PMIC does not charge battery

We’ve been observing that the PMIC does not charge a battery that is below a certain voltage threshold. So obviously, when a battery is at or around 0v it will not charge that battery. As well as when the battery is at around 1v the PMIC still will not charge.

I was wondering if this is normal behavior, and if so, how does one bypass this behavior. I’m not exactly looking for register values and / or code. It would be welcome, but I’m more interested in IF it is possible to bypass, and perhaps which register(s) I need to look at in the datasheet for information. Also helpful would be knowing if it is in fact possible to charge a battery through then PMIC when that battery is low in voltage. Any information on this subject could help . . .

Additionally, I’ve written a Nodejs app that does display all register values. Which should help us troubleshoot this problem. Below is a screenshot of it in action. The link to the project is located at: https://github.com/wphermans/Beaglebone-Web-PMIC-Register-Viewer. For those who wish to experiment with it. A suitable Jessie image is required, based on the requirements listed in the readme. Ultlimately because gcc 4.8 / g++ 4.8 are required for Nodejs 4.6.2 to be functional.

CHGCONFIG0.jpg

I would think this is by design; a lithium battery below some minimum cell voltage is probably damaged and should not be charged.

I don't know how the PMIC decides the charge profile, though, so I don't know what it might be doing.

I’ve been told that you need at least 2.5v on the battery for the PMIC to charge. However, we’ve rigged another charger to charge batteries that are low. It’s lame, that this has to be done, but how it is I suppose. The reason why I think this is lame however is that it only takes around an hour to get a fully charged ~700mA battery to this voltage level . . . However, I think we’ve got that “fixed” too.