Battery that heats itself

[cruising7388]

Originally Posted by Davydd

Yes, he took a shot at me about the heated garage. It was noted. I guess my contributions on this forum are not appreciated by the moderator. I probably should move on.

Move on? The hell you should! Your long term contribution to this forum has been monumental. Without anchors like you, this forum wouldn't even be half of what it is.

[Oliver2017]

Originally Posted by Davydd

I probably should move on.

I believe the silent majority appreciates reading your postings and just shake their heads when uncalled for jabs are made at your comments. Please keep posting and just ignore the jabs!

[tgregg]

Originally Posted by Oliver2017

I believe the silent majority appreciates reading your postings and just shake their heads when uncalled for jabs are made at your comments. Please keep posting and just ignore the jabs!

davydd,

your one of a few people doing new and interesting things and posting about them.

[avanti]

Originally Posted by Davydd

I guess my contributions on this forum are not appreciated by the moderator. I probably should move on.

Just to be perfectly clear, I am not "the moderator". I am a volunteer who helps out a bit with the moderation. This is not my list and I get nothing whatsoever out of the little moderation that I do (except maybe the ability to edit posts further in the past than others). I make no policy decisions, and I try to be scrupulously fair in what little intervention that I do.

Please separate my personal contributions and opinions from those of the list owners.

[cruising7388]

Originally Posted by avanti

Just to be perfectly clear, I am not "the moderator". I am a volunteer who helps out a bit with the moderation. This is not my list and I get nothing whatsoever out of the little moderation that I do (except maybe the ability to edit posts further in the past than others). I make no policy decisions, and I try to be scrupulously fair in what little intervention that I do.

Please separate my personal contributions and opinions from those of the list owners.

I'm pretty sure that anyone that spends time on this forum fully appreciates how instrumental you are in keeping the wheels from falling off. Thank you!

[Boxster1971]

From my view point both Davydd and avanti help make this forum helpful and interesting. They just like to pick on each other from time to time.

[BBQ]

Originally Posted by Boxster1971

From my view point both Davydd and avanti help make this forum helpful and interesting. They just like to pick on each other from time to time.

[SiennaGuy]

Originally Posted by Davydd

Every home built has an outside 15a plug by code.

That may be true, but not every home has a driveway or a garage that can accommodate an RV. Even if you do have an outside outlet, Murphy's Law says that the outlet will be in a place far away from the driveway, like the backyard. Also, codes apparently vary depending on where and when a home was built. I just moved from a house built in the early 1960s that didn't have any outside outlets. That meant no outside hot tub.

[cruising7388]

Originally Posted by SiennaGuy

I just moved from a house built in the early 1960s that didn't have any outside outlets.

The sixties? If the house was wired with aluminum Romex, that was a smart move indeed

[MsNomer]

About that outside plug: People asked why my son drove his Sprinter from SF to Oklahoma so I could upfit it for him. The reality is that he does not even have an off-street spot to park the vehicle, much less a nearby plug.

We all tend to think of what we have as "normal".

[BBQ]

Originally Posted by MsNomer

About that outside plug: People asked why my son drove his Sprinter from SF to Oklahoma so I could upfit it for him. The reality is that he does not even have an off-street spot to park the vehicle, much less a nearby plug.

We all tend to think of what we have as "normal".

.

[VanFan]

Originally Posted by brentfrmMSP

What is the number 1 reason for all of the b van conversions taking place right now?? Is Onan no longer getting the job done or do the new lithium batteries etc offer something that they don't have?? Just curious, been seeing a lot of talk about the conversions lately. Would love to hear from you guys!

To elaborate on what Davydd wrote, for me (being a Texan) it's the ability to run the air conditioner for nearly 7 hours between charges. A close second is the fact that the battery will accept 100% of the output from our twin alternators. That means we can run our air conditioner 24 hours with only 2.5 hours of daily charge time at idle speed while camping, or about 1.5 hours when driving. Of course alternators can be used to charge other battery types, but the lithium fast charge capability means comparatively less wear and tear on the engine. Generators make more sense for batteries requiring longer charge times. Also, with a gas van like ours the exterior noise when idling is significantly less than most on board gensets which is a big plus when camping.

[BBQ]

Originally Posted by VanFan

To elaborate on what Davydd wrote, for me (being a Texan) it's the ability to run the air conditioner for nearly 7 hours between charges. A close second is the fact that the battery will accept 100% of the output from our twin alternators. That means we can run our air conditioner 24 hours with only 2.5 hours of daily charge time at idle speed while camping, or about 1.5 hours when driving. Of course alternators can be used to charge other battery types, but the lithium fast charge capability means comparatively less wear and tear on the engine. Generators make more sense for batteries requiring longer charge times. Also, with a gas van like ours the exterior noise when idling is significantly less than most on board gensets which is a big plus when camping.

Please start a new thread about your van... very interested in your twin alt set up.

[GeorgeRa]

Originally Posted by MsNomer

About that outside plug: People asked why my son drove his Sprinter from SF to Oklahoma so I could upfit it for him. The reality is that he does not even have an off-street spot to park the vehicle, much less a nearby plug.

We all tend to think of what we have as "normal".

Agree, often a point of contention if superimposed on others.

[booster]

Originally Posted by BBQ

Please start a new thread about your van... very interested in your twin alt set up.

Yes, that would be interesting to me also. We have twin alternators in parallel, and it is a good system, but not for what most would think it is for. We do it to get moderate output without overheating them.



Heat kills alternators and the DC Power/Nations alternators can't run anywhere near rated output for very long before they either will destroy themselves or get turned down by an external regulator. 60-65% of rated id probably a reasonable guess at realistic power output over time.



Two 280 amp "normal" add on alternators will get you about 360 amps hot, minus maybe 15 to run the van, and on a Promaster another 30-40+ to run the cooling fans, which I assume are electric because it is front drive. Basically about 300 amps available for charging. At idle, it will be less than 300 amps in most cases as things run hotter and speed is down.


A Promaster may or may not increase idle speed based on loads. Some electric fans are very loud, don't know about Promaster ones.


Even at 360 amps, you are looking at 5K watts, so there is a lot of load on the accessory drive and front of engine parts like the front main bearing and seals. I think an Onan 3.8K genny has an 8hp engine, so 5K would be maybe 10+hp off accessory drive continuously. Most commonly, I have heard that auto AC units use 3-5hp, so the alts would take double to triple that amount. It will be very interesting to see how well the vehicles handle many hours of idling with big loads over time, as I am pretty sure the OEM designers weren't looking at those kinds loads at idle, or the heat the generate. We do not use our parallel system to charge at idle unless absolutely necessary, and then it would be for very short times. It the several years we have had it in place, I would bet the engine has been idled less than 60 minutes total, mostly just for testing, as we don't every seem to need more charging.



Going to a 48 volt system like Volta does solves most of the issues of very high charging, but doesn't change the load the engine sees very much.

[TooMuchHair]

"Going to a 48 volt system like Volta does solves most of the issues of very high charging, but doesn't change the load the engine sees very much."


That is exactly what I said to a VOLTA rep at the 2018 Work Truck Show this spring. We were discussing the ARV system. He kept boasting of lowered amp flow and less voltage drop to the batteries and all of their ability to fast charge while running the roof air. But seemed lost when I said that "watts are watts, and you guys are really asking a lot out of a small frame alternator, 48-56VDC or not." He also was surprised when I gently suggested that they "may" be (they are!) exceeding MB's power limits on the aux PTO location.


Only time will tell the durability of their approach and which components begin to fail. 48 volt systems are likely destined to be the future of RV electric systems, but I think we are still too early to see true reliability yet.

[brentfrmMSP]

Thanks for the insight guys! Good stuff.

[Boxster1971]

Originally Posted by TooMuchHair

"Going to a 48 volt system like Volta does solves most of the issues of very high charging, but doesn't change the load the engine sees very much."





That is exactly what I said to a VOLTA rep at the 2018 Work Truck Show this spring. We were discussing the ARV system. He kept boasting of lowered amp flow and less voltage drop to the batteries and all of their ability to fast charge while running the roof air. But seemed lost when I said that "watts are watts, and you guys are really asking a lot out of a small frame alternator, 48-56VDC or not." He also was surprised when I gently suggested that they "may" be (they are!) exceeding MB's power limits on the aux PTO location.





Only time will tell the durability of their approach and which components begin to fail. 48 volt systems are likely destined to be the future of RV electric systems, but I think we are still too early to see true reliability yet.

Agree that going 48 V does not reduce load on engine.



1. You were probably talking to a sales guy.



2. They are not exceeding Daimler load limits. The largest Volta B-van kit includes a 8000 watt alternator. The Daimler/Mercedes Option N62 for mounting an additional engine driven alternator says max power is 8500 watts. Yes watts are watts.

[wincrasher]

Well it depends on how you are parsing it.

The load on an instantaneous basis is probably the same. In aggregate, it probably is not. I think we all understand the benefit to having a much shorter run time to charge the batteries - not only in wear and tear on the engine, but in the noise created.

So I'll take the choice to go 48v any day of the week and twice on Sundays.

[TooMuchHair]

The MB specification of 8500 watts is "Input watts". The Volta Power 8000 watt alternator specs show the efficiency of that unit to be "80% typical". So that would be require 10,000 watts of input.
https://voltapowersystems.com/wp-con...ts_3.16.18.pdf


I'm not trying to split hairs, but they are exceeding MB's limits.

Plus there already have been many reports of belt issues using alternators with much lower output than the one we are talking about. Many of those include an engine overheat due to the loss of the water pump drive, that to me is an even bigger concern.

Love the forum and appreciate all of your well informed posts!