charge controllers not working

I have two Thunderbolt charge controllers that appear to be non-functional. They have been in use for about 4 months.

Battery voltage went to 15.15 volts but the yellow charge lights were lit. The two controllers went into this mode at the same time.

Hooked to the same batteries are three 100 watt panels working through a SunSaver 20 amp controller.

When I unplugged the two 100 watt panels from the Thunderbolt controller, the voltage began to drop. As soon as the panels are plugged back into the Thunderbolts, the voltage once again climbs.

The yellow charging lights on the Thunderbolts do not turn off.

Robert Harsell wrote:I have two Thunderbolt charge controllers that appear to be non-functional. They have been in use for about 4 months.

Battery voltage went to 15.15 volts but the yellow charge lights were lit. The two controllers went into this mode at the same time.

Hooked to the same batteries are three 100 watt panels working through a SunSaver 20 amp controller.

When I unplugged the two 100 watt panels from the Thunderbolt controller, the voltage began to drop. As soon as the panels are plugged back into the Thunderbolts, the voltage once again climbs.

The yellow charging lights on the Thunderbolts do not turn off.

Hmm sounds like a fried controller. They are pretty entry level. Some cheap pwm controllers have a really high charge voltage or their solenoids fry in the charge position.  The sunsaver is a good unit.

David Baillie wrote:

Robert Harsell wrote:I have two Thunderbolt charge controllers that appear to be non-functional. They have been in use for about 4 months.

Battery voltage went to 15.15 volts but the yellow charge lights were lit. The two controllers went into this mode at the same time.

Hooked to the same batteries are three 100 watt panels working through a SunSaver 20 amp controller.

When I unplugged the two 100 watt panels from the Thunderbolt controller, the voltage began to drop. As soon as the panels are plugged back into the Thunderbolts, the voltage once again climbs.

The yellow charging lights on the Thunderbolts do not turn off.

Hmm sounds like a fried controller. They are pretty entry level. Some cheap pwm controllers have a really high charge voltage or their solenoids fry in the charge position.  The sunsaver is a good unit.

I agree! I bought a bulk of these similar controllers from eBay/amazon. These controllers are hit or miss. I've seen these controller last anywhere from 2 months through a a year. For the price of them, they come in handy as backups or smaller projects.

David Baillie wrote:

Robert Harsell wrote:I have two Thunderbolt charge controllers that appear to be non-functional. They have been in use for about 4 months.

Battery voltage went to 15.15 volts but the yellow charge lights were lit. The two controllers went into this mode at the same time.

Hooked to the same batteries are three 100 watt panels working through a SunSaver 20 amp controller.

When I unplugged the two 100 watt panels from the Thunderbolt controller, the voltage began to drop. As soon as the panels are plugged back into the Thunderbolts, the voltage once again climbs.

The yellow charging lights on the Thunderbolts do not turn off.

Hmm sounds like a fried controller. They are pretty entry level. Some cheap pwm controllers have a really high charge voltage or their solenoids fry in the charge position.  The sunsaver is a good unit.

Thanks for replying, David.

I made a mistake. The charge controllers are working. It was my digital voltage readout that malfunctioned due to a failing battery. Ordinarily, when the battery fails, the digital screen reads zero. This time, it gradually climbed in voltage from the 14s up to over 15 volts. While the readout was this high, the yellow charge lights on the Thunderbolt controllers were still yellow, indicating that they were charging. The actual voltage at the time was just under 13 volts, more than 2 volts under what I was getting from the volt meter.

All is well.