Dual Battery

[bradbne]

Hi all,
My name is Brad, I have been a member for a couple of months now and must say I find this site invaluable. I have been helped no end with the information available on here.
This is my first post....so I hope Im in the proper area.

What I need to know is what should my multimeter read when I test the batteries?...My start(main) battery reads approximately 14.2volts with the engine running and my aux(trojan 100amp deep cycle) battery reads 12.4 or there abouts....I thought the aux would read the same as the main while the engine is running ie 14.2 volts because I thought you had to be in that range to charge a 12 volt battery.
TIA

Regards
Brad

[Pickle]

Something wrong there Brad. Depending on your dual battery controller most throw a charge in the starter battery for a couple of minutes and then charge up the auxhillary. 12.4 volts is not getting a charge from the alternator. Check out your dual battery controller for a fault.
Dave

[bradbne]

Thanks for the quick reply Dave...I will take it back to Opposite Lock tomorrow as I have only had it a week.

Brad

[Pickle]

Is it a Rotronics?
Dave

[bradbne]

No its a redarc, and I have just had a read on their website and it tells me there should be a red light on once the start battery is charged.....well Ive just had a look and no red light.

Brad

[bradbne]

OK....well I have just found the fault......its a bad earth.....where they have earthed it is not earthing it at all.......The red light would come on and off as I move the isolator and I found when I pushed it(earthed it) against the battery tray the red light would stay on and low and behold 13.8 or better going into the aux......Im no tradie but what does it take to get good work now days...

I will be paying them a visit for sure tomorrow to fix it.

Brad

[Pickle]

Good to hear you found the problem Brad. Bit suprised they earthed it to the battery tray. Maybe another earth option should be looked at.
Dave

[bradbne]

No...its earthed between old and new tray, not actually on either tray..not sure where as I cant see there at night. But when I earth it by pushing it against the tray, the red light on the isolator comes on and good volts go into aux battery

Brad

[Lambie]

G'day Bradbne

The redarc gear seems to be the goods - Ive had one fitted to the Paj for the last 4 years and has always done the job - faultlessly. Early on I had a couple of " I dont inderstand" moments and I phoned redarc directly - talk about great support service!! because of the way the redarc 'links and unlinks' the main and 2nd battery based on battery voltage I dont see the red light on all that much - but at the same time the 2nd battery is always ready for the fridge etc and the main battery never misses a beat.

As a 'plug it in and forget' item - its brilliant from my experience.
Cheers
Lambie