House Battery Question.

[Dutch]

I have a 2000 E350 Sportsmobile, and seem to have to replace every year the house Battery. I always buy a marine batterty, deep cycle.
Now it seems it barely hold charge. I somehow feel there is a leak. Any suggestions where to look? Anybody having the same problem?

[jage]

Disconnect your isolator, either side and try starting it. My starter batteries were dragging my house batteries down as the isolator connects them when your key is on, so you may be jump starting bad starter batts everytime you start. Thus draining and/or killing your house battery.

Second is to turn everything off on the house side and disconnect the negative and see if the terminal sparks (you may have to do it in the dark to see a very small spark). If it sparks there is a load- which could be a short or something "on" that you don't realize.

My third thought is that you're draining the battery too much. If your house battery is going lower than some % (40? 60? I forget) on a regular basis you're damaging it. So if you run your marine battery down to say 20% over and over because you don't have the capacity you need, well you could be killing the batteries that way.

I think also check the grounds. Bad battery grounds cause all kinds of problems both charging and using.

[Dutch]

Great tips, I'll check your pointers this weekend !
Thanks.
Evert

[Ford_6L_E350]

Another question is: How do you use the vehicle?

Is it driven daily, weekly, rarely? Is it plugged in when sitting?

Batteries like to be used and charged regularly. Sitting for 3+ months is very hard on a battery that is not being trickle charged. Overcharging is hard on a battery.

Do you have a voltmeter? Can you check the battery voltage under varying conditions to help narrow down a problem?

Driving my van every week, I lost a set of house batteries when minor corrosion prevented charging through the battery isolator. Then I invested in a 130W solar panel (van was built with solar prep and controller) and now all the batteries stay charged. We can dry camp for long periods (2+ weeks) of time without having to start the engine.

Mike

[deminimis]

Mike, is your house batt draining big time at night? As soon as the sun goes low, and my fridge (4CU) is running, my big house batt (4D) seems to really go down (faster than I would think). I would think I'd get a full night's use out of the batt (running the fridge only on 12v and no other large items running), but my solar indicator shows the batt's voltage is very low after only a couple of hours in the dark. Been thinking it was time to replace the house batt, but that's a bitter pill to swallow. I assume the batt is approx 4 years old.

[yvrr]

Here are the numbers jage mentioned:

12.8 volts - 100%
12.7 volts - 90%
12.6 volts - 80%
12.5 volts - 70%
12.4 volts - 60%
12.2 volts - 50%
12.0 volts - 40%
11.8 volts - 30%
11.6 volts - 20%
11.. volts - 10%
10.5 volts - 0%

Lifeline Batteries warns not to discharge an AGM battery to less than 50% (12.2 volts). I suspect that the problem is either discharging too much or overcharging.

[jeff@work]

Something else to consider is most marine deep cycle batteries are dual purpose not true deep cycle batteries, granted if properly maintained i would still expect them to hold up more than a year!
http://www.windsun.com/Batteries/Batter ... 0Batteries

[Scalf77]

One of the best things I purchased and added to my SMB was a Xantrex XMB monitor http://www.xantrex.com. It is an easy way to keep tabs on your battery and battery usage. Consider it a fuel gauge for your battery. It will give you current draw so you quickly determine how much current different devices are using, time left in amp hours, etc. I have used this to monitor when my Isolator cuts over when the alternator is running and a host of other things. I believe Jack Rabbit Marine has the best deal if you get their full installation kit.
http://www.jackrabbitmarine.com. It was pricey, but so was replacing my lifeline 4D battery. The driving factor that lead me to purchase this was I had found a short on the battery cable going from the Isolator to the battery. In my case my 4D sits under the side doors (I have a V10). The battery was held in the mounting bracket by tie wrapping rope handles to the battery bracket frame. One of the tie wraps had failed and the battery was probably bouncing up and down causing the cable to wear against the frame. My first clue that I had a intermittent short was to monitor the voltage while I was in the van, I would occasionally see it drop a volt or so while just walking around in the van. I also had the 12 volt circuit breaker trip a couple of times, of course when I climbed in and reset it everything worked fine.
.


As stated in this thread already if you go down below 50% on a regular basis you will be significantly reducing your battery life. ,

[John and Dana]

Deminimis, From what I understand of lead acid deep cycle bateries 4-5 years is about what you should expect as the life expectancy. Your battery should be able to run the fridge overnight without problem. The formula for calculating how long your battery should run a particular load is the AH rating of the battery/total load in amps. For example if your fridge has and average load of 4 ampl and a new 4D battery is about 200 AH. That means 200/4 would give you a 50 hours run time before the battery is fully depleted.

If you suspect the battery is weak you should take it to a RV shop or battery shop and have it load tested. Most places in my area will do this at no charge.

I hope this helps.
John

[deminimis]

RV place? You mean I can't just check it for juice with my tongue?

Thanks for the info. Batt must be tired. Actually, just priced a batt at our local farm store. Getting a deal at $239, so I'm just gonna replace it. East Penn is the Mfr. Same mfr as the batt that's in there already. Was thinking it was going to be closer to $400, so at $239, I'm making money...right?