- April 8, 2021 at 15:33 #50152CooperParticipant
Came out to the camper yesterday to prep for a trip and both the propane and co detector were giving a low beep. Looked at the solar controller(prostar 30) and it read 5.7 volts. Checked the camper batteries and sure enough 5.7 volts. Went to enter the truck and the fob wouldn’t work. Truck batteries dead at 5.7 volts. Hmmm! I replaced the camper batteries with an old extra and the stuff in the camper started working again including the stereo which must have been left on for a few weeks. Now the only thing I can think of is the stereo killed all 4 batteries(2 camper and 2 truck batteries) because I left the pigtail for the lights plugged in. I usually do this so the 200 watts of solar can keep all 4 batteries charged when the truck and camper are stored. Evidently this is a bad idea? I’m a little surprised that the solar couldn’t overcome the stereo drain but I think that’s what happened. Should I be disconnecting the pigtail and just let the solar keep the camper batteries charged and use a separate maintainer on the truck batteries? Should I disconnect the camper batteries when parked and just top them off occasionally? What do you guys do? By the way, all 4 batteries are done. Couldn’t bring them back. Expensive mistake!
- April 8, 2021 at 16:46 #50153AnonymousInactive
If it is in storage shut the battery switch off and pull the pigtail. If you use the battery disconnect switch the radio and anything else 12v would not discharge any of the batteries. My single 40amp solar panel maintains the battery as it is a direct line to the batteries with a 10 amp controller not that a 10 amp controller is needed. I have 700 watts of solar and open the fuse while in storage. No Problems!
- April 8, 2021 at 20:05 #50158
- April 9, 2021 at 08:19 #50167
In my case (having 440w of solar and a single 200a/h lithium battery), I disabled the charge wire coming from the truck at the pig tail since with sufficient solar theres really not much need for it, and because of lithium’s characteristically high 1C charge receptivity rate, to avoid any possibility of alternator overload…
After doing such, after a month or two of vehicle non-operation I rudely discovered the truck batteries had died, but luckily my uber trusty Optimate 6 maintenance charger (with recovery mode) was able to bring them back to life.
- April 9, 2021 at 17:37 #50204Alex BlasingameModerator
Hello Phil, I posted a reply to Cooper about the Renogy 50DC combi controller. I personally been using this control for about a 1-1/2 year that keeps 3-100Ah Battle Born batteries charged as well as managing 480 watts of solar. This unit has a built in DC to DC controller as well that isolate the truck batteries when the engine isn’t running.
- April 9, 2021 at 08:24 #50169
just goes to show that prior to disabling the charge wire, the camper battery had been ‘quietly back-feeding’ the truck’s parasitical losses. So now, I just leave the Optimate 6 on the truck’s battery during periods of non-operation.
- April 10, 2021 at 08:37 #50259
Hey Alex, Nice, looks like you’ve got all bases covered!!
- April 13, 2021 at 08:34 #50393JoelParticipant
How was the electrolyte level in the batteries? If it is low, then they were probably overcharged which would be a charge controller problem. Otherwise, when you say that all 4 batteries are done, are you sure? I brought a battery back from zero volts 3 years ago and it is still working in the Miata. Most smart chargers will indicate a fault and not charge a deeply discharged battery. Some will, but you would have to check the documentation to know if and how to do it. The trick I used for the Miata battery was to put a good battery in parallel with the bad battery and the charger. Then the charger charged the battery. After several hours, the battery voltage came up and I was able to charge without the parallel battery. Or you can use an old school dumb charger.
I have 360 watts of panel and have no problem keeping the batteries charged even through the winter (only loads are the charge controller and the CO/propane monitor). In the summer, I usually leave the compressor refrigerator on and that is a pretty substantial load. I usually keep the display of the Trimetric battery monitor on percent charge so I can peek in and make sure everything is good. If you charge controller has a current monitor, check that to see what going on with your camper in storage configuration.
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