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Old 04-06-2019, 09:28 PM   #1
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Question EcoTrek battery self-discharge rate?

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?
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Old 04-06-2019, 10:01 PM   #2
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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.
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Old 04-07-2019, 04:39 AM   #3
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There is a new Facebook group that has all the info you need

Roadtrek E-Treks & Ecotreks
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Old 04-09-2019, 06:11 PM   #4
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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.
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Old 04-09-2019, 06:29 PM   #5
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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.
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Old 04-09-2019, 07:12 PM   #6
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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 wonít 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...
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Old 04-10-2019, 12:19 AM   #7
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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.
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Old 04-10-2019, 01:13 AM   #8
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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 donít suppose it is possible that your experience does not represent everyone elseís and that storage at the recommended SOC could actually make a difference for another person...
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Old 04-10-2019, 01:19 AM   #9
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At least I have personal experience.
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Old 04-10-2019, 01:22 AM   #10
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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 donít suppose it is possible that your experience does not represent everyone elseís 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.
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