Community Forums

SyrenSkywolf · 03-02-2014, 11:26 PM

We didn't know it when we purchased it, but our TT has a solar panel on top. I discovered it about a month after we got it by virtue of going up to replace the vent in the bathroom. After sifting through all the documents that came with the TT (what is our luck that both our previous '78 Tioga AND this 92' Dutchmen would come with documentation?!?!?), I came across the basic installation instructions and warranty card and such.

It was installed when the TT was new, so it is ~22 years old. The previous owner had the TT parked under a "carport" for several years though, which actually is the future garage space for his cabin, so it hasn't seen direct light in that time, and I have no clue about the owners before him.

I have no idea if it even works anymore, or is still hooked up, etc...We have a basic gauge inside the RV to show us (didn't realize that it was for the solar panel originally), but with it being winter in Montana, that isn't going to show us anything right now.

What is the general life of a solar panel, and is there a way I can directly check the output during the summer, without relying on the readout inside the TT?

gruelens · 03-02-2014, 11:48 PM

If you can access the back of the panel, there should be junction box there. Open the cover and check for DC voltage across the positive and negative leads/terminals with sun shining on panel front. If no back of panel access then you must find where the wires go and do the same. Many RVs have a small factory panel that is only designed to trickle/maintain charge. They are usually about 12" square or equivalent dimension.

The panel should still work at 22 years old. Of course you don't know exactly what happened during those years.

PyrateSilly · 03-03-2014, 10:40 AM

Our coach is 20 yrs old and still has the original 100 watt solar panel that came with it. It does still work so yours at 22 yrs should still work IF it is still hooked up correctly. You may need a new charge controller as that may not work anymore. That's all we had to do for ours so far.

EngineerMike · 03-03-2014, 10:57 AM

Solar panels are an "array" of photo-voltaic cells. Some rigs come w/a flexible mat type solar panel, as plastic sandwich w/PV cells under a flexible coating & on top of a flexible substrate, with lousy UV resistance, which mats generally burn up in the sun over 10 or so years. Larger panels usually sandwich glass/PV-cells/substrate that remains intact for many years, maybe 30 or more. The real issues are whether the sandwich is sufficiently intact to maintain stability of the PV cells, and whether the electrical connections are intact to pass amperage (volts OK, but amps are the objective since you can have high volts but zero amp capacity once you hook up a load). Stuff degrades in the sun if it isn't up to the task, your only way of testing this is to hook up a load. I have a couple of 12V fans I'd use to see if the panel by itself would power something. You can probably hook up a good VOM inline using the A scale (good VOMs will handle up to ~5 or 6A, usually fused at 10A protection, which should be sufficient for a small load test) to read actual load.

As mentioned earlier, most PV arrays come w/pre-made wiring pigtails which you can unplug. If not, or if yours were bastardized when installed, you'll have to figure out how to get access to the output wires.

The largest panels are not capable of more than maybe 180 watts real time (that's a high end panel), which would be ~13.5-14A at nominal 12V production, so running a small fan or other 12V appliance should be well under that. If it would produce 3A, I'd say the panel is operating. As to the charge controller, do a search here on iRV2 on "solar controller" and you'll find a good basis for research & understanding of what that does & how you might consider proceeding to get properly hooked up & making use of the panel.