A different lithium battery heater setup

[booster]

This showed up on the Yahoo Roadtrek board. Kind of interesting.

Lithium-ion battery warms itself in cold environments to maintain performance

Internal switch would have to be externally controlled, I think, to be really useful, but if you had enough battery left to use it, it would get you up and chargeable in a hurry.

[wincrasher]

Sounds promising. Best way to heat a battery is internal - shows in the low power consumption and quick heat times.

[gregmchugh]

Looks like a useful development.

By the way, Roadtrek does warm up cold soaked Ecotrek batteries from either shore power or by running the engine. The Ecotrek module has two 12 V connections, one for charge sources and one for loads. I suspect there are likely relays on both these to allow disconnecting them from the battery cells. They could be tapping the charge input before the relay to power the battery heaters. Seems like a definite advantage compared to the current ARV setup where you need to warm them from an external heat source.

Didn't want to post this over on Davydd's ARV thread and get things stirred up with him...

[booster]

Originally Posted by gregmchugh

Looks like a useful development.

By the way, Roadtrek does warm up cold soaked Ecotrek batteries from either shore power or by running the engine. The Ecotrek module has two 12 V connections, one for charge sources and one for loads. I suspect there are likely relays on both these to allow disconnecting them from the battery cells. They could be tapping the charge input before the relay to power the battery heaters. Seems like a definite advantage compared to the current ARV setup where you need to warm them from an external heat source.

Didn't want to post this over on Davydd's ARV thread and get things stirred up with him...

Heating off shore and engine just plain makes sense, and there is no reason not to do it, IMO. Looks like Roadtrek got that part right, and heaven forbid, better than ARV .

Having the extra AGM battery probably makes it really easy for them to do as they can get the engine generator and shore charger to initiate even if the main batteries are off line.

[avanti]

Originally Posted by gregmchugh

Didn't want to post this over on Davydd's ARV thread and get things stirred up with him...

...and you think posting it here will help?

[markopolo]

Originally Posted by booster

Heating off shore and engine just plain makes sense, and there is no reason not to do it, IMO. Looks like Roadtrek got that part right, and heaven forbid, better than ARV .

Having the extra AGM battery probably makes it really easy for them to do as they can get the engine generator and shore charger to initiate even if the main batteries are off line.

Hopefully they'll also add the option to just use the AGM as a power source to heat the lifep04 pack. There could be times when your not plugged in and don't want to run a generator or engine but still need to bring the lifep04 pack back online. Some of the best camping sites are within tent camping areas.

By adding the AGM you've given up much of the weight savings on the smaller packs so you might as well integrate it to make it multi-purpose.

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Interesting link in the first post That should broaden the appeal. Most folks probably don't want to think about / worry about warming batteries etc. They just want it to work.

[gregmchugh]

Originally Posted by avanti

...and you think posting it here will help?

He might not notice it over in this thread, I am concerned for his health. It is not good for older people to get all worked up. Risk of stroke is just too high to have him see this discussion...

[booster]

Originally Posted by markopolo

Hopefully they'll also add the option to just use the AGM as a power source to heat the lifep04 pack. There could be times when your not plugged in and don't want to run a generator or engine but still need to bring the lifep04 pack back online. Some of the best camping sites are within tent camping areas.

By adding the AGM you've given up much of the weight savings on the smaller packs so you might as well integrate it to make it multi-purpose.

----------------

Interesting link in the first post That should broaden the appeal. Most folks probably don't want to think about / worry about warming batteries etc. They just want it to work.

There you go, you have just solved the etrek battery problems that have been of such discussion. Replace the rear 6 AGMs with an 800ah lithium pack, and leave the 2 six volt AGMs where they are in the front. Best of all worlds and you would have enough AGM capacity to run the heaters quite a while.

[gregmchugh]

Originally Posted by booster

There you go, you have just solved the etrek battery problems that have been of such discussion. Replace the rear 6 AGMs with an 800ah lithium pack, and leave the 2 six volt AGMs where they are in the front. Best of all worlds and you would have enough AGM capacity to run the heaters quite a while.

We haven't seen how they handle the aux AGM battery in the Sprinter with Ecotreks but leaving them under the hood would make sense. On the Zion they are mounting a single 12 v AGM, probably 80-100 amp hours underneath at the back.

I expect at some point they will change the design to eliminate the AGM but there do seem to be a few positives for having it in the system.

[avanti]

Originally Posted by gregmchugh

I expect at some point they will change the design to eliminate the AGM but there do seem to be a few positives for having it in the system.

Well, as I think I pointed out once before, even Teslas have a standard 12V automotive battery, despite the fact that most of the car is one big Lithium battery. I suspect they thought a bit about this before deciding to go that way. When I first heard this, I thought it was a hack, but the more I think about it, the more sense it makes.

[gregmchugh]

No reason it can't be both an easy fix to a design deficiency and also have advantages of its own. Declare it to be a feature update and move on, not the first time that has been done...

[gregmchugh]

Originally Posted by booster

There you go, you have just solved the etrek battery problems that have been of such discussion. Replace the rear 6 AGMs with an 800ah lithium pack, and leave the 2 six volt AGMs where they are in the front. Best of all worlds and you would have enough AGM capacity to run the heaters quite a while.

You seem to have it nailed, see the post of the new Roadtrek Sprinter with 800 amp hours of Ecotrek and two 6 volt AGMs likely under the hood. In the Mike Wendland Lithium Battery thread...

[Davydd]

This thread just goes to show what little you guys know. ARV heats its batteries off itself automatically and thermostically controlled to keep them above 41F. You don't have to plug in, run your engine or need an AGM battery. As long as you have amp hours you have heat. It does not take much and the heater will draw 10 amps intermittently when heating. The heater may not even come on until air temperatures drop into the teens. The first four days in a row in our current trip were below freezing including camping down to 0 degrees. With battery heaters we still recharged an overnight Boondock in under one hour driving. OK, rant over. Go back to your anal not knowing from experience analysis and your belly button introspection analysis of AGM batteries.

[avanti]

Originally Posted by Davydd

This thread just goes to show what little you guys know. ARV heats its batteries off itself automatically and thermostically controlled to keep them above 41F. You don't have to plug in, run your engine or need an AGM battery. As long as you have amp hours you have heat. It does not take much and the heater will draw 10 amps intermittently when heating. The heater may not even come on until air temperatures drop into the teens. The first four days in a row in our current trip were below freezing including camping down to 0 degrees. With battery heaters we still recharged an overnight Boondock in under one hour driving. OK, rant over. Go back to your anal not knowing from experience analysis and your belly button introspection analysis of AGM batteries.

Sigh......

[booster]

Originally Posted by Davydd

This thread just goes to show what little you guys know. ARV heats its batteries off itself automatically and thermostically controlled to keep them above 41F. You don't have to plug in, run your engine or need an AGM battery. As long as you have amp hours you have heat. It does not take much and the heater will draw 10 amps intermittently when heating. The heater may not even come on until air temperatures drop into the teens. The first four days in a row in our current trip were below freezing including camping down to 0 degrees. With battery heaters we still recharged an overnight Boondock in under one hour driving. OK, rant over. Go back to your anal not knowing from experience analysis and your belly button introspection analysis of AGM batteries.

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

[gregmchugh]

I told you I was worried that he would find this and get all bent out of shape and send his blood pressure up and have a stroke...

Of course, the fact is that the Roadtrek system not only keeps itself warm when it is powered up just like his van does but it also provides a capability that he doesn't need to revive a cold soaked unpowered van. And we know that if it is not needed by an ARV owner, then it must not be something that anyone else in the world could possibly really need.

Now ready for the next response from Crankshaft...

[GeorgeB]

Originally Posted by avanti

Well, as I think I pointed out once before, even Teslas have a standard 12V automotive battery, despite the fact that most of the car is one big Lithium battery. I suspect they thought a bit about this before deciding to go that way. When I first heard this, I thought it was a hack, but the more I think about it, the more sense it makes.

Battery therapy! Love it!

The self heating battery topic that started this thread, also posted (before ) in the other one...
http://www.classbforum.com/forums/f8...ds-4059-4.html
from the Penn State U article
Self-heating lithium-ion battery could beat the winter woes | Penn State University

..is eventually a solution for cold charge but it won't solve the problem of powering the controllers and all essential systems (power brakes in the following article)

I find it very interesting avanti that even Telsa is using an ordinary 12v battery in their space-age system.
I wanted to find the video mentioned in this article (broken video link at the end)
Tesla Owners Encounter Problems with 12-Volt Battery | PluginCars.com but it's not available anymore.

but found another very instructive video for Safety training from Tesla that shows
the configuration of the parallel 12v system

https://www.youtube.com/watch?v=ntK3rvVl2Qw

Looking forward when Tesla will offer off-the-shelf solution for RVs like they did with their Powerwall.


.

[mojoman]

Seems to be a waste of AH to heat batteries outside of the RV when you could utilize the heat inside. I'm installing mine inside for this reason. I was going to initially going to install them in the floor but the Promaster has headroom limitations, I would have lost 2" more than what I have left. Transit and MB have more headroom and could accept a large amount of cells in the floor without taking too much room.

[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.

[wincrasher]

LOL. In technical circles, we call this a kludge.