26' Rv Project.

Let's start over. 12v plan tossed.

I would like to set up a system for "van life". This will include my wife and myself. In our 40's and empty nesting we want to get mobile. We decided one of our first steps is power. This will allow us to start shaving some money of the current monthly expenses and be ready to move into mobile living when we find our platform.

Power Requirements:

Constant 500 watts per hour. After that I would like to be able to run up to 4kW on the constant demand circuit if we choose. Additionally I want to have a high enough surge capacity for things like a skillsaw, shopvac, or small A/C unit.

We are looking at 12'x8' of panel space. Possible up to 26' x8' but I didn't want to use the whole roofline. I was hoping to mount the panels to a framework that would allow me to cover and secure them in transit and deploy them when parked.

For a bank I am considering 15kW-20kW capacity. 12-15KW being the projected daily need. I also would like to have a way to charge the bank from shore & generator power.

I have about $3k for a startup budget. My initial plan was to purchase the inverter. Then batteries over about 4 months. Then start adding the solar to the equation and reaping the rewards. I don't need top end but I would like to avoid total junk.

So I guess the next question is 24v or 48v What costs less to set up and will suit my needs? How much investment am I really looking at over time? I was thinking $6k and I would be well on my way to electrical independence.

I used a 48 volt AIO for my 30amp travel trailer. The AIO works well but has several drawbacks compared with more expensive alternatives. One is that getting the most out of a shore power connection less than 30 amps requires a programming adjustment. The idle power consumption is much greater. Supplying 12 volt coach power requires extra equipment or additional efficiency losses. You can certainly get setup with a working system using good quality budget equipment but you will pay with loss of features, flexibility, and convenience. I don’t regret my installation but probably most people would prefer 3 or 4 thousand dollars more for a set it and forget it system.

Thanks Bobert. AIO is that standing for All In One? I was checking out an eco worthy model and a few others when I first started looking into systems.

Curious what is the difference between 110v/120v and how will it limit me if it doesn't have the 120v standard?

How about this 6kW 48v split phase 120/240?
The info is for both the 5k & 6k models. I do like that it has potential to even run 240V equipment like a clothes dryer. It has more than enough ratings to run the 500 watts constant I'm looking for and the 3600 watts I might push it too. I read it can handle up to 60A combined on all 3 circuits. 3k per pole and 6k when combined poles (240v). That should allow me to run pretty much anything I can see a need for. I also like that it claims to work with underpowered generators for the recharging aspect.

I read some mixed reviews in the ratings section. It does have a 1 year warrantee so I should be able to get a new one if it fails too early and a year is plenty of time to save up reserve capital to replace something down the road. I know I said I wanted to avoid cheap junk. It looks cheap but someone said something about a "toroid transformer" which means nothing to me. I doubt I will push it too hard anyway. It also has an eco-mode that anything less than 10% power (500w?) it cuts load. Depending on how that works out it might save me juice or never get used I dunno. Opinions on this unit?

Batteries? If I get this right as voltage goes up even though capacity is still the same the actual usable wattage is higher correct? v*a=W If I want to hit close to a 20kW bank I need about 400 ah of 48v batteries if I understand correctly.

Next question. 51.2V battery. Is this compatible with a 48v system? It seems to be a pretty odd voltage to match up with an inverter. It allows up to 4P for an 18kW bank at about $5k.

There is also this 48v 100ah I was considering as well. It will allow me to run a larger bank as it accepts 6P and is already 10ah higher. Not sure I really need more than a 15-20kW bank but having the option could be nice.

Both are pretty close price points. My thought were if the 51.2v battery is compatible that it likely has more usable capacity than the 48v since it starts out 3.2v higher It should also recover from discharge to usable state quicker since it is smaller capacity correct? Maybe someone can clarify these areas for me.

For a shore power charger I was looking at the aims or the sterling. The sterling looks to be the better option. Does it do 48v? It is kind of intimidating since it isn't as plug and play looking as the aims.

More reading today. If I am correct all "48v" batteries are 51.2v? 4x12.8V since everything breaks down into 3.2v cells in the end. So go with whatever is in my budget and gives me the most expansion capability.

Now the question begs asking. What is the drawback of using 12.8v batts instead of 51.2v batts?

I saw some 12v 300ah Li Time that claim 4p4s option. The biggest drawback I see is needing to purchase $4k worth of batteries before I can use the system as opposed to $1.4k. Am I better off going with indvidual 48v batteries in parallel rather than 12v batteries in series and parallel? Will 12v 300ah batteries give me a better discharge ability?

With the 12v 300ah I will need a minimal of 2 banks. I was thinking the 300ah will overkill to the point of almost powering my current house with 2 banks. Individually they have 200A BMS's rated at 200A continual draw and 400A max (5seconds) It would also mean the batteries rarely see a low state of charge 600ah=30kW. I understand this to mean they should last a lot longer. In the end I would have invested $8k.

With Vestwood 48v 100ah batteries they are 100A bms with from what I can find a 100a rated discharge current. How will the lower amp BMS influence the system? I can build it up to the same capacity for the same price but that is the limit of the 48v capacity. 12v can still add 2 more banks.

How much does it affect things if the two banks are built 6 months apart and then combined in the system? What if I wanted to add a 3rd bank a year down the road?

From what I understand it is best to get them all at once with same brand and capacity. Realistically I would be saving for years to have $16k to drop on batteries. Just doing 2 banks in a year is going to be a little difficult. Am I better off going with the more affordable 48v batteries for this reason?

Do you have the rig you are planning to travel in? The rig itself will pretty much dictate the equipment you need to use. Each type and size camper comes with unique limitations that affect what components are practical. Is your camper a 30 amp ac system? If so an inverter over 3500 watts can’t be used without tripping the main breaker.

AmpD said:

For a shore power charger I was looking at the aims or the sterling. The sterling looks to be the better option. Does it do 48v? It is kind of intimidating since it isn't as plug and play looking as the aims.

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I’m not sure I understand this statement. The AIO charges the 48 volt battery bank from shore power whenever it is connected unless the user programs it otherwise.

AmpD said:

I saw some 12v 300ah Li Time that claim 4p4s option. The biggest drawback I see is needing to purchase $4k worth of batteries before I can use the system as opposed to $1.4k. Am I better off going with indvidual 48v batteries in parallel rather than 12v batteries in series and parallel? Will 12v 300ah batteries give me a better discharge ability?

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If space considerations allow 48v (nominal) batteries are a lot less complicated. I used 4 12v batteries in series for my setup because a single 48v battery would not fit in the space I had available.

Bobert said:

Do you have the rig you are planning to travel in? The rig itself will pretty much dictate the equipment you need to use. Each type and size camper comes with unique limitations that affect what components are practical. Is your camper a 30 amp ac system? If so an inverter over 3500 watts can’t be used without tripping the main breaker.

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Let me clarify it’s not that a inverter over 3500 watts can’t be used just that if you use over 3500 watts off the inverter the trailers 30 amp breaker will trip. Essentially if you have a 6 k inverter almost half of it’s output cannot be used.

AmpD said:

I would like to set up a system for "van life". This will include my wife and myself. In our 40's and empty nesting we want to get mobile. We decided one of our first steps is power. This will allow us to start shaving some money of the current monthly expenses and be ready to move into mobile living when we find our platform.

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Is this for a mobile van life system?
Or are you building a residential system "to start shaving some money off the current monthly expenses"?

A lot of the equipment for these 2 scenarios are completely different.
And, if you're expecting to "save money" by installing residential solar you may be overly optimistic. If you are fortunate enough to get to a break even point in less than 10 years you will be ahead of most.

But, having emergency power at home is important and has real value. And having solar power in an RV is indispensable.

AmpD said:

12-15KW being the projected daily need.

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Sorry, a lot of stuff was added after i started writing my previous post.

This is where you need to start. I think you're getting bogged down on the batteries and inverters before you have the solar (your main source of power, right?) figured out.

I have not seen or remembered where you are but lets start with 3 solar hours in the winter and 5 solar hours in the summer.
Winter: 15000Wh / 3h solar = 5000W of solar
Summer: 15000Wh / 5h solar = 3000W of solar

Do you have enough space for 12x 400W panels? 20x 250W panels?

If not, somethings gotta give.

As far as a 30a breaker.. If running off battery you can use whatever the batteries will support, up to the watt limit of the inverter. So for example if you have a 6000w onverter, you COULD run ‘6000 watts’ of stuff off battery power, if your battery supported it. But it may not. Batteries have a ‘safe’ range of charge and discharge current based on their type and size. So if for example you had a 51.2v (nominal) lifeo4 battery with a continuous limit of 100a, that specs out to 5120w (assuming voltage is and stays at 51.2 which it wont) and you may or may not be able to run 6000w off of it for more than a few seconds before its BMS disconnects you.

The 30a limit of a shore power connection only dictates what you can pull from shore power. Depending on how your system is set up that might be just the limit of your ‘charge from shore’ rate, or it might the limit of loads you can directly power from shore pwoer while your inverter is ‘bypassing’ shore power directly to your loads. The 2nd would be the more common approach, the 1st is possible but slightly less efficient and requires more hardware. But, it never ‘hard limits’ you to the shore power rating.

End Goal. 26'x8' uhaul possibly schoolie 30'+ in length converted in to an rv/tiny house setup. There is a different fund for this we just haven't purchased it yet. There will be no power installed. We are leaning more towards the 26' uhaul setup for various reasons.

I was thinking 1 or 2 simple circuits running directly from the inverter would suffice for our needs. "kitchen/livingroom" "bedroom/bathroom". atm we have $4k towards solar so I'm definitely not ready to build anything. I had some misconceptions on how much capacity would be needed and battery requirements.


There will be no need for large amounts of water pressure. Less than 50W on a pump for 1gal/min.

500watts per hour is the bare bones no ac setup.

150Wx24hrs laptops (not 24 hour load but counted there)
150Wx24hrs Fridge
50Wx24hrs Heat monitor one propane heater
50Wx24hrs Water pump (again I'm overestimating)
50Wx24hrs Projector tv
10Wx24hrs Internet Service Modem

After that it is more a matter of luxury and wants. We will assume an AC is desired so add

2Kw <4hrs seasonal


Again I have nothing to really go on aside from my home usage. That is 2kW/hr max. Billing varies between 10-18Kw total daily. I don't see that I will be running a dishwashing machine an hour a day or powering 2 fridges and freezer. Most of our use is in the electronics center and we are tossing that to goodwill when we downsize.

I do want to be able to live comfortably and can see usage up to 1-2 kWhr during our days off for 8 hour or more.

Yes I was looking at 400w panels I originally was thinking 9 of them taking half the roof space.

My original thought was we start small and build it up while we are looking for "the one". I see that isn't so feasible now.

It still would be a good time to start planning! I do really appreciate the advice here. I know it looks ill thought out and it is. That is why I need to be here learning.

MT usa but heading south since we are aging. Hence the tiny home on wheels!

@Bobert I haven't ruled AIO's out just not as keen on it. I was thinking of a way to bypass the inverter and direct charge should need occur.

AmpD said:

I do want to be able to live comfortably and can see usage up to 1-2 kWhr during our days off for 8 hour or more.

Yes I was looking at 400w panels I originally was thinking 9 of them taking half the roof space.

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2kW for 8h? Or is that 2kWh over the course of 8h which is a rate of 250W for 8h?

9x 400W panels would likely be about 50V 8A
8 or 12 panels a little more flexible in array config but we can revisit if necessary.

3S3P likely as 9S or 9P are very impractical (maybe impossible):
3S would require an SCC with at least 200V max input voltage.
3P would be about 25A which works with standard solar 10AWG cable and connectors which is good.

9x 400W x "<4hrs seasonal" = less that 14400Wh daily to use and recharge batteries.

Just messing with numbers.

yes, the more I understand all this the more realistic I'm getting on it. I'm pretty ignorant to all this solar stuff so please forgive me while I get down to earth on all this. Figuring out what is needed to complete the system and how much of an investment it will be is my goal. You guys already saved me a massive headache telling me to return that inverter. Thanks!

so 4 hours seasonal is likely unrealistic when looking back at it. I might be able to get away with 12-14kW a day but I don't think my wife will be so happy with it.

500w per hour general usage (18hrs). 2000w per hour high demand (6hrs) usage. 9Kw+12Kw for about 21Kw per day (48v 400ah in batteries). That's where I decided I needed to bump it up to 48v600ah for overall 30kWh capacity. I do feel our usage will be lower than this but I also want to leave room in the system to keep the batteries from constantly over discharging am I correct on that?

We are only up an active in the house/rv for about 2-6 hours a day as the rest of the time is spent working, sleeping, or outdoors. Most of this use will be early morning or evening hours. We work dayshifts so the draw during peak recharge hours will be low. This is where extra capacity would come in handy. Days we have 2 hours peak demand would fill up the excess and give us a reserve for those days we use it 6 hours. That was the thought anyway.

12x400w is looking more reasonable isn't it? At 2'x4' each there is room for up to 24 panels.

I'm pretty sure the 100a BMS batteries are more than enough for me but I like having knowledge. Can someone clarify these BMS questions for me?

4s2p 12v 300ah with 200a bms versus 6px48v 100ah 100A bms. Am I correct in assuming the 200a BMS 12v 4s2p will be a more solid system? With loads under 4kw does it matter much to me?

AmpD said:

12x400w is looking more reasonable isn't it? At 2'x4' each there is room for up to 24 panels.

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What 400 watt panels are 2' x 4'? To the best of my knowledge 1m x 2m is the smallest you might find in that wattage. That works out to over 19 sq ft per panel.
I understand your generous numbers for power estimates, but you will be better served by getting more accurate estimates. I run my entire home in Baja off just over 5kwh a day. Besides saving on the cost of a full system you will find you may need less space for panels, or you now have enough space where you didn't before revising your numbers.

I have a DIY utility trailer conversation 20 feet. I have two windows, 3 inch foam insulation in roof. 1.5 inch foam in walls and 6 inch fiberglass in floor. Loads I have 12 volt lights. 10 cf 12 volt refrigerator. 12 volt water pump. 12 volt usb chargers. 120 volt and Lp tankless water heater. 120 volt microwave. 120 volt vent hood. 120 volt TV and DVD. 120 volt mini split 26 seer. Lp cook stove. Lp backup heating. Growatt 3000 watt 24 volt. I am including the growatt in loads because it’s idle draw is 65 watts.

Power I have 2000 watts of panels 6.5 feet x 15 feet of the roof 8.5x 20. 1000 watts are tiltable to 45 deg. Other is at 4 deg ( so rain and dirt runs off).
3000 120 volt watt growatt with shore power connection. Battery is LFP DIY 7.2 kw.
Summer time with AC all is great especially if inverter is turned off during the night. Saving 0.5 kWh of battery.
Winter with lows in the 20s we use at least 5 kWh from sun down to sunrise 17 hours. So battery has to be fully charged at sundown. Less than a perfect day will require generator to top off the battery( 2500 watt internet generator gasoline).

littleharbor2 said:

What 400 watt panels are 2' x 4'? To the best of my knowledge 1m x 2m is the smallest you might find in that wattage. That works out to over 19 sq ft per panel.
I understand your generous numbers for power estimates, but you will be better served by getting more accurate estimates. I run my entire home in Baja off just over 5kwh a day. Besides saving on the cost of a full system you will find you may need less space for panels, or you now have enough space where you didn't before revising your numbers.

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Cheap ones I saw on amazon that are probably mythical unicorns and nowhere near what they claim ?

I do agree I'm overkilling it. We likely will be just fine with 12kW per day. If I double that from the gate then there is no worry down the road and the system never gets stressed. That was my thought.

acdoctor said:

I have a DIY utility trailer conversation 20 feet. I have two windows, 3 inch foam insulation in roof. 1.5 inch foam in walls and 6 inch fiberglass in floor. Loads I have 12 volt lights. 10 cf 12 volt refrigerator. 12 volt water pump. 12 volt usb chargers. 120 volt and Lp tankless water heater. 120 volt microwave. 120 volt vent hood. 120 volt TV and DVD. 120 volt mini split 26 seer. Lp cook stove. Lp backup heating. Growatt 3000 watt 24 volt. I am including the growatt in loads because it’s idle draw is 65 watts.

Power I have 2000 watts of panels 6.5 feet x 15 feet of the roof 8.5x 20. 1000 watts are tiltable to 45 deg. Other is at 4 deg ( so rain and dirt runs off).
3000 120 volt watt growatt with shore power connection. Battery is LFP DIY 7.2 kw.
Summer time with AC all is great especially if inverter is turned off during the night. Saving 0.5 kWh of battery.
Winter with lows in the 20s we use at least 5 kWh from sun down to sunrise 17 hours. So battery has to be fully charged at sundown. Less than a perfect day will require generator to top off the battery( 2500 watt internet generator gasoline).

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Thank you for sharing your setup. That Is real numbers and use. Much appreciated. Going 48v should allow me to get more wattage per foot right?


I've been looking at going USB for entertainment and using 6w led strips for lighting. For a fridge I was just going off a full size model. I will need to downsize but didn't want to sacrifice too much there. For hot water we have a 12v lpg on demand setup with a 6 watt pump. My wife uses an electric water boiler 2 or 3 times a day.

I am a chef by trade so I do like to cook and that will be where most of the variable energy use will come from. Instapot/crockpots, air fryer, toaster oven, ect... Aside from an AC in the summer to keep things bearable I really don't see any large continual draws more than an hour. Maybe a Sous Vide but things like that can be done according to electrical allowances on a daily. Like not in the winter ect.

I'm looking at this as more of a lets do it once and enjoy life wherever we go type thing. We will likely tramp around for a few years until we find our comfort zone then whatever I invested in can be used to power the new permanent foundation. I do realize it is a considerable investment. I just didn't realize how much that was at first. Seems to me the largest investment is in the batteries.

I'm still not sure how it makes a difference on capacity and charging other than it will take longer to fill a bigger bank?

AmpD said:

Cheap ones I saw on amazon that are probably mythical unicorns and nowhere near what they claim ?

I do agree I'm overkilling it. We likely will be just fine with 12kW per day. If I double that from the gate then there is no worry down the road and the system never gets stressed. That was my thought.

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Well if money is no object and you have the space then go for it. I'm just trying to steer you away from wasting money. As I said I live comfortably on 5+kwh a day.
Best of luck to you.

littleharbor2 said:

Well if money is no object and you have the space then go for it. I'm just trying to steer you away from wasting money. As I said I live comfortably on 5+kwh a day.
Best of luck to you.

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My current home usage is 16kW daily for average. It can be as high as 20 or low as 10.

Money is always an object and space will be a consideration. I'm thinking it might have be 7x550w renogy panels.

Myself I might be able to get away with a 200w/hr system and a 500w/hr system would likely suit my needs as a camper unit just fine. I'm looking at this long term and including my wife in the equation. When it is time to gut the camper then the system starts powering a house. I did have some unrealistic expectations before I understood things better. I'm thinking this will cost about $12k-14k for a dyi 4kw/hr (12kW-16kW daily production) 48v 600 ah capacity system. Does that sound like a realistic number?

I saw a deal on 8x 380w 72cell phono brand panels for $1500. I probably should have jumped on it since it was a one time thing but I still don't know enough about it. I come from a no power zone childhood and most of my knowledge comes from generators charging banks not panels. I didn't realize there was so much more to it when adding panels. I thought you simply plugged them into the controller and let the bank charge at whatever rate your panels could produce. I didn't realize it was so crucial to match panel output, bank capacity, and inverter size. I had thought I could top off as needed from genny or shore if the panels were lacking. That is also why I was going to go with the panels last since just having battery banks when the power goes out would be nice.