12, 24, or 48v Van Preferred Power Systems?

[StogieMan]

What say you?

I’m trying to get an idea of what would be more useable and sellable for potential clients and would love to get some input. I myself have owned 12 and 48v systems and have finally decided on only 48v systems for my van and home. My thoughts on 12 and 24v’s are all over the place and 36v is not even a consideration and a non-starter. 12v’s has been around for a good while and not going anywhere IMO. However, more OEM rig, motorhome, van and trailer manufacturers are pushing the envelope into 24v and 48v arena. I’ve also noticed that folks want to go bigger and push the boundaries as they want the same amenities that they have at home and willing to pay for them. They want all the comforts of home while camping. Personally, I’m moving away from 12v’s and going to focus on 24 & 48v’s initially and then when I’m done with my 24v stock going to straight 48v’s for my power systems. IMO, there comes a point where you have to put your thumb up in the air and see where the wind is blowing to feel things out and think that we are at that crossroads.

I’ve ordered a bunch of 8020 supplies and Hex Plywood to complete some pre-built over the wheel well power systems for my existing stock. I’m strictly using Victron components except for the batteries as I want to give my customers the options on brands and capacity. I’m first going to build some 24v components and then move on to 48v’s. I’m also going to strictly use 5 kVA inverters for both the 24 & 48v systems.

 

[zanzabar]

I would suggest looking at welded steel for any battery racks. A giant lithium battery is going to rip right out of 8020 if there is an accident. IMO...

Aside from that, I see no reason to use anything but 48v. There really isn't an advantage to 12/24.

 

[StogieMan]

I would suggest looking at welded steel for any battery racks. A giant lithium battery is going to rip right out of 8020 if there is an accident. IMO...

Aside from that, I see no reason to use anything but 48v. There really isn't an advantage to 12/24.

Thanks for the feedback and I agree with that the 48v as that’s my thinking, I have two options on where the batteries would lay. If I’m using some shorter 48v Quattros 5 kVA the batteries would be under that. If using the longer Multiplus II 5kkVA then I would either mount the batteries under it or on the side of the wheel well and be bumped out further into the middle of the van. I’m going to test it on my van when I get the 8020 parts to see what I think works well.

 

[johnshmit]

More volts - less coper.

 

[blutow]

I debated 12v vs. 24v on my build. 48v was out because there just weren't many options for 48v components. Not just heaters, fridge, fans, etc., but much of the common hardware, switches, breakers, etc. isn't rated for 48v (which is actually ~54-56v operating voltage). I seriously considered 12v vs. 24 and just couldn't justify adding a 3rd voltage (24v) when I was forced to have 12v any way I sliced it. Adding additional fuse blocks and switch panels and along with a voltage convertor just seemed like too much downside for the upside of smaller wiring and a little efficiency. That said, I might have a different opinion if my inverter wasn't right next to my battery bank or if I was running a DC air conditioner unit. Or if I needed a more powerful inverter. I really wanted a higher voltage system, it's so dumb that so many things are still limited to 12v. I just didn't want a system with 3 voltages.

And I've been very happy with my 12v system after ~5 years of use. I've got about 14kwh of battery capacity and a victron multiplus 3k and I push my system pretty hard. I just got back from a 5 day trip where I ran my air conditioner (set to 66F) off batteries every night and got down to single digit SOC (kind of intentionally as a test). Even down below 10% soc with voltage dropping into the 12's, it passed my test of starting the AC while the microwave was also running (and a bunch of other random DC stuff). I guess there are some people who need more power from their inverter, but we've never been limited by what the inverter can put out. The only limitation we have is battery capacity over time. 12v vs. 24v vs. 48v has basically no impact on that besides possibly opening up bigger alternator options to charge quicker (and I wasn't willing/able to add a 2nd alternator).

 

[Wrinkledpants]

12v here. I don't mind big 4/0 cable runs and most things are 12v. It also allows me to use either of my two alternators to power the van or coach battery. It's just simple.

Maybe on something where weight mattered I'd care, but in a van, simplicity and repairability are important, at least for me.

 

[Midwestdrifter]

If you are under 3kw peak power, don't need a big second alternator, and are under 7kwhr battery, stick with 12v. The exception may be if most of your energy usage is 120vac.

 

[3Play]

I have been preaching for ditching the expensive 12v. stuff and go with 110vac for all the appliances for 6 years.
If you don't use 12v appliances (expensive garbage), there is no reason to stay with 12v.
I went with a 48v inverter charger, a 48v. gyll rack mount battery and built an insulated box under the van to house it.
The electronics are part of the climate controlled cabin. My entire setup including the solar was about $3k.
The only downside is that you have to use a boost converter for alternator charging. I have 800w of solar on the roof and have not needed to charge from the alternator...

 

[Tim Hodgson aka "E350"]

12VDC
Two 320Ah 12VDC Lithionics house batteries
Magnum Energy MS2812 12VDC Pure Sine Inverter Charger
3Kw 12VDC PowerTech Kubota single cylinder diesel generator
Engel 12VDC fridge with separate dedicated freezer on a $800 slider. (Purchased in 2005 and still going strong.)

Engel MT60 Combination Top Opening Fridge Freezer With Transit Bag

Engel MT60 Combi Fridge-Freezer + Transit Bag For those who need true dual-zone cooling on the road, the Engel MT60 Combi delivers home-fridge performance in a portable, rugged design. With separate compartments for refrigeration and freezing, you can keep meat frozen while chilling beverages or...

engelcoolers.com

 

[Shawn182]

I put in a 24v system but that is only because I was running a 110v rooftop AC through my inverter. Unless you have a high draw electrical appliances like AirCon IMO there is really not much advantage to a 24v system taking into consideration that added cost and complexity as you still need a 12v system for a lot of your loads. I want to put in a 24v second alternator but 24v options are much more limited and more expensive than 12v options so I just have a 12 to 24v DC>DC charger.

You can argue wire size but typically your inverter is adjacent to your battery so the cable runs of larger gauges is pretty insignificant.

Only other thing I run that is 24v is my fridge but that could just as easily be 12v, everything else in the van is still 12v..

One upside is that with my 24>12v converter is that I get a constant 13.5v output regardless of battery state of charge.

Knowing what I know now 6 years later I would just stick with 12v in next build assuming no AirCon

 

[blutow]

Unless you have a high draw electrical appliances like AirCon IMO there is really not much advantage to a 24v system

Unless you need more power than the common 12v inverters provide, I'm not sure running a 24v inverter buys you much even if you are running relatively big loads. I cant' speak for all the inverters out there, but I believe the efficiency difference between the 12v and 24v victron 3000w multiplus is around 1%. That's not nothing, but not enough (in my opinion) to add the complexity of a 3rd voltage for the sake of 1% improvement in inverter efficiency. The 24v multiplus does have a higher charging capacity when on shore power, so that's a nice bonus if you need to charge quickly. But again, that benefit wasn't enough for me to justify carrying a 3rd voltage. No wrong answers, some people are very happy with systems that run 3 voltages. I'm a KISS guy, try to eliminate points of failure where possible.

 

[mv1]

Our Storyteller has 51V Lithionics packs and only for that. 12V DC runs for almost everything in the house including tent motors and 110V for microwave and AC. I assume 51V is pretty much 48V (since Lithionics seems to only be listing 51V on the common 48/51 page).

 

[Rocksnsalt]

Our Storyteller has 51V Lithionics packs and only for that. 12V DC runs for almost everything in the house including tent motors and 110V for microwave and AC. I assume 51V is pretty much 48V (since Lithionics seems to only be listing 51V on the common 48/51 page).

Yes “48V” systems are actually 51.2V nominal, similar to 12V systems are actually 12.8V nominal.
24V systems are 25.6V nominal.

 

[StogieMan]

The reason that I went the 48v route on our van was due to the many high load 120v AC loads and also the only reason that we installed a 48v Arco second alternator. The more I talk to the customers, there is one common theme and goal -they ALL want to boondock for days and be able to run the AC and their higher ac loads just like me. Sounds like a darn common generic YT video!

Now that’s a tough task but not if they’re willing to pay for it and some are willing without hesitation. To be able to run your AC for a couple of days either requires a big battery bank, a huge solar array or a generator in the mix if you’re not willing to go for some short drives. The second alternator will work on idle but then you run into the idle charging dilemma if stationary on a Sprinter. If you’re going to be breaking up camp and doing some other things like hiking, site seeing etc. then there’s no problem as a second high voltage alternator will take care of the charging. However, if you’re just going to sit at a spot for a good while then you need to consider adding a generator or a second ground array for charging a depleted big battery bank. You also have to consider that adding a second solar ground array or generator is taking up precious storage space for those with vans. Yes, under the van generator install is a bonus and I’m lucky to have it.

Solar on a van roof is limited and to really make that work you need a bigger second bigger ground array especially for 48v’s. IMO, and as mentioned the biggest benefit of 48v’s on a van is the addition of a second high wattage second alternator and the ability to run those 120v appliance more efficiently. Less copper is also a big bonus.

 

[Lagom]

My van is 12v, but I was replacing a 24v system in a cabin my son bought, and I was surprised how much smaller the required cables were. Short enough that the cost difference wasn’t that much, but easily the work with because of the flexibility.

Nothing connected now other than the inverter/charger/pv combo, but I will probably direct connect the Starlink mini rather than running it off the 110vac system.

 

[blutow]

However, if you’re just going to sit at a spot for a good while then you need to consider adding a generator or a second ground array for charging a depleted big battery bank.

I'd go one step forward (or maybe backward?) and say that a generator is your only reliable option if stationary and wanting to run your A/C for days on end in hot weather. Solar can be nice to supplement, but it's not always sunny and you really need thousands of watts of solar capacity to keep up. You can rely on a generator, solar not so much.

We've never done an extended trip in hot weather, but we do a few 3-4 day trips every year where where we'll bring along the generator to keep the batteries topped off. Sometimes not needed, but nice to have when in doubt. I have a removeable storage box that goes into the receiver hitch to hold the generator and fuel. It's nice that we aren't always hauling around the weight when it's not needed.

Agree that a secondary alternator is one of the most compelling reasons to consider higher voltage. If you want something that is going to push huge watts, there aren't that many options in 12v. And with batteries often in the rear, that is a long run of thick copper.

 

[mercedesstern]

What say you?

It makes the wiring cheaper, but the 48V equipment is more expensive and there isn't the same variety like for 12V available yet. That might change in future but at the moment it is net more expensive. 48V might be a selling point though.

 

[mercedesstern]

I would suggest looking at welded steel for any battery racks. A giant lithium battery is going to rip right out of 8020 if there is an accident. IMO...

Some time ago I built a roof rack for my SUV from 8020 and had a heavy RTT on it. The car was involved in an accident and totaled, but the roof rack was completely undamaged. I could disassemble it and reuse the parts for my Sprinter. The advantage of using 8020 is the flexibility during construction (easy to make changes) and no need for special tools.

Even the most sturdy battery shelf is useless, if the battery attachment is weak. I have a safety cable for the battery connected to the factory floor anchor points in addition.

 

[Midwestdrifter]

8020 can be plenty strong enough for securing heavy objects. The weakest point of 8020 is the joints. Some engineering needs to go into what joints are used, and how they are oriented.

It is possible for an 8020 structure to have stronger joints than welded thin wall mild steel, mostly due to gusseting.

 

[calbiker]

The reason that I went the 48v route on our van was due to the many high load 120v AC loads and also the only reason that we installed a 48v Arco second alternator. The more I talk to the customers, there is one common theme and goal -they ALL want to boondock for days and be able to run the AC and their higher ac loads just like me. Sounds like a darn common generic YT video!

Are you not concerned of the shock hazard that comes with 55V? Is the battery connected to chassis? Then you have a potential dangerous situation.

Shock Threshold
In regards to the voltage limit, the DC limit is 60 V under dry conditions, and 30 V under wet conditions as specified in UL 1310, [4] intending to protect against the inability of let-go shock effects. This limit was selected with the intent to protect 95% of the population including children.