Advancing Alvar

[Davydd]

When we were at Advanced RV Fest they were working on insulated battery boxes and heating them. I'm not all that sure how big an issue this is. Minnesota has electric cars and not much, if anything, has been said. First time I had heard about this was at Advanced RV Fest.

[avanti]

Temperature is a huge issue with lithium ion batteries. Both capacity and battery life is affected significantly by temperature:

http://www.plugincars.com/lithium-io...at-122447.html

The real electric vehicle manufacturers put a lot of engineering into dealing with this. Tesla battery packs, for example, are both actively heated and cooled. There is more than one Li battery technology, and it may be more of an issue with some than with others, but this is certainly not an issue to be ignored. I'm not saying that it's amateur hour in the RV industry...

[Davydd]

Here is what it says at Battery University.

" Li?ion batteries offer reasonably good charging performance at cooler temperatures and allow fast-charging in a temperature bandwidth of 5 to 45°C (41 to 113°F). Below 5°C, the charge current should be reduced, and no charging is permitted at freezing temperatures. During charge, the internal cell resistance causes a slight temperature rise that compensates for some of the cold. With all batteries, cold temperature raises the internal resistance.

Many battery users are unaware that consumer-grade lithium-ion batteries cannot be charged below 0°C (32°F). Although the pack appears to be charging normally, plating of metallic lithium can occur on the anode during a subfreezing charge. The plating is permanent and cannot be removed with cycling. Batteries with lithium plating are known to be more vulnerable to failure if exposed to vibration or other stressful conditions. Advanced chargers, such as those made by Cadex, prevent charging Li-ion below freezing."

My understanding is Advanced RV was working on monitoring cell temperature as well as voltage in the Li-ion batteries and I would think they could program the Silverleaf controller not to charge batteries if temperatures fell below that required. As I mentioned they were working on insulated and heated boxes so you could raise the temperature to charge. Keep in mind you cannot charge in below 0F. That does not mean an already charged battery could not supply energy.

I guess I have a lot of incentive now to build a heated garage.

[Boxster1971]

Originally Posted by Davydd

........

My understanding is Advanced RV was working on monitoring cell temperature as well as voltage in the Li-ion batteries and I would think they could program the Silverleaf controller not to charge batteries if temperatures fell below that required. As I mentioned they were working on insulated and heated boxes so you could raise the temperature to charge. Keep in mind you cannot charge in below 0F. That does not mean an already charged battery could not supply energy.

I guess I have a lot of incentive now to build a heated garage.

Glad to hear that Advanced RV is working to make Lithium batteries work well in an RV. They could be the first to tackle this issue in the RV industry. IIRC Roadtrek dropped their Lithium battery option. AM Solar was also experimenting with Lithium, but dropped the effort as they didn't think any were ready for RVs. It will take engineering special systems like Advanced RV is working to get Lithium into RVs with reliability.



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[gerrym51]

Originally Posted by Boxster1971

Glad to hear that Advanced RV is working to make Lithium batteries work well in an RV. They could be the first to tackle this issue in the RV industry. IIRC Roadtrek dropped their Lithium battery option. AM Solar was also experimenting with Lithium, but dropped the effort as they didn't think any were ready for RVs. It will take engineering special systems like Advanced RV is working to get Lithium into RVs with reliability.



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boxster- although i am not sure the exact reason-lithium batteries were a 17,000 dollar option(yes 17 THOUSAND) from Roadtrek. that might have been the reason they stopped it. I know of no one that got the litium batteries

[pattonsr]

AM Solar had no clue what they were doing when they dropped in Lithionics batteries in an old RV that had an old Magnum remote. When they finally realized that treating Lithium like a Lifeline AGM wasn't working, they couldn't implement what Magnum Energy told them to do since they had never bothered to update their Magnum remote.

In contrast, Advanced RV has spent a great deal of time researching Lithium batteries since first putting in 4 100 amp Smart Battery lithiums. Now I understand they are getting close to field testing a new advanced Lithium system. Hopefully it will be implemented and field tested in the fourth quarter. I would bet Alvar will have a state of the art power system.

[Davydd]

gerryM51,

I'm not sure what Roadtrek was putting in for li-on batteries. Was that $17,000 for just the batteries or for the whole system? My guess is four of those Smart li-on batteries I saw being installed in one Advanced RV probably cost about $5,000 retail. That would be similar to what I think I might put in. Keep in mind 4 li-on 100ah batteries are equivalent to about 7 100ah AGM batteries because of how much capacity you can draw them down. Much more probably would not accomplish much other than that vaunted 9 hours of air conditioning.

Hopefully pattonsr I will have something state of the art if Advanced RV settles on a solution in time. This is the excitement. I've been willing to pioneer. It would be no fun otherwise.

This week I emptied out our Great West Van. I was shocked at how much stuff I took out and stuff I forgot I had tucked away like large golf umbrellas. I think we will be shutting it down for the year to sell.

[gerrym51]

Originally Posted by Davydd

gerryM51,

I'm not sure what Roadtrek was putting in for li-on batteries. Was that $17,000 for just the batteries or for the whole system? My guess is four of those Smart li-on batteries I saw being installed in one Advanced RV probably cost about $5,000 retail. That would be similar to what I think I might put in. Keep in mind 4 li-on 100ah batteries are equivalent to about 7 100ah AGM batteries because of how much capacity you can draw them down. Much more probably would not accomplish much other than that vaunted 9 hours of air conditioning.

Hopefully pattonsr I will have something state of the art if Advanced RV settles on a solution in time. This is the excitement. I've been willing to pioneer. It would be no fun otherwise.

This week I emptied out our Great West Van. I was shocked at how much stuff I took out and stuff I forgot I had tucked away like large golf umbrellas. I think we will be shutting it down for the year to sell.

17,000 was for the 3 lithium batteries to replace the agm. it was 17,000 more. I saw a roadtrek dealer order sheet that was posted by somebody-i will attempt to loccate it and will post it if i find it.

[booster]

Originally Posted by gerrym51

17,000 was for the 3 lithium batteries to replace the agm. it was 17,000 more. I saw a roadtrek dealer order sheet that was posted by somebody-i will attempt to loccate it and will post it if i find it.

Price list is here

http://classbforum.com/phpBB2/viewto...tart=99#p12918

[gerrym51]

Originally Posted by booster

Price list is here

http://classbforum.com/phpBB2/viewto...tart=99#p12918

thanks Booster- i could not remember where i read it-it does say 17,000 dollars though. i did find someone on the sprinter source that did buy the lithium batteries-i was surprised. 17,000 is 17,000

[Davydd]

That is an old price list and I believe li-ion batteries have come down in price. But still that seems rather excessive.

[gerrym51]

Originally Posted by Davydd

That is an old price list and I believe li-ion batteries have come down in price. But still that seems rather excessive.

that may be true-but that's probably why they stopped offering it.


these people agree with you.


http://www.businessspectator.com.au/art ... r-we-think


however i don't know how to compare lithium with AGM. what would 440 amp hours of AGM be in comparison to what size/strength lithium ion


i like this

http://www.powerandmotoryacht.com/refit ... -batteries

[Davydd]

If you have 440 amp hours of AGM batteries or 4 12V Type 31 batteries you can draw them down 50% which means you would have 220 usable amp hours between cycles. To get the 220 amp hours on lithium ion batteries you can get by with three 100 amp hour Smart batteries, draw down as much as 80% and get 240 usable amp hours.

[wincrasher]

the smart batteries are still $1299 each. AGM batteries are around $300. You really have to need the space or weight savings to make it worth going that way. The Roadtrek has 8, 6v AGMs - so around $2400 in batteries for 1600 amp hours and must weigh around 640 lbs.

That's a ton of capacity, especially if you don't plan to run the AC with it.

[gerrym51]

Originally Posted by wincrasher

the smart batteries are still $1299 each. AGM batteries are around $300. You really have to need the space or weight savings to make it worth going that way. The Roadtrek has 8, 6v AGMs - so around $2400 in batteries for 1600 amp hours and must weigh around 640 lbs.

That's a ton of capacity, especially if you don't plan to run the AC with it.

the whole point to me -IS running the air conditioner-if i knew for sure that i would never run the ai rconditioner-i wouldn't worry about it.

[Davydd]

Originally Posted by wincrasher

the smart batteries are still $1299 each. AGM batteries are around $300. You really have to need the space or weight savings to make it worth going that way. The Roadtrek has 8, 6v AGMs - so around $2400 in batteries for 1600 amp hours and must weigh around 640 lbs.

That's a ton of capacity, especially if you don't plan to run the AC with it.

This is where I get electrically dyslexic with all these number but my understanding that if you have 1600 ah of 6 volt batteries you still have to convert to a 12v system which means two 100 ah 6v batteries wired in series delivers 100 ah. So in effect you have 800 ah available with those 6v batteries in a 12v DC power system. Then you only have 50% of those amps to use on a daily basis which brings it down to 400 ah. In comparison I am looking tentatively at four 100 ah 12v lithium ion batteries that will give you 320 ah of daily use at an 80% draw down.

I have calculated without running air conditioning my most optimistic profligate use would be about 220 ah per day. When I dry camp now I have been getting by on less than 50 ah for comparison.

My theory is I only need air conditioning when off shore power on those rare lunch time stops with a pet inside the van. That might draw down another 100 ah if less than an hour. I'm sorry, I am never going to deliberately travel and camp in weather that will require closing up a van and running the air conditioner. I know you can't count on that 100% as it can get over 100F even Minnesota. If that happens I would simply seek shore power no ifs ands or buts. 90F and below the MaxxAir fan, rear door screen and sliding door screen can suffice. I did that in Kansas two weeks ago. Maybe I am lucky I live in the north and scheduling favors my activities. I know southerners can't rely on that logic as easily.

The rule of thumb I read for solar is for every 100 watts of solar you will get about 30 ah per day. 600 watts is about the practical limit on a Class B so that means solar could restore 180 ah on the average. A more reasonable 300 watts could restore 90 ah and I think we could easily stay under that on the average if push came to shove in dry camping.

Bottom line if you put in those 8 6v batteries you are not going to restore power to your batteries with solar and you are going to have a lot of wasted capacity if you are not running an air conditioner. I have come down to 400 ah of 12v batteries and 300 watts of solar in my desires. That number could be 440 and 320 respectively depending on what gets installed, but represents a reasonable amount for average use and occasional maximum use. Without generator, propane and extra weight of AGM batteries I figure to save close to 600 lbs. in weight. For that emergency generator use to top the batteries (which has been rare in our 125,000 miles of touring) I will have the second engine alternator. I think I could fall back to four 110 ah 12v AGM batteries (220 ah available) if lithium ion didn't pan out. Cost is not the issue. I am just looking for a no thinking about it decision to where we can stop for any given night and still have full use of AC outlets, microwave and coffee maker. Chances are since we also have to dump, fill water, do laundry, etc. we will still frequent hookup campgrounds. I think we will also have the capacity for an open ended winter Quartzite, Arizona stay on BLM land.

[wincrasher]

I agree that it's a futile effort to try to design a system around running AC. You end up with a huge capacity bank, but still can't run AC much on it. So you have all these amp hours you are carrying around and not putting a dent in using your cooktop, fridge, TV and lighting.

Last 6v batteries I had were 260 amp hours. You are right, it would take 2 to get 12 volts, and you could only draw them down 50%. I don't see how they are getting to 1600 amp hours. It's more like 1040 (520 useable), which is a tremendous capacity for a coach like this. So even if you are only drawing down 100-150 amp hrs per day, you can certainly put that back with solar, or with the alternator, or some combination. You could even get thru a couple cloudy, rainy days without getting into trouble. It's just alot to carry around for really no purpose.

So I think your plan is pretty good, capacity wise. I assume you could actually idle at a rest stop and run your air conditioner if need for an hour or so.

[Davydd]

Originally Posted by gerrym51

the whole point to me -IS running the air conditioner-if i knew for sure that i would never run the ai rconditioner-i wouldn't worry about it.

Ah, we are back to that reputed 9 hours of air conditioning. I don't think that can happen and if it did with cycling on and off it only means if you opened up the van you might have not needed it at all, and then do you suffer after 9 hours if you did?

Air conditioning is an either you need it or you don't need it situation in my mind. You don't run it for an hour or two and shut it off. If you are in a campground for the day you'll run it all day. No solar and battery system is going to cover all day. My philosophy is if you need air conditioning avoid the season, drive north or up high to get out of it, or seek shore power.

[booster]

I like that Davydd is looking at how it all will work together, but I would put in a couple of things. The 30AH per day per 100 watts of solar is pretty much under ideal conditions for horizontal panels. On a rainy day you could be as low as 3-5AH per day, based on what we have seen. Having the larger battery bank is used to cover these "gaps" in recharging capacity, so you just need to look at what you usage is, what the solar under bad conditions is, throw in any driving and such, and compare it to the battery bank size to determine how long you could stay put offgrid. If Davydd really did use upwards of 200AH a day, he would be limited to under two days with 320AH usable, if it was raining. If he is using 50Ah in his current B, my guess would be he will be closer to 100AH per day in the Advanced, because of the electronics running, compressor frig, inverter always on, etc, but not including any air conditioning. If done at the initial build, the solar is pretty cheap, and it imposes not real operational penalties, so I would put on all that would conveniently fit. The new rig is going to spendy anyway, and this would be a small addition compared to the benefit IMO.

There is also, I think, a bit of confusion on the drawdown of wet cell and agm batteries. Max drawdown is stated for both at 80% for cycling duty with true deep cycle batteries of both types. They will work fine at that drawdown, but you do lose some life compared to 50% drawdown. Even assuming you lost 50% in life, you could buy more than enough new sets to break even on cost when compared to Li batteries, I think, so the justification for the Li would be more along the lines of weight savings, and their tolerance, or even preference, for short charges without getting full. If you use the 50% drawdown as your rating point for usable, the wet and agm batteries have bit of advantage in that you have another 30% capacity in reserve, if you need it sometimes.

[gerrym51]

Originally Posted by Davydd

Ah, we are back to that reputed 9 hours of air conditioning. I don't think that can happen and if it did with cycling on and off it only means if you opened up the van you might have not needed it at all, and then do you suffer after 9 hours if you did?

Air conditioning is an either you need it or you don't need it situation in my mind. You don't run it for an hour or two and shut it off. If you are in a campground for the day you'll run it all day. No solar and battery system is going to cover all day. My philosophy is if you need air conditioning avoid the season, drive north or up high to get out of it, or seek shore power.

Davydd-not true-no way 9 hours AC. i agree-i'm looking for 2 hours for the cats-just in case-that i think is doable