I have a 30 foot travel trailer with plenty of space on the roof and I want to do some remote camping. I'd like to be able to run the refrigerator, watch TV through-out the day, and be able to use laptop, and some other small electrical items.I was planning on getting two of the Grape 250 watt mono panels. I've heard others say the MC4 connectors don't work all that well so they cut the MC4 off and splice in 10 or 8 AWG. I know this likely voids the panel warranty. Either way, I would fish the two sets of wires down an existing vent (refrigerator vent likely). Down into the lower storage bay.There I planned on buying a decent charge controller, something I could use on another project down the road, the midnite classic 150. I would likely install a breaker/shut off box (as smkettners install). I am thinking I could get 8 six volt trojans (T-105) batteries with a 1500w or 2000w inverter. I was even thinking about installing a 30 amp transfer switch, wiring the inverter into the 'generator input' and taking the existing 30 amp shore power plug, wiring that into the 'shore input'. Then wiring the transfer switch output to the existing shore power input. That should give me power to the entire trailer??? I don't think I could run the microwave and everything, but that would allow me to use any receptacle. Does anyone have any suggestions?

renoman's compilation of Member's solar installations Thanks, Reno!The 30 amp direct connection with transfer switch has some merit as all receptacles are then powered. You could also use individual, smaller transfer switches (ala smkettner) to power select circuits. If all you are going to need is screen, laptops, and installed circuit boards, there are lesser systems that will allow that, i.e. you won't need 8 Trojans and 500w of solar charging with 2000w inverter. First step: Downloadable spreadsheet for use and solar calculationsBTW, MC4 connectors are purpose-built for solar application. They are available in 10AWG and you can't find much better.

daveyboy12 wrote:the midnite classic 150. I am thinking I could get 8 six volt trojans (T-105) batteries with a 1500w or 2000w inverter. That should give me power to the entire trailer??? Great controller..good choice. 8 wet batteries is very heavy and a lot of maintenance. If you can afford that controller, perhaps you'd prefer AGM batteries.It will. That's what I do.

Standard RV fridge will mostly run on propane and is not a huge 12v draw.The rest of the stuff can be run from a 300w inverter. Microwave needs 1800+ watts, electric coffee needs 800-1200 watts and other big stuff that can often be avoided.MC4 is excellent IMO. They are specifically designed for all conditions up on a roof for 20+ years.Midnight Classic 150 IIRC goes to 150v Voc so I have to recommend series panel connection with just two wires coming down. Due to the high voltage I do recommend an appropriate switch on the panel connection for ease of service and safety.8x T105 is a lot of battery. With a small inverter and LED lights you may only need two T105s and four would get you through a period of clouds/rain. If you go 2000w inverter then you do need four but I would wait and see if you need the second set of four. Could about go to a 24v system at this level.Whole house inverter connection is fine. I only recommend sine wave inverters.

RV absorption fridge ?leave it on propane Not on electricelectric uses way to much power around 300 watts to power the heating elementthats 24 amps , the avg total output from your solar panels'fridge control' uses very little power

daveyboy12 wrote: I've heard others say the MC4 connectors don't work all that well so they cut the MC4 off and splice in 10 or 8 AWG. This seems odd, why not open the box on the back of the panel and wire directly or open the box and add short MC4 versus cutting.

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red31
Explorer
Oct 19, 2013
daveyboy12 wrote:
I've heard others say the MC4 connectors don't work all that well so they cut the MC4 off and splice in 10 or 8 AWG.

This seems odd, why not open the box on the back of the panel and wire directly or open the box and add short MC4 versus cutting.
MrWizard
Moderator
Oct 19, 2013
RV absorption fridge ?
leave it on propane Not on electric
electric uses way to much power around 300 watts to power the heating element
thats 24 amps , the avg total output from your solar panels
'fridge control' uses very little power
time2roll
Nomad
Oct 19, 2013
Standard RV fridge will mostly run on propane and is not a huge 12v draw.

The rest of the stuff can be run from a 300w inverter. Microwave needs 1800+ watts, electric coffee needs 800-1200 watts and other big stuff that can often be avoided.

MC4 is excellent IMO. They are specifically designed for all conditions up on a roof for 20+ years.

Midnight Classic 150 IIRC goes to 150v Voc so I have to recommend series panel connection with just two wires coming down. Due to the high voltage I do recommend an appropriate switch on the panel connection for ease of service and safety.

8x T105 is a lot of battery. With a small inverter and LED lights you may only need two T105s and four would get you through a period of clouds/rain. If you go 2000w inverter then you do need four but I would wait and see if you need the second set of four. Could about go to a 24v system at this level.

Whole house inverter connection is fine. I only recommend sine wave inverters.
2oldman
Explorer II
Oct 19, 2013
daveyboy12 wrote:
the midnite classic 150.

I am thinking I could get 8 six volt trojans (T-105) batteries with a 1500w or 2000w inverter.

That should give me power to the entire trailer???
Great controller..good choice.

8 wet batteries is very heavy and a lot of maintenance. If you can afford that controller, perhaps you'd prefer AGM batteries.

It will. That's what I do.
westend
Explorer
Oct 19, 2013
renoman's compilation of Member's solar installations Thanks, Reno!

The 30 amp direct connection with transfer switch has some merit as all receptacles are then powered. You could also use individual, smaller transfer switches (ala smkettner) to power select circuits. If all you are going to need is screen, laptops, and installed circuit boards, there are lesser systems that will allow that, i.e. you won't need 8 Trojans and 500w of solar charging with 2000w inverter.

First step: Downloadable spreadsheet for use and solar calculations

BTW, MC4 connectors are purpose-built for solar application. They are available in 10AWG and you can't find much better.

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