Solar Upgrade Planning - Input Welcomed

[Lee-CI]

I realize this will be considered a long post, but I’m looking for input from fellow MOC owners. I know there are several on here that have the larger SolarFlex setups up to and including SuperSolar and beyond. Our 2022 model came with the baseline SolarFlex 200. It is looking like in for a penny, in for a pound.


As for what we will be using our MHC for, on down the road we will be full timing in the future. Currently frequent state parks and COEs. This will change in the future to include overnight boondocking trips during our travels. At this time none of our travels are expected to be extended boondocking trips.


Our MHC is not generator prepped, and as per our signature line I’ve already hardwired a SurgeGuard EMS. With the residential refrigerator, our unit came with a Magnum-Industries 2012 series 2000w inverter, single 200w solar panel and Victron 75/15 MPPT controller.


I’ve already installed a Renogy 40a DC to DC charger for use during travel days and have a pair of 206hr SOK LiFePo4 batteries sitting in my den awaiting installation. My research has indicated that Future Sales has discontinued their 300w solar panels in favor of 330w panels of apparently the same dimensions. I’m considering installing a pair of these panels to up our solar to 860w total, along with a Victron Multi-Plus II 3000w inverter/charger, a 100/50 MPPT controller for the new solar panels to run in parallel with our current 75/15 unit, 500a shunt and Cerbo GX to tie everything together. I’m considering leaving the 200w panel and 75/15 MPPT on it’s own 10awg wiring circuit and running a separate heavier gauge wiring run for the pair of 330w panels and 100/50 MPPT controller. At this time I’m also thinking I’ll leave the 2000w M-I inverter in place on the loop for the refrigerator. One soft start for the bedroom A/C would also be in the works.


I'm planning on discontinuing use of our current converter since the Multi-Plus II incorporates its own converter.



Okay – flaws or issues in my thinking process? I know other’s will surely have thoughts, opinions and maybe even suggestions. Trust me when I say that I’m wearing my big boy pants and would gladly consider any and all suggestions. I am hoping to take advantage of the wealth of knowledge within this group and not make needlessly costly mistakes from poor decisions upon my part. Thanks in advance for everyone’s input on this. Happy camping!

[tjblocker]

I'm doing many of the same things you are doing.

My wife and I are retired fulltimers. We've lived in an Arctic Fox for five years but recently purchased a 2022 3231CK fiver. We spend much of the year off grid in Quartzsite. Ours has 400 watts factory on the roof, and I plan to install an additional 600 watts paired with a 150 | 45 Victron controller. I also have 400 watts of portable. We have a 300ah lifepo4 (LifeBlue) battery and I plan to purchase a second. The bluetooth connection to the battery is pretty useful.

I use two converters. A few years ago I purchased a Progressive Dynamics 60 amp converter for lithium. I left the factory converter in place. Should I need to run the genny for batteries I would use both converters and this would charge batteries very quickly having a charge current of over 100 amps. Two converters loads my Honda 2000 pretty heavily but it handles it. I see not reason to remove a converter. Lead acid battery converters won't hurt lithium; they just won't fully charge the battery. I almost never exceed 14.4 volts on my battery in an effort to be gentle.

I plan to use factory solar prep, but I will have to wire the 600 watts in series to keep current below the 30 amp rating. On the Fox I ran 6 gauge, but want to avoid making more holes in the roof.

I also have 400 watts Zamp portable panels. These are real useful when I want to park the trailer in shade. I can move the panels into the sun. Having both fixed and portable has its advantages.

I plan to install my panels using strut channel. If curious please Youtube "strut channel RV solar". It's a cleaner way to do it.

Oh yea, panels in series don't generate much if there is any shade on any panel. That's the disadvantage of series connection. But the alternative is to run new conductor, which I don't want to do.

I have an RV fridge, but am considering changing the cooling unit to 12volt compressor using products from JC Refrigeration.

I'd be happy to compare notes or answer questions. Good luck
Tom

[PNW Fireguy]

Most modern panels have bypass diodes and shading is contained to the the effected panels only. In addition multiple panels in series raise the PV voltage thereby negating the potential voltage drop between the PV array and SCC. The VOC of our array is 149vdc allowing us to utilize the OEM 10AWG wire with neglible voltage drop. With temp correction the PV voltage can actually approach 187v. Lastly higher PV voltage makes for earlier harvesting in the AM and later harvesting in the evening.

[Lee-CI]

Greatly appreciate folks input, knowledge and suggestions.

In regards to the array, the proposed addition of a pair of 330w panels would be wired in series and have a value of Voc/V: 39.85 and the existing 200w panel has a value of Voc/V: 40.12. Would a single MPPT controller of 100/50 safely handle the input of the array wired series / parallel on the existing 10awg wiring? If I understand correctly, the 10awg wiring is good for 30 amps - with associated line loss of course. I plugged the following into an online calculator. Am I out in left field here or am I on the right track?

[PNW Fireguy]

You are definitely in the MPPT realm if you want to use dissimilar panels. If it were me I would use separate controllers. Just not worth the headache. Also since the Montana roof is convex a single SCC may have issues hitting the max power point since the panels on the door side are at a different angle than the panels on the ODS.

Do you panels have temp coefficient numbers? You need that to temp correct the voltage. As the weather gets colder the panels put out higher output. I think you may be close at correcting 80v to the 100v limit of your SCC. Victron has a online calculator you can verify with.

[Lee-CI]

Originally Posted by PNW Fireguy

You are definitely in the MPPT realm if you want to use dissimilar panels. If it were me I would use separate controllers. Just not worth the headache. Also since the Montana roof is convex a single SCC may have issues hitting the max power point since the panels on the door side are at a different angle than the panels on the ODS.

Cool. Can't say enough how much other's input is appreciated. Original thought process was to utilize two separate MPPTs and running a dedicated heavier gauge wire pair for the expansion panels - with the unlikelihood of even more future additions. Utilizing the existing wiring run would have been the easiest, but easiest is not always the best - or smartest. Thanks for not letting me head off down a rabbit hole with my thought process.