I'm new to solar setups but have some electrical knowledge. I've tried three different Thunderbolt 100W charge controllers from Harbor Freight, and I'm starting to wonder if I'm doing something wrong. The first worked for a couple of days, the second only for a few seconds, and the third never turned on at all.
Here's my setup: I'm using a 100W solar panel connected to the Thunderbolt charge controller via SAE connectors. The charge controller is wired to a NERMAK 12V 20AH LiFePO4 battery. I've double-checked that all the polarities are correct, even using a reverse SAE adapter for the battery connection.
I measured about 2 amps at 19-20V coming from the solar panel, so it seems like power is coming in. However, I'm not getting any readings from the charge controller's SAE terminal that connects to the battery, and the load wires are also dead. At the time of testing, the battery voltage was 11.2V. Am I missing something simple?
1 Answer
It sounds like you're doing a lot right, but there are a few key points to follow. First, remember the connection order: connect your battery to the charge controller before hooking up the solar panel. If you connect the panel first, it could damage the controller. Also, keep in mind that the Thunderbolt controller isn't designed for lithium batteries, which might be a problem here. It might be worth checking if the battery is functioning properly by trying to charge it with a standard battery charger. That way, you'll know if the issue lies with the battery itself.
Would using a lithium battery really fry the controller like that?
I have actually charged the battery separately since the charge controller isn’t working. Each time, I connected the load, then the battery, followed by the panel.