EcoTrek battery self-discharge rate?

[mark9]

Just bought a 2019 Carado Axion with EcoTrek 400 package. We got it in California, but don't have time to drive it home to Massachusetts yet, so it's going to be in indoor storage for two or three months. The storage building has shore power so we could just charge the batteries continuously, but I know that's not good for them. I've read recommendations to get the batteries to about half full (13.1 volts) and just turn them off. The question I have is whether there's any risk that the lithium cells will self-discharge down to the danger zone below 12.4 volts since we can't check them for months? Of course we could start them at a higher voltage like 13.3, so they'd last longer. I've googled lithium iron-phosphate and found references for self-discharge of about 5 percent per month, which sounds safe, but what's the potential for a parasitic draw in the batteries themselves? And do we need to worry about the spare AGM battery that powers the BMS, assuming it's fully charged? Hoping someone has actual data or experience with this issue?

[gerrym51]

Originally Posted by mark9

Just bought a 2019 Carado Axion with EcoTrek 400 package. We got it in California, but don't have time to drive it home to Massachusetts yet, so it's going to be in indoor storage for two or three months. The storage building has shore power so we could just charge the batteries continuously, but I know that's not good for them. I've read recommendations to get the batteries to about half full (13.1 volts) and just turn them off. The question I have is whether there's any risk that the lithium cells will self-discharge down to the danger zone below 12.4 volts since we can't check them for months? Of course we could start them at a higher voltage like 13.3, so they'd last longer. I've googled lithium iron-phosphate and found references for self-discharge of about 5 percent per month, which sounds safe, but what's the potential for a parasitic draw in the batteries themselves? And do we need to worry about the spare AGM battery that powers the BMS, assuming it's fully charged? Hoping someone has actual data or experience with this issue?

how is it going to be stored in massachusetts during the winter months. You also might be better off asking this question on one of the several roadtrek sites on facebook. they will have far more experience with ecotrek.

[gregmchugh]

There is a new Facebook group that has all the info you need

Roadtrek E-Treks & Ecotreks

[chris_g19]

Self discharge will be about 5% as you say. The self discharge of concern is at cold temp because the battery heaters are 40W total. Those are wired internally, so hard to say if they only run when charging or in standby.

Crappy Chinese BMS, so hard to know these things..... Mehaw, ugh, yuck

13.3V is plenty safe for storage of this chemistry.

Ask me anything, I've done a teardown of the Ecotrek Rev H and understand the hardware well.

[Davydd]

You don't have to keep lithium batteries just half full. You can charge them all the way up if you want for storage. They will drop soon enough anyway and I keep my lithium batteries at all times between 90% and 99% in storage and have been doing so for 4-1/2 years with no apparent drop off. There is theory and then there is reality and practical experience.

[gregmchugh]

Originally Posted by Davydd

You don't have to keep lithium batteries just half full. You can charge them all the way up if you want for storage. They will drop soon enough anyway and I keep my lithium batteries at all times between 90% and 99% in storage and have been doing so for 4-1/2 years with no apparent drop off. There is theory and then there is reality and practical experience.

First of all, I recognize that you won’t own this van or your next van long enough to worry about it (as I will not live long enough to worry about it either) but it is very possible that storage at the recommended lower voltage specified for most lithium cells will extend the useful life of the battery for someone young enough to be using it in the long term...

[Davydd]

I doubt few people will own their vans long enough at any age and once a year winter storage as I mentioned need not stop at 50% as the OP surmised reading all the Chicken Little comments I guess online. The fact is with over 2,000 cycles which is 5.5 years of deleting your batteries and recharging to 99% every single day probably is never going to happen to anyone when normal daily full time use of their van that will probably not deplete the batteries much more than 20% on a daily basis. Lithium batteries fail from faulty electrical designs but there is not much evidence or reports based on aging.

[gregmchugh]

Originally Posted by Davydd

I doubt few people will own their vans long enough at any age and once a year winter storage as I mentioned need not stop at 50% as the OP surmised reading all the Chicken Little comments I guess online. The fact is with over 2,000 cycles which is 5.5 years of deleting your batteries and recharging to 99% every single day probably is never going to happen to anyone when normal daily full time use of their van that will probably not deplete the batteries much more than 20% on a daily basis. Lithium batteries fail from faulty electrical designs but there is not much evidence or reports based on aging.

You are a hoot, once again projecting your personal experience to apply to everyone else no matter their projecting usage profile which might include justifying the purchase of lithium based on being able to use them for the next 20-30 years (long after you and I will likely be either dead or at least not traveling in an RV). I don’t suppose it is possible that your experience does not represent everyone else’s and that storage at the recommended SOC could actually make a difference for another person...

[Davydd]

At least I have personal experience.

[booster]

Originally Posted by gregmchugh

You are a hoot, once again projecting your personal experience to apply to everyone else no matter their projecting usage profile which might include justifying the purchase of lithium based on being able to use them for the next 20-30 years (long after you and I will likely be either dead or at least not traveling in an RV). I don’t suppose it is possible that your experience does not represent everyone else’s and that storage at the recommended SOC could actually make a difference for another person...

Add to that there could be users on the max end of the scale in much shorter time periods. Big use, small lithium bank, 3 charge cycles a day is nearly 1100 cycles per year. Those folks could easily age/use up a lithium pack with 3000 cycle predicted life.

[gregmchugh]

Originally Posted by Davydd

At least I have personal experience.

Of course you do, As do many other people.

And on what basis do you dismiss the results of actual testing that has been done to determine optimum usage scenarios for batteries? Is there any reason to assume that this testing is not just as valid and likely more valid across a wide range of usage profiles than your limited range of scenarios?

When you were working as an architect did you not base your designs on material characteristics that were derived from the laboratory testing of these materials to determine their appropriate application in the real world outside the laboratory?

[Davydd]

Originally Posted by gregmchugh

Of course you do, As do many other people.

And on what basis do you dismiss the results of actual testing that has been done to determine optimum usage scenarios for batteries? Is there any reason to assume that this testing is not just as valid and likely more valid across a wide range of usage profiles than your limited range of scenarios?

When you were working as an architect did you not base your designs on material characteristics that were derived from the laboratory testing of these materials to determine their appropriate application in the real world outside the laboratory?

No, I'm talking real world. Let's back up. Did the OP cite leaving your lithium batteries at 50% for storing your van? I suppose in a laboratory that may have the effect of optimum life for lithium batteries. Have you taken or practiced your own advice with lithium batteries you are advocating?

Now let's talk real world. Can you cite any upfitter that doesn't allow you to charge lithium batteries over 90-100%? Does anyone think they can keep batteries under 50% charged while driving and using a van? Are you advocating using only 30% of your lithium battery capacity? That is assuming most upfitters have the good sense of shutting down lithium batteries at 20% as Advanced RV does. Did I not say lithium battery storage with disconnecting them could be fully charged and that it is usually a once a year winter storage of assumed about 5 months duration? Is that so onerous considering when you use your van you are routinely fully charging your batteries? Do you think fully charging in this situation might be more prudent than starting out with a 50% charge that could reach depletion?

I believe that is common sense, and of course, real world practical experience.

[gregmchugh]

Originally Posted by Davydd

No, I'm talking real world. Let's back up. Did the OP cite leaving your lithium batteries at 50% for storing your van? I suppose in a laboratory that may have the effect of optimum life for lithium batteries. Have you taken or practiced your own advice with lithium batteries you are advocating?

Now let's talk real world. Can you cite any upfitter that doesn't allow you to charge lithium batteries over 90-100%? Does anyone think they can keep batteries under 50% charged while driving and using a van? Are you advocating using only 30% of your lithium battery capacity? That is assuming most upfitters have the good sense of shutting down lithium batteries at 20% as Advanced RV does. Did I not say lithium battery storage with disconnecting them could be fully charged and that it is usually a once a year winter storage of assumed about 5 months duration? Is that so onerous considering when you use your van you are routinely fully charging your batteries? Do you think fully charging in this situation might be more prudent than starting out with a 50% charge that could reach depletion?

I believe that is common sense, and of course, real world practical experience.

Not really much more to say about this but I will respond to your question. Yes, I do follow my own advice and follow the recommendations of my lithium battery supplier for how to use and store the batteries. My system is a completely integrated Mastervolt electrical system with only one other device in the system, a Onan QD 6000 watt diesel generator. The 4000 watt/200amp pure sine wave inverter/shore charger, the solar controller, the 720 AH lithium battery bank, and a DC-DC converter used for charging from the truck electrical system are all Mastervolt components that communicate over a network with each other. The lithium battery bank controls the charging of the batteries from all of the chargers using the standard configuration provided by Mastervolt and the upfitter configured the diesel generator to auto start when the batteries reach about 30% SOC and stop when the batteries reach 93% charge. On shore power (rare for us except when we are staying in FL for a couple months in the winter) and on solar the batteries reach 99% SOC based on the control panel but this is not actual full charge on the lithium cells which is not reached using the Mastervolt standard configuration to avoid overcharging the cells. Since we live full time in the truck we never put into storage but if I did, I would check the very detailed manuals that Mastervolt provides for all components in the system to understand their recommendations for storage of the batteries and I would follow their recommendations. Just seems reasonable to follow the manufacturer recommendations since they have the best understanding of the system and in the case of Mastervolt these systems are designed for long term use in the commercial marine industry so they do have experience in long term severe useage of their systems.

I would suggest that anyone who invests in lithium battery systems follow the manufacture recommendations but as with anything every owner is free to do his own thing, as you have done and also advocated that others do the same based on your personal experience.

You stated at one point that a 20% reduction in battery bank capacity was not something you would worry about from a day to day usage point of view. May be true for your system since you have indicated that you have more battery capacity than you really need and take advantage of that by simple leaving the inverter on all the time. I do the same but our inverter has such a low parasitic power draw that it is not really relevant in our case either. If you look at the Lifeline life cycle data from AGM batteries, they use a 20% reduction in battery capacity as the point where they specify the number of life cycles available for the battery so I would expect it to be some indication of the life of the battery in terms of assessing the battery status.

As has been pointed out many times, there are owners who will have different usage scenarios than you do and following your suggestions for ignoring such things as storage conditions could result in negative consequences. I appreciate the fact that you have strong opinions and have no hesitation in suggesting that your experience is somehow more relevant than recommendations provided by battery suppliers but I think it would be prudent for others to consider that they should make their own decisions on what to do. If you have reduced the capacity of your battery bank with your storage scenario then the next owner should expect to see a price reduction to reflect the fact that they are getting batteries that are no longer providing the original capacity that was available when the van was manufactured. If you sell it through ARV then I expect they will give it a thorough inspection and represent the van as it is so I don’t worry much if you sell it through ARV. If you do a private sale then any astute buyer would want to do the same thorough inspection to confirm everything is as advertised but being the honest person who I expect you are then you would also suggest that they confirm that the battery bank is performing as advertised.

Enough on this topic, the horse is very dead at this point, no point in beating it any more...

[Davydd]

Long explanation and I guess I can't respond to a moving target of going from lab theory to manufacturer's recommendations. But you did say you charge your batteries anywhere from 93% to 99% living full time. So what is wrong with full charging before before resting your batteries for maybe up to 5 months? That is all I was saying.

[gregmchugh]

Originally Posted by Davydd

Long explanation and I guess I can't respond to a moving target of going from lab theory to manufacturer's recommendations. But you did say you charge your batteries anywhere from 93% to 99% living full time. So what is wrong with full charging before before resting your batteries for maybe up to 5 months? That is all I was saying.

Is that what Elite Battery Systems recommends for storage?

Here is what I found on their website...

3. How should LFMP Li-ion Batteries be stored ?

Our batteries have characteristics of very low self-leakage rate, ~ 3% per month (NOTE: Recent battery tests have shown that a partially charged battery may loose less than 5% per year), which allows batteries to be stored over extended period of time. Batteries are to be charged to 40-60% full and disconnect all loads before long term storage. Batteries should be stored in cool temperature environment. You should check cell voltages periodically, e.g. every month, to ensure proper voltage level. If any cell voltage drops to 3.0V or under, battery needs to be recharged.

Why do they have this recommendation?

If I was an owner, I would check to see why they recommend it...

Maybe you are right and it doesn't make much difference or maybe you are actually doing something that will reduce the life of your batteries...

But, your van, your choice...

As I pointed out, we never store our truck so storage is not an issue for us...

[gerrym51]

Boys will be boys-lol

[gregmchugh]

Originally Posted by gerrym51

Boys will be boys-lol

Msybe Old Farts will be Old Farts is closer to the truth here...

[VanFan]

Boys will be boys-lol

Good on you for being able to laugh at this childishness. I don't find the tone amusing, especially at a forum that's supposed to be about a topic we all find enjoyable. Isn't there anyplace left on the Internet where people can just have a friendly disagreement without getting all "type A" about it?

[gregmchugh]

Originally Posted by booster

Especially if they are also doing a knuckle lift in the front, be aware that knuckle lifts often will mess up the suspension and steering geometry. I don't know the rear suspension on them to tell if might do the same there. You will also have driveshaft angles that may need to be checked and the heavy weight of the van will make that more important. If possible, it is always desirable to drive one with lift and hopefully weight to see how they drive. Knuckle lifts have been very spotty with success and I think a lot has to do with tolerance of the driver for changes to handling from stock, especially since Promasters appear to handle quite well in stock form.

Booster, I think this is on the wrong thread??

[VanFan]

Originally Posted by booster

Especially if they are also doing a knuckle lift in the front, be aware that knuckle lifts often will mess up the suspension and steering geometry. I don't know the rear suspension on them to tell if might do the same there. You will also have driveshaft angles that may need to be checked and the heavy weight of the van will make that more important. If possible, it is always desirable to drive one with lift and hopefully weight to see how they drive. Knuckle lifts have been very spotty with success and I think a lot has to do with tolerance of the driver for changes to handling from stock, especially since Promasters appear to handle quite well in stock form.

Thanks for the advice. Unfortunately I posted my original comment here, when I meant to post it here:
http://www.classbforum.com/forums/f5...m_medium=email
Probably should move any follow up comments to that thread. EDIT: I deleted that incorrectly located post in about 30 seconds. You're fast!