Solar voltage help...

Captain Obvious wrote:
I just bought that same kit! From the same place!
It's been raining, so I haven't been able to try mine out yet.
I bought the kit knowing I would probably end up replacing the controller at some point with a better one. I also plan to rewire it so that the controller is closer to the batteries.

In looking at it and reading through the engrish manual - it looks like it just dumps solar voltage onto the battery off and on until the battery looks charged around 14v, and then it stops dumping voltage until the battery voltage drops again. It's not a PWM and definitely not an MPPT charger.

I'm curious how your replacement goes.

Once you understand the lights and the blinking pattern on the back of the charge controller, it's really easy to determine the state of charge.

I have the 120 watt version, same controller. It charges at 14.4V until the PWM inside reaches that level while charging at the terminals, then it drops the amps and the voltage down to about 13.6-13.7V. I run the charger while the battery is still attached and getting a draw from my travel trailer, so I've never seen it get to a float voltage, yet. I will sometimes peak at 6.63 amps during charging, but this has been during winter or late fall. You should see a 160/120 factor over what I am seeing for max amps, if your battery is deeply discharged at 40 to 50% SOC and the sun is high up when you START charging. Figure about 8.8 to 9 amps, after the controller. The 3 red lights should either be solid, or have the most difficult and minor flickering occurring to indicate a full charge. Or, you are getting around 12.7 to 12.75V at the battery terminals. Or the specific gravity of your cells is around 1.270 to 1.280 on a hydrometer.

The stock controller is more than adequate. What you should do once every 7 to 10 days, though, is disconnect the batteries from the camper, then bypass the charge controller and wire the panels direct to the battery, and measure the voltage at the batteries. When you see 16.0V at the battery, rewire the solar panel again, back through the charge controller, and put it back to a max of 14.4 V, then reconnect the camper to the batteries. This is for desulfating the battery. It needs to be done every 7 days during heavy discharge /charge cycles, to get the battery fully charged back to 100% state of charge.