Battery Problems - Solar Panel???

LK23 · 01-04-2008, 04:30 PM

If you are like me , battery problems are a royal pain. I thought I had everything under control. I purchased 3 new Trojan house batteries and 2 new Interstate cranking batteries last spring. I also purchased a 15 watt BatteryMinder solar panel with controller for the cranking batteries. I put my coach in storage 2 ½ weeks ago after turning the house battery disconnect switch off and turning the electric steps off. I thought everything would remain charged in storage. Yeah, right.

Today, I visited my coach and found my house batteries at 13.1 volts. Great! However, my cranking batteries were at 11.9 volts. I checked the solar panel and it was outputting 23 volts. I also checked the wiring to ensure the polarity was correct.

How can the cranking batteries be so depleted in only 2 ½ weeks?

Before you tell me to check the amperage, realize I live in Denver, Colorado and I was standing in a foot of snow. I didn't have the time, connecting wires or attitude to check the amperage.

Is it possible the solar panel is draining the batteries in the night hours? Could the controller be defective?

I charged the batteries with the generator for almost an hour before I had to leave. I also disconnected the solar panel since I suspected it to be a problem.

I would appreciate your comments and recommendations.

LK23 · 01-04-2008, 04:30 PM

If you are like me , battery problems are a royal pain. I thought I had everything under control. I purchased 3 new Trojan house batteries and 2 new Interstate cranking batteries last spring. I also purchased a 15 watt BatteryMinder solar panel with controller for the cranking batteries. I put my coach in storage 2 ½ weeks ago after turning the house battery disconnect switch off and turning the electric steps off. I thought everything would remain charged in storage. Yeah, right.

Today, I visited my coach and found my house batteries at 13.1 volts. Great! However, my cranking batteries were at 11.9 volts. I checked the solar panel and it was outputting 23 volts. I also checked the wiring to ensure the polarity was correct.

How can the cranking batteries be so depleted in only 2 ½ weeks?

Before you tell me to check the amperage, realize I live in Denver, Colorado and I was standing in a foot of snow. I didn't have the time, connecting wires or attitude to check the amperage.

Is it possible the solar panel is draining the batteries in the night hours? Could the controller be defective?

I charged the batteries with the generator for almost an hour before I had to leave. I also disconnected the solar panel since I suspected it to be a problem.

I would appreciate your comments and recommendations.

LK23 · 01-05-2008, 07:22 PM

Does anyone have any thoughts about what drained my cranking batteries?

CC38EL · 01-06-2008, 05:27 AM

IMO, the chassis batteries never get turned off unless the cables are disconnected. That means parasitic loads still are drawing your batteries down. If you have had cold and snow is blocking your solar panel, it wouldn't be unusual to find the chassis batts down.

It's possible the controller is defective, but there doesn't seem to be enough equipment here to make the solar panel become the load. Normally they just shut down internally.

Where was the voltage you measured coming from? out of the controller or going into the controller? I would try to find the loads that are still on the chassis batts. Radios, lights, sensors, alarms, etc all have the potential to use standby voltage. The combined values of those loads combined with cold temps could draw more than your BatteryMinder can keep up with.

Another place to look would be any equipment your or someone else has added to the electrial system. Perhaps it is connected to the chassis side and not the house side as you know it. Since I don't know anything about your coach, I'm just making a suggestion. Does your coach have one of those monitoring systems for engine, transmission, etc? My Road Relay 4 was set up to draw from the house batts so that it didn't draw down the chassis batts and would be disconnected by the house battery shutoff.

I hope these thoughts help you in your search. I learned from winters in Indiana that I couldn't leave the coach sit for more than 3 weeks without finding dead chassis batts. But I didn't look for parasitic loads. I just started a routine that starts the coach every 2 weeks at a minimum. But thats not possible for everyone.

Ron and Patti · 01-06-2008, 05:37 AM

LK-23 I have had the same problem in the past that you have (Low Battery Problems). When I lived in (Pennsylvania) every time it would snow I would come out to low batteries and the solar panel on the roof would be covered in snow. My cranking batteries would go down to 11.9 and my house batteries would go down to 12.9. I replaced all my batteries 2 years ago and last winter I had the same problem happen again. (Low Batteries).I noticed my panel inside the coach for the solar panel was not (Lit).I removed the snow from the roof so the sun can hit the panel, after I removed the snow I had no more problem.(Note my coach was always pluged in at the house on 30 AMP service and the batteries still went dead if the solar panel was blocked. We left the house for flordia on December 26th tryed to start the coach December 24th (Dead Coach Batteries Again).With 4 inch of snow on the roof (Pennsylvania)new state law states that no car truck motorhome or trailer is to have snow on the roof when moving so up on the roof I went to remove the snow. The next morning the coach started right up with a little help from the (AUX START). We are in Florida now and the temps this week dropped to 20 at night and every morning the coach started right up. So I am convinced that if the solar panel is blocked the batteries are going to go dead even if the coach is plugged into the house Hope this helps you out it took me 2 years about 600.00 in batteries to figure out that the solar panel needed to be unblocked from the snow. Ron

John_Canfield · 01-06-2008, 06:40 AM

Rex - where did you measure the 23 volts? That sounds like a solar panel with no load. If you have a solar panel regulator, measure the voltage on both sides of it. You should observe a ballpark voltage of ~20 volts on the input, and ~13-14 volts on the output.

If you have no regulator, then it sounds like you have an open circuit between the added panel and the battery bank.

The solar panel needs a diode in series with the positive lead so it won't discharge the battery bank at night (or whenever it is not producing more voltage than the load.) If you have a solar panel regulator, then this function will be managed by the regulator.

Also, did you turn off the chassis battery switch in the engine compartment? Turning the switch off doesn't completely isolate the chassis batteries (as I understand the situation) - at least the starter is still connected and there could be other parasitic loads as well. You would need to study the chassis wiring diagram to fully appreciate the situation.

LK23 · 01-06-2008, 07:31 AM

Thanks for the replies. It gives me more to think about. As far as snow, I have the chassis panel located under the rear of the coach, behind the driver's side rear wheel. The snow only covered about 3 inches of the 14 inch panel. I measured the voltage as it came out of the panel. Later, I realized I should have measured it out of the controller and before the batteries. I will call VDC Electronics tomorrow (the solar panel manufacturer) to see what they say.

LK23 · 01-06-2008, 01:10 PM

I failed to mention that the solar panel is tilted towards the sun at a 45 degree angle. That is why is wasn't covered with snow.

Harry B · 01-06-2008, 02:56 PM

I had left my coach 2 weeks ago the same way as you did. House batteries disconnected and chassis battery switch in the engine compartment left on. Normally I have the coach plugged in at home all the time, but I had a defective temperature sensor on my charger so I decided to fully charge both batteries ( I have an Echo charger for the chassis batteries) and then disconnect the coach from the house until we returned form our holiday trip, specially given the fire problems with the Dimensions inverter / converter I hear of lately.

After getting back yesterday, I checked the batteries today and the house batteries were 12.4 volts (good) and the chassis batteries are 10.9 volts. This is the first time I have seen the chassis batteries discharged.

I guess I'll be looking for the same discharge problem as you will be, though I don't have a solar panel connected to the chassis batteries. The problem is that this should not have happened in a two week period with or without a solar panel.