Adding second LiFePO

[Phildabrit]

Hi , my question is certainly battery related but not currently considering a solar addition.

I purchased my travel trailer new in 2019 and it was supplied with a new GoPower Sun cycle 100 amp LiFePO 4 battery.
I think in the 4 years of ownership I have discharge the battery whilst dry camping once. We always camp with full hookups plus we have probably used our trailer 25 times in the 4 years of ownership so I think the battery has had an “easy “ life.
We plan to dry camp more often now and am considering adding a second battery ( 100amp LiFePO 4) the trailer is equipped with a second compartment with parallel connections.
I have been advised to either use the same make and model as the original for the second battery or to use two new ones that are the same make and model to each other.
My question is why do I need to match batteries? If they are the same capacity and both have individual BMS won’t this take care of any differences in the performance of either of them? Can’t I just add a second battery that is the same specifications as the original, just a different make.
I would be grateful for advice and guidance….

 

[Crowz]

I agree that what you have read is the norm but I have chins and weize batteries in parallel together and they work fine. So I am leaning towards parallel is ok but series is probably not as long as they are all of the same ah rating aka 100ah in my case.

Matching of course is going to be best no matter what but mismatched can work it seems.

 

[mikefitz]

My question is why do I need to match batteries

This was the advice given when using lead batteries In parallel . As your loads are within the BMS current limitation of a single battery, there will not be an issue with lithium , even if the capacity of the added battery is different.
Ideally ensure the BMS charge and discharge current ratings of the additional battery are equal or greater than the existing battery

Before connecting in parallel ensure the voltages are similar.