Renault Master Low Battery

[Lex Andrews]

Hi all,

I have a bit of a head scratcher. I've got a 2016 Renault Master Ambulance which show "Low Battery" approx 30 seconds after starting. Both the chassis battery and Aux battery are good and charging from the alternator. The alternator has been tested and replaced (although not a genuine Renault unit, it's a Lucas 180A one).
One thing that has been noticed it that the fuse board in the engine bay does get warm around a dark grey 12 pin plug, including the plug which due get very warm to the touch.
The aux system has been checked as far as I can get. One thought is that it could be the switch charger unit between the chassis and aux system, but the control panel stays green, with no faults recorded on the Acetech control units.

We've been at this on and off for about 3 months now. It all points to a chassis area fault.

Has anyone had anything similar?

[darbuck]

It sounds like a bad earth did you try clearing the grounding points failing that it could be the earth straps are corroded internally.

[Kernowjon]

Also check not only the batteries to chassis earth strap - nice clean metal, no rust, no paint, and a smear of Copper Grease to improve conductivity.
The same on the earth strap Chassis to engine.
If the earth straps are at all suspect I would change them.