Originally Posted by
drivesafe
Hi Ozzy, it sounds like your batteries are pretty well charged.
Also note, if your auxiliary battery is an Optima Yellowtop, then at 13.71v, you can still fully charge it.
A Ferret pointed out, there are a number of factors the BMS takes into account when setting the operating voltage, so after a week or two, try discharging your setup down a bit and then see how the BMS reacts.
With D3s and 2.7 D4s, they have a 30 second start up routine, where the voltage remains low and the ECU determines what high voltage to operate for the next 30 minutes, then it settles down to a normal operating voltage. There is more to it but that is the basics.
Except for the 2.7 D4s, all D4s have a more complex BMS control and this monitors a range of factors, beginning with the startup voltage. You may not see a rise in your voltage for a number of minutes after starting, or if the cranking battery is low, the voltage may rise very quickly after starting.
Your BM2 monitor is ideal for learning how your vehicle is effected by your driving style.
If you can, post up some graphs when you have done a few days driving. This will help others to compare operating voltages and driving habits.