I'm looking for/designing a Lipo charger which can handle a discharging current of 5A at 5V.

Obviously, the lipo's charge is 3.7V (max 4.2V, min 3.2V), so most charging circuits inside a power bank, which are fed from USB, get 5V in, dissipate a bit and then charge the battery at about 1A (1/2S is advocated by some).

A circuit like the famous TP4056 charges the battery at 1A. This particular version also has a protection circuit, which does some nice protecting against over(dis)charging and overcurrent. (Although this board doesn't provide the 5V output needed in my project, so I don't want to use this particular board).

The term overcurrent is where my problem starts. I want to feed 5V to a LED strip of about 180 LEDs. All RGB LEDs at full power, this strip draws more than 5A (which is a little itsy bitsy bit more (#sarcastic) than the 1A the overcurrent protection is rated for.

My question to you guys:
Is there a power bank all-in-1-circuit which charges a Lipo at 5V, 2A and can handle a discharge at 5V, 5A?

Or, if not:
Do you have any suggestions on how to fix this shortcoming?

As a plan B, I was looking for a step up converter rated 3.7V to 5V, but most of them can't handle the amps (5V * 5A = 3.7V * 6.75A at battery side, not even accounting for dissipation). Combining this with a TP4056, would mean the battery charges at 1A, and discharges at around 2A.

Plan C would be to change my double (parallel) battery (2x 2000mAh = 4000mAh @ 3.7V) to a battery in series (7.4V). But that would make the whole circuit a lot bulkier and less attractive as I would need balancing. Although the discharging current would be a lot less this way (3.38A).

FYI: The batteries I use have a protection board inside by factory, but I don't know the specs of those.

  • \$\begingroup\$ Discharge function has absolutely nothing to do with charger. You have to design the "discharge function" separately. It looks like you want a boost converter from LiPo side (4.2-3.0V) to 5V and 5A. So just get a corresponding booster design, not some "Pololu" stuff. Where is the problem? \$\endgroup\$ – Ale..chenski May 24 '18 at 1:17
  • \$\begingroup\$ That is exactly the problem. I can't find any booster powerful enough to reach 5A, most are rated for 1A, and shut down at 1.5~2A. And then still, most of those are way too big for my project. \$\endgroup\$ – Bartel Meijers Jun 5 '18 at 15:31

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