Having battery issues-Help, please!

[WIyurt]

I’ve been using a ‘Portable Solar Generator for about 4 years now. I burnt through a couple AGM batteries thanks to my lack of knowledge, and upgraded to lithium phosphate this winter.

Now that I’ve learned more about solar, I am less than impressed with the setup I bought. But hindsight is 20/20.

It’s got a 24v inverter, so I have 2-100ah batteries wired in series (which I know is not advisable). Since switching to liFe, I have been overcharging, which causes the inverter to shut down.

The maker of the kit has the battery wires from the charge controller wires right to the lugs on the inverter, which I suspect is contributing to the erratic voltage on the top end of my charge, since voltage is going into the inverter and batteries rather than directly to batteries?

My questions are:
- Am I right in thinking that charge controller directly to batteries is the correct setup?

-Can I hook the charge controller wires to the + on one (series wired) battery and the - on the other?
Would this work temporarily until I can get components to do it right?

-Would a dual battery charge controller work with my series wired batteries?

[Jafo]

Yeah you have a lot going on here. First, there is no problem wiring them in series to 24v and in fact it IS advisable to raise your voltage as much as you can afford. Higher voltage requires smaller wires and they don't heat up as much, ergo it is safer. You're good to go there and I wouldn't worry about that.

I connect my inverter directly to the battery. I never use anything on the charge controller itself except I just plug in the input from the panels and the output to the battery, that's it.

Hooking + on one and - on the other is EXACTLY how you SHOULD do it. Remember, when you are wiring in series, you are essentially making one big battery instead of two batteries in tandem (parallel). You should hook your charge controller up this way AND your inverter.

You should only need one charge controller.

[trihartsfield]

Wires from solar panel to charge controller. Charge controller to batteries. Batteries to inverter. Inverter to appliance(s).

I run my batteries in series also.

[WIyurt]

Thanks folks!

I’ve got it set up properly now. Charge controller to only batteries. Seems to be better this afternoon. We’ll see tomorrow when I have a full day of sun how it goes.

I asked about the dual battery controller because I’ve heard that series wiring lithium can cause problems with equalization. The BMS shuts down whichever is full first causing the other to not charge completely.
I thought the dual bank controller might be a way around this. Any thoughts?

[Bob Rowlands]

Thanks for all the info folks.

[Jafo]

Originally Posted by WIyurt

I asked about the dual battery controller because I’ve heard that series wiring lithium can cause problems with equalization. The BMS shuts down whichever is full first causing the other to not charge completely.
I thought the dual bank controller might be a way around this. Any thoughts?

I'll admit that I am a little out of my expertise with the lithium batteries as they have onboard charge controllers, but if you are hooking them up in series, the charge controllers should be looking at total voltage.

That might be a better question for the battery manufacturer..