Battery over-charged

[Isaac-1]

Ought to was my point above, and that cheap Ideal brand multimeter I used earlier this week should not have read 4.5VDC when testing D size batteries.

 

[Mark_K5LXP]

Only conclusion I would reach is there's more than one failure, i.e. wonky controller and a fried battery. I doubt it's the meter but it's easy enough to correlate one to another and eliminate that variable. Divide and conquer - disconnect the battery, charge with a known charger and load test and see if it passes muster. Then with a tested good or new battery the controller can be evaluated for proper function.

Mark B.
Albuquerque, NM

 

[Bugford]

Update on my solar nightmare. I've removed the controller, and the battery voltage still rises. I removed the battery, and the trailer is still getting voltage from the solar panel enough to run the bathroom fan. I had no idea that was possible. I thought the solar panel was only recharge the battery. Other than just getting on the roof and disconnecting the solar panel, I'm out of ideas. I guess I'm going to have to concede that my capabilities have a limit.

 

[Tulecreeper]

Update on my solar nightmare. I've removed the controller, and the battery voltage still rises. I removed the battery, and the trailer is still getting voltage from the solar panel enough to run the bathroom fan. I had no idea that was possible. I thought the solar panel was only recharge the battery. Other than just getting on the roof and disconnecting the solar panel, I'm out of ideas. I guess I'm going to have to concede that my capabilities have a limit.

Is the bathroom fan the only 12v thing that will run with the battery removed, or do you also have some lights? If so, that tells me that the solar panel not only charges the battery through the controller, it is also direct wired into your 12 volt system prior to/upstream from the controller. Under those conditions, the solar panel will provide direct current to the 12 volt system, but if nothing on the 12 volt circuit is calling for power - the fan is not on, no lights are on, etc. - then the excess that the panel produces goes to charging the battery. At night, of course, everything comes from the battery that hopefully the panel had enough time to charge during the day when the sun was shining and no 12 volt loads were being used.

I realize this doesn't answer your question as to why the battery is being overcharged, but it is a piece of the puzzle.

 

[DonTom]

I had no idea that was possible.

Sure, the solar puts out more voltage than the batteries. Solar usually just doesn't have a lot of current capacity, so it loads down a lot easier when no battery is connected. IOW, it will still run stuff that has a low current draw, could even run the fan a little faster with no battery to load down the solar voltage. Depends on how much current the fan draws.

-Don- Mission, TX

 

[Bugford]

So it sounds like to me, that I need to change out the solar controller first. and go from there. They aren't that expensive. I appreciate the help. I had no idea that it would be wired that way.

 

[Bugford]

But on second thought, if the battery is overcharging with the solar controller removed, which it is, what will change by replacing the contoller?

 

[DonTom]

But on second thought, if the battery is overcharging with the solar controller removed, which it is, what will change by replacing the contoller?

The controller should keep the battery charged without overcharging. The solar controller will increase and decrease the charge current to the batteries automatically as needed.

-Don- Mission, TX

 

[Isaac-1]

It sounds to me like someone wired your solar panels so that they bypass the solar controller, getting on the roof and tracing the wires is the next logical step.

 

[Tulecreeper]

It sounds to me like someone wired your solar panels so that they bypass the solar controller, getting on the roof and tracing the wires is the next logical step.

Actually, I think I would want it wired so that is supplies direct current (not through the charge controller) to my 12v system first...then if there is no power being called for from that circuit it can start charging the battery. During the day you would have no lights on, and other than something like the bathroom fan which would probably only be on for a short period of time, most of the time the panel would be charging the battery anyway.

 

[Isaac-1]

Circuits don't work that way, it would just back flow to the batteries, and a diode inline to block backflow would just likely consume more power than the solar panel generates

 

[Gary RV_Wizard]

If so, that tells me that the solar panel not only charges the battery through the controller, it is also direct wired into your 12 volt system prior to/upstream from the controller.

Not necessarily. The 12v power feed to the RVs 12v power bus is typically the same pair of wires that charge the battery from the converter/charger. As long as the solar panel/controller output is connected to those wires (even without the battery present), solar voltage can reach the RV's house 12v distribution system.

We need to learn where the solar controller output wires terminate.

 

[Bugford]

Not necessarily. The 12v power feed to the RVs 12v power bus is typically the same pair of wires that charge the battery from the converter/charger. As long as the solar panel/controller output is connected to those wires (even without the battery present), solar voltage can reach the RV's house 12v distribution system.

We need to learn where the solar controller output wires terminate.

I going to try and trace all the wires, but it is going to be a trick. It is all factory installed. Any advice appreciated.

 

[Tulecreeper]

Not necessarily. The 12v power feed to the RVs 12v power bus is typically the same pair of wires that charge the battery from the converter/charger. As long as the solar panel/controller output is connected to those wires (even without the battery present), solar voltage can reach the RV's house 12v distribution system.

We need to learn where the solar controller output wires terminate.

True, I hadn't considered that.