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Can I charge two different not connected battery's off one charge controller?

EddieM

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Sep 19, 2020
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If I have two 100ah batteries both in their own box discharged at different amounts never connected together.

Can I use say a 40 amp solar charge controller and split the output one going to each battery so I get around 20amp into each one to charge them up?
This would save some money VS needing to buy two of them.
This would be for 2 100ah Lithium Iron Phosphate Batteries each used for different things.

Looking at maybe a EPEVER MPPT Solar Charge Controller 40A for this.
Thanks
 
Why are they seperated? Can they be wired in parallel to keep voltage the same and then wire both loads to the bank? Then charge the bank with the SCC-assuming the batteries support parallel config.
 
There are several series of the Epever SCC ... which one do you plan to use?

How do you plan to separate the output?
 
I would charge one battery with the solar charge controller. Then use a DC-DC charger to charge the second battery, either from the common bus bar or from the battery. I would probably go from the common bus bar.
 
I think the EPEVER has one output to charge the battery or batteries in parallel. If you connect 2 batteries off of the same output (+ & -) you have effectively connected your batteries in parallel anyway. Why not try to charge both individually first and then connect in parallel once they are balanced ( equal charge). This might give you the desired effect without anything fancy. Try to keep it simple.
 
Why are they seperated? Can they be wired in parallel to keep voltage the same and then wire both loads to the bank? Then charge the bank with the SCC-assuming the batteries support parallel config.

They both run different things so each is in its own box. One is to run a 12-volt fridge and the other runs other items moved around as needed. So that are not connected together.
Just building all this.
 
There are several series of the Epever SCC ... which one do you plan to use?

How do you plan to separate the output?

I was going to make a Y output for each wire coming out?
This would be the Lithium version of it in 40 amps
 
If you connect the SCC to both units that way .... they will now be connected in parallel with the SCC connections acting like a bus bar.
 
You will ned to put an isolator in if you dont want to connect the batteries in parallel.
 
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Consider installing something like this...

Thanks
Wow $99. I think at that price point I would be better off just getting two 20amp versions for around the same price of one 40 and the isolator.
 
Thanks
Wow $99. I think at that price point I would be better off just getting two 20amp versions for around the same price of one 40 and the isolator.

I think you are better off wiring in parallel with one SCC and getting another simple battery/charger of some kind for your mobile needs. Wiring them with a y connection is just more wire length between a parallel connection when you should be going for the shortest length wire or busbar possible there.
 
I have a similar question I was gonna make my own post but this post is fairly close to what i want to do but it slightly different. So i currently have 2x 100amp renogy pure gel batteries. I want to add a lithum ion phosphate battery but the renogy batteries or only 8months old so i don't want to get rid of them quite yet but i was wondering how would be able to have both the renogy batteries and the lithium battery. I was thinking having the panels split into 2 charge controllers one for renogy and the other for lithium ion phosphate battery than they both go into the same inverter. Ideas and helpand recommendations would greatly appreciated ?
 
If the two batteries are on the same circuit then using two controllers isn't going to gain you much unless you have added more panels and the existing controller can't the new panels. Pick the lowest common denominator for a charge profile. It will probably be the gel charge profile, but you need to verify that. You don't want to over/under charge either battery type.
 
If the two batteries are on the same circuit then using two controllers isn't going to gain you much unless you have added more panels and the existing controller can't the new panels. Pick the lowest common denominator for a charge profile. It will probably be the gel charge profile, but you need to verify that. You don't want to over/under charge either battery type.
It seems like you're saying that the cany be connected in parallel as long as i define the charge rate for the lowest and that being the gel batteries wouldn't i need to separate them or something and i don't think i can manually set my charge rate on my controller i have the renogy 40amp rover charge controller.
 
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I saw something like a smart battery isolator from big battery would that useful in this case
 
I don't think you will find an adjustable battery combiner for less than $100

Even with two solar controllers you might want a manual switch if one battery is full and the other is lagging. Protect your wire with a fuse.

Magnum Combiner
 
Sure but that one costs a lot as it is packaged with the Blue Sea battery combiner.
That combiner would be good except the voltages are for FLA and don't appear to be adjustable.
 
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