Originally posted by KB7LAK
What are the plugs called that are on the roof for solar? I have a 2019 172 and I want to wire in a 200 watt set of panels. It says it's wired for solar, so is there a wiring diagram or schematic to how all this wires up? I bought some used lithium iron phosphate batteries that will run the camper. I just want to extend them beyond the 40 amp capacity they have. One of the 2 wiring harnesses has a charging voltage on it when the trailer is plugged into shore power, and the other does not. This tells me there's different places these voltages go.
Does anyone have a schematic of the 172? |
No schematic but as GlueGuy says the circuits are pretty simple. Assuming by "two harnesses" you mean the 4 wires connected to the tongue mounted battery, one pair of these should go to the solar connector on the side of the trailer, the other pair (the ones with voltage on them) to the ac charger and dc fuse panel.
You do not need to use the existing wires going to the solar connector. Many folks find it more convenient to run their own conductors from their batteries to their charge controller and on to their solar modules. Either way, please DO install a fuse or circuit breaker at the battery, it is unsafe to run an unprotected circuit from the battery, if you get a short you can burn up your trailer.
Use at least 10 gauge wire and a 30A fuse. If you plan to keep your solar modules portable and run a longer set of conductors to them (over about 20 feet one way) then go to 8 gauge wire to keep your voltage losses down.
You will need a solar charge controller configured for lithium batteries and should change out your ac charger as well, lithium batteries need a different charge protocol than lead acid batts. Also, you should not attempt to charge lithium batteries when they are below freezing, so many folks relocate them to the inside of their trailers from the tongue so they stay warm.
When you say you want to extend beyond the 40 amp capacity of the batteries you have, I think you probably mean 40 amp hours. Amp hours are a measure of battery capacity. Amps are a measure of instantaneous power from the battery (assuming a nominal 12V battery).
If you add 200 watts of solar to your system that will produce around 12-13 amps at full sun as GlueGuy says. Over a typical 4-5 hours full sun on a decent day you would get around 50 amp hours, more than what your battery can take even if you start with it fully discharged. What I'm leading up to is that 200 watts is really too much for a 40 amp hour battery. I would suggest staying with about 100 watts of solar and consider getting more battery capacity first before adding more solar (assuming you need more).