Battery Charging Question

[edmck]

Getting ready to leave this RV resort in Mesa in a few days and decided to check the battery this morning. It was seriously dry — I should have been checking all winter but kept putting it off. Went out and bought a gallon of distilled water and ended up adding just over half a gallon (!) before all the cells were topped off. My guess is this battery is probably toast but it registers all four lights on the monitor in the hallway. My question is this: Should I slow charge the battery with the Black & Decker charger I borrowed from the guy across the street of just let the coach charge it for me while it's plugged in to shore power? I'm assuming there's an on-board charger built into the electrical system of this coach (2011 3100 RL) but I'm not completely sure. I don't want to "double charge" the battery and do more damage. Thanks in advance for any suggestions.

[jcurtis934]

Sounds like the tops of cells were exposed, so yes...the battery is toast. If your converter on board is a progressive dynamics converter, it is probably a three state charger. You can go to the manufacturers website to check to see if it is or not. Your problem may have originated with the battery, by a bad cell or more so that it continued to demand more charge. Batteries usually are only good for 4 years max and that is if everything is to their liking. I went to agm deep cycle batteries more than a year ago to get away from having to add water or worry about offgassing.

[PNW Fireguy]

I would use the coach's charger. If you were a half gallon dry that is quite a lot, but that alone does not insure your batteries are toast. If you are reading good voltage on the cells that is a good sign. I would not put much faith in the led battery meter but rather use a multimeter or voltage meter. i might be inclined to force an equalization charge, monitoring the cells voltages with a good meter about every 15-20 minutes.

[edmck]

Well guys, about 20 minutes after I topped off the battery water I started getting a serious rotten egg smell throughout the battery compartment. The battery is definitely toasted.

[PNW Fireguy]

The smell is because you are driving all the sulfate back into solution. You may ultimately be right in that the batteries are toast but you won’t know until you put a charge on and lid test. I suggested the equalize because it is the charge type used to redissolve the sulfate from the plates and back into the water. However it is very important to accurately check the voltage frequently during the process. If the resultant curve does not follow the PbSO4 we charge characteristics then you will know for sure the batteries are toast. E

[edmck]

Just curious, with the old battery removed (and no replacement yet) why does the battery meter show a full charge on the monitor panel? Again, there is no battery in the coach. I don't get it.

[jeffba]

Originally Posted by edmck

Just curious, with the old battery removed (and no replacement yet) why does the battery meter show a full charge on the monitor panel? Again, there is no battery in the coach. I don't get it.

It is just reading the voltage put out by the converter

[BuilderBob]

That's Y you don't use the LED lights a a battery test you need to use a battery tester oe a volt meter. Do you trest the LED's for your tanks? they don't work ether.

[rohrmann]

If you don't dry camp, and especially if you only have the one battery, I would get at the minimum an RV/Marine maintenance free battery and you will not need to check for water in the battery. Our rig came with two group 24 RV/Marine batteries and I have since replaced them with two group 27 RV/Marine MF batteries, and never have to check water levels.

[Ram Montana High Country]

What is the easiest way to test if the converter is charging? If the converter needs replaced, what would an upgraded one be? More watts?

[jeffba]

Originally Posted by Ram Montana High Country

What is the easiest way to test if the converter is charging? If the converter needs replaced, what would an upgraded one be? More watts?

If you are typically plugged into shore power, your converter should be able to handle the load. If it doesn't then there is a problem with it or the batteries.

If you are boon docking it may be that you need to increase your input to your batteries, either through increase solar or more generator time.

Your converter goes through different stages based on time and battery charge levels. using a good DVM you can monitor the voltage output to verify it is working properly.

OP's main 2 issues could be not checking water enough and/or older converters are not as good as newer converters at maintaining batteries.

If you are not very vigilant at checking water levels in your batteries, going with AGMs maybe a good choice

[PSFORD99]

Originally Posted by jeffba

If you are typically plugged into shore power, your converter should be able to handle the load. If it doesn't then there is a problem with it or the batteries.

If you are boon docking it may be that you need to increase your input to your batteries, either through increase solar or more generator time.

Your converter goes through different stages based on time and battery charge levels. using a good DVM you can monitor the voltage output to verify it is working properly.

OP's main 2 issues could be not checking water enough and/or older converters are not as good as newer converters at maintaining batteries.

If you are not very vigilant at checking water levels in your batteries, going with AGMs maybe a good choice

I have a 2008 3400RL, and two size 27 Kirkland batteries from Costco that are nearly 10 years old . I keep my fifth wheel plugged in 24/7. I maintain the water level, and they are still going strong.

Just got back from a five day dry camping trip in Moab, Ut. Batteries did well, got charged up every morning with a small generator. Not sure what old converters are, apparently they need to be over 12 years old ,thats what mine will be this fall. Its maintained two batteries for 10 years. Prior to that for nearly 2 years was the cheap OEM size 24 that I removed ,and replaced with the 27's.

My point is, keep them plugged in if possible, water checked , and they will last a long time. I was told if they are discharged below 50% , its shortens their life a lot. I don't know if thats true, but mine have never gone more then overnight running a furnace during the night if needed, and then recharged the next morning.

[cgeis48]

Take your stinky battery to the Interstate battery store in Mesa and have them inspect, test and charge it. They are pros and can tell you if it has any useful life in it.

[DebNJim B]

Originally Posted by jeffba

It is just reading the voltage put out by the converter

Do you know if the level up panel is reading the battery voltage or the converter?

[jeffba]

Battery voltage.

[sunshine 1]

I bought a 25 amp Ctek charger. I plan to charge my batteries with it from my generator. Can I plug in the shore cord into the generator and charge it through the trailers converter at the same time??? I have 210 a/h battery bank.
My thinking is that would charge up the batteries faster.
Would that mess up the batteries???

[AZ Traveler]

Originally Posted by sunshine 1

I bought a 25 amp Ctek charger. I plan to charge my batteries with it from my generator. Can I plug in the shore cord into the generator and charge it through the trailers converter at the same time??? I have 210 a/h battery bank.
My thinking is that would charge up the batteries faster.
Would that mess up the batteries???

If your converter is working properly, there is no real need or benefit to connecting another charger.

Your generator should power the converter to recharge your battery bank.

[jeffba]

[sunshine 1]

Thanks for your response, I have heard that the converters does not charge the batteries very fast, so my thinking was by using another charger the same time, I would speed up the charging so I would not run the generator for 6-8 hours.

[sunshine 1]

I finally got my 3120 Montana today, I drove it home and backed it in beside my house wasn't as bad as I had thought it would be. backing up over the curb made my stabilizer jacks hit the ground. I had to put down some 2by12 planks to clear the ground.