Charging a Lithium ion battery with another lithium ion battery

[CalebWetts]

Hello all,

I live in my Mercedes sprinter conversion with 1kw of solar and 15kw of 48v battery storage. I have 4 48v batteries that I use for ebikes. These add to 3kw of battery and is portable. I can charge this portable set up while I go into work (I have a small 48v charger for this). I would like to be able to plug the freshly charged 3kw 48v battery into my larger 48v when I get home everyday to charge the battery bank. Would there be a way to safely connect the 3kw battery to the bus bars without creating a huge surge of energy damaging to the batteries? I imagine I would need a way to limit the discharge current of the 3kw battery. Can anyone think of a way to safely and conveniently make this work?

Thank you!

 

[Rocketman]

Even though they are both 48v batteries- are they the exact same chemistry? LiFePO4?

My recommendation would be to find a 48v to 48v Dc-Dc charger. That way there is some separation and control of the charging cycle.

Victron makes one Orion-TR 48/48-8a 360w.

I am using a 12v one on my MotorHome and it works great - I have the smart model which allows adjusting via Bluetooth on the phone (and reporting voltage on the phone too). If that’s available it is worth it.

 

[CalebWetts]

Yes, they are the exact same batteries just more/less in parallel. I did not think about that, thank you!