Where to begin

[chadat23]

I have a new to me, stock, shell of a van that I want to build out for camping. Short term I see mostly using it for little weekend trips either solo or with my wife but I have hopes of doing much longer trips with the two of us. Short term I want to be able to run a fridge, a fan, and a few lights so I think a 200W panel and a 12V, 100Ah battery would suffice but long term it's easy to imagine having the equivalent of 600Ah at 12V system with 1000W+ of solar powering a laptop and starlink during workdays, a water heater, cooktop, maybe a bit of AC, etc. If money was no object I suppose I'd build a 24V, 300Ah system but being new to some of this, that sounds like an expensive way to start, but if I start with the minimal system then it'll leave an upgrade path that'll likely be much more expensive both with regards to money and space. Thoughts? Clearly I need to think more about my budget and priorities, but I was wondering if people had any general advice on where to start for systems that have a somewhat yet-to-be-defined use case. I'm assuming that in time I'll be surprised by my power usage, I just don't know if it'll be to the up-side, or down. Also, if it matters, since I seem to be allergic to spending a buck in the name of saving a headache, I'll presumably be doing all my own work, building my own roof rack, and building a LiFePO4 pack from cells. Thanks!

 

[sunshine_eggo]

I have a new to me, stock, shell of a van that I want to build out for camping. Short term I see mostly using it for little weekend trips either solo or with my wife but I have hopes of doing much longer trips with the two of us. Short term I want to be able to run a fridge, a fan, and a few lights so I think a 200W panel and a 12V, 100Ah battery would suffice but long term it's easy to imagine having the equivalent of 600Ah at 12V system

7.68kWh

with 1000W+ of solar powering a laptop and starlink during workdays,

Easy peasy

a water heater,

Ouch!

cooktop,

Manageable for short periods.

maybe a bit of AC,

WHOA NELLY!

etc. If money was no object I suppose I'd build a 24V, 300Ah system but being new to some of this, that sounds like an expensive way to start, but if I start with the minimal system then it'll leave an upgrade path that'll likely be much more expensive both with regards to money and space. Thoughts?

Design your final desired system and figure out how to piecemeal it. IMHO, going from 12 to 24V may actually save you money as you'll only need 1/2 the MPPT for any installed solar, i.e., if you need a 40A controller @ 12V, you only need a 20A controller @ 24V for the same power array.

Clearly I need to think more about my budget and priorities, but I was wondering if people had any general advice on where to start for systems that have a somewhat yet-to-be-defined use case. I'm assuming that in time I'll be surprised by my power usage, I just don't know if it'll be to the up-side, or down. Also, if it matters, since I seem to be allergic to spending a buck in the name of saving a headache, I'll presumably be doing all my own work, building my own roof rack, and building a LiFePO4 pack from cells. Thanks!

Given that you're asking questions before you've bought any equipment, you're already way ahead of the game.

The energy audit link in line 1 of my signature is always a great place to start. Educated guesstimates are better than just winging it.

 

[chadat23]

I have done some pretty hand wavy estimates that implied that I could fairly comfortably work from my van with 3.8kWh, or fairly lavishly for 6.5kWh+, but I see about 0.5 significant digits in those estimates

Converting from 12 to 24V crossed my mind but I didn't take it super seriously, it's nice to hear that I wasn't considering a blatantly stupid idea (or at least one no stupider than the rest of my plan ). I suppose that, even if I get a stop-gap 12V inverter with the expectations of selling it for a bit of a loss, I could still be ahead after considering other costs.

Ouch!

Manageable for short periods.

WHOA NELLY!

And for the record, I'm someone who tends to dream big with the full understanding that many of my dreams will have to be rained in if not abandoned (I'll get zero hot showers if I don't aspire to have them, but I won't be heart broken if they're a treat rather than not a daily ritual)

 

[sunshine_eggo]

I have done some pretty hand wavy estimates that implied that I could fairly comfortably work from my van with 3.8kWh, or fairly lavishly for 6.5kWh+, but I see about 0.5 significant digits in those estimates

Have you tried the energy audit?

Converting from 12 to 24V crossed my mind but I didn't take it super seriously, it's nice to hear that I wasn't considering a blatantly stupid idea (or at least one no stupider than the rest of my plan ). I suppose that, even if I get a stop-gap 12V inverter with the expectations of selling it for a bit of a loss, I could still be ahead after considering other costs.

IMHO, design the the final system and then figure out how to piecemeal it... a 24V inverter may be only marginally more expensive than a 12V.

And for the record, I'm someone who tends to dream big with the full understanding that many of my dreams will have to be rained in if not abandoned (I'll get zero hot showers if I don't aspire to have them, but I won't be heart broken if they're a treat rather than not a daily ritual)

Those were intended to get your attention. WH is going to use a lot of energy, but you can likely manage it opportunistically - only run it when you're confident you'll be fully charged at the end of the day.

A/C is just brutal in most cases. Unless you get a mini-split type, you typically have to deal with large surge currents that overload most cheap inverters.

 

[chadat23]

Have you tried the energy audit?

I have, so the numbers are distinctly plausible, but maybe I'll work from the van a lot, or a little (and right now I only have a desktop so in some regards I have estimates of estimates), same with using a cook top, and a fan, etc.

IMHO, design the the final system and then figure out how to piecemeal it... a 24V inverter may be only marginally more expensive than a 12V.

Cool, that was my very tentative plan.

Those were intended to get your attention. WH is going to use a lot of energy, but you can likely manage it opportunistically - only run it when you're confident you'll be fully charged at the end of the day.

A/C is just brutal in most cases. Unless you get a mini-split type, you typically have to deal with large surge currents that overload most cheap inverters.

My working assumption has been that a WH would only be turned on on days when I won't be working and won't be cooking much to do, and I've been intrigued by some of the little mini splits. I need to do lots more research but it'd be awesome to find one that can heat and cool that I can use to keep the van even just a little above freezing during the winter for the sake of the plumbing and batteries (our winters are pretty mild so that's why I'm daring to consider it)

 

[Tomthumb62]

Or you know, you could just build the system and then find out just how woefully inadequate it is to power your desired load and then have to rebuild it again to meet up. As soon as anyone says "a little bit of air conditioning", your plans just go out the window, lol. I mean by "little bit" you mean you will run it for 12 minutes a day, then perhaps a small system is enough, but if you mean for 3-5 hours a day, then you're going to need a LOT more solar to make it work and a lot more battery if you intend to run A/C at all into the evening.

I will say that our small camp trailer solar system could not run+charge batteries for a 7.2CF fridge on only 200W of panels. 300W the minimum and 400W even better. And 600W for those cloudy days with low energy production. The first 400W are flat mounted on the roof and the other 200W are folding panels on the ground (which can be better angled towards the sun.)

 

[sunshine_eggo]

I have, so the numbers are distinctly plausible, but maybe I'll work from the van a lot, or a little (and right now I only have a desktop so in some regards I have estimates of estimates), same with using a cook top, and a fan, etc.

Design for both cases with an upgrade path to worst case. If worst case is within your reach, why not start out that way?

If you have some devices available now, get yourself a kill-a-watt meter and measure actual power usage now.

Cool, that was my very tentative plan.

Good. I'm glad I said it twice.

My working assumption has been that a WH would only be turned on on days when I won't be working and won't be cooking much to do, and I've been intrigued by some of the little mini splits. I need to do lots more research but it'd be awesome to find one that can heat and cool that I can use to keep the van even just a little above freezing during the winter for the sake of the plumbing and batteries (our winters are pretty mild so that's why I'm daring to consider it)

that sort of use of WH is likely do-able. When I was concerned about freezing while off-site, I had the electric RV water heater on smart wifi plug. It would run for 2 hours in the afternoon to allow the water to get to full temp and survive the night. Also allowed direct control of the unit's power via my smartphone, and I could turn it on or off easily.

From my research, most mini-splits can act as heat pumps.

 

[Zack R]

The first place I'd start is where do you plan on going in the van (weather wise)? If you plan to camp in cold weather (below freezing) its likely the largest energy demand will come from the furnace. The thing about cold weather is that its easy to provide the heating energy with diesel or propane (also some electrical for the fans), whereas hot weather requires a lot of electrical energy for air conditioning. Insulation is key for either option.

The other consideration is how long will you stay in one place without driving? If you only stay somewhere a few nights then much of your battery charging can come from a DC to DC charger (powered by the engine alternator while driving). If you park the van for a week at a time you'll need a lot more solar, more battery capacity, or will need to run the engine at a high idle to top up the batteries. Additionally solar doesn't work well in some of the best places to park and enjoy camping (under the trees in the shade). You can get around this with portable panels but that's an additional hassle to setup and takedown.