TP4056 module current

While going over the schematic of the TP4056 charger module, I noticed that the supplied board has an Rprog resistor of 1K2. This sets the charging current to 1A. This might be fine for some chargers, but there are still a lot of 500mA chargers as this was the maximum current spec of USB. Also my old laptop disconnected the MAKERbuino as soon as I plugged it in.

I changed the resistor to 2K7 to limit the charge current to 445mA (1200/Rprog). Just to be on the safe side. See pictures below.

Also, on a side note, the supplied LiPo has a recommended standard charging current of 0.5C and a 1.0C for fast charging. Respectively 300mA and 600mA for fast charging. So 1A charge current may be too high anyway.

Does anyone have any thoughts on this?

It’s the green resistor marked 272 on the bottom left.

My lab supply showing 449mA of charging current.

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@Ma_X, you’re correct about the charging current being slightly too high and congrats for noticing that (damn, you’re good, how can we hire you :slight_smile: )

I was having trouble sourcing a li-po charger with a different current settings for a reasonable price and the current setting wasn’t causing any problems so we just went with this board… We’ll change that in the near future just to be on the safe side but I’m most sure it won’t cause any problems.

Thanks for the compliment! If I would live a little closer I surely would consider your offer :slight_smile:
Maybe an idea to implement a charger on the main board on the next revision? That would also be visually be more attractive.

Correct, we do plan to do something like that on our next board revision. We’ll keep you updated.