mix & match batteries

I've got two 306ah batteries that I built and just installed, they haven't even used 1 cycle yet. These are batteries I bought from EEL. Is there an issue with buying a 300ah battery like a Chins, Li-Time, Power Queen, Redodo...etc. and adding that in parallel so I have 900ah+ or two and have 1200ah+? Didn't know if mixing and matching same size but different brands would matter. I wouldn't think it would.

Humm

Well the low battery will be the one that will set the amps.
Its will be the first one that shutdown with the bms.

So personal i will not use it that way .
But again some do it and have no problem.

What volt you gone use ?
12/24/48 volts ?
That do not see clear if i read it.

Suijkerbuijk said:

Humm

Well the low battery will be the one that will set the amps.
Its will be the first one that shutdown with the bms.

So personal i will not use it that way .
But again some do it and have no problem.

What volt you gone use ?
12/24/48 volts ?
That do not see clear if i read it.

Click to expand...

It's a 12V system in an enclosed trailer converted to a toy hauler.

No worries. I would not press the voltage on the drop-ins until they seem to work well at 13.8 - 14.0 charging. Then keep track if you bump the voltage.

There's no problem mixing different sized Ah batteries in parallel so long as they are all the same voltage and chemistry.

My 12v battery bank is a mixture of different sizes and brands. They all share the load (and take charge) relative to their size. Like a 200Ah battery may be contributing 20 amps to a load while a 100Ah in parallel would be contributing 10 amps. They roughly stay in state of charge similar with each other.

Kiwi2000 said:

They all share the load (and take charge) relative to their size. Like a 200Ah battery may be contributing 20 amps to a load while a 100Ah in parallel would be contributing 10 amps. They roughly stay in state of charge similar with each other.

Click to expand...

This is what I have seen as well. The capacity of each battery shows up as the ratio of current each ne ends up pulling. It can vary a bit as it goes from charging to discharging and will also vary a bit in different parts of the discharge curve, so don't depend on getting the full current of all the batteries in parallel. When just paralleling 2 of the same size battery, I only hope to pull 50% more current instead of double. When you get to more than 4 batteries in parallel, I think you should be safe pulling half the current the whole array is rated for. With 6 batteries all rated for 100 amps of load current, you can safely pull 300 amps even if the battery balance is bad. In most cases, adding more batteries in parallel is to gain more run time. And that is fine as the current from each battery becomes less and is not a problem.