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Author Topic: Advanced BMS Self Discharging Feature & Zero Cell Storage  (Read 5838 times)

Low On Cash

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Re: Advanced BMS Self Discharging Feature & Zero Cell Storage
« Reply #30 on: February 01, 2017, 06:02:31 AM »

Thanks for the reply’s guys - I would like to remind everyone my original post and my following remarks are for safety reasons only and to help raise awareness of the potential dangers of “Un-Attended Charging” of lithium cells.

Regretfully, some reply’s such as Brian’s “Goofy” comments on this thread are only in place to divert attention from the subject matter because I corrected his mistakes regarding the Zero’s regen and Bluetooth functions. Rather than him learn from his mistakes, he has chosen to follow me around in a futile attempt to dis-credit important safety information such as this one concerning the dangers of charging of lithium cells.

In this same thread Brian is “Once Again” wrong in his mentioning the early “Police Bikes” which caught fire were cylinder cells - as if that would make any difference at all, cylinder cells exhibit the same fire dangers from over charging as pouch cells. 
Brian was wrong again when he mentioned newer pouch cells are safer, when in fact they are more dangerous to a neighboring overheated cell than a cylinder cells. Unlike a cylinder cell which has a hard case and very little contact area to the neighboring cell, a pouch cell has close proximity to the other cells which allows easy convection heating of the neighboring cells and increased possibility of chain-reaction overheating.

Getting back to the topic - please understand, I’m not implying that anyone has to follow my procedures, I’m only attempting to bring attention to Zero’s incorrect storage recommendations and Farisis's flawed storage battery percentage comments. 

Without being redundant - the Zero’s battery management system has been prone to failure - numerous failures are well documented on this same forum and on Facebook. The real question is; why would anyone risk their home on the integrity of this BMS that has already show failure?  Facts are Facts - if the BMS does not conclude a charge as a result of a frozen processor or lightning spike; “It Will Result In a Fire” Period!


Regretfully, a few users have challenged the validity of my threads. I'm not trying to be self-serving here but my line of work requires high levels of mechanical and electronic knowledge and therefore I have a solid background on lithium power vehicles. To my credentials I designed built the worlds first military and aerial drone in 1976, afterwards I consulted for companies around the world at a professional level on military & civilian projects with lithium powered vehicles, long before Zero was even a thought!  If anyone needs proof, I invite you too visit my personal site at: www.rotory.com

In closing, I have included an image of my close Dave's home totally engulfed in flames. He too is in the modeling industry and recently lost everything he owned from a lithium fire which started in his garage which then consumed his home.

I again urge all Zero owners to take what ever precautions you can when charging your bike and disregard any comments with regard to leaving your bike on charge for days, weeks and months, unattended.  There is nothing to debate - lithium cells are dangerous.


Regards - Mike


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clay.leihy

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Re: Advanced BMS Self Discharging Feature & Zero Cell Storage
« Reply #31 on: February 01, 2017, 06:55:09 AM »

Well, I don't feel so bad now about not having a garage to park my bike in.

2015 FX ZF6.5 👹 DoD #2160,6

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Kocho

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Re: Advanced BMS Self Discharging Feature & Zero Cell Storage
« Reply #32 on: February 01, 2017, 08:17:10 PM »

I just want to say something about the argument that Zero and Farazis "have skin in the game". Without defining what their interests are, it is not at all a good argument to support that we should follow their recommendations (or not). Here's what most manufacturers' "skin in the game" is - make as much money with as little investment as possible. Not all are like this, but most. That's how capitalist business works. Simple as that. If that means the products they sell will barely survive the warranty period or fail shortly after it, they've still achieved their objective.

All some of us are saying here is that, while the manufacturer's recommendations will most likely be fine to follow, there is a very solid argument to be made that one can do better than that. Personal feelings aside, the factual arguments presented here by many folks are quite good. The "faith-based" statements without factual substantiation to "just follow the book" don't help one reach a better logical discussion, other than to inform others of how you feel, perhaps...

No offense meant to those who follow "The Book" (in capital letters, whichever book that might be, that's their choice), but I think we should be a bit more analytical about the product manual ;). There are several recent posts on this very form about several Zeros that have not maintained their charge properly when constantly plugged-in. Worse, their cell balance has been messed-up. Answer from Zero has been "a firmware bug". Would these same bikes have lost charge/balance if kept unplugged? Most likely not, since the BMS would have been inactive and the firmware would not matter. So, when presented with clear evidence and solid analytical arguments for one thing, insisting on doing the opposite seems a bit strange to me. And insulting those who dare say otherwise is plain inappropriate...
« Last Edit: February 01, 2017, 08:19:25 PM by Kocho »
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Kocho

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Re: Advanced BMS Self Discharging Feature & Zero Cell Storage
« Reply #33 on: February 01, 2017, 08:25:10 PM »

I should also mention another piece of evidence, from another manufacturer, Vectrix. It is a well-documented fact that certain model chargers had a software bug that resulted in the charger being stuck in full power indefinitely, regardless of SoC. That, as you expect, kills the battery. Luckily, the bikes with those types of chargers had NiMh batteries, so no fires were reported as far as I know. But many costly battery replacements (under and outside of warranty). I have personally experienced that failure mode several times on my own Vectrix. That's despite the fact the charger has 3 "fail-safe" checks to avoid precisely that - SoC, temperature, and time. Yet, since those checks are all software-based, that bug caused the charger to keep charging well past the max SoC and only shut-off at the time limit, which is way past overcharging... Who can guarantee that a big like that won't happen with the next firmware update on a Zero? Bugs like these are hard to catch in production because they do not happen every time, they might happen once in a 300 charge cycles, not happen at all, or happen 2x in a row...
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JaimeC

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Re: Advanced BMS Self Discharging Feature & Zero Cell Storage
« Reply #34 on: February 01, 2017, 08:26:18 PM »

Manufacturers ALSO want to avoid costly lawsuits, class action suits and damaged reputations.  There is more to "Skin in the Game" than simple profit margin, you know.

By the way, the battery is warranted for five years, even though the rest of the bike is only warranted for two.  Based on what I've seen, the cost of replacing the monolith (parts and labor) appear to be prohibitive enough that most people would likely just want to get a new bike anyway.  And considering how much these bikes improve year by year, that would be the wise thing to do anyway.  Look how far they've come in ten years!  Who know where they'll be in another five.  :)

BTW, I know my battery is "only" warranted for five years/100,000 miles BUT there is also no way with the way that I ride the bike that I'll be putting 20,000 miles a year on it so it may as well be five year/unlimited miles (like the 2017 models).  I picked up my bike in April of 2016 and just now scheduled my 8,000 mile service.
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Kocho

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Re: Advanced BMS Self Discharging Feature & Zero Cell Storage
« Reply #35 on: February 01, 2017, 08:32:35 PM »

And that most of us will never even come close to the warranty period for the battery on our bikes is a argument for not worrying about it too much and just keep them plugged in. Let's talk again in 5 years and see if folks are complaining of battery degradation then. There is no data right now, other than for early bikes that exactly that was happening - the batteries on '12 bikes were recalled due to lost capacity. Why? Bad cells? Bad battery management? Who knows... If I can do something to minimize the chance of that, which does not inconvenience me, and which decreases the chance of catastrophic failure, I'm inclined to do it. Might or might not be the best way for others.

Personally, I think the Zero batteries and BMS are fairly safe and I trust them enough to charge them at home :) My argument to myself, which I share here not as a recommendation but as food for thought (and entirely to the discretion of the reader) is to not use them in ways that increase the chance of failure, even if the manual says otherwise.
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Kocho

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Re: Advanced BMS Self Discharging Feature & Zero Cell Storage
« Reply #36 on: February 01, 2017, 08:34:42 PM »

Actually, that's still profit margin. If there were no regulations and laws, you think they'd care much? Seatbelts, tobacco, fuel economy/pollution... Very few out there have my benefit above theirs, most are working for their own interest first and foremost.

Manufacturers ALSO want to avoid costly lawsuits, class action suits and damaged reputations.  There is more to "Skin in the Game" than simple profit margin, you know.
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Richard230

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Re: Advanced BMS Self Discharging Feature & Zero Cell Storage
« Reply #37 on: February 01, 2017, 09:30:02 PM »

As I have mentioned before, my daughter's 2012 S, which has just turned 5 years old last week, has been plugged in continuously all of that time and has had no obvious battery degradation so far.   :)  It still runs as well and as far as it did when it was new.   :)  But I will admit that it has been exposed to very little riding in the rain (and hasn't been washed in years) and almost never gets stressed by its rider.  It is difficult to generalize about any mechanical or electrical product.  Some work as intended and some don't.  There are likely a myriad of reasons why this is.  ??? I go with the manufacturer's recommendations because I figure that they know more about their product than I do.  ;)
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Richard's motorcycle collection:  2018 16.6 kWh Zero S, 2009 BMW F650GS, 2020 KTM 390 Duke, 2002 Yamaha FZ1 (FZS1000N) and a 1978 Honda Kick 'N Go Senior.

Erasmo

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Re: Advanced BMS Self Discharging Feature & Zero Cell Storage
« Reply #38 on: February 01, 2017, 10:02:29 PM »

No offense meant to those who follow "The Book" (in capital letters, whichever book that might be, that's their choice), but I think we should be a bit more analytical about the product manual ;). There are several recent posts on this very form about several Zeros that have not maintained their charge properly when constantly plugged-in. Worse, their cell balance has been messed-up. Answer from Zero has been "a firmware bug". Would these same bikes have lost charge/balance if kept unplugged? Most likely not, since the BMS would have been inactive and the firmware would not matter. So, when presented with clear evidence and solid analytical arguments for one thing, insisting on doing the opposite seems a bit strange to me. And insulting those who dare say otherwise is plain inappropriate...
IIRC the BMS is always on.
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Kocho

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Re: Advanced BMS Self Discharging Feature & Zero Cell Storage
« Reply #39 on: February 02, 2017, 10:15:27 PM »

Good point. I actually do not know if it is always on and what that actually means. As far as I know, the BMS does stay on for a bit after the bike is turned on - I can see the status lights under the front battery cover on initially, but then they turn off. It does wake-up from the two buttons there. But what is it doing otherwise when the bike is off I have no idea. What I'm pretty sure is that the BMS can only do top balance whole charging, so if the bike is off and unplugged, it probably won't do anything to prevent cell discharge or imbalance. What I am more interested in is if it is truly off or almost off, e.g., it is not measuring the cells (or otherwise potentially screwing with their balance or draining the battery).

As for the firmware not mattering, I meant that the bike does wake-up periodically to top-up the charge, so if it is unplugged, it won't be doing that, so whatever it was doing when plugged, I assumed would not be happening when unplugged (perhaps incorrectly, as the BMS might indeed be "on" even if the charger, controller, etc. are "off").

[quote sauthor=Kocho link=topic=6583.msg52403#msg52403 date=1485958630]
...since the BMS would have been inactive and the firmware would not matter.
IIRC the BMS is always on.
[/quote]
« Last Edit: February 02, 2017, 10:18:27 PM by Kocho »
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Chocula

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Re: Advanced BMS Self Discharging Feature & Zero Cell Storage
« Reply #40 on: February 03, 2017, 06:18:16 AM »

...
In closing, I have included an image of my close Dave's home totally engulfed in flames. He too is in the modeling industry and recently lost everything he owned from a lithium fire which started in his garage which then consumed his home.

I again urge all Zero owners to take what ever precautions you can when charging your bike and disregard any comments with regard to leaving your bike on charge for days, weeks and months, unattended.  There is nothing to debate - lithium cells are dangerous.


Regards - Mike
To be fair, there are many, many different types of lithium batteries and they are not all created equally.  You mentioned your friend Dave is in the modeling industry.  In my personal experience, I select batteries for my model aircraft based on energy capacity, discharge rate, and weight.  They have no BMS, are prone to physical damage, intolerant of over charge or discharge, temperature sensitive, etc., and there is no way I would leave them charging unattended.  Every bit of caution you described is completely appropriate when dealing with this type of battery.

At times, manufactures have made some poor selections in battery chemistry trying to squeeze more energy into less space and weight.  Dell had laptop batteries recalled, Samsung Galaxy 7 phones, Boeing 787 Dreamliners are some notorious examples.  The manufactures have taken steps to correct these issues and they are not the same type of cells that are used by Zero.

A123 popularized a type of cylindrical Li-Fe cells which are significantly less volatile than the type typically used in model aircraft because of weight, cost, and slower recharge rates.  A123 batteries are what my car (not a model) uses, and my motorcycle utilizes Farasis NMC batteries.  My cell phone uses yet another type of Lithium ion battery, as does my camera, laptop, tablet, rechargeable headset, video cameras, etc.  Additionally, all of these have some type of BMS and I sleep quite well while all of these get recharged overnight.

Some level of caution is warranted with any battery, but I don't think it is reasonable to lump all lithium batteries into the same category as the ones commonly used for model aircraft.  I consider most of the lithium batteries I use to be far safer than a regular lead acid battery and far safer than liquid fuels such as gasoline.

Stay safe,
Chocula
« Last Edit: February 03, 2017, 06:20:14 AM by Chocula »
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ctrlburn

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Re: Advanced BMS Self Discharging Feature & Zero Cell Storage
« Reply #41 on: February 05, 2017, 06:46:39 AM »

While every EV fire and Telsa crash tries to make the newsfeeds, the model airplane with conventional fuel that burns a few people misses top of Breitbart and is left well below the fold.
http://www.theledger.com/news/20150306/florida-jets-event-rc-plane-crash-injures-pair-of-men-at-airport
http://www.local10.com/news/explosion-leaves-large-hole-in-roof-of-margate-home

(and many more)

RC planes have been catching fire and occasionally burning down houses for ages. I got my FCC license to fly... KBSG5826 "R/C Radio Service Station License" original paperwork dated 5/10/1981. It is just accepted that RC plane fuel burns... you just have to ask:
https://www.rcgroups.com/forums/showthread.php?1987095-Do-fuel-RC-planes-explode/page2


Cars also burn...

http://www.nfpa.org/public-education/by-topic/property-type-and-vehicles/vehicles
http://www.nfpa.org/news-and-research/fire-statistics-and-reports/fire-statistics/vehicle-fires/vehicle-fire-trends-and-patterns
Facts and Figures
  • Automobile fires were involved in 10% of reported U.S. fires, 6% of U.S. fire deaths.
  • On average, 17 automobile fires were reported per hour. These fires killed an average of four people every week.
  • Mechanical or electrical failures or malfunctions were factors in roughly two-thirds of the automobile fires.
  • Collisions and overturns were factors in only 4% of highway vehicle fires, but these incidents accounted for three of every five (60%) automobile fire deaths.
  • Only 2% of automobile fires began in fuel tanks or fuel lines, but these incidents caused 15% of the automobile fire deaths.
According to the U.S Federal Highway Administration data, roughly 2,980 billion miles were driven, on average, per year on U.S. roads during this period. Roughly 90 highway vehicle fires and 0.15 highway vehicle fire deaths were reported per billion miles driven.


Tesla passed a billion fleet miles way back in October 2014, so normal stats would be 90 Tesla fires for that billion miles, but they come up far far short.


Anecdotal is fine for conversation - but to make decisions use aggregate risk.

Propane tanks? Those go in the shed.
Oxyacetylene Torch? That goes in the shed.
Lawn chemicals? Shed.

My Zero - charges in the garage, along side the cars I also park there, attached to the house I sleep in.
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Low On Cash

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Re: Advanced BMS Self Discharging Feature & Zero Cell Storage
« Reply #42 on: March 06, 2017, 06:52:15 AM »

Thanks for the reply's guys!

I'm looking at battery storage from a "Safety" standpoint. Having worked with lithium cells as a profession in my trade, I have seen them fail on too many occasions. It's important to note that all lithium cells offer a potential fire risk. My original post and fallowing messages clearly prove the Zero's battery management system is prone to failure and continues to fail on a daily basis. This combined with the fact the BMS has no redundant back-up system to terminate a charge should the BMS fail, leaves the Zero in a state that overcharging can and will result in a fire - this has already happened to these bikes in the past when left on charge un-attended. 

Most important - there is no basis to leave the Zero on charge unattended when the bike can just as easily be stored with 50-70%  charge and have the same exact security to prevent the battery from reaching critical low conditions. With this in mind - why would anyone risk their family and home on the integrity of a low cost BMS that is know to fail.

Regards - Mike 
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BrianTRice@gmail.com

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Re: Advanced BMS Self Discharging Feature & Zero Cell Storage
« Reply #43 on: March 06, 2017, 08:51:43 AM »

Once again, some solid advice is wrapped in an incredible self-regard and overstated certainty about outcomes with incomplete evidence. No amount of professional background justifies the kind of rhetoric used here, and it detracts heavily from the message. I would rather not see advice like that at all, than see it presented here the way it has. There are plenty of competent engineers in this world; those who practice their profession with insults can be done without.

Here's the conservative safety advice for unattended storage (defined as not checking the vehicle more than once a week, say):

  • Leave the bike unplugged unless there is a below-freezing temperature concern about battery storage.
  • Leave the state of charge at 50-70%.
  • Visit the bike monthly and check on the state of charge; if below 40%, say, initiate a charge to a high end of the range; if there's cell imbalance, ensure cel balance is restored and then discharge the battery to 70-80%, say, before leaving it unplugged and unattended for another month.


I am unconvinced that a BMS failure would be consistent with the charger operating; the onboard charger does not get a connection to the battery without positive BMS response based on what I've learned from engineers, and the contactor would not close without that direction and does not have a fail-closed possibility in the last few years of models. I may have misheard or misunderstood, but I've not heard a single piece of evidence to suggest a failure mode like this, and good engineering fail-safe practice is consistent with this.

I would be more persuaded by a schematic breakdown that illustrates possible system interactions than I am by comparisons to drone aircraft systems that don't hold up when I think of everything I've heard and documented by good engineers on this forum and elsewhere.
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mistasam

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Re: Advanced BMS Self Discharging Feature & Zero Cell Storage
« Reply #44 on: March 06, 2017, 10:38:39 AM »

At any given moment during the work-week there will be around 10 bikes outside of Zero HQ, all plugged in.  Seeing as they practice what they preach, I'll continue to go with their advice.
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