Thread: Another 2nd battery bites the dust.

Originally Posted by walker

Last weekend my my 2nd battery carked it for the 3rd time. Wondered why I could not run the computer for the GPS then I find I have 5v in the battery. Luckily I had another 200AH of batteries in the camper.

I am sure my problems must be related to the output voltage from the alternator.
This is the reason I think this.

I went through my first 2 batteries only about 2 years. All batteries have been Exide Blue top AGM's. When I installed the 3rd battery I also installed an Arrid twin charger before the 2nd battery which boosts up the output voltage to 14v no matter what the input voltage is. This battery had lasted 2.5 years without a problem. Then at christmas I took the new camper away for the first time which has 2x100AH batteries which are connected directly to the 2nd battery on the car via an Anderson plug when driving. I think the extra current pull of charging these 2 extra batteries fried the Arrid as the inline fuse melted and disintergrated. So I pulled out the Arrid at christmas because everyone was telling me it is a waste of time anyway.........and now the battery is dead.


Any ideas?

I would have a serious look at what you are using to charge the 2nd/3rd batteries

If the charge is via your main battery and you use something to control it (traxide/redarc etc) this will /should balance the charge - if the alternator was/is the problem surely your 1st battery would also have carped it.

Have a look at the traxide SC40 or 80 this could be the solution for you.

the sc80 i would think....

i have a similar setup and i use an sc40, no dead batteries yet....

good gear that traxide gear imho

it sounds to me like he is running 3-5 batteries all together with the trailer connected.....

i think he will need an SC-80 and also an SC-40 at least.....if not two SC-80s......


and a hell of a lot of driving to charge the lot up fully.......

I am running an SC-80.

I charge up the 2 trailer batteries via a 240v 3 stage battery charger (a good one). Once the batteries in the trailer are charged up I can run the Engel and lights for a week without needing to recharge.

The main battery is just a cranking battery so it is not as affected by the charging voltage. It is not getting drained down all the time.

I think I will have to do some more tests to find out exactly how many volts my alternator is putting out. I don't think it has ever been right from new. I thought remembered reading somewhere that the AGM batteries need a higher charging voltage than normal deep cycle batteries but I am not sure if this is true.

I don't think it has anything to do with the battery controller as the problem existed before I had the trailer. This was the reason I installed the Arrid and it seemed to work ok but now with the trailer I can't use it.

drivesafe is the right person to answer your questions here.......
give him a chance to read this thread and im sure he will have a solution for you......

Hi Walker, I’m pretty sure the SC80 should not be the problem as we make a similar unit for motor homes and caravans with banks of batteries bigger than what you are running and don’t have any problems, BUT won’t rule that out at this time.

lots of questions for you.

The first is one you may have already done but is probably the most important.

When you do a trip, do you measure the voltage after the disco warms up and do you measure the voltage at your alternator and at all the batteries.

You may, with all those batteries, be causing a fair sort of a voltage drop, particularly if the cable is not thick enough.

As far as the cable goes, do you run both a positive and a negative between the front battery and the rear battery and what size cable do you run.

With all those batteries you have, the stepup charger was probably the cause of or at least added to the problem. With around 300 A/H and say they were at about 50% discharged when you set off home after your trip. If the stepup charger was the 20 amp version, you would need at least 7 hours driving, just to get the bulk of the charge back into the batteries and this does not allow for a fridge to be powered at the same time. If it was a 10 amp version, won’t even go there.

If you have heavy enough cable in the first place, you will still get a voltage drop but you will be getting a much high current to the batteries so they will charge quicker and the quicker they charge to sooner the voltage drop reduces and the higher voltage means the batteries will charge even quicker and so on.

Last but not least, when you go on your trips, do you park the camper and go for day drive in the disco, then connect to the camper again when you get back to your camp site?

Give me an idea of you operating habits including your every day driving while at home and the time you spend driving to and from your holiday location and I’ll see if I can give you some ideas to solve the problem.

Cheers.

That's pretty impressive, charging 4 batteries

i presume your car has a 100 amp alternator, which sounds as if it is working to its limit, meaning higher brush wear rate, i would also look at the alternator to see that it's not going to die with all that load.