Bought a van! Now what? 12 or 48 volt?

[justinm001]

So for delay, my internet has been out since right after I made this post and it will be out again soon! ;-(

WOW you are amazing!!! Thank you for being so detailed with the power everything consumes! Awesome! I could not even find a lot of this info!!

You referred to "Airco" a lot, and I have no clue what that is?

Also the crusin N comfort AC, DOES make a 24 volt version of their AC unit as well. In my reaseach of van solar systems, it seemed the consensus was to stay away from 24 volt, and to either 12 or 48...so confusing.

Thank you for your thoughts on this matter!

Airco short for air conditioning. 24 volt is fine there just isn't much reasoning for it. Everything's 12v so if you're going to convert might as well use the highest voltage and 48v is really the highest you can go with being considered low voltage and not having to deal with all the electrical codes and everything.

 

[Ariel188]

BTW that alternator is rated at 100amps, almost 5000w of power when driving. OP couldn't get close to this on a 12v system says their 12v verson gets 220a max (2500w).

This makes a huge difference because it means she can charge entire system in 2 hours just by driving.... or 4 by just running the engine parked.

I am SOOOO confused bu all these posts, I wanna cry.......
I would REALLY love someones to help who knows this stuff as well as Will Prowse! I WILL PAY for this expert help of designing a system for my van and my specific needs! I listed what I will have in the van in the original post. I am OPEN to anything else. Size of watts on roof, amps of batteries, which second alternator to get, 12, 24, or 48 volts. I AM OPEN! I think I allocated A LOT of money for a steller solar system that should run my needs indefinalty without needing to be hooked into shore power. (The solar panels will probably be around $4200 of the budget since they are SUPER expensive walk on panels I listed above.). The roof rack will be Orion 100%,! ;-)

Can these both be used together? Should they be? I need massive help please!

Off Grid Solar Inverters

Building a vehicle mounted solar power system? Let me help.

www.mobile-solarpower.com

Victron MPPT RS 450V/100A, 450V/200A SmartSolar Charge Controller | Current Connected

Optimize your solar energy generation with Victron's RS 450V MPPT Charge Controller. Programmable settings, seamless setup, & enhanced connectivity options.

www.currentconnected.com

 

[Dave in AZ]

I am SOOOO confused bu all these posts, I wanna cry.......
I would REALLY love someones to help who knows this stuff as well as Will Prowse! I WILL PAY for this expert help of designing a system for my van and my specific needs! I listed what I will have in the van in the original post. I am OPEN to anything else. Size of watts on roof, amps of batteries, which second alternator to get, 12, 24, or 48 volts. I AM OPEN! I think I allocated A LOT of money for a steller solar system that should run my needs indefinalty without needing to be hooked into shore power. (The solar panels will probably be around $4200 of the budget since they are SUPER expensive walk on panels I listed above.). The roof rack will be Orion 100%, as I just WON IT with their give a way!!! ;-)

Can these both be used together? Should they be? I need massive help please!

Off Grid Solar Inverters

Building a vehicle mounted solar power system? Let me help.

www.mobile-solarpower.com

Victron MPPT RS 450V/100A, 450V/200A SmartSolar Charge Controller | Current Connected

Optimize your solar energy generation with Victron's RS 450V MPPT Charge Controller. Programmable settings, seamless setup, & enhanced connectivity options.

www.currentconnected.com

So, are you in the US? May make a difference for parts available. Most folks here know airco means air-conditioning, makes me think not US? I will assume you can get everything I can on Amazon though, for same prices as Phoenix. But location affects power usage for air-conditioning.

I went through your list of items to run, and looked up or calculated the power use on every one I thought. You don't really have many 12v things to use-- these are LED lights, maxxair fans, chinese diesel heaters, small fans. And most all 12v stuff ALSO works on 24v--LED lights, small fans. Only the Fantastic Fan from Dometic or Maxxair fan need 12v, and your diesel heater.

This is why I like 24v better than 48v-- all that low power super cheap stuff like lights can be had in 24v. And so can all the system parts! Fuses, fuseboxes, cheap circuit breakers, on/off switches-- all work at 24v and are inexpensive. But fuses stop at 32 or 36v, and most all the inexpensive switches and circuit breakers used in marine and RVs do NOT cover the 56v needed to charge 48v! Every single item now costs $200 instead of $30, is hard to find, and has to be diligently looked at for function above 32 or 48v.

24v gives you the same advantages for smaller cables, and ability to power larger inverters. Not as much as 48v, but ENOUGH, and you don't have the parts issues, while still getting all the small 12-24v stuff to work.

So, what do you need? Look at Will Prowses video for a 24v system, this is basically a good example of what you need. With a few tweaks for a van-- you want to use more power than you can get from the solar panels you can fit on a van! So power comes from 800 to 1000w solar (max you can fit), your 2nd alternator, and shore power.

Since it is a 2nd alternator, can just use a dcdc convertor, cheaper, as it won't be a smart alternator. And for shore power, either a charger inverter with pass thru OR a transfer switch like he shows in video below.

RV Solar Power Blue Prints

Building a vehicle mounted solar power system? Let me help.

www.mobile-solarpower.com

As you can see in this video, if you choose parts smartly, that already have overcurrent protection in them, you may not need those fuses etc, making 48v the smarter choice if designed with right parts!

Your desired system-- reread those amounts of power I listed. Your air-conditioning is the main power use.
For 24 hrs of highish airco, plus your cooking use etc, I figure 22,000wh of batteries. Your AC power use, you can get by with a 2000w inverter that has a surge ability over 3000w. But I would go with a 3000w inverter. Either 24 or 48v system can support a 3000w inverter, but a 12v system would be sketchy. A 12v could do 2000w, but if you're spending all this money, don't get yourself a limited system that can never grow! You sound like someone who would use a lot of ac power if it was available.

If you need to run airco for 24 hrs off batteries, that is the big item in your system. 916Ah if 24v battery, or 458Ah if 48v system. So with 4x 230ah 24v LiFePO4 battery, that is 920ah and $5600.

Here, go watch some of this guys videos. He builds van electrical systems, exactly what you're asking for. Watch his start to finish video

And this one, 12, 24, or 48v?

I don't know why you want those expensive walk on panels though, no one walks on a van roof, biiig waste of $$$$. For what you want, your budget, and your knowledge level to fix stuff, I would just get all Victron parts, except batteries and panels.

 

[Isaac-1]

Don't forget to keep track of how much all this stuff weighs, and keep your gross vehicle weight rating in mind. Years ago I had a friend that rebuilt an old TransVan camper van with all new cabinet work, got done and realized it was too heavy to drive, had to tear it all out and start over. You are likely looking at 350 pounds in just the LiFePo4 batteries for this.

 

[HarryN]

If your builder is mostly used to 12 volt systems, then they probably can build a 24 volt one as well, since the components are largely identical.

Switching to 48 volt means many of the components will need to change and the wiring / connections details are substantially different vs 12 or 24 volt.

Many van and RV components are available in both 12 and 24 volt if you look closely for them, fewer are available in 48 volt, so often what happens is that your main power is 48 VDC + 120 vac, and then a DC - DC converter is used for the 12 volt items.

At the power levels that you are looking at, running the air conditioner off of DC vs off of 120 vac will be a toss up. The compressor motor will be more efficient as the voltage rises to 120 vac, so I am not convinced that the DC versions really are a benefit vs a similarly priced 120 vac unit.

The reality of alternator charging is that many suppliers have backed down their charge rates from their original goal of "as much as it can do" to more like 3 - 3.5 kW. The sprinter engine mount maxes out at 7 kW and you don't want it to break off while driving around.

 

[Ariel188]

So, are you in the US? May make a difference for parts available. Most folks here know airco means air-conditioning, makes me think not US? I will assume you can get everything I can on Amazon though, for same prices as Phoenix. But location affects power usage for air-conditioning. I went through your list of items to run, and looked up or calculated the power use on every one I thought. You don't really have many 12v things to use-- these are LED lights, maxxair fans, chinese diesel heaters, small fans. And most all 12v stuff ALSO works on 24v--LED lights, small fans. Only the Fantastic Fan from Dometic or Maxxair fan need 12v, and your diesel heater. This is why I like 24v better than 48v-- all that low power super cheap stuff like lights can be had in 24v. And so can all the system parts! Fuses, fuseboxes, cheap circuit breakers, on/off switches-- all work at 24v and are inexpensive. But fuses stop at 32 or 36v, and most all the inexpensive switches and circuit breakers used in marine and RVs do NOT cover the 56v needed to charge 48v! Every single item now costs $200 instead of $30, is hard to find, and has to be diligently looked at for function above 32 or 48v. 24v gives you the same advantages for smaller cables, and ability to power larger inverters. Not as much as 48v, but ENOUGH, and you don't have the parts issues, while still getting all the small 12-24v stuff to work. So, what do you need? Look at Will Prowses video for a 24v system, this is basically a good example of what you need. With a few tweaks for a van-- you want to use more power than you can get from the solar panels you can fit on a van! So power comes from 800 to 1000w solar (max you can fit), your 2nd alternator, and shore power. Since it is a 2nd alternator, can just use a dcdc convertor, cheaper, as it won't be a smart alternator. And for shore power, either a charger inverter with pass thru OR a transfer switch like he shows in video below.

RV Solar Power Blue Prints

Building a vehicle mounted solar power system? Let me help.

www.mobile-solarpower.com

As you can see in this video, if you choose parts smartly, that already have overcurrent protection in them, you may not need those fuses etc, making 48v the smarter choice if designed with right parts! Your desired system-- reread those amounts of power I listed. Your air-conditioning is the main power use. For 24 hrs of highish airco, plus your cooking use etc, I figure 22,000wh of batteries. Your AC power use, you can get by with a 2000w inverter that has a surge ability over 3000w. But I would go with a 3000w inverter. Either 24 or 48v system can support a 3000w inverter, but a 12v system would be sketchy. A 12v could do 2000w, but if you're spending all this money, don't get yourself a limited system that can never grow! You sound like someone who would use a lot of ac power if it was available. If you need to run airco for 24 hrs off batteries, that is the big item in your system. 916Ah if 24v battery, or 458Ah if 48v system. So with 4x 230ah 24v LiFePO4 battery, that is 920ah and $5600. Here, go watch some of this guys videos. He builds van electrical systems, exactly what you're asking for. Watch his start to finish video

And this one, 12, 24, or 48v?

I don't know why you want those expensive walk on panels though, no one walks on a van roof, biiig waste of $$$$. For what you want, your budget, and your knowledge level to fix stuff, I would just get all Victron parts, except batteries and panels.

Hello, wow thank you so much for your very detailed explanation I really appreciate it even though it's over my head and I still really don't understand a lot of it. I am actually in the USA in California I'm just a dumb girl with electrical and I have no idea what the abbreviations mean. I'm more of an aesthetic person with design but not the background of what's behind the Walls LOL

Once I get my Internet working again I will watch all the links thank you so much I'm sure I'm going to have a million more questions. I really just love to have somebody design me a system that would work for me.
I'm actually in a 42 ft RV right now and it's been a living nightmare for the last 15 months. It's all victron and a 48 volt system but it's for chin batteries 300 watts each and they are tied in series to make a 48 volt but I found out later it needed battery balancers that were never put in so I had somebody come do that but I did not help

I'm off grid here and the Onan generator is constantly breaking I have a guess that the inverter settings talking to the generators not correct and I only have a Mac laptop and you need a regular PC to hook into the victron inverters.

So alas I am struggling with the power and constantly turning off on me and the generator shutting down with code 15 and code 36 all the time I've had so many people out here and no one can seem to figure out any of this. It's very distressing I sit in the dark and cold a lot this is what I want to avoid a million percent in my van and I will spend whatever I need to so that I can make sure I will have plenty of power and no more BS like this. This rig is too big to move, and I'm in a rural area with not much help for people to fix things. Big reason why I'm getting the van so I can drive around myself and get help if I need or what not.

So that's why I'm desperate to have a really good design system that will not fail me and shut off and break and I don't know how to do any of this or fix any of it so I'll spend what I need to to get it done right and I don't want to make bad choices on what parts to get because I don't know what the heck I'm doing......

 

[Ariel188]

Don't forget to keep track of how much all this stuff weighs, and keep your gross vehicle weight rating in mind. Years ago I had a friend that rebuilt an old TransVan camper van with all new cabinet work, got done and realized it was too heavy to drive, had to tear it all out and start over. You are likely looking at 350 pounds in just the LiFePo4 batteries for this.

Thank you so much for this. I did get a dually so that I don't have to worry about weight as much it's an extended also. I've seen YouTube videos where people with the same band were at 11,000 and they're going to upgrade their suspension with agile off-road I plan to do that as well. I will have 64 gallons of water. Two 32 gallon tanks over each wheel well. And then this stuff I listed above Plus cabinetries so hopefully I'll be at a good weight my builder is done lots of Vans before so he does know light and heavy woods because I know wood can add up fast as can water! The electrical components will be upfront behind the passenger seat in a cabinet actually I will post my floor plan

 

[Ariel188]

The floorplan for my Sprinter 170" ext 3500 dually. Under bed is not drawn on the front view, but the bed will be on a happy jack so I can access the cabinets and countertops under bed easily.

 

[Ariel188]

Van? I would be at 12v. Works fine in my RV trailer. Or are you planning 1000+ watts solar and 3000+ watts inverter? 12v accessories are so much easier to find over 48v.

Most I can get is about 800 w on the roof and I will have a 3000 watt inverter. Please check out the long list of 110 items I'll be using often that will use a lot of power that's what I thought a 48 volt would keep me more power but I don't really understand all this stuff.

 

[Dave in AZ]

Most I can get is about 800 w on the roof and I will have a 3000 watt inverter. Please check out the long list of 110 items I'll be using often that will use a lot of power that's what I thought a 48 volt would keep me more power but I don't really understand all this stuff.

Hey, just so you understand, 48v system doesn't give you ANY more power than a 12v system! The only difference, and alllll the stuff we talked about, is it changes the wiring size, that is IT. 48v lets you run smaller wires, which makes it easier to do a 3000w inverter. But you can do it with 12v. But BOTH USE THE SAME TOTAL POWER!
Your system power limit comes from the 800w solar on roof limit. Or your 2nd alternator. And then how much batteries you have to store that for later use. Panels and batteries define your system power. If you thought you'd have more power from 48v, that is 100% false, same power as 12v. Just some easier engineering is all.

 

[brb58]

The only reason to do 48V is if you are going to have huge current draws, a very large battery bank and have a dedicated 48V alternator to charge it. You will never have enough solar on a van to charge a large battery bank and why have a large battery bank if you can't charge it up fast.

Check out the Volta systems that a lot of custom van manufacturers are putting in. They have 14KWH battery banks and 48V(Actually 56V) alternators.

Specs - Volta Power Systems

voltapowersystems.com

 

[justinm001]

I'm sure there's quite a few companies locally that'll do the electrical for you and help build out.

If I were you I'd get a cerbogx for the current system and then you can use the web to change everything even on a Mac. Then move it to the new van.

Victron is by far the best. If you get everything victron it'll all connect.

Just like others said 12/24/48v is just the voltage things run at so 48v uses 1/4 the wire size and 24v uses 1/2, and wiring is expensive. Volts times Amps equal watts so 3000w at 12v is 250amps but 125a on 24v and 62.5a on 48v. You can Google a wire gauge amp sheet to see what size wire you need and how much they cost... copper is expensive. With solar the MPPTs are based on voltage so they can pump 4x as much for a 48v vs 12v

 

[HarryN]

I am in the San Francisco area east bay - I could at least look at your RV if it is in the general area.

Take some photos of your various items and post them if possible - sometimes things become more clear after enough people stare at things.

December and January are the toughest months to get through - not much sun, and heat is needed.

Just bring enough coffee to keep my IV drip going......

 

[Ariel188]

The only reason to do 48V is if you are going to have huge current draws, a very large battery bank and have a dedicated 48V alternator to charge it. You will never have enough solar on a van to charge a large battery bank and why have a large battery bank if you can't charge it up fast.

Check out the Volta systems that a lot of custom van manufacturers are putting in. They have 14KWH battery banks and 48V(Actually 56V) alternators.

Specs - Volta Power Systems

voltapowersystems.com

I will look at this link when I get internet thank you. As far as why have a big battery Bank if you can't charge it all off the panels? Well because if you want to drive a few hours to get to a location that you want to stay at a week or two and not drive then you have a huge battery bank with which to draw from and your solar can probably sustain you so you could probably last a week or two but if you had a smaller battery Bank you'd have to constantly drive and I don't want to have to constantly drive. So unless I'm missing something that's why I want a bigger battery Bank to start with

 

[Ariel188]

Hey, just so you understand, 48v system doesn't give you ANY more power than a 12v system! The only difference, and alllll the stuff we talked about, is it changes the wiring size, that is IT. 48v lets you run smaller wires, which makes it easier to do a 3000w inverter. But you can do it with 12v. But BOTH USE THE SAME TOTAL POWER!
Your system power limit comes from the 800w solar on roof limit. Or your 2nd alternator. And then how much batteries you have to store that for later use. Panels and batteries define your system power. If you thought you'd have more power from 48v, that is 100% false, same power as 12v. Just some easier engineering is all.

Hmmm yes I really was under the impression you get more power from a 48 volt system. At least in terms of it not taking as much power to charge things so in essence you save power meaning it's more power. And I don't understand why wire size is such a big deal if it's only a couple hundred bucks up front why is it a big deal in the long run. I thought the whole point of a 48 volt was to do more power draws efficiently meaning wasting less power

 

[Reed Cole]

Hmmm yes I really was under the impression you get more power from a 48 volt system. At least in terms of it not taking as much power to charge things so in essence you save power meaning it's more power. And I don't understand why wire size is such a big deal if it's only a couple hundred bucks up front why is it a big deal in the long run. I thought the whole point of a 48 volt was to do more power draws efficiently meaning wasting less power

Watts are measurement of power. Amps are a measurement of current. Amps = Watts/Voltage.

Let's say you the only thing you want to power in your van is a 1200 watt light bulb. Both a 12v and 48v would require 1200 watts to turn on the light.

But in a 12v system it would require 100 amps.
1200 watts / 12v = 100 amps

And in a 48v system it would require 25 amps.
1200 watts / 12v = 25 amps.

Current is what is used to determine wire size. The more amps a load requires the thicker the wire you need.

If I recall correctly, you were wanting an 800ah battery bank at 12v. That's 9,600 watt hours. If you wanted to be able to charge it in three hours of driving you would need to charge at a rate of 266 Amps. The wire size for that is literally off the charts, you would need multiple cables to safely conduct that much current.

The same size battery at 48v would only require 66 amps to charge in three hours, and you would only need 3 awg wire.

Apart from smaller wires, it's generally safer to use lower currents, and it's easier to engineer the various components that make up a system if they require less current since the same principle of needing thicker wire applies to the internals of a solar charge controller or inverter, etc.

 

[Isaac-1]

To add the last post it helps to understand that wire sizing is somewhat exponential as amps go up. Meaning a tiny little 18 gauge wire will handle about 6 amps of DC power, but to carry 60 amps requires a fairly large 4 gauge wire (this is the size seen for battery cables on small cars), and even a giant 4/0 can only handle about 216 amps. This is where we hit the practical upper limit for any given voltage 216 amps at 12V is 2592 watts, hence why everyone says if you have a 3,000 watt inverter you need higher than 12V. (note amp rating for wires depends on allowable temperature rise and some other factors so the above numbers are just approximate guidelines for relative reference)

 

[RV8R]

To add the last post it helps to understand that wire sizing is somewhat exponential as amps go up. Meaning a tiny little 18 gauge wire will handle about 6 amps of DC power, but to carry 60 amps requires a fairly large 4 gauge wire (this is the size seen for battery cables on small cars), and even a giant 4/0 can only handle about 216 amps. This is where we hit the practical upper limit for any given voltage 216 amps at 12V is 2592 watts, hence why everyone says if you have a 3,000 watt inverter you need higher than 12V. (note amp rating for wires depends on allowable temperature rise and some other factors so the above numbers are just approximate guidelines for relative reference)

current


Well That & “Voltage Drop” ?

 

[k490]

Friend bought a new small single axle travel trailer about 20 feet long. Had a single 12V deep cycle lead acid battery it would go dead when boondocking. We put 200 watts of panels on it and a Renogy charge controller. I was really surprised how entire RV 12V system could run without ever plugging it in. The stove, heater, refrigerator was all propane powered, so it was mostly just small fans and lights, and water pump runs for a short time. If you don't need lot of power, why not stick with 12V system. We ran both exhaust fans for 10 straight days the battery never went below 75%.

 

[Dave in AZ]

Friend bought a new small single axle travel trailer about 20 feet long. Had a single 12V deep cycle lead acid battery it would go dead when boondocking. We put 200 watts of panels on it and a Renogy charge controller. I was really surprised how entire RV 12V system could run without ever plugging it in. The stove, heater, refrigerator was all propane powered, so it was mostly just small fans and lights, and water pump runs for a short time. If you don't need lot of power, why not stick with 12V system. We ran both exhaust fans for 10 straight days the battery never went below 75%.

She listed her desired usage, it is a LOT OF watts of power. And a good bit of ac power. Air-conditioning, washer, cooking devices.