Hi all,
I’ve researched and purchased some parts for this build but I’m having trouble getting a consistent phone charge rate of 1A. I’m very confused, I’ve not found any rhyme nor reason as to why the build charges one phone ok and a second not at all, then the same circuit charges both at 0.25A, and also why when I plug it into a LiPo cell the voltage collapses completely.
Build:
- 2x 3V PV cells in series (link)
- 1x CN3791-based MPTT solar battery charger module (link)
- 1x 3.7V 1Ah LiPo cell with protection module (link)
- 1x TPS61088-based USB boost module with a fast charge identification chip (link)
What works:
The panels provide 6V to the CN3791
The cell is charged by the CN3791 under solar power
What doesn’t work:
The cell voltage collapses when a phone is plugged in (down to about 2V). I have to unplug it from the system to reset it, which makes me think it’s the cell protection circuit kicking in.
The TPS module in isolation (hooked up to a bench power supply) draws less than 0.1A when trying to charge a phone.
What I’ve tried:
I’ve purchased an MT3608 boost module, hooked it up to a bench power supply and soldered a USB 2.0 breakout to the output. I get weirdly different results, but the best I’ve got is about 1A 5V (which is what I’m after) but it’s not consistent.
I’m aware there’s various configurations when it comes to how to hook up the D- and D+ pins of the USB port, e.g. to tell the phone it’s a DCP dedicated charging port, but nothing I’ve changed has seemed to make a repeatable difference.
What I’d like help with:
Debugging/troubleshooting! Is there anyone who could meet me at the space and help me figure out what’s going on here? Anyone from @electrotechs could possibly lend a hand?
Thanks so much!