Choosing the battery management IC and looking at extra features

Originally published at:

In this video, Chris reviews the impacts of battery chemistry and power charging, and also ultimately picks out a part. As an added bonus, there is a feature on the chosen part that may reduce overall part count on the final product! Li-Ion Battery Discharge Curve We have chosen a part! The BQ25895 BQ25895 Datasheet…

Kudos for reading all those datasheets… The vendor-specific terminology for those features (like “Power Path”, “NVDC”, and so on) seems pretty tough to deal with. You need something like with a “vendor terminology translator” to map between whatever TI calls something and whatever Analog or whoever else calls it. is a bit defunct now, unfortunately. But yes, it would be great if there was ever a 3rd party company that would try and map apples to apples features between vendors. They all want their proprietary names attached to things! (trademarks, etc)

I didn’t realise was defunct. I’ve been watching the old CE videos, and you use it all the time!

Well, it’s still there, but it requires an account now (used to have free versions), so I figure it is effectively defunct for CE users.

I’ve been doing some datasheet digging on battery charger ICs too… thought I’d share:

I’m skeptical of the BQ25895 for use with a solar panel.
14V max input seems too low for use with “12V” solar panels (which will output up to ~20V)
I guess 6V panels would be ok though.

No MPPT built in is a pity. I’d rather have all that handled automatically and not have to worry about the software side.

Also, the USB-OTG functionality looks great, except I believe it only works when you don’t have an input supply (i.e. can’t be used at the same time as a solar panel). This isn’t so surprising, as I think 2 inductors would be required to charge the battery and provide a 5V output simultaneously.

I’m likely going with the LTC4162-S instead
(I’m gonna be doing lead-acid primarily, but they do lithium versions too)

Hopefully this helps someone :slight_smile:

Agree, I had hoped for that and even considered one or two, but the higher cost was a barrier on one and leakage current on another.

Correct! In fact, if you have a higher voltage on the input, it will be passed through to the PMID, which could be an unpleasant surprise if you expect 5V on PMID and instead get…14V :smiley:

Thanks to the pointer to that datasheet, looks quite interesting!