27 volts

Did you use water in the battery or red bull?? with the motor stopped, does it read 14ish? if so, alt reg is had it...

I'd start by doing a check of the gauge........ Is it one of those Jaycar units? They are not top quality.......
I would think that battery would have just about exploded if it was @ 27v!!!

This is a common problem with a very simple answer: the solution is to gently remove you digital voltage thingie and beat it to death with a large rock - seriously! :)

Following that, buy a $50 digital multimeter and see what it says.

Do not trust measurement instruments without due consideration.

Mike Harding

slightly off topic ( and not the cause of your 27v) but I note that you say you '...topped it up with ordinary water"
Most battery manufacturers would say that you should only use de-ionised water to top up as the dissolved minerals and trace chlorine found in most tap waters is deterimental to the battery life.
NOTE: I am not a battery expert :-)

Hi,
Mike's answer fairly well covers the technical aspects of dealing with errant test equipment, I won't repeat it here.

But another good test is, does the interior light still work? At 27 volts a small festoon lamp would almost certainly burst. If the light works then your battery voltage is normal.

Geoff

Im guessing one of the batteries has a bad earth, and the reading is actually coming from both batteries in series...13.8 plus 13.8 = 27.6

Tvl.
If the connections to your battery got acid on then you could have a high resistance to earth from the meter, but that is probably the minor problem, if the water you used had fluoride in it you battery is doomed. good luck Eric.

tvl,

I used to use those types of volt gauges, but as mentioned above, they are poor quality. Mine were consistently about 0.5v out and would occasionally do what you see.

Chuck them in the bin and spend the $$ on something decent. That being said, there is a bit of a gap in the market for good quality digital volt gauges, which are simple and son't cost the earth. I did a bit of searching, but couldn't find much in Australia under about $150.

Anybody have any suggestions on how to 'simply' monitor the voltages on 2 batteries - aux and main without spending a fortune?

Cheers,

Mark

I had a similar experience on an irrigation pump motor, it was in our case a regulator on the alternator.......
NickR

I also have a few of these jaycar units.

The thing is not stuffed. This unit can run on 12v or 24v systems.

For some reason, they occasionally will go into 24v mode if the power has been interupted (eg dirty terminal loosing connection for a split second). They then seem to show double the 12v voltage measured.

Disconnect the power to it, and reconnect it and it will go back into 12v mode.
Try more than once if it doesnt work the first time.

Flux.