EvaKool 100w solar panel problems

Matt

Not technical in this area but coincidentally I had someone check my panels today.
Depending on how much sun was on them (cloudy day) the panels went up to 21 point something volts. Less in part shade.

My panels have a sticker on the back that states, along with other info, 'Open Circuit voltage 23.8v'.

Paul

Depending on the state of charge of your battery this will change the voltage it can accept. As the battery fills up the more voltage is required to fill it up that little bit more.

There are others that are better to describe this in more detail so hopefully they will be along soon :-)

Matt,

Depends on the type of controller and just where you are taking your measurements. Simple controllers operate by connecting the panel directly to the battery until the battery voltage rises to about 14.7 (depending on the type of battery), then disconnecting the battery from the controller. Once disconnected the battery voltage drops slowly until the controller decides to cut in again, pushes the voltage up, disconnects..........and the cycle repeats. Until the battery approaches fully charged its voltage will not rise far enough for the controller to turn off, but when fully charged the controller may cycle on and off a few times per minute. This sounds pretty much like what you have observed, assuming that you were monitoring the battery voltage. The story is quite different if you have a more intelligent or mppt controller.

After the system had been running for a while you observed over 20 volts. I would expect that you were measuring the panel voltage, not the battery voltage. When the controller has disconnected the battery from the panel the panel voltage should be about 22V. This is the open circuit voltage. If your measurement of 22V was in fact at the battery, then you may well have a warranty issue, and an overcharged battery. It would be worth measuring right at the battery, between the terminals, to rule out any wiring problems, but if you see more than 15V between the battery terminals I'd suggest look to your warranty.

HTH

John

Open curcuit the panel can go up over 20 volt in good sun but the reg should never let the output charge go up this high. Are you sure it was connected to the battery when checking the voltage?

Hi Matt,


The regulator will normally be outputting a higher voltage when not connected to a battery, once the battery is connected properly the regulator "sees" the battery and automatically reduces the voltage to the correct voltage for the state of charge the battery is in.

I can advise that the EPHC regulator is a 4 stage PWM regulator / Charger. The 4 stages are Bulk, PWM, Boost and Float.
The EPHC also has a regulation point of 14.4 volts, so it is designed not to over-charge your batteries.

Measuring across the solar panels, or also across terminals 1 and 2 on the EPHC, it is not surprising if you are measuring over 20 volts. The higher the voltage, the more sunlight (power) the panels are receiving.

You may see the the voltage fluctuate while charging, this is just a part of PWM charging.



Thanks, Brodie
Warranty Manager
Evakool