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Help me decide on voltage and batteries for our new RV

Watts Happening

Watts Happening

I call it like I see it.
Joined
May 3, 2022
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Picking up our new to us 42’ Monaco Dynasty tag axle diesel pusher next week. I’ve done many large RV solar power systems in the past, but with this I’m trying to consider everything in detail before I start. I’ve typically done all Victron equipment and Battle Born in the past. Our last 5th wheel was 24v, at the time I did Tesla packs and a 24-12v Victron Orion, later converted to (12) Battle Born batteries.

On the new rig, I prefer 48v, but then I feel like I’m leaving a lot of energy on the table in regards to alternator charging. Anyone have any clever ideas there?

I could stay 12v for simplicity sake, but then the damn amperage is wild if I want to run a couple or even all three air conditioners. Roof will be covered in solar which will start creating multiple charge controllers.

So, what say everyone? 48v and an all in one? Victron everything? 12v and simple?

I forgot to mention, this RV will probably be doing less “boondocking” than our prior setups, I’m imagining more RV parks/campgrounds. That said, I still want it to be capable. Another plus for the 48v setup is the onboard Onan 10kw generator. Pair that with a chargeverter I already have and now we’re cooking on the charge times.

Thanks and happy 4th!

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I just saw that Epoch has dropped their 48V 100ah marine battery down to $1799, plus you can get another 10% off with the coupons around. That is a really nice battery for your RV imo.
 
I've seen something about using 2 victron orion-tr units in series to boost the alternator charge to 48v but the wattage seems to be only 750w there's likely better solutions out there and I'm sure others can comment but go big or go home seems to be the American way so go with the 48v
 
Just use a extra 48volt alternator to charge the battery bank.
So you have 2 alternator on your RV.

balmar.net

96-Series (48V) Alternators - Balmar

96-Series (48V) Alternators Mid-Duty Cycle, Large Frame Alternators 60A (2.9kW) and 100A (4.8kW) at 48 Volts! Industry Best Turn-on Thresholds Low Power Take-Off at Idle Speeed Designed for External Regulation Works with the New Balmar MC-620 Regulator Ideal for 48V Lithium Battery Banks New...
balmar.net balmar.net
 
Considering the future use I would skip on the alternator charging the main battery completely. Big solar works fine while driving. Generator is available if desperate.

Yes main inverter battery at 48 volts if running more than a single A/C.
 
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Yeah I guess that makes sense, I’ll eyeball an additional alternator.

I also agree, cheap and easy to run the generator but for whatever reason my mind prefers not having to run it more than required. Love the idea of charging while driving, not like the motor is going to notice the difference regardless.

So it’s set, 48v which I prefer anyway. Toss some spare server rack batteries in? Which AIO?

I’m struggling with the idea of most AIO’s, there are great units from many manufacturers, but I keep coming back to some of the great features Victron has.

Open to ideas though!
 
Watts Happening said:
Yeah I guess that makes sense, I’ll eyeball an additional alternator.

I also agree, cheap and easy to run the generator but for whatever reason my mind prefers not having to run it more than required. Love the idea of charging while driving, not like the motor is going to notice the difference regardless.

So it’s set, 48v which I prefer anyway. Toss some spare server rack batteries in? Which AIO?

I’m struggling with the idea of most AIO’s, there are great units from many manufacturers, but I keep coming back to some of the great features Victron has.

Open to ideas though!
Click to expand...
I will go for Victron.
Pay a extra 10% over the stuf and you have 10 years warranty by officiële Victron store (normal 5 years)
My self use years Victron and set in vw t4/t5 vw lt/Crafter for road repair
Its one of my old jobs .

Today i'm in the boats and all ready see a lot of broken mastervolt and other strange inverters .
 
Suijkerbuijk said:
I will go for Victron.
Pay a extra 10% over the stuf and you have 10 years warranty by officiële Victron store (normal 5 years)
My self use years Victron and set in vw t4/t5 vw lt/Crafter for road repair
Its one of my old jobs .

Today i'm in the boats and all ready see a lot of broken mastervolt and other strange inverters .
Click to expand...

Watts Happening said:
Yeah I guess that makes sense, I’ll eyeball an additional alternator.

I also agree, cheap and easy to run the generator but for whatever reason my mind prefers not having to run it more than required. Love the idea of charging while driving, not like the motor is going to notice the difference regardless.

So it’s set, 48v which I prefer anyway. Toss some spare server rack batteries in? Which AIO?

I’m struggling with the idea of most AIO’s, there are great units from many manufacturers, but I keep coming back to some of the great features Victron has.

Open to ideas though!
Click to expand...
There was another thread on here about charging 48V from 12V. They linked a Victron charger which doesn't appear on Victron's website, and also this charger https://sterling-power.com/products...verse-charging-feature?variant=43421414228157
 
Found it. Not really a battery charger, but with todays smart protected BMS, I would not really have an issue with setting the output voltage at a constant 56V, which would be 3.5V per cell on a 16s 48V LiFePO4 and just let it run. From what I have seen, most chargers seem to just do this anyway, except they try to get that last 1% by charging up to 3.65v...but they don't do individual cell monitoring, the BMS in the battery does that.
 

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IGBT said:
Found it. Not really a battery charger, but with todays smart protected BMS, I would not really have an issue with setting the output voltage at a constant 56V, which would be 3.5V per cell on a 16s 48V LiFePO4 and just let it run. From what I have seen, most chargers seem to just do this anyway, except they try to get that last 1% by charging up to 3.65v...but they don't do individual cell monitoring, the BMS in the battery does that.
Click to expand...
Its fully program
So you can set all volt you like

Just download Victron app.
See in the app the function demo library .
This way you can see what you can do with it for you have the hardware.
 
Suijkerbuijk said:
Its fully program
So you can set all volt you like

Just download Victron app.
See in the app the function demo library .
This way you can see what you can do with it for you have the hardware.
Click to expand...
I just assumed you set the constant voltage output with a trimpot or something. The OP could hook his alternator directly up to this DC-DC (10 to 17 volt input range) and then have 380 watts of 56 or 58volt power to charge his 48V LiFePO4 while driving. Pretty sweet.
 
if you going to go 48v then I would suggest keeping that whole system as only DC to AC power meaning for inverters, then add another few 12v batters as your main coach batteries that run the 12v stuff. If you want to use everything from the same bank then you should go 12v.

Trying to get 12v from the 48v bank is going to be a a pain it requires dc-dc regulators, and other stuff, usually over priced vs the 12v versions.

Because of this most people I know end up going with 12v simply because the amount of products that work at 12v.
 
Alkaline said:
if you going to go 48v then I would suggest keeping that whole system as only DC to AC power meaning for inverters, then add another few 12v batters as your main coach batteries that run the 12v stuff. If you want to use everything from the same bank then you should go 12v.

Trying to get 12v from the 48v bank is going to be a a pain it requires dc-dc regulators, and other stuff, usually over priced vs the 12v versions.

Because of this most people I know end up going with 12v simply because the amount of products that work at 12v.
Click to expand...
Than i will go for a 24volt systeem .
A lot of stuf can run on 12 or 24 volt .
My fridge can run on 12 or 24 volt .
My leds can run 12 to 30 volt.
A 24v dc to 12v dc are cheap for the other stuff .
 
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Suijkerbuijk said:
Just use a extra 48volt alternator to charge the battery bank.
So you have 2 alternator on your RV.

balmar.net

96-Series (48V) Alternators - Balmar

96-Series (48V) Alternators Mid-Duty Cycle, Large Frame Alternators 60A (2.9kW) and 100A (4.8kW) at 48 Volts! Industry Best Turn-on Thresholds Low Power Take-Off at Idle Speeed Designed for External Regulation Works with the New Balmar MC-620 Regulator Ideal for 48V Lithium Battery Banks New...
balmar.net balmar.net
Click to expand...
Looked into this today and holy hell, they want $3,500 for the alternator and another $500 for their regulator. The alternator looks and sounds great, but for THAT kind of money I’ll just press the start button on the existing 10Kw generator…
 
Running 3 air conditioners on 12v sound like a nightmare. 24v would work, there are more affordable 24v alternators on the market. It is limiting in the AIO and Server rack department.

Do you have any 240v appliances? Do you ever hook up to 15/30 amp shore power?
 
Dooug said:
Running 3 air conditioners on 12v sound like a nightmare. 24v would work, there are more affordable 24v alternators on the market. It is limiting in the AIO and Server rack department.

Do you have any 240v appliances? Do you ever hook up to 15/30 amp shore power?
Click to expand...
I think my mind is made up, like I said I prefer 48v anyhow.

I don’t take possession of the RV till next weekend but I don’t imagine there are any 240v appliances.

I can absolutely see connecting to 15/30 amp which is a major plus on the Victron side of things.

The sol-ark isn’t going to appreciate the 120v power, it won’t charge at all with it. But, I could use a chargeverter in those instances.

Or just use all Victron and deal with the annoying one time wiring
 
Watts Happening said:
Looked into this today and holy hell, they want $3,500 for the alternator and another $500 for their regulator. The alternator looks and sounds great, but for THAT kind of money I’ll just press the start button on the existing 10Kw generator…
Click to expand...
Ali its cheaper about 1300 dollar.

But wel go for 48 volt than you have all the stuf you need for cheaper.
 
Watts Happening said:
I think my mind is made up, like I said I prefer 48v anyhow.

I don’t take possession of the RV till next weekend but I don’t imagine there are any 240v appliances.

I can absolutely see connecting to 15/30 amp which is a major plus on the Victron side of things.

The sol-ark isn’t going to appreciate the 120v power, it won’t charge at all with it. But, I could use a chargeverter in those instances.

Or just use all Victron and deal with the annoying one time wiring
Click to expand...
I don't recall who it was but there's someone here with a big bus with five ac units, I want to say he had either two Quattro 3 or 5kVA, and had two on one and three on the other.
 
Watts Happening said:
I can absolutely see connecting to 15/30 amp which is a major plus on the Victron side of things.
Click to expand...
I understand power assist although between the solar and the 15/30 just charging the battery direct there should be plenty of power to stay cool.
 
Sterling does this dc to dc charger, that does 1400 output at 54 volts. More than the victrons and can reverse current to charge the leisure battery.
sterling-power.com

12V (only) to 48V Battery to Battery Charger w/ reverse charging feature + Jump Start Assistance

12V (only) to 48V DC to DC Chargers 115A input and 26A output model (1600W input and 1500W output) - E-Marking | BB1248120 If you need 24V input and 48V - click here BB124865 - a smaller / lower powered derivative of the BB1248120. 12V and 24V input to 48V 750W battery to battery charger...
sterling-power.com sterling-power.com

Otherwise runs the biggest cable from the 12v alternator that you can stomach and add Orions to suit the load/wire

A have seen other install a large 12v inverter on the leisure side to power a AC/DC charger on the RV side. Seems crazy to go dc/ac/dc but over distance it may come out a wash vs trying to move a bunch of DC current long distance. Im sure it could be calculated.
 
DC current isn't any more of an issue than AC current.
It's the lower voltage that's hard to move over distance.
 
Alrighty, after ~10 nights in the motorhome I’m beginning to think I may actually want to go 12v, still seeking input.

There is absolutely zero hope of running all of the rooftop air conditioners from solar, it’s simply a math problem. I can’t get anywhere near enough panels on the roof to pull it off, and over the last 10 days we’ve needed all three almost nonstop.

For me, it’s basically a pass/fail of “all solar” or not. Being that I can’t do it, I revert to assuming I’ll be using the generator a fair bit, or fill hook ups.

At that point, I think I damn near outta just stick with the existing 2,800w Magnum inverter, toss a couple 12v EG4 server rack batteries in it and a couple 400w panels on the roof and call it good.

Anyone care to agree or disagree? I’m just trying to make sense of an entire rewire/upgrade that ultimately ends in having to run the generator anyways. Future resale is also an idea, hard to convince the boomers it made sense to go wild and adopt 48v components vs the standard and simple 12v setup.
 
A little experience goes a long way. I agree with 12v if the inverter is under 3000w and solar is under 1000w.
Although I do prefer a large battery as I don't carry much of a generator. In winter that furnace can still delete the battery over time.

Otherwise need to head north and to a high mountain or a western beach.
 
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