Can you connect lithium cells in parallel - of course you can. But can you connect cells of different capacities in parallel?
By Julian
Youtuber, shed dweller, solar charge controller aficionado
Good morning all…
Youtuber, shed dweller, solar charge controller aficionado
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I know this is old, but you had me cracking up when you pulled out all those multimeters.
In physics we were taught the basics of V=IR and loads in parallel and series, it's one thing to learn about the concept but we never really put it into practice. So here I am practicing on my own with arduino projects and wondering if I can charge multiple 18650 batteries in parallel with a TP4056. I had read how a lot of people are saying limit one TP4056 per battery and only now do I understand the monkeys on the internet were referring to connections in series, not parallel. I really appreciate your clear and informative video still being here years after it was made!
Hello,
I want an SMPS with 5v USB input and dual output of 12v and 5V for Battery and Ardunio respectively. I would request you to suggest a PCB board or an IC.
Thanks and Regards
Yes you can. Doing so is major Bad Ju Ju. The lower capacity cells would Dump what they could as long as they could and end up going way past they're lower discharge limits. MERDERIZING the poor creatures. Surely going on a one way trip. Other then in a Absolute EMERGENCY situation even thinking of doing so is extremely NONSMART !. LOL You sure come up with some Froggy Idea's some times . LOL Was this a Test ? Testing Testing All Dummies Try This At Home ??? LOL
I think it's series connection rather than parallel
Correct me I can be wronge
You are a mad man Julian
A question raised in my mind. Can we use 4 3.7v 2100mAh cells in parallel, each cell connected with charge and discharge module(tp4056) . it makes 3.7v dc with 8400mA, than boost the voltage with boost converter upto 12v . Will it work? will such system charge each cell equally and of course discharge them in equally?
It's simple; the cell with the lowest internal resistance will provide the highest current and the cell with the highest internal resistance will provide the least current. And higher capacity cells obviously have lower internal resistance, so they provide more current while the opposite is true for smaller cells. Imagine both smaller and larger cell as two resistors that are connected in parallel and the value of those two resistors is the same as the internal resistance of those two cells. Smaller cell represents higher value resistor and the larger one represents lower value. When you apply voltage to those two resistors in parallel, the lower value one will let more current through – same with those batteries – larger one with lower internal resistance will provide more current at the same voltage drop. If you connected the same load to both of those cells separately, the smaller cell will have a higher voltage drop due to its high internal resistance. When both are connected in parallel, the smaller one, due to its higher internal resistance simply cannot provide as much current as the larger one at the same voltage.
Did the robot build actually ever get finished? 😁😀
great video!
so If I have understood, no problem if I mix different current cell in parrallel, but I cannot mix different voltage cell? I there any trick to make it safer, I would like to built a big 18v battery for my drill, from old laptop 18650 (so lots of different cells) I didn't found chiness board for balancing parallel batteries, I was thinking about using diodes, but I'm concern about the voltage-drop, I have also to bypass them for charging
many thanks!
LOL
Maybe put the cells in holders then connect to power bank with alligator clips or magnets ?
new video?
So pulling many amps can hurt if one battery is "active" for that moment
tricky