charging probs on my saf

[PigFmr]

twice in the last 6mths my 12v side battery (passenger side) goes flat,i have 2 new batterys and recon alternator which was dne 6mths ago,its like right hand side battery is not getting enough charge,drivers side battery reads 13.3volts passengers side 10.9 the other day when it was flat and few mths ago,the alternator is charging at 28volts i have checked this,i might be wrong does it charge drivers side 1st then over to the other battery ??
any help would good before i take to auto sparky

thanks vince

[SV1K]

Vince, do you have any 12V items wired directly to the passengers side battery? If so remove it, this is what is causing it to lose it's charge, I had the same problem.

Earth cable is tight? I changed the place where mine went to the body as I thought it wasn't the best place.

If not, then you have a problem with the charging circuit. You can get a battery balancer but they are not cheap and it ensures that both batteries are being charged at the same time and the same voltage is going to both batteries.

Other than that, I don't know why you would be getting only one flat battery.

Cheers
Reece

[Swamped]

I had this problem and it got worse when I put more and more electronics on the 12v feed in the cab. Bought a redarc charge equaliser for a couple hundy and it fixed it straight off. When one battery dies the other one won't be far behind it i found. The auto sparky explained what was going on but I don't remember what it was. I think swapping the batteries side for side will solve the problem but its still hard on the batteries.

[darinz]

I had this problem and it got worse when I put more and more electronics on the 12v feed in the cab. Bought a redarc charge equaliser for a couple hundy and it fixed it straight off. When one battery dies the other one won't be far behind it i found. The auto sparky explained what was going on but I don't remember what it was. I think swapping the batteries side for side will solve the problem but its still hard on the batteries.

You must have had 12v coming off one battery for this to happen.
The problem is the alternator only sees one 24v battery so if you drain part of it it will try and charge the whole. It doesn't matter if you swap the batteries around as it can't tell where they are.

Think of it this way. if you have 2 drums of water with an equal sized hole draining them. Now you have a hose feeding equal water into both drums and it shuts off as soon as one (either one) is full. Now put a bigger hole into one of the drums so it drain faster.
The hose feeding water in is still giving equal amounts of water to each drum and still shuts off when a drum (either drum) is full. Eventually the drum with the bigger hole is going to be emptied. It doesn't matter how much or how fast the water goes in as it will always turn off when one drum is full.
The hose is the alternator, the holes are the power to the truck and the drums are the batteries.
Clear as mud as to why you don't take power off one battery? (unless you have a charge equaliser)

[PigFmr]

Vince, do you have any 12V items wired directly to the passengers side battery? If so remove it, this is what is causing it to lose it's charge, I had the same problem.

Earth cable is tight? I changed the place where mine went to the body as I thought it wasn't the best place.

If not, then you have a problem with the charging circuit. You can get a battery balancer but they are not cheap and it ensures that both batteries are being charged at the same time and the same voltage is going to both batteries.

Other than that, I don't know why you would be getting only one flat battery.


Cheers
Reece

reece
have checked earth straps and cleaned them,put new batterys termnals on both batteries got know drain any where when the key is off,
the joys of owning a saf,
thanks for your answer...i get there 1day
vince

[PigFmr]

You must have had 12v coming off one battery for this to happen.
The problem is the alternator only sees one 24v battery so if you drain part of it it will try and charge the whole. It doesn't matter if you swap the batteries around as it can't tell where they are.

Think of it this way. if you have 2 drums of water with an equal sized hole draining them. Now you have a hose feeding equal water into both drums and it shuts off as soon as one (either one) is full. Now put a bigger hole into one of the drums so it drain faster.
The hose feeding water in is still giving equal amounts of water to each drum and still shuts off when a drum (either drum) is full. Eventually the drum with the bigger hole is going to be emptied. It doesn't matter how much or how fast the water goes in as it will always turn off when one drum is full.
The hose is the alternator, the holes are the power to the truck and the drums are the batteries.
Clear as mud as to why you don't take power off one battery? (unless you have a charge equaliser)

[/quote]

thanks for explaining that i see what u mean, when i first brought my saf 5 yrs ago i did have my radio memory on my 12volt side for permant live feed,but removed it soon after reading about it saying its a no go,so no i have nothing coming off that side now for many years,guna book it in next week at auto sparky,thank you for your reply
vince

[sibainmud]

On the boats with 24v and 12v accessories it is the norm to fit a 50-100amp step down convertor to the 24v side and 12v comes out of that. Not a good practice to take 12volts out of a 24 volt bank. I have built change over solinoids to charge two 12 volt batteries and on demand they hook together in series to give 24 volt output.

Cheers,

[bobrocket]

I've got a similar problem, if I leave the truck sitting for a week I get a flat battery on the 12v side, dunno why, only have factory stuff coming off it, leads are good, connections good, even if I swap batteries it'll still go flat first.
What darinz said is right but I was looking for a factory drain somewhere
It sounds like your 12v isnt charging, you should get 13ish on each battery or 28ish across the two batteries, might be a kick in the dark but you might just have a poked battery.
Am keen to hear if you find a solution, good luck anyway

[Swamped]

Yeah my harness had a 12v wire in it for dash accessories. looked to be pretty factory.