Using/charging multiple li ion batteries

So i have a project (a LED light up staff) where i am trying to get a smaller more integrated battery pack (rather than the usb power bank thats crudely taped on currently).

My plan was to make make my own little rechargeable battery pack, but after reading a bunch of threads, i am more confused than ever. From what i read, this will either work fine, need a small tweak and work ok, or explode.

The approach i am currently taking is to have two 3.7 v 3000mAh 18650 li ion batteries (specifically these guys), and wire them in parallel (giving just enough Ahs for a night of partying, though 3 might be ideal), and use a single embedded TP4056 board to charge them both (on the idea the they'd effectively be a single cell).

Is this going to work or kill me? what other approaches could i take?


I would guess you will be o.k. 18650 Li-ion cells are fairly resistant to abuse and in parallel and charged at only 1A they should be fine.

If I was doing it, for my own comfort, I would probably charge each cell individually from time to time just to make sure that they are both still behaving similarly. The problem with permanently connected parallel packs is that you can't easily tell if one of the cells is dying while the other is taking all the load.


whats the failure senario of one cell dying? If it just leads to both batteries being useless, i'd probably be ok with that, bit i am concerned it would lead to them catching fire or something similar

Li-ion round cells like 18650 don't really catch fire or "explode" unless they are seriously overcharged or externally overheated (though I'm not guaranteeing that there's absolutely nothing you can do to cause problems).

But the normal failure mode is just to refuse to take a charge or to deliver any real not a problem in your scenario.