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let's say I have 4x 3.7V LiPo batteries connected parallel. I want to use TP4056 charger boards to charge them. (see picture) As a power supply, I use a 5V 15A adapter, so there is plenty of power available.

So why it's charging with only less than 2A? TP4056 is 1A charger, so with empty batteries, I assume it should take 4A from power supply right? But it doesn't...

If I use 4 separate power supplies, then it works. But I want to use only one. What am I doing wrong?

Thanks

Scheme

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  • \$\begingroup\$ Could you 75W adapter be at fault? Do you have bench top power supply you could use instead for testing purposes? Also, how is B+, B-, and GND wired? \$\endgroup\$
    – Jay
    Mar 31, 2020 at 3:22
  • \$\begingroup\$ My guess is the tp4056 components might not be rated for your application. \$\endgroup\$
    – JoeyB
    Mar 31, 2020 at 10:12
  • \$\begingroup\$ At 4A you definitely need to consider the wire gauge you're using. Measure voltage. You may have 5V at the supply and much less at the TP4056es. \$\endgroup\$
    – user16324
    Mar 31, 2020 at 13:25

2 Answers 2

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I think you should not connect the batteries (B+ & B-) in parralel connnection since it is connected to a tp4056 board which is a single-cell battery charging module only. But, the tp4056 (V+ & V-) must be connected in parralel connection to use only one power supply. And for the Output, if it is use for long capacity batt usage, VOut should be connected also as parallel connection. Let me know if this suggestion works. enter image description here

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"What am I doing wrong?" Trying to charge them in parallel.

Don't do it. You are supposed to constant current charge these batteries until a certain voltage, then go to constant voltage for the last part of the charge. If they are directly connected in parallel and the cells are charged at different voltages (perhaps one is at 3.9V and another at 3.6V), they will be sending uncontrolled current, possibly quite high, from one to the other. LiPo is more stable than some other chemistries, but everything has a limit. You do not want a lithium fire on your hands. Bad idea.

(This also explains why you do not see increased current when you parallel them - the charger is just working in constant current mode, unaware of the unexpected load you have given it.)

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