LilLiPo Charger behaviour while charging

I’ve started to use a LilLiPo, and while I think I’m understanding the behaviour, since there’s no status LEDs I wanted to check. I’ve read LilLiPo Charger + Under/Short LiPo Protection – ElectroMage Shop but my questions aren’t answered there.

While I’m supplying power to the LilLiPo via 5v (I’m using a USB PD trigger, set to 5v), it powers the PB and charges the battery? It’s easy for me to tell the PB is powered, but, I’m not sure if the battery is being charged. I think I measure approx 200mA current (I don’t remember exactly) between the LilLiPo and the battery, so I think that’s charging OK. Will it charge slower if I’m also running LEDs?

If the the PB isn’t powered, this means it’s also not charging the battery? I had a cell that maybe under voltage, so maybe the LilLiPo decided it’s faulty and so doesn’t charge battery nor power the PB?

It doesn’t pass power through, only supplies what it thinks the battery needs.

If there was a very low cell, it will go into a soft recovery mode where it slow charges the cell back to a good voltage. After it gets to a good voltage it switches over to the higher current.

That low current mode may not be enough to run PB. So I would have a power switch between LilLiPo and the PB/rest of the system where you can turn it off when charging or at least when the battery is low.

Thanks @wizard . Do you have the behaviours written out someplace? E.g., PB is powered when X, battery power is used instead of 5v feed when X.

I think I observe that:

  • With 5v to the Lilipo In, but without a battery attached, it doesn’t power PB
  • With 5v to the Lilipo In, when attaching a low battery, the PB Leds are briefly lit, and then go off
  • Sometimes my pixel LEDs seem to be a dim red, I’m unsure why - I think it’s when the battery is very low and I’ve got 5v external power connected to Lillipo

I’m unsure if

  • Charging speed is reduced when PB Leds are bright
  • Is output current shared between battery and PB? (So that, if Lillipo determines very low battery charge current is required, then PB also gets low current)
  • If I have external power attached, can I be sure that the battery isn’t being depleted ?

I designed and built my enclosure before I knew of the suggestion to be able to disconnect the PB from the Lillipo, so I’m hoping I can understand how to still have reasonable charging experience without the switch between Lillipo and PB

Without any status LEDs on the Lilipo, it’s not possible to know why PB isn’t lit - no way to know if it’s because the battery isn’t seated properly, battery is too low, some wiring problem or PB pattern/brightness setting. Actually the last one I could probably tell if I created a LED light tube from the PB body to the enclosure walls

It is possible that Lilipo was the wrong choice for my use-case, since I think I’d like:

  • To know if the battery is charging or not
  • To power the PB from external power 5v even when no battery is attached or battery is very low
  • To be able to charge the battery without PB pattern running (these last two items do somewhat conflict - I think if I could pick only one, I’d pick to be able to run PB when battery is very low, since I could use a ‘black’ pattern if I didn’t want animation to be playing)

On the other hand, it’s a good fit for me since:

  • It physically fits the space on the wearable, anything much larger would not
  • The 5v feed is separate, so I could use a USB PD trigger board which I locate in a different position in the enclosure
  • It likely is a good pairing with the PB, since both are from the same designer

That sounds about right. It wasn’t designed to operate without a battery, or to pass through power for a high current system. Only charge and protect the battery.

Quite possibly, the max power LilLiPo will take from the power input is what it is giving the battery (212ma for that model). Any load on the output takes away from what would charge the battery. If your total load on the system exceeds that (which is quite easy to do with LEDs), you will likely be discharging the battery, even with power applied, since the battery has to make up the difference.

Yes, with a low battery the charge current is reduced to bring the battery back up to safe charge levels, and if a load is still connected, it will likely not be enough to power anything.