James86004
Expedition Leader
I need help diagnosing before I start throwing money at the problem of our house battery not holding a charge. I can't decide if it is because it is old and abused, or there is something intermittently drawing it down.
In July, we bought a 2004 Sprinter with 45 kilomiles on it. It is an Airstream Interstate RV conversion. In 2014 the previous owner replaced the house battery under the passenger seat with a "Global Source One" 92 Ah AGM battery. In addition, he installed a second 82 Ah AGM battery in parallel, which I don't think was a good idea.
We took the long way home from where we bought it in California, traveling up to Mt. St. Helens, across to North Dakota, then home to Tucson over 25 days. We spent some nights in RV parks plugged in, others wild camping for one or two nights. On the wild camping nights we used the lights, the roof fan, and the fresh water pump. It worked perfectly.
When we got home we put our ARB refrigerator in it, connected to the underseat house battery. Then we left for a 3 night camping trip on the Mogollon Rim. We arrived after dark, and within 10 minutes of turning the interior lights one, we noticed they were really dim. I measured the voltage on the house batteries and it was 10 Volts. We shut everything off and went to bed.
The next morning I started the engine to see if the batteries were getting charge, they had 13.8 volts, so the charging relay was working. I let the engine idle for an hour and then shut it off. After another hour the battery voltage was 12.3. By the evening, it had dropped to 10. We decided we didn't need cold beverages so we disconnected the fridge, and dealt with the lack of lighting with our flashlights.
At home, I got out my clamp meter and measured the current draw of everything, With the engine running, there are a lot of amps flowing into the house batteries. Engine off, the relay opens and the current draw drops to around 1/4 amp, which I think is mainly the propane leak monitor. Plugged in to AC, there is current flowing into the battery trying to charge it.
I removed both house batteries and put them on a Noco charger. After 24 hours, the 92 Ah battery would drop to 9 volts within seconds of removing the charger. The 82 Ah would still be at 12.6 volts the next morning. So, I put the 82 Ah battery back in the van and removed the parallel wiring.
Two weeks later the 82 Ah battery is not holding a charge, either. So do I get a new battery, or should I investigate if there is an intermittent draw that is flattening the battery? Is there a battery monitor that records that?
In July, we bought a 2004 Sprinter with 45 kilomiles on it. It is an Airstream Interstate RV conversion. In 2014 the previous owner replaced the house battery under the passenger seat with a "Global Source One" 92 Ah AGM battery. In addition, he installed a second 82 Ah AGM battery in parallel, which I don't think was a good idea.
We took the long way home from where we bought it in California, traveling up to Mt. St. Helens, across to North Dakota, then home to Tucson over 25 days. We spent some nights in RV parks plugged in, others wild camping for one or two nights. On the wild camping nights we used the lights, the roof fan, and the fresh water pump. It worked perfectly.
When we got home we put our ARB refrigerator in it, connected to the underseat house battery. Then we left for a 3 night camping trip on the Mogollon Rim. We arrived after dark, and within 10 minutes of turning the interior lights one, we noticed they were really dim. I measured the voltage on the house batteries and it was 10 Volts. We shut everything off and went to bed.
The next morning I started the engine to see if the batteries were getting charge, they had 13.8 volts, so the charging relay was working. I let the engine idle for an hour and then shut it off. After another hour the battery voltage was 12.3. By the evening, it had dropped to 10. We decided we didn't need cold beverages so we disconnected the fridge, and dealt with the lack of lighting with our flashlights.
At home, I got out my clamp meter and measured the current draw of everything, With the engine running, there are a lot of amps flowing into the house batteries. Engine off, the relay opens and the current draw drops to around 1/4 amp, which I think is mainly the propane leak monitor. Plugged in to AC, there is current flowing into the battery trying to charge it.
I removed both house batteries and put them on a Noco charger. After 24 hours, the 92 Ah battery would drop to 9 volts within seconds of removing the charger. The 82 Ah would still be at 12.6 volts the next morning. So, I put the 82 Ah battery back in the van and removed the parallel wiring.
Two weeks later the 82 Ah battery is not holding a charge, either. So do I get a new battery, or should I investigate if there is an intermittent draw that is flattening the battery? Is there a battery monitor that records that?
