RV solar.

[kscott]

Hello, I'm a new member looking for help. I have a class A RV that I use 3, 100 watt panels with a windy nation controller when boondocking. My last time out, which was the the first time I used 3 panels, something happened. When I was ready to leave, my alternator light came on. The alt was still putting out 14.2v, but the light stayed on. I took it to the shop, and the Tech said I had a bad diode in the alt. Could the solar panels have caused the damage to the alt .If so, how do I prevent that next time? The vehicle is 4yo, and 16,000 miles.
Thanks

[SunEagle]

Hello kscott and welcome to Solar Panel Talk

Based on what you have posted unless there is a direct path between the coach batteries and the alternator I doubt the solar pv system is the cause of the bad diode. Still it might be wise to have an electrician check out the circuit to see if the pv system is backfeeding the alternator circuit.

[SolTex]

Hi kscott,

We have solar on our class A coach so I'm familiar with that type system. Does your coach have two battery banks I.E. separate house and chassis batteries? If so, then the solar controller output is normally connected directly to the house batteries, and the alternator is connected to the start batteries. There should be some kind of device that keeps the two battery banks separated, but still allows the alternator to charge both banks. On our 1993 model coach we have a diode battery isolator. Newer model coaches usually have a smart battery combiner. Either way, it should not be possible for the solar panels to ever cause any damage to the alternator, assuming everything is connected properly.

[Calsun]

A failed diode is the most common reason to need to replace an alternator in any vehicle.