What is Eating Those Batteries?
I went to Quartzite yesterday to visit an old friend who is dry-camping on BLM land and has been having some electrical problems with his travel trailer, a 2001 KZ model. The problem is that even with 2 new 12V Group 29 Marine/RV batteries (Walmart), he will go from fully charged one afternoon to 12.05 volts by the end of breakfast the next morning.
I should tell you that this guy is a very experienced RVer who has dry camped a lot and understands what he needs to do to conserve battery, but this has him stumped. He uses one light, sometimes 2, in the evening for a couple of hours; listens to his 12V stereo for an hour or so, runs the heater in the morning for about an hour, water pump as needed charges his cell phone. Couldn't be that hard to figure out, right? Has to be that there is a parasitic load draining the battery, or that some appliance is pulling lots of amps, way more than it should be. So we got out the electrical tester and checked for parasitic load. Results were 25 milliamps, everything off that can be turned off. No parasitic load, at least not while we were testing.
So, if the problem isn't a parasitic load, it must be that something is pulling lots of amps while it is running. I decided that the easiest and most rational way to test was to pull the 12V fuses, one by one, and see what appliances were on a given circuit and to determine how many amps they were pulling while in actual use. Sure enough, nothing turned up as unusual. The item that pulled the most amps was the furnace, and that was 5 amps, just about what it should be. All other items were exactly what you would expect. I don't have the complete list to publish here, but absolutely nothing jumped out as being unusual.
So if no parasitic load, and nothing is pulling more amps that what you would expect, what is eating the battery? And how do you go about systematically testing to find out what it is? The trailer does have some age, and my suspicion - backed by absolutely nothing - is that it's the converter/charger. But why would that cause a large discharge from the batteries? I don't have any idea.
Any suggestions? Any help? Anyone have a similar problem who has solved it and willing to share their knowledge?
I should tell you that this guy is a very experienced RVer who has dry camped a lot and understands what he needs to do to conserve battery, but this has him stumped. He uses one light, sometimes 2, in the evening for a couple of hours; listens to his 12V stereo for an hour or so, runs the heater in the morning for about an hour, water pump as needed charges his cell phone. Couldn't be that hard to figure out, right? Has to be that there is a parasitic load draining the battery, or that some appliance is pulling lots of amps, way more than it should be. So we got out the electrical tester and checked for parasitic load. Results were 25 milliamps, everything off that can be turned off. No parasitic load, at least not while we were testing.
So, if the problem isn't a parasitic load, it must be that something is pulling lots of amps while it is running. I decided that the easiest and most rational way to test was to pull the 12V fuses, one by one, and see what appliances were on a given circuit and to determine how many amps they were pulling while in actual use. Sure enough, nothing turned up as unusual. The item that pulled the most amps was the furnace, and that was 5 amps, just about what it should be. All other items were exactly what you would expect. I don't have the complete list to publish here, but absolutely nothing jumped out as being unusual.
So if no parasitic load, and nothing is pulling more amps that what you would expect, what is eating the battery? And how do you go about systematically testing to find out what it is? The trailer does have some age, and my suspicion - backed by absolutely nothing - is that it's the converter/charger. But why would that cause a large discharge from the batteries? I don't have any idea.
Any suggestions? Any help? Anyone have a similar problem who has solved it and willing to share their knowledge?
