Battery Failure

[Sdigs]

I have 2 deep cycle 12 volt baterries in parrallel. I replaced them in early November becuase on our last trip they did not seem to be holding a charge. They were about 2 years old. We went on another trip in mid november and found that they were not getting a charge from the onboard converter. They would take a charge if i connected an automotive type charger directly to the batteries.

I took them out of the 5th wheel this weekend and tried to charge them and they both show internal cell shorts on my tester.

Can a bad converter damage batteries?
How can I test the converter?
is a converter replacement a DIY project?

I have decent technical skills, i sell and service boilers and low voltage controls so i should be able to handle 12 volt charging systems. Any help would be appreciated.

[UFO Pilot]

I just replaced the converter in my MH. It took me about 15 or 20 minutes to swap it out. The majority of the time was mounting it. Mine sits vertically and the mounting holes did not match. I replaced my Parallax 7455 with a Progressive Industries 9260. You can see it here

[Sdigs]

Thanks, then ext question is where is the converter located? i'm guessing it's probably colocated with the fuse panel...right?

[UFO Pilot]

Mine is in the electrical bay. The power cord, transfer switch, inverter and converter are all there. I don't know where yours might be located. I believe I have read that some are located under the refrigerator.

[450Donn]

Batteries can fail for a variety of reasons.
Vibration is one of the biggies. Overcharging and boiling the water is another, along with the wrong type. It also could be a simple matter of bad battery design, or really cheap batteries.

[Ray,IN]

I once bought two WalMart gp 27 batteries for my 5er. They both shorted out at the same time-8 months old. I replaced them with Interstate gp27's 3 years ago and they are performing fine.

[wingnut60]

There is a reason most mfgs don't warranty 12 volt deep cycle beyond 18-24 months. If you have the opportunity, would suggest you consider 2 6-volt batts in series. They are designed to take many more charge/discharge cycles. And a converter can be checked by using a voltmeter across the output terminals when it is on (with the batts disconnected) should show 13.8v I believe.

[powerboatr]

i just replaced both of my batteries with gell types, because one blew up from no water and the other was pretty dry. I had not checked em in a few months. not again
dropped some coin and got some gell sealed up batteries, the damage from the one exploding blew the battery box cover OFF

[K-Star]

Quote:

Originally posted by Sdigs: Thanks, then ext question is where is the converter located? i'm guessing it's probably colocated with the fuse panel...right?

Different manufacturers put them in different places. My first 5er it was under the kitchen sink. My 2nd 5er it was in the Battery cabinet. In my current 5er it is in a cabinet all to its' own.

Moral of the story; it could be anywhere. But, in my examples above, it was always in a spot [physically] between the batteries and the 12V distribution panel.

[FiverBob]

One thing not mentioned here is a reason batteries can fail. Many converters are single voltage units rather than multistage converters. A single voltage unit will boil out the water on batteries if left hooked up for a period of time. Multistage units back off on the voltage as the batteries reach full charge and act more like a trickle charger. If you find you have to replace the converter, be sure the new one is multistage - - you will pay the difference in one set of batteries.

Bob