess that would mean approximately a 20A charger?

I'd appreciate it if someone could tell me if I'm way off track here. If not, could you guide me to some charger options? Unfortunately, I'm on a really tight budget these days (otherwise I'd already have a new inverter), so taking that into account would be appreciated. Nothing fancy, bare-bones is what I'm looking for, as long as it treats the batteries well.

One other question: If the generator is running a charger, how does the panel charge controller respond to this?

Much thanks.

Edit: One other, other question: I guess there's an option to run a second charge controller to the 12V bank so I can hook up the other panels, rather than get a new inverter and run 24V. Does that seem wise, or no?

[Mike90250]

Google shopping is your friend. Any large automotive/truck 12/24v battery charger would work, you would be looking for about a 20A/24V 40A/12V charger
Since you are running off a generator, you are likely to be attending it and manually terminate the charge, so dont look for 3 stage or 7 stage chargers, simple charger is all you need

[PNW_Steve]

I asked a similar question recently and was pointed to Iota chargers. They seem to have a good reputation and are available in various configurations.

https://www.iotaengineering.com/dls.htm

[sleepless]

Thanks for the input.

I think I'm gonna have to commit to buying a 12V charger. I havn't found any 12V/24V options that I like. The Iota's look alright, but because I live in a cold climate, I always check the minimum storage and operating temperatures of my equipment. Those Iota's show a storage minimum of -20 C, and operating minimum of 0 C. That could never do.

I checked out various standard auto type chargers in the range of 20A - 40A, but often it seems they provide inadequate cables for the charge. Still looking for something quality and affordable.

Any thoughts on the question regarding a second charge controller rather than moving to 24V and buying a new inverter? Does running two controllers cause problems?

Thanks.

[Sunking]

Hi folks. I am currently using a 40A 12v/24v mppt charge controller (100V max, 500W/1000W max) to charge four 6V 225ah batteries tied series/parallell for 12V at 450ah. I have four 240W panels, but am currently only using two because it is a 12V system.

So what does that have to do with your question? Why would you need a generator to charge the last 2 batteries. Pretty silly.

Wire all your batteries to make 12 volts and use the solar to charge. You do not have to buy anything, rather learn what you are doing, and right now you do not know what you are doing. 500 watts into a 12 volt battery is 40 amps of charge current, enough to charge all 4 of your batteries at C/11 which is fine. You only need the charger and generator to top off all the batteries when solar fails.

Last there is no reason to buy a unitasker 12 volt charger. What a waste of money. Buy one that will charge any battery from 12 to 48 volts.

[sleepless]

1. I need the extra 2 panels (480W + 480W = 960W) because where I am in the winter time, I get very little sunlight. I can easily disconnect those panels in summer with a breaker if needed.

2. I can't connect those panels because the CC wont allow for them to be connected to a 12V system. (500W max). That's why I had the question about the second controller.

3. I already have a generator, and because I can't yet connect those other two panels, I thought it might be a good idea to get a charger to get me through the winter.

4. Despite offering your advice, you come off like an arrogant prick. Maybe don't bother giving advice to people if tou're going to be resentful about it.

"You do not have to buy anything, rather learn what you are doing, and right now you do not know what you are doing."

I thought that was what I was doing by asking questions on this forum. Maybe you should stick to the expert threads if people who are learning cause you so much frustration.