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Author Topic: Balance Voltage in Storage  (Read 1469 times)

stevenh

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Balance Voltage in Storage
« on: January 22, 2017, 06:20:34 PM »

I took a quick look at my '16 DSR in storage in the basement this weekend.  It has been plugged in for a few weeks now without being used.  It is at 100% charge, but the cell balance voltage showed 44mv, this is much higher than I have ever seen before, but the bike has never been idle for this long.  Anyone else seeing similar results in storage?

Steve
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2016 DSR

Lenny

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Re: Balance Voltage in Storage
« Reply #1 on: January 22, 2017, 06:50:37 PM »

As the app is not very reliable at the moment, I would do several reconnects and see if the results differ. Maybe you could also plug it out and back in once or even key it on for a minute and back off.

Otherwise you could also pull the complete logs via the app and send them to your own E-Mail and use the online log decoder.
« Last Edit: January 22, 2017, 07:15:00 PM by Lenny »
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Zero FXS 6.5 MY16
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Kocho

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Re: Balance Voltage in Storage
« Reply #2 on: January 23, 2017, 12:34:17 AM »

The last time I charged my '15 SR was probably in November last year (so over a month ago). I always keep it unplugged when I'm not charging it for my next use. I had charged it to 100% back then, expecting to ride it, but that did not happen due to poor weather for about a month, other than for a couple miles running errands. The dash continued to show 100% until late in December, then we hit 65-70F unexpectedly, and I ran some more errands that brought the charge down to mid 80%. The bike has been parked in the garage since then and not ridden. It is indoors garage, which even in freezing outside temps stays in the 45F-55F inside.

Anyway, I just checked my bike with the app and it shows 3mv unbalance only, and 87% SoC (same as on the dash).

So, just sitting there, unplugged, my bike does not seem to loose charge or get cell imbalance. I will test the range in the Spring as I do not expect to ride it again until then. I won't be plugging it in though, unless I see the charge falling much below 40% SoC, which I suspect will not happen. At the rate it is loosing charge, I don't think it will loose more than a few % if that for the 3-4 winter months than I don't ride it.

For my Vectrix with Nissan Leaf cells conversion and no BMS, I too kept it off the grid for the winter. Similarly, the voltage on the battery stayed within just a couple of volts from when last charged. And the cells were always in balance (they are top-balanced, like on the Zero, but because there is no BMS to mess with their balance, these good quality cells tend to stay in balance and do not need rebalancing for many years).

Li batteries, unless there is a defective or poorly designed or implemented BMS, should be perfectly fine spending a few months off the grid. I see absolutely no reason to keep my SR plugged when not in use. Yup, everyone is free to do what they want, including follow the manual ;), but in this case, for Winter storage, I think it makes a lot more sense to charge it to 100%, make sure equalization has finished (i.e., very small, under 3mv cell imbalance), then ride it not too aggressively until SoC drops to something like 60%, then park it for the  cold season off the grid. Do check the SoC and cell balance by turning on the bike every now and then to make sure there is not surprise malfunction of some sort. Mine is charged a bit more at nearly 90%, but that's just because I did not get a chance to discharge it more. Will do next year :)
« Last Edit: January 23, 2017, 12:39:38 AM by Kocho »
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'15 Zero SR

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Re: Balance Voltage in Storage
« Reply #3 on: January 23, 2017, 02:46:49 AM »

As the app is not very reliable at the moment, I would do several reconnects and see if the results differ. Maybe you could also plug it out and back in once or even key it on for a minute and back off.

Otherwise you could also pull the complete logs via the app and send them to your own E-Mail and use the online log decoder.

Lenny - I'm on a I-Mac and I always get an error when trying to decipher my logs - are they optimized for just PC's? Thanks
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Lenny

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Re: Balance Voltage in Storage
« Reply #4 on: January 23, 2017, 03:35:02 AM »

So which tool do you use to decode the logs? Don't know why there should be any difference if you are using a browser-based tool.

Anyway you can send your logs to me and I will decode them for you if want.
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clay.leihy

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Re: Balance Voltage in Storage
« Reply #5 on: January 23, 2017, 05:10:46 AM »

As the app is not very reliable at the moment, I would do several reconnects and see if the results differ. Maybe you could also plug it out and back in once or even key it on for a minute and back off.

Otherwise you could also pull the complete logs via the app and send them to your own E-Mail and use the online log decoder.

Lenny - I'm on a I-Mac and I always get an error when trying to decipher my logs - are they optimized for just PC's? Thanks
Doesn't it run a Python script? Should do great on a Linux based system. Of course you need the right version, and dependencies, and permissions, etc. 😵

2015 FX ZF6.5 👹 DoD #2160,6

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MajorMajor

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Re: Balance Voltage in Storage
« Reply #6 on: January 23, 2017, 05:42:25 AM »

Use the online log parser if your computer can't handle it
http://electricmotorcycleforum.com/boards/index.php?topic=6474.0

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Low On Cash

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Re: Balance Voltage in Storage
« Reply #7 on: January 23, 2017, 06:33:27 AM »

Thanks hate to be a pain for you guys but here's what happens:

 I went to the page:

Selected my file (1) Browse  (Found my Bin file)

Next I selected 2) Upload & Parse

This is what I got:

Parsing of ./logs/538SDBZ63HCG07126_MbbD_2016-12-08.bin failed.

[5804 entries found]

Try downloading the results anyway: ./logs/538SDBZ63HCG07126_MbbD_2016-12-08.txt


When I try to open the txt file I get:

Zero MBB log
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BrianTRice

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Re: Balance Voltage in Storage
« Reply #8 on: January 23, 2017, 10:34:56 AM »

Thanks hate to be a pain for you guys but here's what happens:

Lenny's advice above to keep retrying until it works is about all we can suggest from afar. Someone else would have to run the file with the script to debug it.
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2016 Zero DSR, 2013 Zero DS, 2012 Suzuki DL-650 V-Strom Adv

MajorMajor

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Re: Balance Voltage in Storage
« Reply #9 on: January 23, 2017, 02:59:19 PM »

Your file name has MbbD instead of MBB on the bin files I get from my bike.
Could be irrelevant.
« Last Edit: January 24, 2017, 03:46:59 AM by MajorMajor »
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Low On Cash

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Re: Balance Voltage in Storage
« Reply #10 on: January 24, 2017, 12:18:09 AM »

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Kocho

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Re: Balance Voltage in Storage
« Reply #11 on: January 24, 2017, 12:41:41 AM »

That's not a public document - I can't access it ...
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'15 Zero SR

BrianTRice

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Re: Balance Voltage in Storage
« Reply #12 on: February 13, 2017, 06:00:13 AM »

I've updated the storage recommendations on the wiki: http://zeromanual.com/index.php/Usage#Storage

Someone made a good estimate once of how much the battery discharges over time with only the BMS on but I can't remember what that is or where I saw it. So the estimate there is on the high side to be safe.
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Kocho

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Re: Balance Voltage in Storage
« Reply #13 on: February 13, 2017, 08:03:04 AM »

Thanks for posting, Brian!

Yup, conservative estimate is better than finding the bike dead one day.

Still, 10% SoC loss a week is way too much, I think, for a healthy bike. My '15 SR has been sitting unplugged in the garage since mid November if I remember right. Back then it was left at 100% SoC and only about 2.5 miles traveled on that last charge. I don't think I saw any % drop over several weeks - it stayed at 100%. When a warm day came unexpectedly in December, I rode for about 15 miles and the charge went down accordingly to the upper 80% SoC. Sat unused for another few weeks, then another warm day came and I rode it for another 20-30 miles, in order to bring the charge down to 50% or so. Just went down in the garage to check on it - 53% SoC, with 4mV to 5mV cell balance. These numbers are consistent with what I expect to see in normal daily usage at the same mileage on this last charge. There is virtually no loss in SoC reported and the cells stay very well balanced according to the bike and the app. On the last ride (couple of months into inactivity) the bike was using about 1% per mile in suburban traffic, which is about normal and consistent with its energy use in daily charging use (so the SoC is not just fake/surface charge, the battery is actually holding a good charge).

So it has been over 3 months now in storage, unplugged, and by the looks of it, the bike could happily spend many more months unplugged without loosing much charge (if any).

Yes, I plan to charge it fully to get the pack rebalanced before my next use when warm spring weather returns in March or April down here. But 4-5mV imbalance at near 50% SoC and over 3 months unplugged is pretty darn good, if these numbers can be trusted...

This is just another data point, may or may not be valid for everyone's bike due to who knows what factors, including firmware differences, age, model, etc.
« Last Edit: February 13, 2017, 08:06:27 AM by Kocho »
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BrianTRice

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Re: Balance Voltage in Storage
« Reply #14 on: February 13, 2017, 03:10:10 PM »

I went to go fix that section and realized I shuffled some notes into the wrong section and fixed that.

I did make a back-of-the-napkin calculation, though: if the BMS continuously drew 5W, a 2016 11.4kWh nominal battery would draw down 100% SoC to 0% in about three months.

So, 10% per week is a reasonable figure if conservative; kind of a worst case way to know when to go check on the bike just in case.
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2016 Zero DSR, 2013 Zero DS, 2012 Suzuki DL-650 V-Strom Adv
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