48VDC Air Conditioner

[Chance]

I received confirmation of the anticipated 48VDC air conditioner that was to be introduced at RVX; but wasn’t as far as I know. Initial manufacture is scheduled for end of July, and production is reportedly sold out through October. Airxcel is not disclosing any information yet to general public, so don’t know any details including its cooling capacity or efficiency. Obviously the companies placing orders must have this information already so it may leak out soon.

This could be a major step towards battery-based overnight air conditioning for RVs. I’m curious to see which companies have placed orders, and how the air conditioner will be marketed.

Glad to see 48V equipment coming to market.

[Long & Winding road]

That sounds awesome. I think you will see a lot of 24 v system in the future but really 48 v would be even better.

[The Gritz Carlton]

I always had trouble putting batteries in a flashlight the right direction. What's the advantage of 24 or 48V A/C?

[Chance]

Originally Posted by Long & Winding road

That sounds awesome. I think you will see a lot of 24 v system in the future but really 48 v would be even better.

I would not invest a penny on 24V anything.

The future is 48V, and I only look back to make sure I don’t repeat the mistakes others have made. Going forward for me it’s 48V if I can justify it, or stay with 12V. I don’t want to end up with a bunch of obsolete 24V stuff.

To be clear, those who own rigs with 24V electrical systems, like large diesel buses, are a different matter. But given time they will convert to 48V also.

[Chance]

Originally Posted by The Gritz Carlton

I always had trouble putting batteries in a flashlight the right direction. What's the advantage of 24 or 48V A/C?

Basically, for the same amount of power, you only need 1/4 the current. That means wire sizes can be reduced significantly, which is more important as we make RVs more electrical. At really low power levels like LED lights it’s no big deal, but when we start talking air conditioners which may require 100 Amps at 12V, reducing it to 25A at 48V is a lot better.

Even worse are large inverters that may see up to 3 times their current rating for a few seconds. When you have close to 10,000 Watts even for a few seconds, amperage at 12V would need to be close to 1,000 Amps from battery bank. Cable sizes and voltage drops are just much easier to handle at 1/4 the current. That’s why the auto industry adopted 48V.

They could have gone even higher voltage to reduce current even more, but above 60V there is a significant safety issue. Hence 48V is the sweet spot.

[Long & Winding road]

Originally Posted by Chance

Basically, for the same amount of power, you only need 1/4 the current. That means wire sizes can be reduced significantly, which is more important as we make RVs more electrical. At really low power levels like LED lights it’s no big deal, but when we start talking air conditioners which may require 100 Amps at 12V, reducing it to 25A at 48V is a lot better.

Even worse are large inverters that may see up to 3 times their current rating for a few seconds. When you have close to 10,000 Watts even for a few seconds, amperage at 12V would need to be close to 1,000 Amps from battery bank. Cable sizes and voltage drops are just much easier to handle at 1/4 the current. That’s why the auto industry adopted 48V.

They could have gone even higher voltage to reduce current even more, but above 60V there is a significant safety issue. Hence 48V is the sweet spot.

Sweet.

[Long & Winding road]

Originally Posted by Chance

I would not invest a penny on 24V anything.

I don’t want to end up with a bunch of obsolete 24V stuff.

To be clear, those who own rigs with 24V electrical systems, like large diesel buses, are a different matter. But given time they will convert to 48V also.

Like the Military using 24 volt? "Obsolete" and "military intellegents" go hand in hand.

I can see the advantages of 48 v. I just figured we would have a step in between (24 v) before everyone accepts 48 v. But then again why waste anymore time.... lets just jump to 48v.

Now that we (the entire world) is accepting electric vehicles and litium batteries in everything I can see us slowly switching to 48v in the next 5 to 7 years (in the RV world - sooner elsewhere.

I think I read by 2025 that EV's will outsell combustion autos ....so they will drop them lot hotcakes. Going to be a sad day ...

[The Gritz Carlton]

"I think I read by 2025 that EV's will outsell combustion autos ....so they will drop them lot hotcakes. Going to be a sad day ..."

I'd bet the farm that will not happenby then. Probably not happen in the next 10 years...at least.

[Chance]

I agree, thinking internal combustion engines will be around in large numbers for a while still. If or when electric cars become cheaper to manufacture is when they will take off in large numbers IMO.

It may also take years for motorhomes to adopt 48V battery systems, but since Volta has had relative success, progression may speed up now, particularly if another company emerges to compete. Or if some RV manufacturers start to go to 48V on their own.

I mentioned benefit of smaller wiring sizes if switching from 12 to 48 Volts, but didn’t say the lower current rate could also reduce size of fuses, switches, relays, etc. Also the size/rating of solar controllers is reduced. Many solar controllers are rated at four times the wattage at 48 vs 12 Volts.

The remaining piece that’s still missing is the 48V (~ 56 for charging) alternator. As long as chassis manufacturers don’t offer an easy way to install a 48-Volt alternator, progress will continue to be slow in my opinion.

I’m hoping the new Ford electrical architecture they have been announcing with dual alternators may make the conversion simpler and much less expensive.

[Chance]

Back to 48VDC Air Conditioner:


In my opinion the key spec to look for when it’s announced is the Energy Efficiency Ratio, or EER. The main reason for having a DC air conditioner will be to get more cooling out of a given battery bank capacity, and if it doesn’t improve significantly over a standard A/C powered by an inverter, then what’s the point. Elimination of an inverter itself doesn’t seem enough.

A big plus will be if it can run more efficiently at lower capacity (running compressor slower) which could extend run time at night even more.

[Long & Winding road]

Originally Posted by The Gritz Carlton

"I think I read by 2025 that EV's will outsell combustion autos ....so they will drop them lot hotcakes. Going to be a sad day ..."

I'd bet the farm that will not happenby then. Probably not happen in the next 10 years...at least.

Its going to sooner than that. Do some searches on your own.....

"The internal combustion engine appears to be on its last lap. More than nine countries and a dozen cities or states have announced what the media has called “bans” in the last few years. Copenhagen mayor Frank Jensen wants the city to end all new diesel cars starting next year. Last December, Paris, Madrid, Athens and Mexico City said they would remove diesel cars and vans by 2025. Norway will phase out conventional cars by 2025, followed by by France and the United Kingdom in 2040 and 2050, respectively."

"In a sign of things to come, Jaguar Land Rover has become the second large-scale car manufacturer to announce that it will cease producing cars based around the internal combustion engine from 2020."

Sure they will still make trucks and HD vehicles with IC engines - that will take much longer. But it sounds like cars will start fading out around 2025.

[The Gritz Carlton]

I Double Down.....this is America. This economy thrives on fossil fuel products. You'll never see this in your lifetime...I bet.

[16ACE27]

Originally Posted by The Gritz Carlton

I Double Down.....this is America. This economy thrives on fossil fuel products. You'll never see this in your lifetime...I bet.

I'd have to agree with Gritz on this one. Look around at all the IC vehicles currently operating, and imagine having to pull all (or even half) that power from our current electrical grid, especially in the summertime when we can't even support the current electrical load in some places.

As long as we have relatively cheap fossil fuel available there will be IC vehicles in abundance.

[Chance]

I expect to see considerable numbers first in large cities when price drops a lot. People who mostly use them to go to work, shopping, or occasional visit to nearby doctors, family, friends, etc. will start buying them as second cars.

Electric city cars won’t need the 200-plus mile range or performance of primary vehicles like a Tesla. I recently saw pictures of compact cars in China that compared to cars like scooters compare to motorcycles — OK in cities, not so much on interstate highways.

Charging from grid should be OK as long as it’s done at night in summer when A/C loads are much lower. It may even help keep electric power plants loaded more evenly to increase efficiency.

[JamieGeek]

Originally Posted by Chance

...
Charging from grid should be OK as long as it’s done at night in summer when A/C loads are much lower. It may even help keep electric power plants loaded more evenly to increase efficiency.

It is and does. This is why many electric companies offer time-of-day pricing for EV owners. Our supplier cuts the price way down overnight ($0.02/kwh)--and also why just about every EV can be set to charge at a given time (e.g. overnight--my Bolt starts charging after 11pm).

[Long & Winding road]

Originally Posted by The Gritz Carlton

I Double Down.....this is America. This economy thrives on fossil fuel products. You'll never see this in your lifetime...I bet.

Oh it will happen in my lifetime. Manufactures area already saying they will ramp up EV's from now to 2025 and ramp down IC engines at the same time .....so if you want a new "car" around 2026 / 2027 it will most likely be electic. And most likley you will WANT an EV because they will be so much better than a IC and as cheap or cheaper.

But trucks and RV's etc may never phase out in my liftime.

And of coarse you have millions IC of cars on the road so it will be 10+ years for the avg Joe and Never for someone with a classic car or an IC diehard.

Only time will tell but its coming sooner than later.

[JamieGeek]

Did you see this commercial? (They showed this one during the NBA playoffs!)

https://www.youtube.com/watch?v=qEvNL6oEr0U

Almost makes you feel sad for them LOL!

A really good EV commercial is this one from Audi, however (even Elon was impressed on twitter): (I see the Audi one all over primtime now)

https://www.youtube.com/watch?v=5llo...ature=youtu.be

At the moment no US company will touch EV marketing with a 1,000 ft pole however, LOL.

[The Gritz Carlton]

I'm not anti-EV. My wife drives 15 miles one way to work and her car sits in the garage at home and at work. We never drive it on weekends. Tried to get her to go that route 10 years ago. As has been said here...the short runners and city dwellers will go EV way before us "out back". The nation-wide infrastructure for EV's would take many years to develop for EV's to take over IC. Then...we'll take the same fossil fuel we burn in our IC's, and start burning it to produce electricity. It will not happen. No incentive for it here. Let Europe keep it. It's a nice dream though.

[The Gritz Carlton]

Excellent song...my favorite during my short stint in Guam...a few tears an years ago. Loved the bus...had one in those days. If they built the same one today and put huge battery banks in the back...maybe. That commercial hit an old, soft spot!!

[JamieGeek]

Originally Posted by The Gritz Carlton

I'm not anti-EV. My wife drives 15 miles one way to work and her car sits in the garage at home and at work. We never drive it on weekends. Tried to get her to go that route 10 years ago. As has been said here...the short runners and city dwellers will go EV way before us "out back". The nation-wide infrastructure for EV's would take many years to develop for EV's to take over IC. Then...we'll take the same fossil fuel we burn in our IC's, and start burning it to produce electricity. It will not happen. No incentive for it here. Let Europe keep it. It's a nice dream though.

Infrastructure for EV's is already in place: Your house.

I charge at home 99.99% of the time and the other 0.01% of the time I plug into the 50Amp plug at a campground. The only time I ever use public charging is when I want to see if that station works ! LOL

My commute is similar to your wife's and the Focus Electric with its meager 70 mile range worked perfectly for me (although since its my car the EV is usually the car we drive when we go anywhere and the Focus still worked out well). With you being in Georgia you don't even have to worry about winter driving range. Sheesh EV's are really cheap now on the used market (especially the <100 mile ones).

On top of all that: Where do you think the fine money that VW paid went to? Establishing a nationwide infrastructure for fast EV charging:
https://www.electrifyamerica.com/index