Hi. We're having some trouble with battery charging on the Tracker SOM. When the battery goes completely flat it doesn't seem to charge anymore. Below is the circuit for powering the tracker and under it is the charge and temperature circuit with Battery switched going to the battery input on the tracker.
Has anyone any ideas as to what's causing this issue and how to solve it?
Thank you.
That's by design. If a Tracker has very low battery it will go into shipping mode to prevent complete discharge of the battery. The only way to get out of shipping mode is to power the Tracker by something other than battery, typically USB or VIN.
In shipping mode the battery is disconnected using the BATFAT so it can't be charged, either.
To disable this behavior you'll need to make a minor change to Tracker Edge as there is no configuration setting for it. I think you can just return from this function always.
Hi, Thanks for your help.
So should it come out of shipping mode automatically when it's powered by VIN, or will this code need to be added then too?
Currently when we connect the charger to VIN to charge a flat battery (presumably in shipping mode) it doesn't seem to charge. We're using a 103450 Particle 1800mAh battery.
Thanks,
If you power by VIN and the device boots, it should exit shipping mode and the battery should resume charging, assuming VIN is a sufficiently high voltage to enable charging.
If that's not happening, what happens? Does the device not boot when VIN is powered? Or does the device boot but not enable charging?
And how do you get it out of this state? Do you need to completely unplug the battery and power everyting down or something else?
Vin is set to a fixed 7.96V. Is this sufficient to charge it from when the battery's at 0%?
The device boots, but just doesn't charge the battery. We've got a few of these built with this circuit and they all do the same.
It's unclear to me because I don't fully understand how your circuit works. However, you should probably test it in a few cases to narrow it down.
Use the cloud command to enter shipping mode manually, and see what the circuit does. This essentially puts the battery input in Hi-Z mode, which is probably an edge case in how your circuit performs. It may be fine, but it's good to test that.
If you have the Tracker SoM CHRG LED populated that would be useful information. If it's flickering at a high rate your circuit has probably disconnected the battery. If it's blinking at 1 Hz, the bq24195 PMIC thinks the battery has failed and that's why it's not charging. If it's on, then it should be charging. You could probably just probe the pin on the SoM if you don't have the LED, but you'll probably need a scope to tell if it's flickering.
Is shipping mode provided by the bq24195? (datasheet here)
If so, here are more details about what happens at circuit level:
@colt1 FYI
