Best battery system for all Electric skoolie

[ethanjune]

Hello all,

I'm in the very beginning stages of wrapping my head around the electrical. I've been running through different options and am curious what some of you more seasoned skooliers with comprehensive battery/solar systems would do to achieve an all Electric skoolie.

I have 2400 Watts of Solar up top. We're trying to go all Electric as much as possible with a few LP back-ups, like an Electric induction and Gas cooktop in case of emergency. Electric oven. Potentially converting a 120v freezer into a fridge for efficiency. Possibly a SetPower 12v chest freezer that we might mount in the jockey boxes below, as we have tons of storage down there. Electric water heater,, like the Bosch. Looking into a potential Clearsource Filter/Water Pump for ultra off grid capabilities, but that would likely run off the generator if needed. I was going to carry a small genny for emergencies. We're taking the bus further and further south, so we're driving away from the cold. Right now we're putting in a Cubic Mini, cause we also want the option to cook on top of it. We might add a Diesel heater some day if needed, but I don't think it's necessary for our situation. We'll have a 12,000BTU Minisplit for AC and heat. We have a dog and want to be able to run the Minisplit as long as possible.

So my question is where would you start with a battery system if you had 2400 watts of solar to accommodate as much electric appliances as possible, trying to preserve as much as you can for maximum hours of running Minisplit? I have a basic electric knowledge from my 10 years working in the film industry as a lighting technician, but solar, batteries, and 12v-48v is a whole new world for me. I've been watching some Will Prowse YouTube videos about comprehensive solar and inverter setups. I'm curious about the pros and cons of bumping from 12v up to 24, or even 48 volt to get the most ergonomic situation going. Is it worth it to get into the 240 world with a powerful inverter/charge controller combo? 240v appliances any better? Minisplit makes a 240 version. I don't think my generator could handle a Minisplit. I know some of you run your Minisplit strictly off genny. I'd like to use the Solar as much as possible for it, but maybe that's ridiculous and I should isolate it to the genny?

Sorry this question seems so rudimentary. My brain is just going all over the place with 5 different voltage systems and a lot of different appliances to keep plugging in. That's why I was curious to see what some of you seasoned RV electric pros with more comprehensive solar and battery setups would do in this situation. Where would you start in building a 2400 watt solar system, all electric appliances, with maximum amount of time on the Minisplit? 24 or 48v batteries? 240v inverter capabilities?

[dbsoundman]

Welcome to the fun!

My short answers to get it started: get as much battery capacity as you can accommodate and afford. You’ll need it to run the mini split overnight especially, my 120v 12000 BTU unit can pull up to 1000 watts but usually closer to 6-700. Don’t bother with 240v, that’s way too much cost and complexity. Do consider 48v battery banks.

Oh, and start thinking in watt hours, not amp hours, that will make your math so much easier. Watts are the same no matter the voltage, so you can figure out the wattage or watt hours needed for a given appliance and then work that out with various battery voltages to find the needed watt hours of battery capacity. Then convert to amp hours at the end to figure out how many batteries you’ll need.

[Dbacks2k4]

Originally Posted by ethanjune

Hello all,

I'm in the very beginning stages of wrapping my head around the electrical. I've been running through different options and am curious what some of you more seasoned skooliers with comprehensive battery/solar systems would do to achieve an all Electric skoolie.

I have 2400 Watts of Solar up top. We're trying to go all Electric as much as possible with a few LP back-ups, like an Electric induction and Gas cooktop in case of emergency. Electric oven. Potentially converting a 120v freezer into a fridge for efficiency. Possibly a SetPower 12v chest freezer that we might mount in the jockey boxes below, as we have tons of storage down there. Electric water heater,, like the Bosch. Looking into a potential Clearsource Filter/Water Pump for ultra off grid capabilities, but that would likely run off the generator if needed. I was going to carry a small genny for emergencies. We're taking the bus further and further south, so we're driving away from the cold. Right now we're putting in a Cubic Mini, cause we also want the option to cook on top of it. We might add a Diesel heater some day if needed, but I don't think it's necessary for our situation. We'll have a 12,000BTU Minisplit for AC and heat. We have a dog and want to be able to run the Minisplit as long as possible.

So my question is where would you start with a battery system if you had 2400 watts of solar to accommodate as much electric appliances as possible, trying to preserve as much as you can for maximum hours of running Minisplit? I have a basic electric knowledge from my 10 years working in the film industry as a lighting technician, but solar, batteries, and 12v-48v is a whole new world for me. I've been watching some Will Prowse YouTube videos about comprehensive solar and inverter setups. I'm curious about the pros and cons of bumping from 12v up to 24, or even 48 volt to get the most ergonomic situation going. Is it worth it to get into the 240 world with a powerful inverter/charge controller combo? 240v appliances any better? Minisplit makes a 240 version. I don't think my generator could handle a Minisplit. I know some of you run your Minisplit strictly off genny. I'd like to use the Solar as much as possible for it, but maybe that's ridiculous and I should isolate it to the genny?

Sorry this question seems so rudimentary. My brain is just going all over the place with 5 different voltage systems and a lot of different appliances to keep plugging in. That's why I was curious to see what some of you seasoned RV electric pros with more comprehensive solar and battery setups would do in this situation. Where would you start in building a 2400 watt solar system, all electric appliances, with maximum amount of time on the Minisplit? 24 or 48v batteries? 240v inverter capabilities?

Your system sounds similarly sized to mine. One of the best pieces of advice I got early on was to ditch 12v and jump to 24 or 48 - I wound up going 48. I'll have to use some 48 to 12v converters for things like lights, phone chargers, etc, but I can do that at the "last mile" to keep those 12V runs pretty small to minimize losses. It reduces your wire size as well as the number of amps flowing through those connections. I went with Signature Solar EG4 for batteries and the 6500EX inverter. I'm not doing 240V, just 120, but you could chain them together for 240V if needed.

I'm going with a pair of 12K BTU 120V minis. From what I was looking at, two of them provide more cooling power than a single 240V unit, plus I like redundancy and do two of everything where possible...

The number of batteries really depends on how long you want to be able to run on battery with no solar or genny input. That's where I made a ridiculous spreadsheet of all my anticipated workloads to calculate my needs.

[DeMac]

An all electric skoolie is easy. Just add a power pole next to the bus. Done. ☺ (jk)



To produce the electricity, onboard, you'll need to size your energy production equiptment to supply your required demand.

How much electricity do you intend to use, produce & store per day?

[ethanjune]

Originally Posted by dbsoundman

Welcome to the fun!

My short answers to get it started: get as much battery capacity as you can accommodate and afford. You’ll need it to run the mini split overnight especially, my 120v 12000 BTU unit can pull up to 1000 watts but usually closer to 6-700. Don’t bother with 240v, that’s way too much cost and complexity. Do consider 48v battery banks.

Oh, and start thinking in watt hours, not amp hours, that will make your math so much easier. Watts are the same no matter the voltage, so you can figure out the wattage or watt hours needed for a given appliance and then work that out with various battery voltages to find the needed watt hours of battery capacity. Then convert to amp hours at the end to figure out how many batteries you’ll need.

Thank you. Yes Im thinking 24v or 48. There's the on going debate about safety, but is it that much more significant jumping up from 24?

Copy, yeah that's a good way of looking at it. Watt hours is looking anywhere from 10-15kwh at the moment.

[ethanjune]

Originally Posted by Dbacks2k4

Your system sounds similarly sized to mine. One of the best pieces of advice I got early on was to ditch 12v and jump to 24 or 48 - I wound up going 48. I'll have to use some 48 to 12v converters for things like lights, phone chargers, etc, but I can do that at the "last mile" to keep those 12V runs pretty small to minimize losses. It reduces your wire size as well as the number of amps flowing through those connections. I went with Signature Solar EG4 for batteries and the 6500EX inverter. I'm not doing 240V, just 120, but you could chain them together for 240V if needed.

I'm going with a pair of 12K BTU 120V minis. From what I was looking at, two of them provide more cooling power than a single 240V unit, plus I like redundancy and do two of everything where possible...

The number of batteries really depends on how long you want to be able to run on battery with no solar or genny input. That's where I made a ridiculous spreadsheet of all my anticipated workloads to calculate my needs.

Thank-you! This response is very helpful.

Looks close, bit more firepower though! Those two Minisplits are really doing some heavy duty pulls there. Why is the refrigerator so low? Curious how big your bus is..4800 watts of solar is a lot, double mine! I'm looking in the 10kwh-15kwh range. With almost 20kwh of needs, do you find your system being efficient? Curious what your 48V system looks like. Can you share?

[Dbacks2k4]

Originally Posted by ethanjune

Thank-you! This response is very helpful.

Looks close, bit more firepower though! Those two Minisplits are really doing some heavy duty pulls there. Why is the refrigerator so low? Curious how big your bus is..4800 watts of solar is a lot, double mine! I'm looking in the 10kwh-15kwh range. With almost 20kwh of needs, do you find your system being efficient? Curious what your 48V system looks like. Can you share?

To be transparent, my bus currently looks like this


That entire chart is conceptual. My bus is an 06 International Conventional - 40 ft. If I go with the flexible solar panels I can get a higher watt capability per square foot. If I go with more traditional residential panels they seem to have better life expectancy, but less efficiency per square foot. That's where my portable external panel plan comes into play.

The power system is ordered, it's 4 Signature Solar EG4 LifePOWER batteries and one EG4 6500EX inverter-charger. Its the panels I haven't decided on yet.

If I remember right I was looking at a pair of chest-style 12V refridgerators. I may need to double check those numbers as 120W does seem low....

[Dragonpop]

I’ve been running 4 6 volt batteries 410 amps each which gives me 410 usable amps at 12 volts at 50% depth of discharge. My 12 volt Aims inverter is now dying so I’m moving up to 48 volts with 2 server rack trident batteries rated at 100 amps at 48 volts. They are actually 105 amp units that come with the bms built in and an electric heater installed as well with a 10 year warranty as well. One lifpo unit weighs around 100 lbs while my lead acid L16 6volt battery weighs 110 lbs each. If you check the capacity of one server rack battery it has the same capacity as my 4 lead acid batteries since dept of discharge is greater.

[brokedown]

I recommend anyone doing a non-trivial power system take the jump right to 48v. You'll save a lot of money and headaches vs trying to make it work on 12 or 24v.

When you get to 48v you need to be more aware of where your hands are, though. You don't think twice about touching the terminals on a 12 volt battery with your hands, at that level nothing happens. At 48v you're going to get a nasty shock.

Another thing to consider is the arrangement of your battery bank. Expanding a 12v system is fairly trivial, but expanding a 48v system properly takes a bit more thought. For best results, you want your bank to be as balanced as possible, with equal cells of equal capacity.

[Rucker]

Originally Posted by ethanjune

I know some of you run your Minisplit strictly off genny. I'd like to use the Solar as much as possible for it, but maybe that's ridiculous and I should isolate it to the genny?

What are your plans-full timing, extended trips, just weekends?

[LargeMargeInBaja]

We have six 305-Watt photovoltaic panels, a total of 1,830-Watts.
These top our bank of eight Lifeline Concorde 105ah AGM.
.
Our route to independence is the opposite of most folks attempting to duplicate the 'conveniences' of a stand-still house.
We eliminated everything, all the draws, right down to nothing.
.
Camping at its pristine best.
.
At that point, we looked at the usual 'up-grades':
* cooking
* showers
... and the bane blight burden of the Twen-teeth Century....
* charging the carnsnargled telephone.
.
We reduce our Heat and Cooling requirements by moving with the weather.
We also reduce our Heat and Cooling requirements by living outside the rig.
Eventually, we discovered we are as comfortable in 85°f summers as we are in 40°f winters (or summer evenings in a low-humidity Baja or Apache Junction).
.
Sincerely, we applaud your ambition.
Your intentions to purchase then cart around multiple tons of electronics and cables and couplers, and your intentions to engineer and maintain said gadgets is... astonishing.
.
We are in awe, we bow to your abilities and perseverance.
Your systems, working as one integrated unit, will be on-par with those other enduring symbols of civilization:
* the Temple Of Artemis,
* the Colossus Of Rhodes,
* the Hanging Gardens Of Babylon
...the mind boggles, the heart quickens, the breath bates.
.
If only our intention was to create such magnificence.
Tragically, our intention is to camp, sit around the campfire with our caravan chums, sharing meals and singing and telling tall tales... with the occasional coupled dance into the shadows.

[ethanjune]

Originally Posted by LargeMargeInBaja

We have six 305-Watt photovoltaic panels, a total of 1,830-Watts.
These top our bank of eight Lifeline Concorde 105ah AGM.
.
Our route to independence is the opposite of most folks attempting to duplicate the 'conveniences' of a stand-still house.
We eliminated everything, all the draws, right down to nothing.
.
Camping at its pristine best.
.
At that point, we looked at the usual 'up-grades':
* cooking
* showers
... and the bane blight burden of the Twen-teeth Century....
* charging the carnsnargled telephone.
.
We reduce our Heat and Cooling requirements by moving with the weather.
We also reduce our Heat and Cooling requirements by living outside the rig.
Eventually, we discovered we are as comfortable in 85°f summers as we are in 40°f winters (or summer evenings in a low-humidity Baja or Apache Junction).
.
Sincerely, we applaud your ambition.
Your intentions to purchase then cart around multiple tons of electronics and cables and couplers, and your intentions to engineer and maintain said gadgets is... astonishing.
.
We are in awe, we bow to your abilities and perseverance.
Your systems, working as one integrated unit, will be on-par with those other enduring symbols of civilization:
* the Temple Of Artemis,
* the Colossus Of Rhodes,
* the Hanging Gardens Of Babylon
...the mind boggles, the heart quickens, the breath bates.
.
If only our intention was to create such magnificence.
Tragically, our intention is to camp, sit around the campfire with our caravan chums, sharing meals and singing and telling tall tales... with the occasional coupled dance into the shadows.

Thank you for this. The sarcasm and vocabulary is nothing short of poetic and had me laughing. Your ideals are somewhat aligned with that of my partner and I's. I come from a long career of mechanical and engineering work as a lighting technician in the film industry where I built out a lot of tractor trailers and box trucks into mobile work stations. Since my partner and I left our jobs, we're on a much different kind of soul quest. Our goal is to get back to ancestral ways of living through primitive technology sans modern conveniences. We plan to do most of our cooking in underground ovens we dig, smoking, and stone cooking. This is not just a goal of ours, but our own personal art. Using freshwater, pumps and filtering, rainwater catches, even mycelial grey water filtering (kidding - this is our plan for our future home ;) We have dreams of living one way, but are also being responsible. You could say that the need for an extensive solar and battery setup is mostly due to the fact that we have our dog, Oso. We want to protect him from hyperventilating in the heat, as we plan to drive further and further South toward our community in Central America. Though we are both very eco conscious, we understand that the Minisplit is a necessary safety measure to protect Oso in the grueling heat, and our aim is to prioritize as much run time per day as we can for him. This bus is as much an adventure expedition home as it is an Apocalypse vehicle. We've carefully been designing it from multiple angles that accommodate fuel shortages and the increasing threat of climate change. In addition to our extensive solar setup (that we see as a safety net/back up), we are also inserting natural energy sources that bypass batteries altogether, like my custom solar hot water heater (even though we take cold showers more often, with the occasional luxury of a hot shower after a long day of LSD - quite lovely).
On top of that, this bus is a temporary home, meant to provide us a comfortable living space while we build out our self sustaining food forest and eco villa on our property, completely off-grid. This is why im caravanning a lot of solar with me, because I'm going to need it on my permanent home. This is also why a battery setup more like 48V will come in handy, so I'm trying to learn all the ins and outs now. So don't be too quick to categorize. I'm trying to build the best of both words into a bus and get the best bang for my buck out of an electrical system, (since it will be very important to my future endeavors as well).

[ethanjune]

Originally Posted by Rucker

What are your plans-full timing, extended trips, just weekends?

full timing!

[ethanjune]

Originally Posted by brokedown

I recommend anyone doing a non-trivial power system take the jump right to 48v. You'll save a lot of money and headaches vs trying to make it work on 12 or 24v.

When you get to 48v you need to be more aware of where your hands are, though. You don't think twice about touching the terminals on a 12 volt battery with your hands, at that level nothing happens. At 48v you're going to get a nasty shock.

Another thing to consider is the arrangement of your battery bank. Expanding a 12v system is fairly trivial, but expanding a 48v system properly takes a bit more thought. For best results, you want your bank to be as balanced as possible, with equal cells of equal capacity.

Copy shock. We used to have a guy "holding the stick" for someone doing a 240v hot tie-in, ready to smack his hands off if he becomes a full circuit. I've held the stick a few times and got "bit" a few times with 120AC. Direct current at 48V might be a different beast. Still all that electricity in a recreational vehicle seems a little testy. As of late, I've been retreating back to 24V, for availability of appliances that don't have to go through inversions/conversions. 48 seems to come with a lot of extra headache as you mentioned...plans of expanding, as well as availability of parts (I'm taking this bus away from civilization). Anyway, not sold on that yet, still need to do a bit of math to compare what's best for my system. Thank you for your input.

[LargeMargeInBaja]

re -- 'climate change'
.
That phrase went out years ago.
The trendy new term -- 'weather dithering'.
True fact...

[Rwnielsen]

Originally Posted by ethanjune

Copy shock. We used to have a guy "holding the stick" for someone doing a 240v hot tie-in, ready to smack his hands off if he becomes a full circuit. I've held the stick a few times and got "bit" a few times with 120AC. Direct current at 48V might be a different beast. Still all that electricity in a recreational vehicle seems a little testy. As of late, I've been retreating back to 24V, for availability of appliances that don't have to go through inversions/conversions. 48 seems to come with a lot of extra headache as you mentioned...plans of expanding, as well as availability of parts (I'm taking this bus away from civilization). Anyway, not sold on that yet, still need to do a bit of math to compare what's best for my system. Thank you for your input.

Higher voltage DC shocks are far more painful than AC. I used to maintain a few roof top arrays for a large grocery store chain. I was hit with 360v DC on an overcast day and it was no joke.

[HamSkoolie]

Originally Posted by LargeMargeInBaja

re -- 'climate change'
.
That phrase went out years ago.
The trendy new term -- 'weather dithering'.
True fact...

And the correct term scientifically: NATURAL, unstoppable forces riven by sun activity.

[Rucker]

Originally Posted by ethanjune

full timing!

Gotcha. I recommend very solid systems, no shortcuts, with quality components and plenty of spare parts where you're going.

The state of technology is not so robust you can take it off into the wilderness and rely on it without a nearby Home Depot or Ace Hardware (or Amazon Address).

I read your manifesto (:-'). C'mon, that A/C ain't for the dogs!

[DeMac]

Originally Posted by Rucker

I read your manifesto (:-'). C'mon, that A/C ain't for the dogs!

😂 I've heard that, before AC, dogs did not exist.

Here, in Central Florida, we don't really need AC and truely don't use it often. Mostly, good insulation managing fans, windows & timing.

Our animals utilize the shade, soil & water holes. The pens are simplified to prevent their cages from becoming uncomfortable or worse, death-traps.

Would you consider providing acess to the underside of the vehicle as a 'failsafe'? A free-range escape from any unforseen internal risk. A rodent-free 🐀 undercarriage is a bonus! (Park on outdoor carpet & add skirt to keep pets clean.)