I want to mount my solar panels on my van roof, but I am not a fulltimer and only use the van for occasional getaways. I am concerned about panels continuously producing electricity when it is not being used regularly. My system is 200 watts with a 30 amp pmw charger, and I think I have everything wired correctly. Has anyone who has panels mounted on their rooftop ever had a fire? If so, do you know the cause?
Solar system fires?
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Seminole Wind
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i have lived off grid and on solar both mobile and stationary since 1997, i have seen and learned a thing or 2. with a properly (heck even reasonably) installed system there is no more danger of fire than any 12 volt electrical system. properly sized wires, good connections, and proper size and location of fuses gives you a good measure of "fail safe"
MrNoodly
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Probably nothing to worry about, but if you have a fuse between the panel(s) and controller, just pop it out, breaking the circuit.
Or disconnect one of the MC4 connectors.
Or you could cover the panel(s) with something opaque, like cardboard, plywood, a rug, a tarp, even a garbage bag.
Or disconnect one of the MC4 connectors.
Or you could cover the panel(s) with something opaque, like cardboard, plywood, a rug, a tarp, even a garbage bag.
lenny flank
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The controller should cut off the flow of electricity from the panels whenever the battery is full.
Thanks for the replies. I wondered if it would be ok to just disconnect the m4 connections, but when I was installing the system, the instructions said to keep the panels covered while installing since they produce electricity whether or not they are connected to anything. My concern is if the controller fails (Renogy Wanderer - not the best) and I am not immediately aware of it, I don't want a fire on the roof or fried batteries. I do have a fuse on hot wires to and from the controller. So will I be safe to just disconnect the panels entirely and not worry about it? Even though they are still producing electricity but not connected to anything?
Don't overthink it.
Correct Wire sizes and Fuse sizes between the components. The Renogy docs have that information.
Each Renogy panel outputs 100 watts max. A light bulb. Five amps at 20 volts. Two in parallel will be 10 amps at 20V.
Your battery bank has the most energy. That is where a short or an undersized wire can cause fires.
Why are you down on the Wanderer? For a basic setup it is more than adequate. Don't add more panels than the Wanderer can take maximum and there should be no problem.
Correct Wire sizes and Fuse sizes between the components. The Renogy docs have that information.
Each Renogy panel outputs 100 watts max. A light bulb. Five amps at 20 volts. Two in parallel will be 10 amps at 20V.
Your battery bank has the most energy. That is where a short or an undersized wire can cause fires.
Why are you down on the Wanderer? For a basic setup it is more than adequate. Don't add more panels than the Wanderer can take maximum and there should be no problem.
Seminole Wind
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if you disconnect the solar how will you maintain a float voltage on your batteries?
you will need to check on your batteries from time to time regardless of whether or not you have the solar hooked up.
you will need to check on your batteries from time to time regardless of whether or not you have the solar hooked up.
Ticklebellly
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Once established and working, there is no special danger of fire in a solar supplied power system. Fusing and switching should be part of the system allowing protection and isolating of components. Covering a panel to effectively turn off a panel is standard procedure.
A solar panel co be with a dead short and not cause a fire. The wires supplied are way over sized for the maximum amperage ever produced. A fuse is not need between the panel and controller unless more than three panels in parallel. It is nice to have a means to switch the panel to controller off.
Seminole Wind
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Weight, the 3 panel rule is just a rule of thumb. each panel has a different level of over current protection. to be safe, one needs to check the internal current protection specs and do the basic math. i have seen some that were just over the limit at 2 panels and others that could easily go 4. also in general, when calculating fuse size you multiply the "rated" max current by 1.25. while most of the time panels will put out some what less than their rated max. it is not uncommon to exceed that in good conditions. 2 days ago here at the RTR, low sun in the winter i was getting 320 watts at times out of my 295 watt spec'd panels.
My four panels do not have built in over current protection. Called fuse or breaker. They do have reverse current protection. Called diode. The 10awg wires are heavy enough to not be a fire hazard even if 3 panels short through the failed panel connections. But with a fuse for each panel before the combiner, I will not be surprised by a non-charging battery. The danger is in much larger systems where the wires cannot handle the amps from the rest of the panels. And overheating wires are near flammable stuff.
I often see high watt numbers. When the sun is just right at cold temperatures the voltage can get high and, with even lower amps, can be lots-of-watts. Amps cause fires and blow fuses.
I often see high watt numbers. When the sun is just right at cold temperatures the voltage can get high and, with even lower amps, can be lots-of-watts. Amps cause fires and blow fuses.
Seminole Wind
Well-known member
whether it is actual over current protection or max internal current rating i dont care to bicker over semantics. the fact remains the 3 panel rule is just a rule of thumb. there are some that can handle more, some that can handle less. it is always best to consult the specs for the actual panels a person is using to confirm the safety of the system rather than go by a rule of thumb and get burnt
gp said:
Assuming everything is wired correctly, good batteries, decent solar controller, proper fuses are in place, adequate wire gauges, etc etc, your only real concern for a solar installation when un-used for a period of time is either outgassing the battery acid (flooded or AGM) and/or drying out the plates of a flooded battery. This can happen especially if the ambient temps are warm or hot.
Choose the least aggressive setting on the controller (usually GEL) when in storage, and make sure the batteries are looked after every week or two, and things should be fine.
The controller has a maximum limit for solar input. Unfortunately they bury the value in fine print specifications in the documentation.
The controller's package will visibly announce the max output to the battery bank.
I have a 20amp Renogy controller that has a 236 watt limit on solar. Ran 4 100 watt panels through it. Eventually it caught up to me, but the only damage was the case around the battery + connection melted. Still was working when replaced with 45 amp MPPT.
Solar is designed to operate 24x7 all year long. Batteries are something else.
The controller's package will visibly announce the max output to the battery bank.
I have a 20amp Renogy controller that has a 236 watt limit on solar. Ran 4 100 watt panels through it. Eventually it caught up to me, but the only damage was the case around the battery + connection melted. Still was working when replaced with 45 amp MPPT.
Solar is designed to operate 24x7 all year long. Batteries are something else.
