Melted Fuse

[Chuck Q]

I have a new GoPower 30 Controller and 400 watts of solar, Panels are 5 years old. On Friday the Panel started blinking and would only show a 90% charge. After checking panels and connections I found the 30 amp inline fuse was melted. The waterproof case was heated and stuck to the strap handle of the 6V battery. Have been using solar since 2002 and never blown the 30 amp fuse. Looking for suggestions as to cause. Also I replaced the fuse on Saturday and the system is working great. Thanks in advance.

[drdarrin]

This fuse was on the panel or battery side of your controller? At 400W and approximately 17V, your controller should be getting ~24A input. At 15.3V output, that's a little over 26A.

I think your 30A fuse was a little over rated. It happens. If another one pops, I'd start checking voltages.

I had something similar happened on my home AC a couple years ago. 30A fuse just decided it had had enough. Replaced it and no problems since with it.

[John Hilley]

Might have been a loose connection on fuse.

[PbdBlue]

My guess bad connection at the fuse - loose, corroded, etc. Have seen this many times on industrial equipment during my career.

[336muffin]

Originally Posted by John Hilley

Might have been a loose connection on fuse.

Bingo! One receptacle that the fuse plugs into is slightly loose. This causes heat and leads toa melted fuse rather than a blown fuse. Use a new fuse as a "feeler gauge" to find the loose side.