Parallel Battery set ups

[E-StreetBikes]

Hey guys i see alot if people argue about running 2 batteries parallel. I see people that have parallel set ups on their E-Bikes and they work no problem but them i see people say mot to run 2 batteries on your E-Bike parallel. Can some one please explain how a parallel battery set up works? Also what to do and what not to do? And what battery to buy as a second battery. For example a Ariel Rider X-Class its 52v 18Ah 35A. People say that the voltage of the batteries must be the same. How do you make sure their the same if both batteries ate 52v 35Ah wouldnt they always be the same as long as their always charged together? Will some one please explain this to me and tell me how to correctly do a parallel battery set up for a E-Bike please

 

[Chalo]

Both batteries should be the same chemistry and number of cells in series. (They don't have to be the same capacity.) Charge them both separately until they're full. Verify that the fully charged voltage is identical between the two packs. Then connect them in parallel with a splitter harness and treat them as a single pack.

If they become separated, don't reconnect them unless they're both fully recharged or you can otherwise verify that their voltage is the same.

If you run parallel packs all the way down, then one pack's BMS will cut off before the other. This could be a problem if one pack alone isn't sufficient to carry the load you're putting on it. Best not to run them all the way down. Also in that case, separate the packs to recharge them (because one pack cutting off is the same as unplugging it, and you have to sync them back up).

 

[dogman dan]

Yes, as long as both are the same voltage, 52v, 48v, 36v, or whatever, and the same type of cell you can parallel them with a simple connector.

But always disconnect them, and charge them full separately. You can have big problems with a bms, including a fire, if you try to charge one battery while its still connected to the other.

Then reconnect once both are full.

Or, if more convenient, and both batteries are as large as your current one, just run one for awhile, then switch to the other.