Battery voltage is high and does not match controller display

Well Lucky Boggers,

There is no telling what the previous well intentioned Owner has done to that secondhand van... He did a lot of tinkering, but little travel, I think it had only done 4000 km. But I will guess at the likely priorities, blindly, but hey I have more experience with Bushtrackers than anyone else to speculate, so here goes... And mind you I am blind, and speculating, and would really have to see the van wiring and the charger and what had been tampered with and modified, and I do not even know what batteries you have.... But here is my best:

1) I would first check the battery in your voltmeter, as I learned long ago that they give wild high readings when the battery is about dead... You need to start by checking it against a know value, like the battery in your tow vehicle. At "resting state" an hour or two after not running, you would expect a reading of 13v plus or minus .2 of a volt on healthy batteries..

2) If that checks out, then you have a peculiar problem because the voltmeter on the regulator is of a much higher calibre.... And I am only guessing, but next check that the battery charger is off for at least 1 hour and check again....

3) Then push the disconnect on the solar regulator, wait an hour and check again.

4) If all else fails and you indeed have that kind of a reading, which is nearly impossible, but I have seen the phenomenon: It sounds like "surface voltage" on the batteries.... You have trouble somewhere, most likely Culprit is the batteries....

5) Fifth possibility is the Regulator going bad, but that is not likely... Most likely is damaged batteries... If they are the old AGM, those proved to be a bit fragile to being run down too far, or being left down too long... Check out everything and get back to me...

Our new batteries, out about the same time the beginning of this year, have proven near bulletproof, and so far no one has even been able to kill them... And they have gotten some real abuse unintentionally...

One more thing, be amazed, at the level of service you get from that Bloody Lone Ranger, at seven in the Monday Morning, even though you are a second hand Owner....

Happy Trails....

I strongly recommend that you check the polarity of the connections from each battery!!

If two batteries are connected in series, and the third is in parallel, this will give you a voltage readout of approx 20v.

To be in parallel, terminals must be connected +ve to +ve and -ve to -ve. I suspect that one of the batteries is +ve to -ve.

If each battery is at a charge of 13.5V, you have a total of 40.5V available. When divided by 3 batteries this still gives 13.5V, as it should. But if you have two batteries in series, you effectively only have two batteries now, so 40.5 divided by 2 becomes 20.25V.

Throw your voltmeter away

Bob
Luke Electrical Pty Ltd

D'oh!

Thanks Steve and others. Yes it was a dying multimeter. Sorry!

My only defense is that I only recently replaced the battery in the multimeter for the first time after about a decade of (very intermittent) use and don't recall having left it switched on recently to flatten itself. Never occurred to me it might be going flat.

But dead the battery was and with a new 9V one installed - presto the van is now running at 13 volts again! Cheapest caravan fix I've ever seen!

I'm going to go and stand in the corner now ...

Clueless Matt