installing a 48v 200a system with a Balmer alt

[SafariBen]

I meant nothing disparaging by referring to your comments as disparaging. I especially agreed with that comment, and don't have any argument with these comments.


"Ridiculous" was not the right word for 12V 3000w inverters. 12v 32KWH or 6 parallel 24V battery systems are not my thing, I'll let anyone do their own comparisons on if they'd choose that approach.

[powercat_ras]

You can do some reading on the Winnebago Travato 48 V Lithium Version on the Dodge Promaster Chassis. It has a 48V LiFe04 battery pack, a 48 V alternator, 48 V to 12 V DC-DC charger, an AC to 48 VDC charger, a 4000 W PSW 48 V inverter, a battery cooling system, and a BMS that includes chassis engine auto-start.

The main advantage is that at 48V your DC current flow 1/4 of a 12V system so you can use 0 gauge DC power wiring and save a lot of weight.

Be sure to consider battery cooling and / or heating (if you want to operate in very cold temperatures) in your design.

Good luck.

[d23haynes57]

For these coaches the effort is to avoid adding a generator or propane. They usually include a significant solar setup. An advantage of having these installed as part of the new RV purchase is most extended warranties will usually cover the system except for the batteries. For the Pro Master gas engine chassis, the alternator install is nicely done. I have worked on a number of the early 12-volt versions.

[RVfixit]

A lot of information here. I like visuals. The information below is basic but easily explains how a "higher" voltage can be an advantage without getting into all of the semantics. I hope this can provide some insight as to what the OP is trying to accomplish;





BATTERIES can be thought of as water pumps that circulate water through a hose that travels in a closed loop back to the battery. There are many metrics used for the capacity of batteries and not all are immediately logical. They include amp-hours and kilowatt hours. Batteries can only generate DC power.

Now the comparison-

48-volt (48V) systems are generally more powerful, efficient, and scalable than 12-volt (12V) systems. 48V systems are a good choice for solar energy solutions and can be used in a variety of applications, including food trucks and businesses. 12V systems are often used in small living spaces and can be more sustainable.

Power:
48V: Can output more power than 12V systems, up to 50 kilowatts (kW)
12V: Can output up to 3.5 kW

Other advantages:
48V systems can have improved voltage regulation, reduced I2R losses, and enhanced power density.
Just some publicly available information that might be helpful!

Good Luck and Safe Travels!

[d23haynes57]

Looking at some Prevost and Newell stuff. 24 volt and 500 amp engine driven alternators are one of 2 or sometimes 3. Goes with the 18 or 20 kw generator sets. 4 and 8 kw inverters.

[SafariBen]

The huge reason to stay with 12V is that's what starting batteries are, and that's what RV pumps, fans etc. are most commonly run at. The big enough reason to stay with 24V is alternators and some pumps, fans etc. can be found in that voltage.



Demanding more AC power, and/or solar, makes 48V more attractive, you'll still have the chassis battery to power 12V leds, pumps etc. Right now, the alternator choice is limited and expensive.

[RVfixit]

Originally Posted by SafariBen

The huge reason to stay with 12V is that's what starting batteries are, and that's what RV pumps, fans etc. are most commonly run at. The big enough reason to stay with 24V is alternators and some pumps, fans etc. can be found in that voltage.



Demanding more AC power, and/or solar, makes 48V more attractive, you'll still have the chassis battery to power 12V leds, pumps etc. Right now, the alternator choice is limited and expensive.

Totally agree with you but look at electric vehicles and how they operate- Tesla's on average have battery voltages between 375 and 400 volts. All of the peripherals are lower voltages such as 12v for lighting, etc. and have 120v outlets as well. The higher voltage is more efficient and can power lower voltage devices for a longer period of time and is why their drive motors are generally around 320 volts.

The same logic can be applied here. A 48 volt battery pack can power lower voltage devices in RVs more efficiently and for longer periods of time. I don't think the OP had intended to change everything to 48 volt even if the parts were out there.

Would I do this conversion? Nope! Too many moving parts here as you have already eluded too. Everywhere there are 12v devices, the voltage would need to be stepped down using some type of transformer or the more modern control boards but even still, so many devices with limited advantages. If you did one step down to all devices, well, then you have kind of limited the advantage of doing all of this. I'll keep my 6v deep cycle batteries and maybe, just maybe someday finally bite the bullet and convert to Lithium batteries. Maybe...

Safe Travels!
Larry

[SafariBen]

Originally Posted by RVfixit

... Too many moving parts here as you have already eluded too... If you did one step down to all devices, well, then you have kind of limited the advantage of doing all of this.

On the contrary, the system I linked to had THREE solar charge controllers, I think two inverters, countless other blue boxes. 48V all in one inverter, charger, solar controllers are common, then you'd still need a 48-12 converter SO FAR. And that would not include engine charging. So I don't see 48V as "too many moving parts" if you're talking about a certain size system.



Whether someone goes with a 100-300V battery at some point, in RVs, I don't see the infrastructure, or need. But 48V seems to be common in new stuff with the demands, and the affordability of solar and batteries. And I think 48v should be considered for many upgrades.

[d23haynes57]

Lets just skip the voltage increase part of the inverter all together and go with 340 volts DC solar and battery. Then all we need to do is switch it to get the 240 volt RMS sine wave. Actually 170 would be easier, then we can just switch plus minus to get the 120 over a center neutral.

[Dodge Guy]

That’s a lot of work and changing parts for little gain. I would just go with a 12V system and be done with it. 12 V works well and has been done many times. Unless you plan on living full time and running your AC off of the batteries I don’t see the benefit.

[Argosy]

Originally Posted by rmanbike

First of all, two hours of driving we fully charge the lithium batteries, so yes I will be Boondocking at least five out of ever seven days. You assume so many things you know nothing about. I don't need your opinion, so let's just keep it technically if you're able to do that.

If you don't want people to make assumptions post a fact as essential as you'll mainly be boon docking. At the least don't blame when you don't inform.

I'll stand by the rest of my advice as much better way to go than what you proposed for a brand new motor home- work out the warranty issues before making major alterations, use it and find any other issues that will only become evident through use. Every day you spend on a MAJOR upgrade the first year of ownership is a day of warranty the dealer will love you burning up.

Learn how you use it, start making basic upgrades for efficiency. It's an entry level RV, there will be a lot of opportunities for improvement. Replace incandescent with LED, add small spot lights that use far less energy than area lights and provide better illumination where you spend the most time. All my lights are dimmable, the PWM will use some power but it saves more, consider that. Fans will cut down on AC usage. If it has an inverter look at the specs for efficiency and idle current, some are very inefficient. Look at space that could be use for components, and what you will do with what is there. How you will run wires, cables, where monitors can be installed and where that wiring will run.

The basic idea of boon docking is to run out of everything at the same time. Clean clothes, food, water, empty tank space, power. What you proposed will take space for other essentials. The size of the motor home is a limiting factor you need to consider in the balance of dry camping.

Keep us posted, I'll be interested in the installation, what you run into and how it works out.

[antiguasky]

I would find it hard to go back to 12V. The much faster charging speed and smaller component sizes are the two biggest benefits. I used a Wakespeed Regulator with an American Power 160A 56V alternator. The battery is a self build 320Ah LiFeP04 with a RecBMS 2Q. The rest of the system is Victron.

[SafariBen]

Welcome! that's quite the first post.
Do you have shore power charging? or solar? and how do you handle the 12V house loads?

[Bonron]

Originally Posted by rmanbike

First of all, two hours of driving we fully charge the lithium batteries, so yes I will be Boondocking at least five out of ever seven days. You assume so many things you know nothing about. I don't need your opinion, so let's just keep it technically if you're able to do that.

Interesting, you put out this thread with your quest and when common sense is provided by the forum, you insult them. They provided an honest answer to your proposed idea. Leave it at that and move on.