Join lifepo4 batteries

Hello dear friends,

My name is David, I'm from Chile. I need your help with a doubt i have.

I have 2 batteries and I would like to join them to see if I can make my ebike go faster, the batteries are:

- Lifepo4 48v 20ah used.
- Lifepo4 24v 10ah new.

Is there any way to join them so I can get a 72v 10ah?, if it's possible could you draw me how to do it, I have a (2 FET 4110 Mark II Extreme Modder LYEN Edition Controller) a magic pie 3 motor on my ebike and a Large Screen Cycle Analyst, but I'm to ignorant to put it all together.

Thanks a lot for your help.

can you take the batteries apart so you can split out some pouches from the 20Ah section and put them into the 10Ah section? do you have the 24S BMS already?

when you get the batteries open then post up pictures so we can see how they are constructed and how you can rearrange them to make it go to 72V.

Plug the positive output of one into the negative output of the other. Then take the remaining positive and negative 72V to your controller power input leads. As long as each pack separately will support the amp draw of the controller, there won't be a problem until the 24v 10ah battery gets low. Set the controller LVC for a 72V battery to avoid this and damage to the 24V pack. Or you can rework both packs into one with another bms as previously pointed out.