Arduino MKR ZERO battery charge timeout (not in datasheet) ?

Hello everybody,

I am planning to use few Arduino MKR Zero boards in my project. But I am also considering developing my own based MCU board beasuse of this weird statement from official board page (here) :

"The chip is programmed with 4 hours of charging time, then it goes into automatic sleep mode. This will limit the amount of charge to max 1400 mAh per charging round. "

I know that some och these chargers have this function because of security. But I can NOT find anything about this in official datasheet. From official schematics - charger is Microchip MCP73832X3DFN and there is no mention about any kind of this timeout or any kind of "sleep" mode.

I need to use bigger battery (about 3300 mAh). I could change Rprog to max and force 500mA charging. But this would in theory mean that I can charge max 2000mAh, if there really is some kind of timer.

Anybode could explain this to me? If it wouldnt be on main Arduino page, I would say this is a mistake (or copy-paste error from different product)...


Just a quick info (if somebody will find this thread interesting).

It really seems to be a mistake.

I checked Microchip site (here) and there is no other single Li-ion cell charger in 2x3 DFN package than MCP73832 used in MKR Zero.
Only similar product is MCP73830/L - single cell charger in 2x2 TDFN package. This charger actually does have a 4 hour "safety timer" and is described in datasheet properly.

My guess is that original design of MKR Zero had MCP73830, and was later for some reason changed to MCP73832. Maybe because MCP73832 is bigger and should have better thermal dissipation? Or maybe designers wanted to prevent stupid users torturing this tiny charger trying to charge huge batteries for like 10 hours...

There still seems to be very small possibility that MKR Zero uses factory customized MCP73832 with additional features. I will try to test it - have one MKR Zero with dead MCU (charger is OK).

We will see :slight_smile: