Thread: Electrical Alternator Charging Question

Originally Posted by gruntfuttock

How much are you driving the car? and how much is the dual system consuming when the ignition is switched off?

To test that, remove positive terminal (ignition in off position) place multi meter between battery and clamp (one side on clamp other on terminal)and read, then disconnect positive battery clamp from other battery and read again the difference will be what the dual system is consuming.

Mine consumes about .04 of an amp, from memory I think, so I have put a switch on the earth wire from the dual system, that way I can totally isolate one battery if I want to store the car for a while and the dual system is totally switched off.


I think Justin could be on the money

Best of luck

Yeah have looked at that and it was in spec with the clamp meter. I charged both batteries up and then drove 100kms, parked car for about 8hrs and drove 100kms back. Was a crappy day so headlights on radio on and then put window demisters on. When I put the window demisters on the volt meter for main battery dropped from 14v to 12.5v. Turned the heater off and went back to 14v sort of indicating charging however did notice deep cycle battery was getting pulled down with bugger all running off it. My assumption is the main battery was pulling this down via the dual battery system, but should not. Will have to start investigating. Dont really want to buy a new alternator if it is not required.

If the main battery is a calcium ????, then it may need a charge, that is not to say your alternator is not charging, calcium batteries need a bit of a tickle with a special charger every now and then, it seems as though they don't hold or accept charge correctly, but once you give them a charge with a charger that has a calcium cycle on it they perform much better. Mine was doing something similar, but if your battery voltage is about 14.5 (much under this and they will not charge the calcium battery properly) when the engine is running, at about 1000 / 1500 rpms then turn your headlights on full, you should see the voltage drop then pickup straight away, if it does this, then the alternator is charging. Do this with a multimetre on the battery not the nanocom. The bloke who sold me my dual battery system said that a calcium battery needs about 4 - 5 hours driving to bring it up, but they do need to be charged every now and then with a charger that has a special calcium cycle on it especially if only doing short runs. He was the one who advised me to put in a switch on the earth wire on the dual battery regulator to totally isolate the batteries thus turning off totally the isolator as it was drawing power and running the battery down

You could also try putting a multi meter on the power line that supplies the heater, then switch it on and that will give you a reading of just how much current it is drawing

It seems to be good practise to run alike batteries in a dual battery system, that have the same charge rates as well. The Optima is a glass mat type battery and the other is lead plate/acid, if they have different charging regimes you may not be charging one battery enough, Regards Frank.

OK does not appear to be the alternator, getting 14 - 14.5 at the battery. So probablly a power drain from somewhere.

Craig.
Do you leave a Nanocom permantly plugged in?????
I do or did and have the same issue.
Have been unpluging it and not had the issue for some time now.
Pretty sure it prevents the electronics from going to sleep????? I just pull the plug at the Nannycom.
Worth looking into.
Andrew