Questions about specific components in prep for first off-grid system

Roger456

New Member
Hello everyone,

I currently live full-time in an RV I bought new last year, 2019 Wildwood X-Lite 241QBXL. I'd like to buy, install an off-grid system with batteries for my RV, BUT also scalable & powerful enough to remove and install the system in a medium size cabin that I will build or renovate (approx. 400-1000 sqft) in AZ, NV, or UT.

For the RV, I'd like to power everything off-grid (including heavily used 20amp Coleman Mack AC, fridge & even want to charge my BMW i3) but want the flexibility of a system that will auto-detect/auto-shift load needs & battery recharging between shore power, battery bank & solar array.

For the cabin, I'd like to remove the system from the RV and install for the cabin to power everything. I will avoid high voltage appliances and go with 110v mini-split for AC, low voltage fridge, low voltage washer/dryer combo. My reason for avoiding high voltage appliances is to decrease the load on the system but please let me know if my reasoning is flawed. My guess-timations on the power needs of the system are about 3-4kw, so as to accommodate 1-3 conscientious people simultaneously. As for higher loads that are unknown at this point such as a cabin well pump, I'll exclude that in my scenarios and would likely do a stand-alone system in a small well house.

I have read and watched the videos from Will Prowse (thanks Will!) and was very impressed by the MPP Solar all-in-one device. I really like the idea of building a system without having to put together all the components. However, convenience is secondary to function, scalability and stability based on my stated purposes. Cost is less critical because I really need a system that is low maintenance, stable and powerful. I understand that putting together a system piece by piece is more educational and makes for a better owner but I'll be building or renovating a cabin so the systems will get less attention than the larger project.

So here's my questions about the specific two options as I see it, but feel free to comment on alternatives. My budget is between $4-10k but obviously lower is better.

My main question is... Is Option 1, the high entry All-in-One a stable, reliable and easier replacement realistic and a better option? Secondary question.. As Will Prowse states on his website, the All-in-One is cheaper AND easier for his needs. As you increase the cost of the All-in-One devices to meet the higher power & more scalable scenarios, is it still a better option based on cost and complexity? Additional questions are at the end of my post.

Option 1 - Separate components:
Solar panels:
5ea x 400watts = 2000watts initially for the RV expanded to 8-12ea x 400watts = 3200-4800watts; Q Cells G5.3 Q.PEAK DUO L; $260x5=$1300
Batteries:
4ea x 100Ah 12V LifePO4 Battle Born; $950x4=$3800 OR 2ea x 200Ah Lithium LiFePO4 ExpertPower 12V; $1450x2=$2900
Charge Controller:
1ea Midnite Classic 250; $1050
Inverter:
1ea Magnasine MSH3012RV 3000W 12VDC Pure Hybrid Inverter Charger; $1800 or some other Magnasine Inverter/Charger if more suitable
Disconnects, cables, breakers, shunts, etc
...; $500

Total costs: $7550 - 8450

Option 2 - Less components
Solar panels:
5ea x 400watts = 2000watts initially for the RV expanded to 8-12ea x 400watts = 3200-4800watts; Q Cells G5.3 Q.PEAK DUO L; $260x5=$1300
Batteries:
4ea x 100Ah 12V LifePO4 Battle Born; $950x4=$3800 OR 2ea x 200Ah Lithium LiFePO4 ExpertPower 12V; $1450x2=$2900
Controller/Inverter All-in-one:
MPP Solar 5kva 5000w 48v 230vac solar inverter + High PV input 500vdc 80A MPPT solar charger + battery charger 60A; $550 OR MPP Solar Hybrid Solar inverter 5000w 48vdc 230vac MPPT solar charger PV input 900vdc VDE certifed Parallel-able solar inverter; $1300
Cables, but NO disconnects, breakers, shunts between controller & inverter?...; $200

Total costs: $4950 - 6600


I'm aware that my understanding of electrical systems and provisioning is novice level so please correct me if I've mismatched voltage, watts, amps, etc. I don't put forth my plans as an expert and have learned other trades by necessity, study, and doing it and being prepared for failure/retry.

As for the EV car charging, it is not a must have but I'd really like to be able to at least do Level 1 charging and the possibility of Level 2 charging under certain circumstances, i.e. shore power sometimes or super sunny days in which I'm willing to turn everything off and only charge the car (BMW i3).

I would really appreciate your feedback regarding comparisons I'm attempting to make between batteries, inverters and All-in-One's. For example, I don't really understand the usage/capacity differences between the two battery types I'm considering. Obviously the costs are different but which is the better value, longer life, etc?

Another point I'd like to mention in soliciting your advice, is that there is a company in northern California about a 5hr drive from me now that offers to help build my system on a board as long as I buy the products from them. They are very reputable and have a long history. So I'd be up for that adventure if you think that Option 1 far outweighs Option 2. They sell the brands I've mentioned in Option 1 btw.

Lastly, sorry for the long post especially given it's my first and a big thanks for your advice. Special thanks to Will Prowse for the excellent website, videos. It's especially helpful that he includes information from an RV-er perspective and not just off-grid system in general.

Thanks,
Roger
 
Last edited:

DASH

Solar Addict
I would first consider Your estimated energy use per hour during a 24 hour period. The easiest way I found is to convert everything to watts. For example 8-9 am run microwave for 10 minutes. (120 volts X 10 amps) X (10/60)=200 watts used. Also figure out your peak electrical load (Some people like to run several electrical appliances at the same time). This will give You an idea of the size of your panels, batteries, and inverter. Browse this forum, and You'll see what others have done. On a side note, for those who already have an RV and wish to have a off grid cabin. I always thought it would be a great idea to build the cabin such a way that the RV can be temporarily attached to it, when the cabin is being used.
 

mapguy525

Solar Addict
A caution on the use of an All in One(AIO) for RV. There are challenges to maintaining proper ground and neutral bonding utilizing an AIO in a mobile application. This is a situation where price shopping upfront can cause the need for lots of head scratching to solve issues with open grounds and or open neutrals at project end.

Remember three distinct situations involving neutral bonding are present in RV's
1. When connected to shorepower -neutral bond is upstream in the primary panel providing the shorepower circuit.
2. Not connected to shorepower but using DC consumers
3. Not connected to shorepower but providing power inversion

Personally, for the large loads described, a hybrid inverter like the Victron Multiplus is a better fit as it abilities for load support and battery charging, plus more...yes it is not cheap like the mpp or other brands of inexpensive AIO. It will however support your stated goals in a more seamless manner and safely.
 

Roger456

New Member
I would first consider Your estimated energy use per hour during a 24 hour period. The easiest way I found is to convert everything to watts. For example 8-9 am run microwave for 10 minutes. (120 volts X 10 amps) X (10/60)=200 watts used. Also figure out your peak electrical load (Some people like to run several electrical appliances at the same time). This will give You an idea of the size of your panels, batteries, and inverter. Browse this forum, and You'll see what others have done. On a side note, for those who already have an RV and wish to have a off grid cabin. I always thought it would be a great idea to build the cabin such a way that the RV can be temporarily attached to it, when the cabin is being used.

Thanks for your reply. I already have considered energy usage (2-5kw) but my question was about two specific technologies based on a specific scenario. Specifically, I'm asking about the scalability & reliability of the All-in-One devices (Option 2) on the higher end of energy usage & capacity vs. the more traditional route of separate, high end components described by Option 1.
 

Roger456

New Member
A caution on the use of an All in One(AIO) for RV. There are challenges to maintaining proper ground and neutral bonding utilizing an AIO in a mobile application. This is a situation where price shopping upfront can cause the need for lots of head scratching to solve issues with open grounds and or open neutrals at project end.

Remember three distinct situations involving neutral bonding are present in RV's
1. When connected to shorepower -neutral bond is upstream in the primary panel providing the shorepower circuit.
2. Not connected to shorepower but using DC consumers
3. Not connected to shorepower but providing power inversion

Personally, for the large loads described, a hybrid inverter like the Victron Multiplus is a better fit as it abilities for load support and battery charging, plus more...yes it is not cheap like the mpp or other brands of inexpensive AIO. It will however support your stated goals in a more seamless manner and safely.
Thanks very much for your reply & the advice. Excellent suggestion, given that my Option 1 scenario was buying separate inverter & charge controller. You also accurately considered my priorities & complete question.

I looked at the Victron you mention. It does look ideal as a combined inverter & charge controller so thanks for the recommendation. What are a couple of reputable online dealers for the device? What is your opinion regarding ROI & reliability when it comes to buying a 3k then adding a 3k later vs. buying a 5k in one box? Setting aside the 1k difference, obviously.

I chose the Magnasine because I'd still need a charge controller and the Midnite Classic seemed to have the largest support library online. The Magnasine MSH3012RV is advertised as "Designed specifically for use in RVs" and mentions "Built-in RV-C Connector: The built in RV-C connector and protocol allows the MSH-RV Series to multiplex directly with the RV’s network bus/backbone. Program your inverter/charger settings using the RV’s system monitoring display." Do you have an opinion about the Magnasine MSH-RV, in the context of my Option 1 scenario?

Your comments about AIO's "maintaining proper ground and neutral bonding" were over my head so if you don't mind breaking that down for a beginner I'd appreciate it. I did Google "Neutral bonding" but it sounded like lightning rod in the ground stuff. Wouldn't the AIO physical box be grounded to the frame of my travel trailer when I install it?

Thanks again for the excellent suggestion on the Victron.
 
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