House Battery Question

oceansrealm · 12-10-2012, 02:20 PM

Hello,

I am new to the SMB world. I have a 2000 EB350 I just purchased. The house battery was replaced about 18 months ago (Deka 4D). We went on our first day outing yesterday and I noticed the battery started at about 12.8 V (no load), but would drop to about 12.3 V or so with the fridge compressor running (4.7 Norcold). We were parked, not running anything else aside from sporadic water pump use, for about 4 hrs, and the under load voltage dropped below 12 V. The no load voltage was about 12.2 V.

Before the outing, I plugged the van into AC for 24hrs and put blue ice into the freezer to help the fridge cool down. The fridge was full of cold liquid refreshments for the outing.

Not having any past experience with house batteries, I would like to ask you guys if you feel this is a battery on it's way out. We are planning a trip into the mountains over christmas, part of which will be off the grid, so I would like to make sure we will be able to run at least the furnace and fridge for a day or two.

How low can you safely draw these things down? I am using the cheap cigarette lighter plug in voltmeter.

Cheers,

Martin

**daveb** · 12-10-2012, 04:15 PM

You're not supposed to take them down below 12.2 and let them sit with no charge for lenghty periods of time, such as longer than a week.

I would take a look at all the battery connections and if they are OK, you can do a load test if you find somebody with a tester. You can do the test yourself but a good load tester is easier.

Next you need to look at your charging methods. That battery should go 5 years.

[edit] I also noticed you have a 2000. Those generally have solid state battery isolators. Make sure a charge is getting through the house battery and take a look at the isolators connections as well. Sometimes they corrode too. Test voltage (while the engine is running) at the battery terminal (not the lug) and see if it's close to the voltage at the starting battery.

Good luck

Dave

oceansrealm · 12-11-2012, 08:58 AM

Thank Dave,

The problem was obvious once I looked (I actually feel kind of stupid). The main breaker was off! The battery was not taking a charge while plugged in... hence we started low on the get go. And since we only drove about an hour or so to the mountains, that explains why it was a bit on the low end.

Cheers,

Martin