Solar charger

[DC_MC]

We bought a 50 watt solar panel to put on our batteries when in storage. Today we went and checked it after two days hooked up and the wires by the controller were all melted! Why would this happen? We were clamped to positive and negative correctly. We were clamped to one of the brand new 12 volt batteries that we had just installed. Nothing at all was running in the motorhome when we were clamped on.

[ppine]

Did you use a controller?
If you did then it was probably reverse polarity.

[ktmrfs]

KD4UPL wrote:
Clamps are a poor means of connection. Bad connections cause heat. However, that little panel shouldn't generate enough current to make much difference.
Did you install a fuse on the positive cable near the battery? It should have one to prevent this sort of thing.
Do you have a charge controller or did you just hook the panel straight to the battery? You really should have at least a basic charge controller to keep the battery from being over charged.
I'm going to guess a cheap solar panel that shorted out with no fuse or charge controller to protect it.

I'd say cheap fuse..... a length of 20ga or so wire as a fuseable link!!!! something shorted in the panel and the battery tried to light it up!!

[KD4UPL]

Clamps are a poor means of connection. Bad connections cause heat. However, that little panel shouldn't generate enough current to make much difference.
Did you install a fuse on the positive cable near the battery? It should have one to prevent this sort of thing.
Do you have a charge controller or did you just hook the panel straight to the battery? You really should have at least a basic charge controller to keep the battery from being over charged.
I'm going to guess a cheap solar panel that shorted out with no fuse or charge controller to protect it.

[CA_Traveler]

i'd guess the controller has a short or if no controller the panel is shorted.

For a followup check the panels Voc and Isc to be sure it's OK. Then reconnect with new wires and check V and A on the battery wires.

[ppine]

Reverse polarity is the usual culprit with melted wires.

[larry_cad]

Was it a real bright sunny day?

[ktmrfs]

no way a 50W panel would have enough current to melt the wires. Max current would be on the order of 4 amps, most likely in the range of 3A from a typical PWM controller. even 20ga wire can handle 3 A continous,

My guess is that the issue is with the connection to the battery, and it was reversed, damaged the controller, caused a overcurrent in the cables.

However, the controller should have protected against reverse hookup w/o any damage.

So.... w/o more info puzzling.