A different lithium battery heater setup

[gregmchugh]

Originally Posted by booster

The new Zion owner on the Yahoo Roadtrek board has put up a bit more information about how the battery heaters work. She lives in a cold climate so it has been ongoing.

Recovery of a cold battery shutdown only works off of the engine running, it appears. The heaters run on shore power, but only if the batteries are on line and not in cold shutdown. Kind of a bummer because she had to run 3 hours to get them back on line so the shore charger could handle it.

This sounds like it may be a hangover from before the AGM battery was in the system to activate things, as it would seem simple to have the charging system come on from the AGM.

I hope Roadtrek decides to fix the issue, as they are really close to having it all covered.

I think there are still some questions about how this works. Jim Hammill said you could heat up the batteries from running the engine or from shore power. When on shore power with the inverter on should be no different than running the engine in terms of what the Ecotrek module is seeing on the charge side input terminal, battery charge from the inverter or from the auxiliary alternator. If it works on one it should work on the other.

[booster]

Originally Posted by gregmchugh

I think there are still some questions about how this works. Jim Hammill said you could heat up the batteries from running the engine or from shore power. When on shore power with the inverter on should be no different than running the engine in terms of what the Ecotrek module is seeing on the charge side input terminal, battery charge from the inverter or from the auxiliary alternator. If it works on one it should work on the other.

That's what I would think, also, but she was quite sure about it from what she said. What she didn't say was whether the inverter, and thus charger, would come on with the batteries in shutdown. If it didn't, she could have shore power without charging. It seems like it should initiate off the AGM, but who knows if there may be a glitch somewhere. Hopefully, we will get some more clarification.

[gregmchugh]

If the various reports are all correct about what people have experienced then the AGMs must be connected to the charge input terminal on the Ecotreks to provide the battery load needed by the chargers and for the case where disconnecting the Ecotreks from the loads also disconnects the AGMs from the loads. We will see how it all plays out...

[booster]

Here is how she phrased it in her post. Sounds like no 12v power when on shore power with the lithium pack locked out, and no inverter so no charger.

The heaters for the lithium are supposed to work by either the engine generator or by plugging in. Well, I found out, yes, the heaters do work by plugging in, but the lithiums have to be warmed up first so the main battery switch will turn on so the inverter will power up so the heaters get juice. Cold lithiums produce no power, so no warming up them up via being plugging in

[gregmchugh]

Originally Posted by booster

Here is how she phrased it in her post. Sounds like no 12v power when on shore power with the lithium pack locked out, and no inverter so no charger.

Yes, I saw that but do not understand why the inverter would not turn on when plugged into shore power which would provide charge current in the same way the engine generator is doing. These new vans are very much a mystery at times and many times different results from what should be similar configurations.

I am still happy with my 08 RS with its old technology, all this new stuff is an interesting mental exercise for me but not something I would want or need at the moment.

I expect we are getting close to seeing it all working and understanding how to operate it...

[booster]

I would suspect that before they had the AGM, the battery lockout system locked out the charger (inverter) also, and after they added the AGM they didn't change it. I see no reason for it to be different from the engine charging, either.

[gregmchugh]

The final intriguing question for me is how the Ecotrek handles charging with none of the three chargers really configured as one would expect for lithium batteries. I can imagine a sophisticated approach with charge circuitry that converts the input charge voltage to the desired voltage for lithium charging but who knows what is really going on. Maybe they just don't worry about getting very close to full charge and just make sure the cells stay balanced.

[mojoman]

It is quite safe to use the lithium batteries when freezing. I'm guessing it is cheaper and easier to shut off the batteries completely when freezing. It would require more wire and solenoids to allow use but not charge.

[Oliver]

Originally Posted by booster

...I hope Roadtrek decides to fix the issue, as they are really close to having it all covered.

Booster ... I am not so convinced Roadtrek has "it all covered" .... I toured a 2016 Roadtrek E-Trek in Houston this week where the outside temp was 65 F in the afternoon .... the Coach had not been opened all day according to the sales rep so I used my Laser temperature gun and got an inside floor reading of 74 and an inside ceiling reading of 95 (Sprinter was parked outside in the afternoon sun for several days)

We opened up the Battery bank compartment under the rear sofa below the floor and the battery casing temp was 71 inside .... this is early February, not July/August .... there was no evidence of any cooling mechanism to keep the temperature of the batteries near optimal 74 degrees or at least under 91 degrees

Forgive the repeat posting, but my concern with no answer yet is this - from a technomadia article on information from Elite:

Premature Battery Aging? - Suspect #1: Temperature

According to the specifications for GBS-LFMP100AHX cells published on the Elite Power Solutions website, our battery cells are rated for:

Operating Temperature: -20C to 65C or -4F to 149F.

But while brainstorming potential causes for our diminished capacity recently, Elite let me know that in their experience heat has a huge impact – even within that operating range.

They have observed that a 10C (18F) temperature increase over a baseline room temperature of ~23C (74F) results in the number of lifetime cycles being cut in half.

This means at 33C (91F) usable battery life will be cut in half, and presumably to a quarter at 43C (109F). This is VERY substantial.

.... so I headed down to the Houston RV Show to ask Roadtrek if they were addressing this over heating issue of lithium iron systems, however no one from Roadtrek could be found to answer my query

Wally the rep from Winnebago did address the issue and said this is why Winnebago decided to go with AGM batteries instead since they could not manage the overheating issue, even after trying a 2nd ghost floor

[booster]

I was referring to the cold battery recovery procedure only when I said they were close to having everything covered, I should have been more clear on that. As to the rest, I don't think any of us know yet how it will all shake out. As far as I know, none of the manufacturers add cooling to the battery packs, only heaters, and then only some of them. Davydd's ARV doesn't do anything about cooling either.

The "normal" rule that I have seen multiple places is the halving of life with every 10*C of temp above 25*C, so if it gets really hot the go south quickly (pun intended).

What may be of interest is that if you look up the test data on AGMs, they list the same halving at the same 10* increases, so they deteriorate at just as fast an accelerated rate. But they are cheaper to replace.

Cooling to less than ambient can be a very power intensive proposition, so it could be tough. Passive air or fans can only get close to ambient.

[Oliver]

Booster - so true .... I lived in Vegas for 10 years and I was replacing the best 5 year car batteries every 18 months heat kills

.... and you are correct, I have yet to find a RV builder to cool battery banks like Ford did with their electric cars

To combat the extreme temperature effect and keep batteries within their optimal temperature range, automakers use thermal management systems relying on either air or liquid cooling. As the EERE data shows, liquid cooling is generally more likely to preserve a battery’s capacity than air cooling, though performance variations will occur depending on how well a battery management system was designed to control temperature. According to Ford, the liquids used in cooling systems can retain a temperature for a long time, which contributed to Ford’s decision to use liquid cooling on the Ford Focus EV. Ford has also used air cooling on its hybrid Escape and Fusion, as have Nissan and other BEV manufacturers on their vehicles.

[mikes47]

Another ARV owner chiming in. This discussion wanders a bit, but I think there remains a misunderstanding about how ARV manages battery temperature. Heaters are interspersed within and among the cells. Those heaters draw directly from the cells in the battery. No engine or shore power is required; the BMS handles it. There is a switch on the Silverleaf controller to turn those heaters within the sealed battery compartment on or off.

[wincrasher]

You miss the point of the original posting. The battery tech that was mentioned uses a technique that heats the cells from inside the cells, not external heat pads. It is cleaver and sounds fairly simple.

[booster]

So true on the wandering

I think most do understand that is how ARV does it. The big question has been what happens when it is too cold to heat that way (battery capacity and time) and no other way to recover from a cold shutoff but to go someplace warm. This recently happened a couple of nights to a Roadtrek lithium owner, and like an ARV, plugging in didn't work to reheat the batteries. Roadtrek did make it so the engine running would run the heaters even if all the other stuff is locked out, so she was able to get it going again, without having to find someplace to get the van inside and warm up. Many of us just think it makes sense to have a fallback heating power source other than the batteries themselves for times when the unit might be very cold (storage without shore power for instance) and the batteries were either low or couldn't keep up with the cold temp long enough. At that point the only option is to find a warm place vs running the engine a while in the Roadtrek.

Where you live, and how the van is stored or parked would have a very big influence on how important the optional heating would be.

[Davydd]

Originally Posted by booster

And just where does it indicate that nobody knows how ARV does the heating? We all understand how they do it, I think. The setup being talked about heats the batteries internally within the cell, so it is much faster and more efficient.

The rest of the discussion was about how Roadtrek has upped the anti by making it possible to heat the batteries off the engine or shore power. You have repeatedly said your heaters aren't big enough, and there wouldn't be enough just battery capacity anyway if it was really cold. ARV can't do that, you have to go someplace warm.

Methinks davydd needs to calm down and quit looking for made up reasons to call other folks stupid and inferior

And I will repeat. You don't have a clue about li-ion other than your armchair reading and can't even understand what I have been saying. I've been on the road boondocking for over two weeks now down to camping in ZERO degrees and continuous days below freezing. Cold shut down and battery temps are a non issue. If you had any experience maybe you would understand. You, Greg and Avanti are Chicken Little specialist. You didn't even understand my 300 amp charging comment in another thread. Go back and read what I originally said. ARV takes simultaneous charging from shore, engine running and solar. I've observed over 300 amps. BTW, ARV has advanced beyond the Nations alternator. They have a new brand. One second alternator is more than adequate to run air conditioning and my observation is there is no place to put a third one in a Sprinter anyway and it would be needlessly complicated. Air conditioning is more a function of battery capacity and the inverter. Idling an engine delivers more than double than shore power. So now I suppose you would like to discuss the horrors of engine idling. For starters I have the high idle option which Avanti and Roadtrek don't have which is more efficient. It is kind of moot for me. I haven't had a need to idle yet this year other than to test.

OK, I'll be off the grid again soon high up in a mountain back in the snow, then Salton Sea and then Quartzsite in our immediate future. We been in Death Valley, Sequoia NP, Obama's new Mojave National Monument, Amboy Crater and Joshua Tree NP. You guys ought to get out and enjoy your Bs.

[mikes47]

Originally Posted by Davydd

For starters I have the high idle option which Avanti and Roadtrek don't have which is more efficient. It is kind of moot for me. I haven't had a need to idle yet this year other than to test.

David's Alvar has the 800 AH battery while my Imagine has the 600 AH battery. The auto-generator at high idle has come in to play a couple of times for me in our 14 months of ownership. This weekend, for example, it kicked in after boon docking for 18 hours in 3 degree temps. Battery was down to the 30% SOC that I had programmed to invoke the auto-generator. Each of the 12 cells read 50 degrees and the coach was kept 60-65 degrees the whole 18 hours. Inverter, CPAP machine, Refrigerator and Keurig all kept on all the time. We went another night with 1 degree temps with the same features available.

Imagine is my daily driver and I have 30,000 miles on it. I plug it in over night and keep the inside at 50 degrees when we are not sleeping in the coach. That circulates the hydronic fluids and warms the plumbing as well as providing power to keep the batteries and their heaters at full capacity.

[booster]

But davydd, you didn't answer what part of the ARV heating system we didn't understand, or what part of the Roadtrek system we didn't understand, or why internal heating of the cells themselves might not be a good idea, which were the discussions. I didn't see anything about stated that had anything to do with the stuff you just listed about your travels.

I think you need to call up that Roadtrek owner who had cold battery shutoff in very cold weather and explain to her it would be better is she couldn't heat the batteries with the engine, because you don't think you need it

[avanti]

There is no way to make progress with him. Even if you somehow got him to focus on the issue of a cold start with a low battery (which is where RT innovated), he would just go back to saying that he doesn't care and we shouldn't either. And, if you managed to get past that, he would fall back on one of his standard dismissives ("chicken little", "Google Jockey", "you don't have a clue"...). You can't win.

As for the internal heating innovation, he hasn't been willing to even acknowledge the topic.

It is quite stunning. I generally share his tastes, and I agree with him on so many topics, but on any subject that implies that *anybody* else has done better than ARV in any way (no matter how trivial), he immediately becomes irrational.

[Davydd]

Roadtrek is innovative adding additional AGM batteries to a lithium ion system just to warm up li-ion batteries? Guys give me a break. They are trying to fix a failure and doing so badly. Avanti, you know what we have in that space under the hood in place of another 140 lbs plus batteries. Would you want to give it up?

If Roadtrek went cold and permanently damaged the Li-ion batteries that is because they didn't have shut off protection. I already told you Advanced RV's solution was to automatically disconnect the batteries if they got too cold and it is easy to bring them back online. My inquisitiveness tested all this. In lieu of carrying around another 140 lbs of seldom if if ever used batteries, I already told you the many ways to warm a battery back up and as long as you are on shore power there is no chance batteries will go cold. Yes, leaving an ARV in cold storage and trying to use it in freezing weather could present a problem but only a nuisance not a catastrophe. Common sense says you should be able to anticipate this. I did. I left Minnesota in freezing temperatures. I camped in Michigan's UP in January. I camped in 0 degree weather as I said. While you agonize over this I would guess none of you will be hitting the road soon until temperatures are above freezing (and really more like 20 degrees F.) In that case if you had a Li-ion system your problem is solved. Once on the road, did I not tell you there is no chance in hell of an ARV going cold in any temperature you could withstand? ARV's own li-ion batteries power the battery heaters at 10 amps per hour. You have to be pretty dumb to let the battery drain down. Oh, wait! There is an Autogen engine start program that solves that issue that is considerably more sophisticated than Roadtrek Voltstart.

Bottom line. I know what to do in probably the coldest climate in the lower 48. My batteries will never go cold and if they do, they are protected. I don't need a second AGM battery system for something that most likely will never happen.

Don't you find it a bit strange that if you plug in or run your engine which both solves my problem would only charge expensive, heavy, space filling and additional maintenance AGM batteries with attendant wiring complexity which in turn would heat li-ion batteries on a Roadtrek? That's innovative? I could put a 1500w ceramic cube heater (which I carry in the B) under the battery box to solve my problem if I weren't plugged in to do the same and once on the road it is self-perpetuating. But that most likely will never be needed or happen as I said.

OH well, we went over this before in Advancing Alvar thread. You are making a mountain out of a mole hill which leads me to question your common sense. You drive me up a wall with your inanity. Maybe you could explain it better with a Roadtrek wiring diagram the umpteenth time. <sarcasm>

[wincrasher]

Ah, rabbit holes. They go deep!