[Rampage_Rick]

Nigeria... Bit of a ways away from a GM dealership?

Sounds like it might be an issue with the APM which converts 360V to 14V. Do you have access to an OBDII code reader?

There is also a couple big fuses immediately adjacent to the 12V battery. I believe the black fuse on the right leads to the APM.

 

[Rampage_Rick]

Uhh, he did?

SERVICE BATTERY CHARGING SYSTEM
This message displays when there is a fault in the 12-volt battery charging system. Take the vehicle to your dealer for service.

To start with I would check those fuses, check that all terminals are tight, and check for codes relating to the APM

 

[Rampage_Rick]

You may have an issue with the Lear 3.3kW High Voltage Charger on your Gen1.

I wouldn't think that would cause the symptoms described here. If the OBC was bad the 12V battery would still be charged via the APM any time the Volt was "running". Think of the handful of Volts that are never plugged in (thus no OBC use)

In the picture I posted above, the wire shown on the right hand side with the red 90° angle is the one that connects to the APM. The APM is also in the trunk adjacent to the battery: http://gm-volt.com/forum/showthread...12-volt-battery-charged&p=1755057#post1755057

If the black fuse tests OK (zero ohms) and all the related fuse bolts are tight, I would also verify all of the bolts on the left side of the APM. With luck it's nothing more than a loose connection otherwise a replacement APM may be in order.

 

[Rampage_Rick]

0 ohms is good. If the fuse was blown you'd see infinite ohms. Good chance it's the APM then. I believe the correct part number for the 2013 Volt is 24261518.

Read about it here: http://media3.ev-tv.me/VoltAPMUserGuide.pdf

There's one on eBay here: www.ebay.com/itm/222140134880

I'd still try to check codes via OBDII before buying a new APM.