Help with my Flat Battery (I think its catching)

Joined: 20 Oct 2002 Location: Melbourne

Ok, I have wired up my dual batteries and smart charge solenoid as per instructions. 1st battery set up as normal, with +ve running to solenoid. Cable then goes from solenoid to second battery in tray that is earthed to a bolt under the body.

Now I have had this set up for a week but only driven maybe twice in the week, drives of about 30 minutes.

Now went to start the lux up tonight for the first time in 2 days and it didnt have enough charge to turn over. Lights would come on, glow plugs would heat just not enough to kick over. 2nd battery is still working fine as I ran the compressor off it to check. So it seems my main battery isnt being charged anymore, i dunno?

So any ideas on what could be wrong?

When i wire it up, I can put an overide switch on the solenoid so that I can start the lux of the 2nd battery.

Joined: 20 Oct 2002 Location: Melbourne

Just measured the batteries.

Main start battery is 12.15V

Second Battery is 12.8V

I just dont have enough juice to start the lux. the solenoid has the provision to start off the second battery with the aid of a dash mounted switch, i just havent wired it up yet......

Could something be draining my main battery? Have I wired something wrong?

Only things on the main battery are winch and starter.

Both batteries are 600CC heavy duty 4x4 batteries (not deep cycles etc)

Joined: 20 Oct 2002 Location: Melbourne

So should I test my Alternator output?
And if so.............How?

How do i test for leaks?

Anything?

Joined: 01 Nov 2002 Location: Sydney. NSW Australia

stop parking near my GQ flat batteries are contageous Confused

to check the alternator is workin all the dude did on mine was put a multi meter on the batt terminals with it runnin, should be 13.9 volts (or close to) that means its charging from what i was told?? id go start mine now and double check but its got no fuel tank in it Very Happy

Joined: 03 Nov 2003 Location: Brisbane Southside

I did mine a few moments ago, its a 750cc and it was hitting 14, so I'd say doing it that way would tell you if its charging or not. Otherwise try disconnecting the dual battery and solenoid and see if it starts, you may have a faulty solenoid.

Joined: 24 Aug 2003 Location: Launceston

Leprecaun wrote:

I did mine a few moments ago, its a 750cc and it was hitting 14, so I'd say doing it that way would tell you if its charging or not. Otherwise try disconnecting the dual battery and solenoid and see if it starts, you may have a faulty solenoid.

wot he said Very Happy

normally if recently modify something and then doesnt work as should do, return system to standard and then slowly re-modify untill find faul. btw, those battery voltages dont seem to low to me

Joined: 20 Oct 2002 Location: Melbourne

Cant start the truck though.

Joined: 24 Aug 2003 Location: Launceston

are they both starter batteries? either way should still be able to start car from starter battery or deep cycle

wire it up straight to each battery to try to start, if wont work that way chuck on battery chargher for a while then try again. once you have car running check voltage at terminals, then you'll know if alternator works.

if you can rule out alternator, then time to investigate wiring of solenoid or actual solenoid itself. what does smart charge solenoid mean anyway Very Happy

Joined: 20 Oct 2002 Location: Melbourne

Means it will only charge main battery and once charged, solenoid will allow charging of second battery.

Joined: 19 May 2003 Location: Gold Coast

Maybe the starter battery has died as well. I just found out one of mine has carked it. Shows 12.8 volts after being charged on battery charger. When cranking it drops to 8.1 volt. Cant hurt to test it and see if there is a big voltage drop when cranking. If there is, it may be a shagged battery

Joined: 20 Oct 2002 Location: Melbourne

Ok. Jump started the car to get it going. Starting battery came in at 13.8 volts and the second battery around the same.

When I turned the truck off the second battery measured in at 12.8V while the main battery dropped off to 12.31V While I held the meter on it, it dropped quite quickly from around 12.79 to 21.31V.

So the main battery which only has winch and starter seems to be draining somewhere..........

Joined: 03 Nov 2003 Location: Brisbane Southside

Could also be your battery as well, may of dropped of have a slow leak in a cell. Considering you only have two things attached and I'd imagine you'd of disconnected the winch. If you experienced the same kind of drop I'd say the battery is a gonner. Might be ideal as a spare Rolling Eyes

Joined: 20 Oct 2002 Location: Melbourne

Havent disconnected anything as I have been away for 4 days and just jump started the truck tonight. Will see what happens in the morning.

If it were the winch thats draining the battery, what would actually be draining it so much? Ie: what would cause the power leak?

Joined: 02 Apr 2004 Location: Central Victoria

might pay to take your starting battery to a battery place, they can test them by applying a load and measuring the voltage, they can then tell you how many amps the battery can put out.
I had a 670amp battery which measured around 12v but would only just turn the car over, they tested it and it was only good for about 250amps, was stuffed Rolling Eyes

At least this way you'll eliminate the battery from the eqaution, they shouldn't charge either as they might make a sale armsup

Joined: 02 Apr 2004 Location: Central Victoria

could test to see if the winch is draining the battery by disconnecting its positive lead and checking for continuity between it and the negative lead, shouldn't be any continuity if winch is turned off, hence no current flow.

Joined: 11 Jan 2004 Location: Adelaide

A fully charged 12V lead acid battery should be between 12.6 and 12.9V with no load. The second battery sounds good.

Most charging systems typically charge a little higher than 13.8V, but 13.8V should still give you a full charge if given long enough.

The battery voltage dropping back to 12.3 when you stop the engine is simply indicating the battery isn't fully charged. The next test should be to disconnect it. If the terminal voltage rises at all (or you get a spark as you pull the connector off) then yes, something is draining the battery.

A battery dropping to 8V while cranking isn't unusual. A starter motor draws huge amounts of current (like a winch can) and the internal resistance of the battery creates a significant voltage drop. I'd get the battery professionally load tested before I throw it out - and don't tell the tester what you're thinking, or he might confirm your suspicions for you so you buy a new battery.

Good luck,

Scott