Hi all,

Two 18650 li-ion batteries packed parallelly feed my load and I use a TP4056 module with protection (three ships) to recharge the batteries. Everything works (the load needs 3.2V to 4.2V to work). The issue is recaching the batteries takes eg 10 hours! And that's because TP4056 allows at most 1A current.

1- Is it possible to modify that TP4056 to allow more current eg 2A to recharge the batteries faster?
2- If not, what other module (still with full protection) allowing higher current (>2A) do you suggest I use for my circuit?

 

Welcome to AAC

1- Is it possible to modify that TP4056 to allow more current eg 2A to recharge the batteries faster?

No, 1A is it's maximum.

2- If not, what other module (still with full protection) allowing higher current (>2A) do you suggest I use for my circuit?

There are AFAIK no other single chip *linear* chargers that can do >2A and certainly none in a ready to use module that I've seen. There are switched mode ones that can do 3A but that's a much more complex solution.

What is your required discharge current? One option might be a TP4056 per cell...


[Edit] this module claims a 2A charge rate (it's an smps one) but I'm not convinced, I can't find a proper datasheet for the chip (yet).

 

@Irving
The module that claims a 2A charge rate has 5V output. My load needs 3V to 4.2V.

 

You can’t charge a 4-volt battery with 4 volts. It will take an eternity to reach 4 volts, and by the time it’s fully charged (assuming a perfect world), the battery will be useless. Regardless of the load, two 18650 batteries in parallel will still provide a maximum voltage of 4.2 volts. To charge these batteries, you need at least 5 volts. The module appears to achieve this effectively.

If you desire faster charging, as you mentioned, a proper Battery Management System (BMS) will ensure the appropriate current at different stages of the recharge. You can supply it with 10 amps, but it won’t make a difference. Batteries will still charge properly if they are under the control of a BMS. If not, you’re in for a smoke and excitement. Force-feeding Li-Ion batteries is a sure way to fill your house with poisonous smoke.

Instead of charging batteries faster, consider having more batteries on hand to meet your operational needs. Swap a dead battery for a fresh one while the dead one is charging. When the second battery is done, you still have a third. The first battery will continue to charge. It’s just the way things are.

 

@Irving
The module that claims a 2A charge rate has 5V output. My load needs 3V to 4.2V.

Ah, yes, it's a boost circuit too, which many require! You may have to split the charging side from the discharge protection side.

 

Instead of charging batteries faster, consider having more batteries on hand to meet your operational needs. Swap a dead battery for a fresh one while the dead one is charging. When the second battery is done, you still have a third. The first battery will continue to charge. It’s just the way things are.

Depending on the application, that may not be a viable option. It may not be practical to swap out batteries. Also, the average charging capacity has to be at least as great as the average discharge rate. If not, all that having more batteries buys you is more time before you can't feed your load any more. A number of years ago, back when rechargeable tool were still relatively new and the batteries weren't as advanced as now, I had to have three chargers and four sets of batteries to keep up with my usage of one of my drills on a heavy-use day. Fortunately, back then, a charger and set of batteries came with each tool and I had bought four different tools that used the same batteries, so I had what I needed -- though it did mean that I lost the built-in excuse that I had enjoyed previously to take occasional long breaks while my batteries were recharging. Nowadays, most of my tools can be kept in operation more-or-less continuously with just one charger and a second battery.