Adding a second pack of 48V Battery.

[iJeiCee01]

Hi,

I have an electric scooter that is working on 48V Battery 12Ah (13s3p) using a Lishen LR2170SA 12A 4000mAhcells and I would like to add a 2nd 48V battery pack for an increase range but my problem is it's hard to find a LR2170SA cells on my country to create the new battery pack. Now, I want to use other brand 21700 with same capacity but different discharge rate (higher), is it okay to just use a Y splitter? Does it make the old battery to bear more stress? and more importantly is it safe?

or adding a 2nd battery pack with entirely different capacity and just adding a battery selector switch is the best course of action?


Lishen LR2170SA data from Mooch

 

[Voltron]

It should be ok. Just make sure they're at the same voltage when connecting them.
It should actually stress the old battery less, with the other one sharing the load. Some on here have even done it with different battery mixes like 18650/lipo, yours will probably be fine. Some BMSs don't always work together on joined packs, so there's that to think about.

If you go selector switch, then you have to also charge the separately too.
Usually separate pack is better if you want to leave one battery off to be light for short trips. If you're carrying both batteries all the time, then less reason to keep them separate instead of acting like one big battery.

I ran a 3 module pack of different brand and discharge cells...

 

[john61ct]

It is **much** better to treat multiple paralleled sub packs as one monolithic pack

than to switch from one to the other.

The former gives a lower C-rate thus greater total energy capacity, higher peak power output and better longevity

see Peukert's Law

 

[iJeiCee01]

Thank you both for your inputs, I will be doing the parallel Y split for my 2nd battery pack.