TT Solar array expansion and electrical upgrade complete.

[Davexxxx]

I did mine in phases.

600ah of LiFePO4 batts, with a 2,400W inverter /charger and a solar charge controller big enough to handle the now, 1,200 watts on the roof. It came with 200W

The first part was done last spring, the panels were done just before winter hit.

Still need to do roof wire mgmt. but need warmer and drier weather for that.

2 series strings of 3, then wired in parallel.

Mapped out the roof with a stud finder, so that at least the lead hole of each mounting bracket, are in a rafter. This did require drilling new holes on a couple of the panel frames.

Haven't really put it through it's paces yet but have noticed a pretty radical increase in low light PV production. It was even charging through some of the recent ice / sleet / snow. Not a lot obviously but a trickle is better than none and I'm confident that even on shady sites, or cloudy days, it will charge at least some. Absent heavy Aircon, or space heating loads, probably won't have to plug it into the PPOB at all.

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[Buyer2021]

Looking good

My own rig has 5x 200W = 1000W nominal rated PV array (all in parallel), a 400Ah LiFePO4 battery, with a 3000W inverter (actually a Xantrex Freedom XC all-in-one charger / inverter / transfer switch). I use a Victron BMV-712 monitor with shunt for keeping track of the battery I/O, SOC, etc.

Four of my panels are Rich Solar 200W / 24-volt managed through a VIctron 150|60 MPPT controller, then a single Grape Solar 200W / 12-volt panel managed through a separate Victron MPPT 75|15 controller. I really like that the 24-volt panels begin charging at low sun-angles continuing very late each day, and the whole array provides at least some charge even in overcast / partial shade.

Victron's downloadable Excel MPPT Calculator was an invaluable aid when designing / sizing / choosing components for my all-DIY system.

We all have different electrical demands when camping, I'm able to enjoy essentially unlimited boondocking with my system and use-habits, hope you achieve the same with your setup!

 

[Buyer2021]

BTW @Davexxxx , are you charging your LiFePO4 battery via the truck's 7-pin connector when towing? Using a DC-DC Charge controller to facilitate that?

Myself, I decided that the truck's wiring and fuse-limited charging feed current wasn't worth messing with or upgrading (which is a bit of a PITA) so disconnected the battery-charging feed from the truck inside the trailer (no mod to the truck-side of things, the 7-pin still provides the usual charging feed for other trailers).

I've found that the solar array does just fine keeping my trailer's LiFePO4 battery charged when towing, making the feed from the truck unnecessary and eliminating that load on the truck's battery / charging system.

 

[Davexxxx]

BTW @Davexxxx , are you charging your LiFePO4 battery via the truck's 7-pin connector when towing? Using a DC-DC Charge controller to facilitate that?

Myself, I decided that the truck's wiring and fuse-limited charging feed current wasn't worth messing with or upgrading (which is a bit of a PITA) so disconnected the battery-charging feed from the truck inside the trailer (no mod to the truck-side of things, the 7-pin still provides the usual charging feed for other trailers).

I've found that the solar array does just fine keeping my trailer's LiFePO4 battery charged when towing, making the feed from the truck unnecessary and eliminating that load on the truck's battery / charging system.

No, no Dc to DC charger. Being the Powerboost, I could just plug in if needed and didn't want to add any complications, on an already electrically complicated truck. On an ICE, it would be a no brainer.

I've left the 7 pin charging alone but did a test after the Lithium install, checking the draw at various states of charge. I think the max I ever saw it draw, was 8 amps or something. A non issue, as far as I'm concerned.

I thought about going 24V on the system but at the time, Will Prowse and Nate Yarborough both, considered my sized system to be more or less border line on the benefit of making the change from 12V. Lighter, easier to handle and much less expensive wire, would have been nice but then you need the extra converter and they both warned of parts availability on the road, should something happen, relative to 12V.

My original design, also was to use all parallel connections for the panels, for the improved shade performance but when I sketched out all those combiners, 2 series strings looked a lot better

 

[Buyer2021]

I thought about going 24V on the system

Yeah, that introduces a whole set of complications I didn't see worth dealing with at all.

Just to be clear, my '24-volt nominal' PV panels are 'converted' to 12-volt nominal output to the trailer's 12-volt system by the Victron charge controller.

My original design, also was to use all parallel connections for the panels, for the improved shade performance but when I sketched out all those combiners, 2 series strings looked a lot better

That's the analysis that the Victron VE-MPPT calculator really helps facilitate / quantify. I ran multiple scenarios of parallel, series, and parallel/series mixed strings to evaluate those options, here's an example of a set of runs evaluating one array I considered:

Each situation is specific to the components used of course. In my final implemented design, given that the 200W Rich Solar panels have a Vmpp=37.6 V and Voc=45.4V (vs 20.3V / 24.3V for the 200W Grape Solar panels), I found no benefit in going to a series / parallel arrangement so decided to run all parallel for maximum gain in partial-shading conditions.

YMMV, no worries!

 

[Davexxxx]

Well yeah, there is a lot to consider.

One of mine, was the existing 200W Go Power panel.

I knew there'd be room for and wanted 1200W, to pair with the 600 ahs of batts. The year before, the stock panel was just 80W, which I was going to remove and use as a ground deploy.

When they switched to 200W, I checked the specs against the Rich's and the loss of efficiency, of mixing and matching, was minimal. 3% of the array total, or something like that. IOW, taken off paper and put in real life, less than the effect of a single tree leaf, shading a single panel, at noon, at the equator

Hardly seemed worth an additional charge controller and wiring, in my already crowded equipment area.

 

[HammaMan]

Nice setup! Another option to consider is getting 2 large size solar panels that you just carry with you and set up as practical. It's a small bit of 'labor' to set them for catching the sun in any position be it early morning, over head, or catching the sunset. The PB is handy, but panel prices are the cheapest they've ever been and not having to run the truck for extended boondocking has its benefits.

 

[Los150]

I did mine in phases.

600ah of LiFePO4 batts, with a 2,400W inverter /charger and a solar charge controller big enough to handle the now, 1,200 watts on the roof. It came with 200W

The first part was done last spring, the panels were done just before winter hit.

Hmmm.......I wonder which ones are the newer ones.

 

[tsigwing]

Originally installed the two panels in the center, a 100W panel and a 50W panel. After a bit added the 4 additional 50w panels. Yes, I know I am not getting full usage out of the 100W panel, don't care. With my victron controller, I usually get a full 15A out of it. My camper is at the house, so I can keep it plugged in. Mainly I did this to run my fridge on DC while traveling. Panels are held down with VHB and eternabond.

 

[Davexxxx]

Panels are held down with VHB and eternabond.

Both are really good stuff and for fiberglass or metal roofs, thats the way I'd go too but for any membrane roof, a potential disaster in waiting. You just can't count on the bond between the membrane and the sheathing, holding up to those wind loads. Some of them bubble up and flop in the wind, without any additional loads.

 

[Stormpeakco]

Nice.

Check out 'MYT Solar' (videos and Outdoors RVowners forum).

In May '25, Tom will install six 250W Rich panels on the roof (two 200W Rich mobile on the ground) combined w/ full Victron components & Cerbo-Touch, two 200Ah 24V Victron Li batteries on our generator-less ORV 21MKS TT and integrated w/ our coming '25 KR/PPO 7.2Kw inverter (also no DC-DC chargers).

 

[Davexxxx]

Nice.

Check out 'MYT Solar' (videos and Outdoors RVowners)).

In May '25, Tom will install six 250W Rich panels on the roof (two 200W Rich mobile on the ground) combined w/ full Victron components w/ Cerbo, two 200W 24V Victron Li batteries on our generator-less TT and integrated w/ our coming '25 KR/PPO 7.2Kw inverter (also no DC-DC chargers).

I am familiar with his vids.

Looking forward to seeing the project.

 

[22Platinum]

Looking good

My own rig has 5x 200W = 1000W nominal rated PV array (all in parallel), a 400Ah LiFePO4 battery, with a 3000W inverter (actually a Xantrex Freedom XC all-in-one charger / inverter / transfer switch). I use a Victron BMV-712 monitor with shunt for keeping track of the battery I/O, SOC, etc.

Four of my panels are Rich Solar 200W / 24-volt managed through a VIctron 150|60 MPPT controller, then a single Grape Solar 200W / 12-volt panel managed through a separate Victron MPPT 75|15 controller. I really like that the 24-volt panels begin charging at low sun-angles continuing very late each day, and the whole array provides at least some charge even in overcast / partial shade.

Victron's downloadable Excel MPPT Calculator was an invaluable aid when designing / sizing / choosing components for my all-DIY system.

We all have different electrical demands when camping, I'm able to enjoy essentially unlimited boondocking with my system and use-habits, hope you achieve the same with your setup!

Curious if yall considered one of those "all in one" solutions (also called solar generators) such as EcoFlow Delta Pro 3?

It's the direction I went; just plug in the solar panels and you are done. An app on my tablet tells me all the data points, and it has 12/120/240 outputs. I cut my 12v consumption in half by eliminating the lossy converter my TT came with.

So far I've managed to only need shore power one time since I started camping on January 5th

 

[Stormpeakco]

Looked at the Epoch systems for 4 season, remote-off the grid and off groomed trail experience and balanced that w/ 'MYT Solar' install videos (top shelf monitoring w/ all Victron components, plus lifetime of technical support/trouble shooting, post install).

Like Inspector Harry Callahan famously stated about 'men and limitations' , I felt my 'DIY capabilities/experience-comfort level' did NOT add up to the Li-Solar system that I want to use on Day #1 this spring (the ORV TT 21MKS model doesn't have an Onan, I ain't no spring chicken or electrical engineer and the $ for the install is nearly a wash after selling our previous Sprinter based RV and buying a new TT plus new '25 KR).

Like this quote..."Electrician here, just wanted to say van builders are wildly entertaining and dangerous all at the same time. "Bringing third world electrical work to first world luxury."

 

[Buyer2021]

Curious if yall considered one of those "all in one" solutions (also called solar generators) such as EcoFlow Delta Pro 3?

I considered but quickly eliminated this approach as not meeting my objective of fitting the unit within the limited physical space(s) available in my trailer for a dedicated / integrated full-time RV installation.

I had / have no interest in a physically separate unit / 'solar generator' requiring connection of any sort to the trailer and its PV array to place in-use. I have no interest / need of a 'solar generator' for use other than in the RV.

For my purposes I have no need of 240VAC output.

So, for me, the tailored solution, fully and 'permanently' integrated in my trailer, was a better 'fit'.

YMMV, no worries (no 'solution' is perfect for everyone, choices are good)!

(BTW, my system provides the full-suite of Bluetooth monitoring and control capability via my iPad)

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