Solar Charging

[Oregun]

Bought my used camper last year and a solar panel was already installed when I got it.
My last camping trip I ran the heater overnight for two nights with no problems and was camped under trees so doubt there was much charging during the day. Got home and and after several days figured the batteries should be recharged. Measured the voltage on the two batteries in parallel and it was 14.46 Volts. I then switched off the main 12v battery switch figuring the batteries should be sufficiently recharged. Then I measured the battery voltage and it was still reading 14.46V, I was expecting it to drop down. So is it normal to hardwire the solar panels directly to the batteries rather than going through the 12v disconnect switch? Or perhaps there is a way to turn off the collector panel via its controller that I am not aware of or is it safe to never turn off the charging panel?
Any help is appreciated.

[Oregun]

Update:
I ended up getting this controller on Amazon.
Installed it and it seems to working well fixing the overcharging problem.
Floating about 13.5V. It's not an MPPT charger but it had good reviews and shows voltages & currents for
the battery & collector.

I also installed inline fuses on the solar panel and the battery so that I can disconnect everything
during the off season months.
I tried measuring the truck battery voltage and it obviously isn't connected to the camper battery circuit. Does anyone charge their truck battery with their camper collector?
Or is there a problem with the alternator and collectors fighting each other going down the road?

[Oregun]

pianotuna wrote:
What make and model is the MPPT charge controller?

Is there a temperature sensor on the battery bank that is connected to the controller?

Any idea how much wattage for the actual panels?

Finally found the old controller online it 20A mine is only 10A . It's the cheapest one I've seen online. Controller

Mine has wires on the load circuit but when I traced them they weren't connected to anything.
I disconnected the hot wire of the solar panel so it won't boil the batteries until I get a new controller.

I also won't buy the unit above on ebay.

Thanks

[Oregun]

The load terminals are connected to something on my unit.
Based on what you guys told me I'll guess it is connected to outdoor light circuit.

[pianotuna]

Hi,

I'd suggest the Grape pwm controller from Home Depot. It is fully featured.

They make an MPPT model as well.

[pianotuna]

Hi,

The "load" is used when some one wishes to use a light at night (for example) but wish it to turn on at dusk and perhaps turn off at 1 a.m.

Oregun wrote:

Output Load Timer set to 1.00

Don't understand what the Output Load Timer is used for, I expected it to limit the daytime ON hours but the
instructions shows the timer working during night time which makes no sense.
Anyone familiar with what the timer is used for?

[Oregun]

Ok, thanks that makes sense.
Any recommendations for a replacement controller?
I could probably use this one if I installed a switch to be able to turn it off but would rather fix it than
try to switch it on/off manually.

[time2roll]

Usually a load control is not used in the RV world. Timer is probably to set a cut off for some lights that go all night. RV does not use this.

Picture is fuzzy but I believe the timer controls the load terminals.

[Oregun]

On the controller. Panel light and battery light alternately flashing
Panel light means panel is lit, battery flashing means battery is overcharged

Looked at the controller settings.
Charging Voltage = 19.4V
Charge current = 0.00 Amps
Load Power = 0.00 Watts
Load Voltage = 0.00 Volts
Load Current = 0.00 Amps
Battery Voltage = 14.55 Volts
Output Load Timer set to 1.00 .XX can be set to 1 to 15 Hours
Testing Mode set to 2.00. OFF. .00 = OFF .01 = ON
Output Mode set to 3.00 .00 = OFF .01 = ON Load 24x7 working

Battery is fully charged so no charging current or watts
Problem remains it is not switching to float mode and doesn't appear to be any way to to program that.

Don't understand what the Output Load Timer is used for, I expected it to limit the daytime ON hours but the
instructions shows the timer working during night time which makes no sense.
Also expected the Output Mode to be enabled for 24/7 but its not.

Anyone familiar with what the timer is used for?

[Oregun]

I'll delve into the programing of the controller before replacing. I think it has a timer on where I could limit
the charging to a couple hours a day in the interim.

[time2roll]

Controller will provide a very small but persistent draw on the battery even when off.
A second switch between the controller and battery is good if stored without power for an extended period. Use the panel switch first. Many controllers can be damaged if fed solar power and not connected to a battery. Connected to a battery and no solar is no issue or there would be trouble every night.

For all the effort I would look at a new controller if this one does not operate as expected.

[pianotuna]

X2 but it should be a dc rated switch.

time2roll wrote:
I recommend a switch between the PV Array and DC/DC to stop charging.

[Oregun]

Checked batteries again they read same as this morning. They are completely disconnected. Checked them with my old triplette meter with a mirrored scale and they read 12.9. I measured battery on my car and it was 12.4v with the digital meter. These batteries are RV deep cycle type.

Edit: I ranged up the digital meter up to the 200v scale and it reads 12.9v
reads 13.02v on the 20v scale

[2oldman]

Batteries at rest don't measure 13 volts..at least none I've ever owned.

[Oregun]

time2roll wrote:
I recommend a switch between the PV Array and DC/DC to stop charging.

That is what I was thinking too. That would remove power from all the controller electronics and the battery would still be connected before switching the solar panel in the circuit.
Hopefully a disconnected solar panel would not put the controller in a mode where it would drain the battery.