Beginner questions - Solar boondocking a micro minnie

[backtrack15]

Originally Posted by Marine359

Thanks for the info about your solar setup. I was unsure how much we needed, but from your post, it appears 200w is enough. Although I use a cpap and we have a compressor fridge, we’ve got plenty usable AH, so if the solar panel can deliver 25 amps per day, we’ll be able to boondock for 5 days without using generator. Let us know how the Maxxfan install goes please. Easy-Peasy install next to bed on 12v car adapter outlet, wired to 20amp blade fuse. Maybe harder for you to find a good location.

Just FYI: Installing a MaxxFan Deluxe required me to make a 1" offset to lift the vent 1" off the roof of the trailer. This is because the MC4 ports on the roof are directly behind the vent and in the way of the "overhanging" bit of the Deluxe model.

I advised Winnebago to move the MC4 ports back a few inches... not sure if they took my advice or not on newer trailers.

[marc]

Originally Posted by Marine359

Thanks for the info about your solar setup. I was unsure how much we needed, but from your post, it appears 200w is enough. Although I use a cpap and we have a compressor fridge, we’ve got plenty usable AH, so if the solar panel can deliver 25 amps per day, we’ll be able to boondock for 5 days without using generator. Let us know how the Maxxfan install goes please. Easy-Peasy install next to bed on 12v car adapter outlet, wired to 20amp blade fuse. Maybe harder for you to find a good location.

The important point to know about solar is that panel power can fall off a cliff with any shadows on it. That's why I pointed out Utah (but should have added treeless area). I started with one 24V 200W panel, but my backyard experiments indicated it may not have many (any) bipass diodes. So I am switching to 100W panels in series, and for shade/clouds will increase to 4x of them.

I forgot earlier: no TV use is desired.

Also, almost all of my camping is in the sunny western US.

I think all I will need in the summer is one unobstructed hour of sun at noon (<30ah/day), 2 of those hours in spring or fall (~40ah for some furnace blower use, more lighting, less solar energy), and I have a lot of margin to catch up during suboptimal times if I don't get that ideal noon sun.

But, we'll see. I'm open to supplementing with additional panels, though I only sized the MPPT for 400W. I am reluctant to add more batteries (tongue weight if lead; $$ otherwise).

[backtrack15]

I think the rate at which you can charge the battery will limit you more than the 200W vs 400W. I forget the terminology but even with 200W it isn’t long until I’m out of the bulk charge mode and having the proceedings throttled by the voltage limits on the battery.

[marc]

Originally Posted by backtrack15

Just FYI: Installing a MaxxFan Deluxe required me to make a 1" offset to lift the vent 1" off the roof of the trailer. This is because the MC4 ports on the roof are directly behind the vent and in the way of the "overhanging" bit of the Deluxe model.

I advised Winnebago to move the MC4 ports back a few inches... not sure if they took my advice or not on newer trailers.

Oh, no... I am looking at a photo I have of the roof, and the MC4 entry port is 1/4" behind the factory vent flange, all Dicor'd together! So, I guess I can either move that port and repair the existing entry hole, or create something like you did. Obviously you favored the latter. What did you use to make the lift? Thanks.

[backtrack15]

Originally Posted by marc

Oh, no... I am looking at a photo I have of the roof, and the MC4 entry port is 1/4" behind the factory vent flange, all Dicor'd together! So, I guess I can either move that port and repair the existing entry hole, or create something like you did. Obviously you favored the latter. What did you use to make the lift? Thanks.

I made the offset frame out of 1/2" plywood (2 layers thick, overlapped at corners, glued together). I then wrapped the frame in white Eternabond tape. I bought longer SS screws to replace those that come with the vent fan so that they would have enough length to go through the whole assembly. I used the non-sag Dicor to seal the offset frame to the roof and self-leveling Dicor for the normal stuff (screws and vent flange). I also used butyl tape as is typical.

Moving the MC-4 is a good option. The frame seemed easier for me given what I had on hand at the time.

[Old Navy]

Originally Posted by backtrack15

Just FYI: Installing a MaxxFan Deluxe required me to make a 1" offset to lift the vent 1" off the roof of the trailer. This is because the MC4 ports on the roof are directly behind the vent and in the way of the "overhanging" bit of the Deluxe model.

so, your MC4 connectors were positioned similar to this?

[backtrack15]

Yep.

[marc]

Originally Posted by Old Navy

so, your MC4 connectors were positioned similar to this?

Mine are exactly like that, too.

Originally Posted by backtrack15

Moving the MC-4 is a good option. The frame seemed easier for me given what I had on hand at the time.

Thanks. I understand what you did. I'm thinking I may do what you did, since I'll be working on that roof penetration anyway...

[Marine359]

Would it not be easier to put the Maxxfan where the bathroom fan is now. And bathroom fan is already wired. I dunno.

[backtrack15]

Originally Posted by Marine359

Would it not be easier to put the Maxxfan where the bathroom fan is now. And bathroom fan is already wired. I dunno.

On my trailer the bathroom vent is pretty far back, so the rear of the Maxxfan Deluxe would likely have hung over the back wall of the trailer. I remember measuring it and not being thrilled. The other issue was the black tank vent, which was a bit too close laterally if I remember correctly.

I don’t think other fans (beyond the Deluxe) would pose a problem. The elongated top of the Deluxe was the issue for me.

[Marine359]

Oh, OK
Thank you.

[tinglett]

Originally Posted by marc

I am going to install a "cigarette lighter" style 12V port to power a mobile signal booster.

Rather than a bulky cigarette lighter jack, I went with 5.5mm x 2.1mm barrel jacks which I added to my existing USB jacks like this.




These are easy parts to find, and seem to be somewhat of a 12v standard as I've noticed many portable power stations using the exact same jack. Rather than mod my CPAP's 12v power brick, I bought a barrel plug to cig lighter adapter that you can see in the attached photo. The setup works well. I'm not 100% sure of the max amp rating of these jacks, though, so maybe I should be fusing them. But so far I haven't.

[Marine359]

The wires for these 12v receptacles are pretty small. I installed next to bed and matched mine to 12awg, and wired to 20amp spade fuse on my blue sea fuse block mounted next to my battery. My receptacle is rated to 120 watts, and most cpaps do not exceed 60 watts, so there’s a margin of errors before wires melt. However, I felt safer wiring in a fuse. I bought a 12v car adapter plug with embedded fuse for my cpap, so the receptacle now works great.

[Marine359]

Summer is coming, and I’m close to pulling the trigger on a buying solar for our 2108ds. I’m totally undecided on rooftop or suitcase. I don’t have the budget for both. I really could use some practical advice from owners who have solar boondocked their MM. We want to run the generator as little as possible except on the hottest days. Large battery cap, low power use while boondocking.

Iin practical use, is it better to park the MM in the shade to decrease the need for A/C and reduce fridge compressor use? But, I guess the trade off is reduced watts produced by rooftop solar. If you park the MM in the sun does the increased rooftop solar production offset the increased power consumption?

If you park in the shade and use suitcase solar, can you get a reasonable amount of production by putting the panel in the sun with a longer cable and bite the voltage drop?

Thinking 200w mppt either way, roof or suitcase. Appreciate any and all input.

[RocknRoll]

Originally Posted by Marine359

Thinking 200w mppt either way, roof or suitcase. Appreciate any and all input.

Hi Jim, I use a combo of both and just posted about it a few days ago.
https://www.winnieowners.com/forums/...ml#post3894209

One thing I didn't mention is that regular solar panels, depending on the wattage, can weigh 30-40 pounds each and that was something I didn't want to add right now, so I opted for a flex panel.

Solar Panel (used with roof inputs)
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Suitcase (used with "solar" battery)
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[Fred 2106DS]

Originally Posted by Marine359

Thinking 200w mppt either way, roof or suitcase. Appreciate any and all input.

Hi Jim, We have both rooftop (280W) and suitcase (120W) solar. We dry camp at state park campgrounds most of the time. The parks we camp at are heavily wooded so neither our rooftop or suitcase solar do us much good while camping. Our generator and two 45A lithium chargers make quick work of charging our 200 Ah of lithium batteries and is the best option for us. That being said, I do find the roof top solar the most useful for the way we travel. We use the rooftop solar and 20A DC/DC charger to recharge the batteries when we're towing since we run our absorption refrigerator on AC when we on the road and then switch to propane once we've reached our destination. The rooftop solar also keeps our batteries charged when the MM is setting in the driveway between trips. Our suitcase solar is made of two mono-crystalline panels, weighs over 30 lbs. and is bulky so we rarely carry it anymore. If we start camping in areas that aren't as heavily wooded my opinions on solar may change.

Also, to get the most out of using a suitcase, you should keep moving it with the sun throughout the day. For us, that is a major downside since we don't tend to stay around the campsite on nice days.

To bad we don't live closer, I would let you have our suitcase to try out for the summer.

[Marine359]

Thanks Fred,
I’m thinking maybe one 100w fixed panel on roof, and one of the new Renogy lightweight 100w suitcase. If the panels are electrically similar, I should be able to wire them into the pass thru to a 1/2/both/off disconnect switch, then wire the switch to CC then to my Blue Sea spade fuse block. We have low power demands when boondocking, except our compressor fridge consumes 25-30 ah/day. Battery is big enough to go for a week with no genny if I can replace 30 ah per day. I don’t want to park MM in sun to collect the ah needed. Do you think the lightweight suitcase will give me enough if placed in the sun? You tubers say it delivers 5 amps.

[jwiebe]

My 2100BH came with 100W solar pre-installed (GoPower). It has the GP-PWM-10-SQ solar controller installed in the pass-through storage compartment. Do you think I could install an additional Renogy 100W flex panel on the and use the existing MC-4 connectors on the roof? Or would I have to run new wiring?


I suppose an alternative option would be to buy a standalone suitcase setup with it's own controller and just run that directly to the battery with alligator clips. Or would I need to connect that into my existing controller?

[Marine359]

Originally Posted by jwiebe

My 2100BH came with 100W solar pre-installed (GoPower). It has the GP-PWM-10-SQ solar controller installed in the pass-through storage compartment. Do you think I could install an additional Renogy 100W flex panel on the and use the existing MC-4 connectors on the roof? Or would I have to run new wiring?


I suppose an alternative option would be to buy a standalone suitcase setup with it's own controller and just run that directly to the battery with alligator clips. Or would I need to connect that into my existing controller?

If I go with two panels, I’ll buy a Victron 20amp mppt controller, which is capable of charging at a much higher rate than a Pwm CC, and can support two or three 100w panels. Since most 100w panels produce 5-6 amps @18v, If you connect a second 100w panel in parallel with your first panel, you will likely burn out your 10amp charge controller. Mounting a second panel on the roof and sharing the gland wiring with the other panel will require a higher rated CC. When wiring in parallel, power (amperage) is additive, and voltage stays the same. Ask Fred for confirmation.

[jwiebe]

It was more a question of whether the connectors/wiring would work. Seems like the MC4 is fairly standard so I don’t see why not. Will look at buying a new charge controller if I pursue this option. Swapping it out should be trivial.

Why the Victron over the Renogy MPPT controller?