Tesla to announce new revolutionary product Apr 30

[Davydd]

Advanced RV has put in a mind boggling amount of energy management into their lithium ion battery packs. Silverleaf is a reporter not a controller only in the sense control is a touch screen like a light switch. It just relays your action. The actual battery management system is computer boards on each cell and an energy management module developed by Elite Power Systems. Then there is a custom interface partnership between ARV, EPS and Silverleaf. You are controlling voltage and temperature right down to the individual cell level for both low and high with safeguards. I already know the batteries will shut down and not accept a charge when below freezing. There are heating pads to keep temps above 40. If the heating fails the batteries will disconnect and not accept a charge. I also know low and top limits are set on battery charge. A hard set is arbitrarily at 20% and the user can set it higher. I have mine set right now at 25%. In theory the batteries will last much longer than the 10 year warranty Tesla is confidently giving.

What it comes down to is something like those Smart Batteries or DIY efforts might not be enough. Even Technomadia's work was comparatively crude.

I don't see Tesla being in the RV market. Those packages are slick looking to be seen in a space and the bigger one is the same as mine right down to the 220 lbs in weight only mine are more optimally sized to fit in a B.

My home is a different story. It is all electric and I originally designed it to optimize passive solar. I also designed a roof with an optimum winter angle to accept I am guessing about 7,000 to 8,000 watts of solar panel. The passive solar worked so well I never pursued active solar at the time 33 years ago. Now I could possibly go completely off the grid if desired just as I have with our RV.

[booster]

When you talk about warranties, you can't really compare a home system, be it off peak storage or solar storage, to an RV setup. The home system is going to get 365 cycles per year, plus one every 4 years, in nearly every house. That is 3651 cycles in 10 years. How long would it take you to do that in a RV, if weren't living in it?

[avanti]

Originally Posted by Davydd

Advanced RV has put in a mind boggling amount of energy management into their lithium ion battery packs.

I agree. I am not worried about their approach to energy management, or any of the other things that they attended to -- they are very thorough. It is the things that they didn't attend to (because they and the rest of the RV industry don't understand them) that I worry about--in particular temperature management and fire safety. If you read the Tesla white papers on the design of their battery packs, you will see just how primitive the RV deployments of Li technology are. "Heat pads" to support sub-freezing charging are just the beginning. Given the tiny scale of the RV industry and the available dollars for R&D, it could hardly be otherwise.

Please note that I am NOT saying that there is any problem--I hope there isn't. And, I am certainly not criticizing ARV or any of the other pioneers. All I am saying is that these are early days and the possibility of unknown issues--even catastrophic ones --cannot be dismissed out of hand. As I say, I sincerely hope not.

As for warranty: I agree that it is unlikely to be an issue in the RV world--I said that in my original post. My point concerned the price comparisons. With the Tesla product you are getting a lot more than just batteries and controllers, so a dollars/watt comparison significantly understates the relative value of the Tesla packs.

[booster]

I agree with Avanti- Tesla is extremely technically competent, and also very, very, safety minded, but they still had to address some fires do to unforeseen, odd, circumstances.

It is not usually the things you know you need to address that come and bite you, it is the ones you don't know need attention that cause the problems.

[Boxster1971]

I also agree with avanti. The Advanced RV lithium battery pack is nearly identical to that used by Technomadia, GBS cells built up by Elite Power, using their BMS. The problem for Technomadia was heat damage, in hot climates the Advanced RV batteries could face the same problem since they have no cooling provisions.


- - Mike
2013 Airstream Interstate from 2012 Sprinter 3500 tall & long

[Davydd]

The only similarity of Advanced RV with Technomadia is Elite Power Systems and GBS batteries. But the batteries are different and a newer generation for ARV, the battery management is newer and the controls are more sophisticated than Technomadia. As far as I can tell Technomadia had no way to monitor cell voltage and temperature and control limits of charging and discharging. Comparing the two because of same brand would be like saying they were both Fords though one is a Model A and one is a Mustang.

I agree temperature could be a concern but I think living in the southwest those Technomadia batteries got abused more than speculated. I also know if I continue my 10 year B habits that heat will not be a concern. I am betting if heat is an issue ARV will waste little time solving it. The heat issue was one of only life of the batteries not safety and the Technomadia batteries still performed better than lead acid batteries would after 4 years. One forgets that in the environment they were in they were destroying AGMs at a much faster rate and their cost benefit analysis for lithium ion still held up.

Does anyone else other than ARV build in fail safe controls for the most damaging issue of any battery kind of preventing over discharging? That to me is the number one culprit for battery life.

Batteries are entering an era where it might be nearly impossible for just DIY substitutions as we went through in the last decade from wet cell to AGM. But if you want a B with true off-grid forever battery power it won't happen without lithium ion.

[Boxster1971]

I do agree that in the RV domain Advanced RV has the best lithium solution. They also stand behind their products like no one else in the industry. Yesterday I watched an Airstream video from a dealer's meeting. Clearly the large RV manufacturers really treat their dealers as customers. Advanced RV has a much different business model. They respond to the ultimate customers - bravo for them!

Regarding fire safety the LiFePO4 chemistry used by Advanced RV is the safest Li available. Lithium ion batteries come in many variations and Tesla chose the less common nickel cobalt aluminum because it has a high specific energy.

- - Mike
2013 Airstream Interstate from 2012 Sprinter 3500 tall & long

[avanti]

The biggest single concern with Li, as I understand it, is the risk of fire as a result of physical damage. Li batteries have energy densities approaching that of dynamite and even trivial physical damage to the very thin internal plates can lead to "thermal runaway" and catastrophic fires. The first of the Tesla fire incidents that Booster mentioned was the result of a hit by an odd-shaped piece of road debris. The Tesla battery pack design has numerous separate compartments with firewalls between them. In addition, after the fire incidents, they added three layers of protection against road debris, including a massive titanium shield. By comparison, the common practice of mounting RV house batteries underneath the vehicle on pieces of angle iron or in sheet-metal compartments gives one pause.

[Davydd]

The customers, not dealers, is what is driving ARV faster than anyone else. The customers have been mind-boggling creative. We will soon see a super high model Sprinter with all new features from ARV and the 4x4s are driving some developments. My little front computer desk is primitive compared to some others desiring in B offices. We have already seen a half dozen dog and cat accommodation designs. Of course it cost money but you get more bang for your buck and what you want - now. For older B owners time can't wait. Does anyone want to speculate how soon Winnebago will offer an off-grid boondocking solution?

[booster]

"If you never have a failure, you are not being very innovative."

Old engineers line, but very true, and it applies to all of this we are discussing, I think. If you just do what has been done or things that are sure to work, you aren't going to move very far forward, and will be left in the dust.

Tesla and ARV both push the leading edge of stuff, which is a very good thing. I don't think the innovation is a problem with either of them, the problems come with the unexpected as mentioned earlier. Even Tesla can get burned and they do a superb job of testing.

ARV is different than Tesla, and IMO we shouldn't even expect the same level of perfection from them. ARV is building this early stuff and putting it right out in the market, without the luxury of long term testing and evaluation, where Tesla tests everything to the max. That is not easy to do. I do think ARV will miss some things or have to change path sometimes because of unanticipated problems. Leading edge works that way. All that really counts is that the products are safe, and they react well to fixing issues, IMO.

Davydd had a problem with his solar output on the ARV, so obviously something was not done perfectly or missed. ARV fixed it and it now appears to be working well. I would rate that as not a big deal, but a normal part of the process, and shows ARV is not infallible, but responsive.

But, by the same logic, I think it is unrealistic to think that because ARV is very skilled and careful, that any other item they build will not have issues. I would certainly put the batteries in that category. The lithium system may work fine, it may have minor issues that need tweaking, it may not last as long as anticipated, etc. It may even fail, although that is less likely I think. Again, not that big a deal, as it is an early technology that realistically can't be tested to the predicted life before release. How it gets addressed if there is a problem would be much more important to me. But, again, to think it is infallible is probably not realistic.

In the long run, a lot of this stuff will find its way into the mainstream products, at which point I would start to expect less problems.

[Davydd]

Originally Posted by avanti

The biggest single concern with Li, as I understand it, is the risk of fire as a result of physical damage. Li batteries have energy densities approaching that of dynamite and even trivial physical damage to the very thin internal plates can lead to "thermal runaway" and catastrophic fires. The first of the Tesla fire incidents that Booster mentioned was the result of a hit by an odd-shaped piece of road debris. The Tesla battery pack design has numerous separate compartments with firewalls between them. In addition, after the fire incidents, they added three layers of protection against road debris, including a massive titanium shield. By comparison, the common practice of mounting RV house batteries underneath the vehicle on pieces of angle iron or in sheet-metal compartments gives one pause.

ARV lithium ion batteries are protected all around with heavy steel angles, bars and plate base, then encased in an insulated box with a fiberglass exterior finish. Then that assembly is protected completely with about a quarter inch thick aluminum skid plate. I doubt any road debris is going to cause any damage to the batteries.

I can't speak for Roadtrek. Their hinted video of the Wendland/Campskunk lithium ion boxes did look like sheet metal compartments not much different than what we had in our Great West Van.

[Boxster1971]

I've been researching Lithium batteries for the past two months. I was planning to add my own 400 AH pack. In the end I've decided to stay with Lifeline AGMs. The conversion to Lithium would just require too much effort to get a reliable system like ARV installs. My biggest problem is the limited 4 gauge wire that Airstream installed to charge the house batteries.

The LiFePO4 (LFP) chemistry is very safe. The trade off is less energy than other Lithium chemistries. Here is a good summary from the Battery University.
http://batteryuniversity.com/learn/arti ... _batteries

All batteries have some risk. If you overcharge lead acid batteries they give off hydrogen gas that can exploded.

The sailboat cruiser folks seem to be out front on using Lithium batteries that are in similar use to RVs.
http://www.cruisersforum.com/forums/f14 ... 9-250.html

The best article I've found was by a Marine Electrical Engineer. He has great advice for any DYI lithium project.
http://www.marinehowto.com/

The Mastervolt or Genasun have top quality LFP battery packs. But they start at about $7,000 for a 400 AH pack. That does not include the relays, displays and wiring required to make a complete system.


- - Mike
2013 Airstream Interstate from 2012 Sprinter 3500 tall & long

[avanti]

Originally Posted by Boxster1971

The LiFePO4 (LFP) chemistry is very safe. The trade off is less energy than other Lithium chemistries.

Yes, it is absolutely true that LFP batteries (which is what ARV wisely uses) are significantly safer from ignition than some other Li technologies, including those used by Tesla, although the energy densities are a reality and ignition isn't the only serious failure mode in any high-capacity battery. I don't mean to sound like I am worried for Davydd's life. The only point I am trying to make is that we are early on the learning curve and the resources available to anyone in the RV business to climb that curve are very limited. That said, if Li batteries were available as an option on a vehicle that I was interested in buying, I would probably select that option. I am excited about what ARV and RT are doing in this area.

[booster]

I think that the final solution for this will a standalone system that includes everything needed, whatever that is (I don't think we know yet). Be it heaters, coolers, voltage limiters, current limiters or boosters, whatever. Drop it in, hit it with whatever voltage and current you have available, and be good to go. They already do that on the compressor frigs that can handle anything from 110v/220 AC to 10-24(?) DC without issue. My (very uninformed) guess is that the lithium technology is going to be too complex for most DIY installs with individual components. I would compare it to where we are now with AGM and also wet cells to some extent. All the stuff works, but 99% of the systems do not maximize battery life or capacity use. Give me a 500ah lithium bank that I can hit with anything from 110v AC or 10-20 volts DC and will be a happy camper, so to speak.

[Boxster1971]

I just came across this good paper on lithium cell maintenance from the guru of the DIY electric vehicle folks.
http://media3.ev-tv.me/cellcare.pdf


- - Mike
2013 Airstream Interstate from 2012 Sprinter 3500 tall & long

[mlts22]

Originally Posted by Boxster1971

I just came across this good paper on lithium cell maintenance from the guru of the DIY electric vehicle folks.
http://media3.ev-tv.me/cellcare.pdf


- - Mike
2013 Airstream Interstate from 2012 Sprinter 3500 tall & long

Thank you for that PDF. It definitely holds true... especially the shorting across the terminals of the battery pack (nothing like arc sunburn.) I do get concerned about the runaway thermal issues, especially with how common wrecks are.

[wincrasher]

LOL. Winnebago has offered a completely reliable, durable and cheap off-grid boondocking solution for many years. It's called propane. You should try it sometime. You can even make expresso with it in the middle of a desert or the arctic.

[booster]

Originally Posted by wincrasher

LOL. Winnebago has offered a completely reliable, durable and cheap off-grid boondocking solution for many years. It's called propane. You should try it sometime. You can even make expresso with it in the middle of a desert or the arctic.

You must be referring to this statement

Originally Posted by Davydd

Of course it cost money but you get more bang for your buck and what you want - now. For older B owners time can't wait. Does anyone want to speculate how soon Winnebago will offer an off-grid boondocking solution?

I totally agree with Wincrasher about the propane, and many folks with older units have added a couple batteries, some solar, and a big alternator. With their propane to run heat, frig, cooking, they can offgrid for very long times--and they don't have to drive every day or two. I think that this setup would be rated at much higher bang for buck than a very expensive new RV, if you are looking to off grid camp.

[mlts22]

The reason I like propane is its simplicity. You have a tank, Extend-A-Stay, regulator, manifold, valves, then appliances. Maybe I am a Luddite, but I wish RV fridges could run like the older models that didn't require power for for a circuit board. Having an elaborate electric system is nice, but the new, multiplexed ones, if they break, they may not be fixable by any means, especially if they patch into the vehicle's core CANBus, where one mistake there can render a vehicle into scrap metal.

Stuff like the E-Trek is nice... but if I went with a Sprinter, I'd go with diesel appliances (like the diesel Truma Combi, Webasto stove), so I have the same functionality as the E-trek, but without the need for the large battery bank. On a gasser, propane has proven itself quite reliable, and what would help tremendously is if Truma sold their VeGA propane fuel cell here, which would be a very useful 10-20 amp-hour input 24/7, which would more than offset the energy use of a compressor fridge and furnace fan. The ideal is having the ability to use two fuels for each appliance. That way, on hookups, the furnace, WH, and a portable induction burner can be used, while when dry camping, those functions would be fueled by propane or diesel.

[booster]

Mlts22-has anyone done a comparison of propane use between an absorption frig on propane, and a compressor frig being run on power from the Truma propane fuel cell. If equal, you could have the benefits of the compressor frig with the offgrid benefits of the absorption frig.