high voltage alarm

vince · 02 April 2007, 16:13

Can anyone tell me why our navman 7200 dsc would emit a high voltage alarm? it only does it every now and then, we turn off then on and it goes away for a bit. It seems to happen at any speed or revs. Its wired through the navman hub, and we`ve followed the wiring instructions. It has been alright for a good few months since we fitted it, but has only just started doing it. The display varies as to how many volts, usualy between 18-24. Hasnt blown up yet! Any help greatly appreciated.

Limey Linda · 02 April 2007, 18:43

Sounds like you have a bad voltage regulator. Measure voltage across battery with engine running at 2000 rpm. Should be no more than 14.5 volts.
Suggest you fix it before it blows your electronics.

vince · 02 April 2007, 22:51

OK will do, thanks for that, everything else seems fine, although we have a bit of green corrosion across some of the wires.
cheers

al40 · 03 April 2007, 22:57

If it truly is getting to 18V it could be related to your "green" (copper sulphate) wires. If there is a momentary disconnect to the battery (or bad connection) then voltage can go sky high. Even if regulator was faulty, it would probably take a while to get to 18V and by then the battery would be boiling and probably smoking.

Corrosion anywhere in the electrical system is not good news. If you do have corrosion on connectors then rub them down with wet-n-dry until they are clean again. If it's on a terminal block, then replace it. I cover my battery terminals in silicon grease to stop them corroding (vaselene is also OK) - also spray terminal blocks with silicon grease.

It only takes a tiny amount of time for a working connector to go faulty. I soaked my battery last year when putting the boat back on the trailer (waves were breaking over the transom) and the next day the battery switch didn't work. It was hugely corroded even tho it was fine at the start of the week.

Good Luck!