914 Inconsistent Charging

Did you install the new battery after the fault developed? If you did, can you temporarily swap back to the original battery?

Failing that I would start by checking all of the connections, particularly the crimps that connect to the regulator.How stable is the voltage on the regulator output? You should get something in the region of 14V which may drop slightly as you switch on your electrical loads. It shouldn't drop below 13.8V. Mine stays at 14V no matter what loads I have switched on. That said, I don't have anywhere near the loads that you have with dual screens, etc.

If you don't find a problem with the voltage on the regulator output then check the voltage on the battery. Have you got a current shunt? Check the connections there too.

If the voltage on the regultor output is good but it is low down stream then I would get hold of a DC clamp ammeter, something like the UNI-T UT210E so that you can start measuring the current in various circuits to see where it is going.

Dave,

Fellow Bristell owner here.  Do you have the optional (secondary) belt driven alternator, or just the standard internally driven alternator? Also, how long has this been going on?

With any 12 V electrical problem:

Start by checking all earth/ground connections are clean & tight.

Then check your wiring harness connections - all clean & tight.

Check for continuity - a fatigued or stretched wire may be broken/high resistance inside the insulation.

Solves most issues (definitely not all) .

Good luck

What Sean said.  ? 

Just the standard only.