Electrical system discharging WAY too quickly
I’m having an issue with my electrical setup. A few days ago my system began going from a full charge to 50% overnight instead of in it’s usual ~3 days. We have been on the road for a little over 4 months without issue until now.
A little about my setup. I have two 124 amp hour Everstart deep cycle batteries in a vented box. The main draw on the system is a 12v electric compressor style fridge with a very efficient compressor. It draws around 40 amps in 24 hours. We also have a Fantastic Fan that we run at night if it’s hot. There’s a couple LED lights and a small pump for the sink but those are such small draws they’re not really relevant. The stereo and GPS are wired to the house batteries too, but we really only use those while driving and the alternator should be supplying the amps in that case - which brings me to charging.
We have a voltage sensitive relay that establishes a 1 way connection between the engine battery and the house batteries when we’re driving (and the engine battery is fully charged). I also have a 195 watt solar panel on the roof that pushes 15 amps in full sun. Finally, I have a inverter/charger for plugging into the grid.
I also have a device that senses when the batteries are at 50% and disconnects all loads. It has an override switch in case I desire to go past 50%.
Here is an example of what is happening now: I was parked at a campsite with electrical and plugged in overnight. The 3 stage charger indicated the bank was full. It was floating at 13v. I unplugged, then drove for about three hours. During that time it was also sunny. I parked and had maybe an hour or two of indirect light on the panel. At this point, normally, I could stay off the grid for about 3 days before the 50% switch would cut things off. It doesn’t even last through the night. I wake up to find the 50% switch kicked in and the system around 12.0v.
With three different functioning means of charging, I have to assume it’s not an issue with charging. That leaves either a bad battery or something sucking the life out of them. So, I figured I had a bad cell. I inspected the batteries and topped them off with distilled water. They seem fine. No heat, they read the same (connected or disconnected from the system). I even took them to a battery store and had them checked. My spanish is basic so I had a hard time determining what kind of test the guy did on them, but I did note the tester he used. I looked it up and it’s not a load tester, but it certainly appeared to be much more than a volt meter. It was a Bosch Bat131. The Bosch said they were both good. He used a hydrometer and showed me that they really needed charging.
I thought maybe the fridge was draining them, but I can hear the thermostat turn off and if it were running constantly we’d have frozen solid drinks. Again, this all points to a bad battery. Does the Bosch Bat131 provide a true indicator of a battery’s health? Any ideas on how to move forward from here?
My next step is to run only one of the batteries and see if things appear more normal. That would indicate which battery is bad. Tomorrow, I also plan on turning the fridge off. If one of the batteries is bad, I presume the system will still drain even with little to no load on it. Any other ideas? HELP!!! It’’s really hot in Costa Rica and the fridge and the fan are about all that make over landing here tolerable!!! :)
A little about my setup. I have two 124 amp hour Everstart deep cycle batteries in a vented box. The main draw on the system is a 12v electric compressor style fridge with a very efficient compressor. It draws around 40 amps in 24 hours. We also have a Fantastic Fan that we run at night if it’s hot. There’s a couple LED lights and a small pump for the sink but those are such small draws they’re not really relevant. The stereo and GPS are wired to the house batteries too, but we really only use those while driving and the alternator should be supplying the amps in that case - which brings me to charging.
We have a voltage sensitive relay that establishes a 1 way connection between the engine battery and the house batteries when we’re driving (and the engine battery is fully charged). I also have a 195 watt solar panel on the roof that pushes 15 amps in full sun. Finally, I have a inverter/charger for plugging into the grid.
I also have a device that senses when the batteries are at 50% and disconnects all loads. It has an override switch in case I desire to go past 50%.
Here is an example of what is happening now: I was parked at a campsite with electrical and plugged in overnight. The 3 stage charger indicated the bank was full. It was floating at 13v. I unplugged, then drove for about three hours. During that time it was also sunny. I parked and had maybe an hour or two of indirect light on the panel. At this point, normally, I could stay off the grid for about 3 days before the 50% switch would cut things off. It doesn’t even last through the night. I wake up to find the 50% switch kicked in and the system around 12.0v.
With three different functioning means of charging, I have to assume it’s not an issue with charging. That leaves either a bad battery or something sucking the life out of them. So, I figured I had a bad cell. I inspected the batteries and topped them off with distilled water. They seem fine. No heat, they read the same (connected or disconnected from the system). I even took them to a battery store and had them checked. My spanish is basic so I had a hard time determining what kind of test the guy did on them, but I did note the tester he used. I looked it up and it’s not a load tester, but it certainly appeared to be much more than a volt meter. It was a Bosch Bat131. The Bosch said they were both good. He used a hydrometer and showed me that they really needed charging.
I thought maybe the fridge was draining them, but I can hear the thermostat turn off and if it were running constantly we’d have frozen solid drinks. Again, this all points to a bad battery. Does the Bosch Bat131 provide a true indicator of a battery’s health? Any ideas on how to move forward from here?
My next step is to run only one of the batteries and see if things appear more normal. That would indicate which battery is bad. Tomorrow, I also plan on turning the fridge off. If one of the batteries is bad, I presume the system will still drain even with little to no load on it. Any other ideas? HELP!!! It’’s really hot in Costa Rica and the fridge and the fan are about all that make over landing here tolerable!!! :)
