Posts
http://www.pressdemocrat.com/article/20110319/NEWS/110319406/1350?p=1&tc=pg&tc=ar
1. Total destruction - intense heat.
2. Unattended charging
3. 11:00 PM
Number 15 to my count.
There is nothing more to say. It doesn't matter which BMS. It isn't about a "debate". It no longer matters what your opinion is. You don't get an opinion.
These are no longer a series of "freak" accidents. There is no "lack of installation expertise". Nothing is "set up wrong." It is a FULLY FORMED pattern that any moron can see. And if they cannot see it, I"m betting they have a United States Dollar opinion on it. And that IS evil. When does someone have to die?
This project was sponsored by AAA. AAA happens to be an automobile insurance company.
We are MOMENTS AWAY from having all Lithium based cells declared hazardous material and hazmat licensing required to even HANDLE them. NO ONE will be able to get automobile insurance for ANY electric vehicle using ANY lithium battery EVER.
We have ALREADY lost the air freight battle on these cells. They haven't released the final ruling yet, but its already a done deal.
And here I sit. I can hit them with a MAPP torch and I can't GET them to go off. It is NOT hte batteries. But it's ALWAYS the batteries. This is an argument that CANNOT be won. They will take away our cells. And there is nothing to be said. They are a violent hazard, while at the same time being perfectly safe and totally inert.
All because of this BMS idiocy and an absolute panic among the BMS heralds to make Jack Rickard sit down and shut up or otherwise be widely KNOWN to be irrelevant on the subject. And not a ONE of them makes enough money out of it to BUY PIZZA ANYWAY!!!! They're ALL starving to DEATH. Still they chant nonsense and point out that it cannot be "proven" (to their satisfaction).
The inability of this community to identify and agree on the cause, will result in your forfeiture, most likely, of the batteries AND the cars. TYPE YOURSELF SMART WITH THAT!
The oil companies and OEM's need do nothing but smirk while you all gather in a circle, pour gasoline over your heads and immoliate yourselves. All from a handful of smart ass geniuses that wanted to make a buck in the EV business and didn't mind staying up day and night typing themselves smart and dragging anyone that would listen down into the hole with them.
I give up.....
Jack Rickard
Just reading the article reveals the level of misunderstanding out there. Why the hell do they think there was any acid to clean up? Pretty much by the time the fie service arrived the entire car could have been swept up with a brush and shovel anyway.
ReplyDeletePerceptions are a hard thing to change. How many people still think the Hindenberg was a hydrogen fire? Maybe it is up to the followers of the Rickard school to start using the BMS camps tricks and start "typing the BMS guys stupid". Smear them - mud sticks eventually. Reverse the whole thing. Insist on them proving it wasn't the BMS. Insist that BMS boards are carcinogenic, explosive, and cause birth defects in lab animals!
Please don't give up Jack. Every cause needs a champion.
How many cars have been burned up with LiFePO4 cells, no BMS, and a properly set cutoff voltage on the charger? None of Jack's, not JRP3's, not mine (the bms boards don't do anything but sound an alarm at the moment), others? Oh, and I still haven't seen any "cell drift" in the 8 months I've been keeping track.
ReplyDeleteDavid D. Nelson
David:
ReplyDeleteYou understand we have NEVER received a SINGLE report from ANYWHERE of a substantial vehicle fire WITHOUT A BMS.
THree was one guy in Florida who one of the vendors was TOUTING as evidence of NEED of BMS. I tracked it down - 100% bullshit. In fact, the guy who sold the batteries readily admitted that this car was done so badly that it was going to burn no matter what. The guy had the cell terminals TOUCHING the frame of the car in numerous places. And it was still a small time fire - none of the intense heat of these fires we're talking about.
I talked to him on the phone for an hour. He said no BMS could have stopped this. It was just an incredibly bad conversion - beyond belief.
Jack
More details Santa Rosa Jr College fire. Elithion BMS and Brusa charger.
ReplyDeleteMain engineer indicates the charger was NOT plugged in. Or he doesn't think it was plugged in anyway.
Jack Rickard
We all know that cells don't spontaneously combust - otherwise you would be in great peril Jack, so that leave a BMS board as the culprit.
ReplyDeleteA shorted BMS board will sooon generate enough heat for a circut board fire, then a plastic battery case fire, and then a full on aluminium and copper fire. The British discovered during the Falklands war what aluminium burns like. And if you want any further proof, just watch a space shuttle launch and pay attention to them solid rocket boosters.
I have reached the conclusion that basically, there is no reason to connect ANYTHING across two terminals of one cell - you are just asking for trouble!
Jack,
ReplyDeleteI see where you're coming from about how BMS is a snafu to the EV community at large. So much for the battle of ideas being won with logic and deductive reasoning... and testing...and example...and experience...and video.
IMO, the Rickard school IS THE example to counter against EV conversion negligence. You have many in your camp.
The only challenge would be for a BMS person to actually disprove you. I look forward to hearing your speaker with Reap systems.
?Does Winston Battery or Thundersky Battery provide warranties for BMS? I'm curious what are their thoughts on this. Perhaps they should begin to ask questions. It would be a sham if fingers were pointed at the batteries just when things were getting good.
Respects.
"You understand we have NEVER received a SINGLE report from ANYWHERE of a substantial vehicle fire WITHOUT A BMS.
ReplyDeleteTHree was one guy in Florida..."
I hadn't heard of any either. So it is either people unwilling to admit they were wrong about a BMS being mandatory and/or they have $ to make on selling a BMS.
At this point it sounds like the ONLY risk of running a LiFePO4 pack without a BMS and not over charging them or over discharging them is that there MAY be a dead cell turn up. Sure sounds like a better option than a burned up car, garage, and not being able to get insurance or being allowed to even buy LiFePO4 cells.
David D. Nelson
(The conversion of the 2005 Ford Focus over the past year-and-a-half had involved dozens of students and teachers, who were planning the first test drive on Saturday.)
ReplyDeleteI'd bet the charger was on. I know the main engineer said maybe it was not but this one looks mighty familiar to a recent loss. BMS controlling a Brusa?
It was unattended too. Mmmmmmmmm.
"...my rage at my own failures here...". I don't think you can do more than you are doing: I would not have understood this issue without your videos and writing. Once you explained and demonstrated the point, it became very clear. It is however difficult to make someone understand something if their livelihood depends upon them not understanding it.
ReplyDeleteOne thing that would really help is if these vehicles were fitted with some kind of "black box" data logger that recorded battery pack terminal voltage and transmitted it somwhere safe in real time. A trace of terminal voltage soaring past 5 volts per cell would be all that anyone would need to know.
It looks like all 15 of the BMS were centralized and all wires were coming to the single point ....
ReplyDeleteWould be nice to help to develop the ASE standards, they should have something already by now, but ASE only have this doc on the website http://www.ase.com/Content/ContentGroups/Service_Professionals/Tech_News_Downloads/Clean_Fuels_Clean_Vehicle_Technology/6-BatteryElectricVehicles.pdf
ReplyDeleteWe all should form a EV Conversion Consortium with different expert involved to defend our position....
otherwise I am 100% agree with Jack: "We are MOMENTS AWAY from having all Lithium based cells declared hazardous material and hazmat licensing required to even HANDLE them. NO ONE will be able to get automobile insurance for ANY electric vehicle using ANY lithium battery EVER."
My 2 cents...
Please don't give up Jack. Thank you.
here is a link to the project.
ReplyDeletehttp://nbeaa.org/osev/sota/SRJC-AAA-EAA_EV_Conversion_Plan.doc
Michael
I think we should form an "EV Conversion Consortium" and get involved experts to defend our position...
ReplyDeleteASE has only one doc, that I could find, they should have some cert by now... http://www.ase.com/Content/ContentGroups/Service_Professionals/Tech_News_Downloads/Clean_Fuels_Clean_Vehicle_Technology/6-BatteryElectricVehicles.pdf
my 2 cents ...
Please don't give up Jack. Thank you.
http://nbeaa.org/osev/sota/index.htm
ReplyDeleteFirst to post was a pro-BMS'er but once again couldn't give cold hard numbers to prove words otherwise.
ReplyDeleteBlack Boxes.. Not so much voltages, (3.5V/cell to me seems plenty) but noting cell temperatures or no might get these BMS'ers somewhere. Especially useful if excess cell/board warmth also knocked off the charger. The Charging system should run its charging regime independently to external circuitry.
My fears are those mad hot summer days where a car is cooking in the sun then plugging a strong charge which bring the cells over the edge and vent. Any ignition source close enough to the cells and whumph! It's off.
A close friend of mine has recently lost her house to a laptop left on charge in the bedroom.
A lesson for all those BMS'ers.
We can comb through every make of car and not one wire has a soldered connection. Every connector is a latched block . No electrical or electronic unit is unboxed and all such items are positioned and hardened from unreasonable interference, climate and vibration. So why haven't these BMS makers learned from the professionals?
Dennis Doerffels paper did have a temperature probe mounted into a drilled bolt but he mounted it to an anode (-) terminal for operational reasons. I was of the understanding the hottest terminal was the cathode on discharge. However, much was to be gleaned from his temperature readings, bits can be ringed off.
Even well made "lead sleds" ensure any inflammable gasses are cleanly vented away so why not on something that can out gas so violently like a lithium celled car?
Andrew
Hey Jack,
ReplyDeleteWith respect to:
>>You understand we have NEVER received a SINGLE report from ANYWHERE of a substantial vehicle fire WITHOUT A BMS.
Here's one fire that happened without a BMS:
http://www.plasmaboyracing.com/history/1998e.php
- corbin
Andrew - "First to post was a pro-BMS'er but once again couldn't give cold hard numbers to prove words otherwise"
ReplyDeleteYou get an 'F' for reading comprehension! I was trying to point out that once the public and authorities get it into their thick heads that litium batteries are "dangerous" we will NEVER be able to convince them otherwise. Same with the BMS guys and their opinions about "balancing" cells. There are none so deaf as those who will not hear!
Anonymous:
ReplyDeleteYes, sorry, my bad. I read your post incorrectly. I'll accept that "F". Was just about to correct myself. :)
corbin dunn:
http://www.tpub.com/content/doe/hdbk1084/css/hdbk1084_22.htm
Hawker Genesis Batteries do vent Hydrogen and oxygen if the safety valve (as in LiFePo4's) has popped.
All the SLI's in motorcycles used to have a venting tube - sensible enough to me!
Andrew
I give up for misreading peeps! Too dry for me. Does a violent plasma discharge constitute a fire?
ReplyDeleteAndrew, lol
> Does a violent plasma discharge constitute a fire?
ReplyDeleteOf course it does! It caused a fire after all...
The instructor from the class posted to EVDL. He confirmed it was:
* Not the charger (not hooked up, not ever plugged in).
* Not the BMS (it was partially hooked up)
-corbin
Corbin,
ReplyDelete"(1) 'Famous 'Plasma Boy' incident days before the races. Accidentally dropped the positive-most brass conducting bar onto the battery pack, created a high current short circuit resulting in a plasma incident that melted-down a good portion of the brand new 336V pack of 28 Hawker Genesis batteries...kids, don't try this at home: "
Do you really think this counts as showing why a BMS is needed? This would have happened either way. Or were you just trying to be humorous?
David D. Nelson
Corbin:
ReplyDeleteThose were lead batteries. Another world. Hydrogen is easy. I don't care if they DO ban lead batteries. And in any event, he dropped something into the pack.
There are any number of small electrical fires in reality. They just don't do much damage. A circuit board burns or some insulation on a fan wire.
The intense heat and total destruction of these fires is the sign. And they are all BMS related.
Jack Rickard
I was going to post about the new battery technology- you may already be up on this.
ReplyDeleteInteresting 3-d lattice structure explained.
http://www.sciencedaily.com/releases/2011/03/110320164225.htm
This is just one more step on the way to petrol automobilia. Cars will be electric soon.
I think that even with BMS systems burning down cars. We will still have electric cars.
Well... You know what, the GE designed nuke plants could have been designed for failsafe operation. BUT THEY WERE NOT! And they built them anyway. It is interesting to hear a reporter say a "failsafe system failed" to fail safely. I heard one say this!
Hear is another interesting link for vehicle fires.(219,000 per year USA)
http://www.nfpa.org/categoryList.asp?categoryID=953&URL=Research/Fire%20statistics/The%20U.S.%20fire%20problem&cookie_test=1
And finaly, Jack I'm still trying to get my head around the idea that voltage does not realy exist.
Thanks for your hard work.
JMS
Ah, my point was that fires in cars can happen for many reasons, and Plasma Boy's was one that happened when not using a BMS. Sure, it was for totally different reasons: someone was working on the car, and dropped a wrench on a bus bar. I'm not really trying to get into a discussion on BMS vs no BMS.
ReplyDelete--corbin
I think we should consider to form a "EV Conversion Consortium" with different experts involved and write recommendations to the Industry ... :-)
ReplyDeleteAnd advise ASE and others ...
my 2 cents.
-Youri 1-ev.com
BMSs will save your battery cells, and I agree that they add many wires which can affect the reliability of the pack (especially if they are poorly wired).
ReplyDeleteMy simple point is - why not add an inline fuse onto each cell board where it connects across each battery?
Seems too simple, but gives you the best of both worlds...
It seems too simple because it is too simple. The problem is overcharging. These chargers are pretty reliable I feel in charging cells and terminating the charge. THe problem is, they use these BMS to top balance the cells, and alter the charger operation to put control under the BMS.
ReplyDeleteIn this case, there was lightning activity in the area. BMS's have microcontrollers in them. They get lost on an EMI spike. Jump the track.
Now the charger just keeps charging.
ALL of these fires appear to be a case of OVERCHARGING the cells. That's what I'm looking for. In the end, there is always some story about the BMS being improperly installed, or improperly operated, or something. It doesn't matter. You have added too much complexity to a process that works quite well already - charging. When the additional components fail, so does the mechanism to STOP charging.
The solution everyone goes for is to add MORE components. Yes, a fuse. And a coffee pot. And a big screen tv. Put in a TANNING BED if you like. You're not improving it, you're making it worse.
The only thing I would add to the basic charger is perhaps a temperature monitor that would disconnect the charger entirely - a simple failsafe that does not affect charger or battery operation at ALL except to remove electrical power. This will undoubtedly lead to some mornings where your car didn't get charged because this tripped on a false positive.
Jack Rickard
Might be worth adding a timer to the wall socket the charger is plugged into as a backup. That way even if the charger fails to shut down for some reason the wall timer will time out and stop the charging. My electric water heater has a 240V timer to heat up only at night when rates are low, you could wire the same thing to your charger circuit.
ReplyDeleteJack Rickard said...
ReplyDeleteMore details Santa Rosa Jr College fire. Elithion BMS and Brusa charger.
Main engineer indicates the charger was NOT plugged in. Or he doesn't think it was plugged in anyway.
Jack Rickard
March 20, 2011 8:43 PM
Why not just post up what the instructor said?
To:ev@lists.sjsu.edu
Message-ID:<1300737285163-3394583.post@n4.nabble.com>
Content-Type: text/plain; charset=us-ascii
I am the instructor of the EV class at the SRJC. This project was
done outside of the normal class functions and I was not actually
involved with the planning, construction or build.
That said I am aware of the circumstances surrounding the fire, I just
came from a detailed inspection tour.
These things are known:
The vehicle was NEVER charged. The charger was installed but was not
functional. It was NOT plugged in at the time of the fire.
The BMS was partially installed, but there was no interface between
the charger or the controller.
The 12 volt accessory battery was not installed in the vehicle at the
time of the fire.
The vehicle was NOT ready for a test drive as the cells were not
brought up to proper charge.
We know a lot, but we do not know what caused the fire. I just
started looking into the matter this AM, about 11:00AM CA time.
I will keep all of you posted and provide the results, when we have a
clear picture. In the meantime ALL of you who blamed the BMS, the
Charger or anything are wrong at this time.
We just started gathering information about who had recently worked on
the car and what they did. When I know you will know. In the mean
time give us a few days, this is very unfortunate for all of us
involved with the program.
It kinda blows a hole in the theory that THis was caused by a BMS, or could it be that he is somehow profiting from the sale of BMS's so he is just saying that?!?! A little shut-up money?!?!?!? It will be nice to actually know the REal reason of the fire in THis case, without actually doing the investigation, well it is all just speculation right now.
Okay, I thought I'd correctly read Jack's response to David Nelson, in which he said, "You understand we have NEVER received a SINGLE report from ANYWHERE of a substantial vehicle fire WITHOUT A BMS." I re-read it and knew that I had understood it well.
ReplyDeleteThe KEY word in that statement is "SUBSTANTIAL".
Was Plasmaboy's incident and others' a fire? Yes! Were they SUBSTANTIAL fires? Only to the guy who had to replace a few hundreds of dollars worth of whatever got scorched.
The car wasn't burned to the ground, complete with glass and metal liquefaction, a state which would probably be considered a total loss.
Jack, we all know that your name is not Job, but please don't give up. Just keep pointing out the fires, and if you find a car that didn't have a BMS, then tell us about that too. Just keep on doing your long term experiments (science) and let the others type their pseudoscience. You could continue to try to find a place in EVERY Friday show to say, "BMS free, one day at a time."
Then someday, maybe 15 or 20 years down the road, we'll (well perhaps you'll) see whether that works or not. I'll be over 90 by then. My $5.00 Canadian is on the BMS free side.
Keep up the good work.
Joe Jackman,
Vancouver, Canada.
Talking of vehicle fires I actually found this simple wiki quite enlightening.
ReplyDeletehttp://en.wikipedia.org/wiki/Vehicle_fire
Note what they say about EV's. At least the horrendous statistics are not mentioned.
This happened near to my family location the previous winter. The hapless driver didn't have a clue what started the fire in his "gas" car but he did have the 'wherewithall' to park it on the wrong side to keep away from the tree's..
http://www.youtube.com/watch?v=7ldZyrskdcE
Jack:
ReplyDeleteI know of a substantial car fire in a Thundersky-powered car without a BMS.
Two years ago the one-and-only completed conversion of Electric Cars of NY was totally damaged in a fire that originated in the battery pack on the highway during operation. The car, a DC converted Saab 900S sedan, was a total loss, as the front battery bank caught fire and damaged the front bodywork and chassis beyond practical repair. It was salvaged for the drive system, various other components, and junked. There were no injuries.
I interviewed Eric Illowsky, owner of Electric Cars of NY and the ill-fated Saab, who was driving it, alone, at the time of the incident. No BMS was installed on the car. It was a recent conversion in the hands of a novice owner, (Illowsky,) who had driven and charged it daily in the three months or so since it was completed. The car was running at 144V or 156V nominal on TS LFP100 AH cells, about a third under the hood and most in the trunk.
While motoring down the Saw Mill Parkway in ideal sunny, clear weather at highway speed, Eric smelled smoke, pulled over and opened the hood to see flames licking around the tops of the batteries in the middle of the front pack. He had no fire extinguisher, and could not blow out the flames. The batteries were semi-covered by other components and relatively inaccessible, so he couldn't smother the flames directly. By the time the FD responded to his *999 call, the front battery pack was totally involved. It was extinguished without drama, and also without an official investigation, as there were no injuries or third party damage, and the lost vehicle was the company demonstrator of an EV conversion shop. NY is too busy a place to spend a fire investigator's time on a situation like that.
--cont. next post--
So what happened to cause the Electric Vehicles of NY Saab 900S demonstrator fire?
ReplyDeleteOddly enough, Eric Illowsky really has no idea. He told me he "pushed the batteries too hard and they caught fire." Improbable. Illowsky owns the company, but he's not really an EV guy. He didn't build the conversion himself, and wasn't very sensitive to what driving an EV every day entails. He couldn't recall what kind of charger it had, for example, and as for his CC/CV profile, he either couldn't really remember or perhaps never know exactly what his charging scheme ever was, other than that it had been created by others, seemed to work well, and he hadn't had any problems charging the batteries or using the car. The fire occurred under high drain conditions while discharging the batteries on the road at 9am, not at low amperage while charging the batteries in the garage at 2am. I noted that at no time did the car lose power, nor did the 500A pack fuse blow- it just caught fire in the area of the tops of the front batteries at 65mph.
I was able to establish that in the three months he operated the conversion after the day it was completed, neither Illowsky nor anyone else even once checked the battery terminal connections for tightness or temperature. No special precautions, like Nordlock or Belleville washers, loctite, noalox, or even a torque wrench were used to assemble the pack. No one can say for sure what happened to this car, but my best guess, based on the available information, is that a very high resistance condition developed at one or more battery connection within the forward, partially inaccessible pack, and that that resistance increased until it ultimately started a fire on the insulation of an interconnect jumper, a terminal or battery case, or on the structure immediately above and partially covering the forward pack.
So, Jack, you wanted a prismatic cell powered car fire without a BMS- well, I informally investigated one. The conclusion, however, is not even remotely BMS, or even charger related. This car probably burned because the owner never checked or tightened the terminal connections on cells in an inaccessible, high shock and vibration location, over a three month period of otherwise uneventful, if blissfully ignorant use.
So there's ONE, but it doesn't really count, either.
Just for the record;
TomA
I'd say it counts well enough...sounds plausible...
ReplyDeleteJack Rickard
I've been researching/playing around with LiFePo4's for over a year now. (portable inverter application, so my energy storage requirements are much, much smaller than yours). I'm an engineer (BSEE'76) but not a battery expert, so my comments are offered "for what they're worth".
ReplyDeleteOne of the biggest challenges seems to be safely dealing with the large series/parallel arrays.
The batteries are mass manufactured.. there's going to be differences.. differences in electrolyte purity, mechanical construction, and materials. Some of the differences will be considerable. One of the more measurable properties affected will be capacity, but certainly there will be others.
If it's possible a cell to die short in a large series/parallel array, that's a problem. If it's possible for a BMS element to die short across a cell in a large array, that's a problem. Why couldn't it be both (either?) of these scenarios at work?
The array seems to be a big part of the problem... the good cells eating the bad cell(s) like a "pack of dogs" (to coin a phrase).
Doug,
ReplyDelete"pack of dogs". Don't drain them, then it will not happen. If you get to such a low SoC then you are attempting to destroy the cells by your own actions anyway.
Wouldn't paralleling the cells average out capacity variations? If you do note a strong cell and a weak cell, tie them together. You have parallelism, yes? Always assume your weakest (tied) AH cell is weaker and set the whole pack use to that amperage and less.
Why worry about battery life if you are not stressing them. It should be a non issue.
If you play between say >3.1V and <3.5V on low C rates then you should end up bequeathing your portable (LiFePo4) inverter to your Grandkids, even with continual use.
Andrew
Murphy's law is brutally unforgiving. To me, the series/parallel array just seems to be a risk that should be designed away. I've had a lot of people tell me "can't happen" over the years.. most of the time they were wrong.
ReplyDeleteThanks for voltage targets.. I've been using 2.9V and 3.65V.. I think I like yours a little better.
The 3.5V is difficult. I'm doing my own charger, and that's only 0.2V higher than a cell that's "mostly" charged. I'd like my charger to be able to top them off when they're like this... 0.2V is not much to work with.
Why would you want to top off your cells when they will last longer if they are undercharged?
ReplyDeleteJust so that I "know" they're fully charged. If you pick up a random cell and it reads 3.3V, you pretty much have no idea the state of charge. So, in this situation, I want to charge until I know the cell is fully charged (top it off). Charging to 3.5V would work fine.. it's just that my charging circuit is constant voltage / constant current (CV/CC). It's going to be tricky to have the CV part set to 3.5V and have the CC part reliably deliver current at 3.3V.
ReplyDeleteDoug:
ReplyDeleteThen you want to dispose of that charger carefully and get a different one. These cells are charged to a CC/CV curve. You charge at constant current UNTIL they reach 3.5v, and then you hold THAT until the current decreases to 0.05C. That's fully charged. A few hours AFTER charging, you should read about 3.35v and never over 3.4 open circuit voltage.
Jack Rickard
Thanks for the enlightenment. It never occurred to me that the order of writing (saying?) the "CC" or the "CV" (as in "CV/CC" versus "CC/CV") was significant, or that there would be such a thing as a charger that charges with constant voltage first (regardless of current draw!?), and then switches to constant current.
ReplyDeleteThe circuit I'm using doesn't do them sequentially.. or said differently.. there's not two separate circuits that get switched in sequentially as the charging progresses. it's a current limiting source that has a maximum open circuit voltage... so you can never get more than the current limit setting, or more than the maximum voltage setting.
It works pretty much as you described, except my maximum voltage has to be somewhat higher than 3.5V in order to insure that the circuit reliably delivers current when the battery measures 3.3V. (I currently need 3.65V to reliably deliver charging current into a battery at 3.3v). The 3.5V maximum sounds like good advice, just need to figure out how I can get there.
After a full work week to investigate this incident, what has come out of the investigation? I see lots of speculation on the web, and several people indicating that it could not be a BMS/Charger issue because it was not connected or installed and the car was not plugged into the wall when the fire was discovered. But in the same breath they indicate that they were going to take the car for its first drive the morning the fire was discovered. Seems to me like more people trying to cover over their own mistakes instead of allowing the community to learn from the incident.
ReplyDeleteDoes anybody have any news to report on this?
Doug, what is the voltage drop in the leads from your charger to your cells? If your wiring is too small the voltage drop will cause what you describe. I charge my pack to 3.485vpc and the current doesn't start to cut back until the last ~15min on a 200Ah pack.
ReplyDeleteDavid D. Nelson
That's pretty much it, a lot of CYA and Oh My God without much information. I talked with a couple of them a few days ago and the main guy was going on a ski vacation for a week. He was actually pretty lucid.
ReplyDeleteHe said he did not THINK it was connected. he did say they had had some indications from the BMS indicating a problem with some cells. The BMS was supposed to be "turned off."' Of course all the little modules were connected to all the cells.
Now I hear nothing was connected, nothing was on, and they don't know WHAT was the problem but they DO know that charging, batteries, and BMS were NOT the problem - utter jibberish and ass cover.
There is NO doubt it was the BMS. What I think is interesting is whether it was charging at the time, or not charging at the time.
An interesting twist is that there was lightning inn the area at the time. BUT it was in a metal building....essentially a Faraday cage.
Jack Rickard
Gizmo, thanks for the reminder. The whole thing is on my bench and the leads are pretty short and fairly heavy, but even so, it's a 50mV drop on each lead... 50mV here.. 50mV there.. it all adds up.
ReplyDeleteJack, thank you for posting this. I've spent the last month with my head buried in as much EV conversion information as I can find out there.
ReplyDeleteWhen I first saw what they refer to as a "Battery Management System" I said to myself, "This looks useless and probably unsafe." A flimsy circuit, connected across all of the terminals of the pack, whose only function is to turn off the charger and SOMETIMES show you which batteries MAY be unbalanced.
My common sense was tingling.
Worse yet, here you have circuits, which obviously aren't designed to handle much in the way of current, strapped into the entire pack. It should be obvious to anyone with a basic understanding of electronics that a short circuit in this system could lead to a catastrophic event. System damage and fire would likely be the result of this event.
Having read this news article, I too come to the conclusion that the BMS installed in this car is the most likely culprit in the fire. I've seen the safety demonstration video comparing Lithium Ion to LiFePO4 cells. I know the abuse you can inflict upon a LiFePO4 cell that would blow up a standard Lithium Ion cell.
...and I'm a total n00b who has absolutely no hands-on experience with electric vehicle conversions.
What I'm trying to say here Jack is that your message is not lost. In fact, what you've done is confirmed my suspicions about the BMS. I'm now 100% convinced this is not something I will want in my EV and when I start my own preaching, I will discourage others from using them.
Intelligent charging systems and testing circuits are the way to go.
I do know of several fires that were not BMS related. All three had one thing in common. Two were small fires that were repairable. The third one burnt to the ground. All three were lead acid batteries and all had battery's from the same manufacture and they knew their battery's were bad. You could see were the battery's started to burn in the middle of the case. all three were being driven at the time they stared on fire.
ReplyDeleteWe do not even offer BMS to our lithium battery customers and recommend against their use on our battery's We will stand by Jack on this No BMS issue.
Dave
We know just about enough about lead acid cells to BE dangerous. I put 6 brand new Trojans in a GEM, and almost immediately blew a battery post off of one of the batteries. No fire. But it blew it off good.
ReplyDeleteThey do give off hydrogen gas when charging, and so that by itself is a little bit frightening. Most EV guys use AGM but these were flooded lead acid. You have to add distilled water to them. The acid eats up everything in the car. They're too heavy and they don't provide any reasonable range.
To my way of thinking they are not even inexpensive. You can easily pay $2500 for a good set of AGM's and they last two or three seasons. Then you have to replace them or suffer such limited range as to be useless. This is kind of the death of an EV. Three years later it isn't new anymore, and the $2500 expense is daunting. A lot of them wind up on eBay, and CAN be a good start on a budget EV - you pick up a nice one cheap and put $10K in LiFePo4 cells and you have an entirely different car.
So why is $10K not daunting when $2500 IS? Well, after the $2500, you get to do it again in 2 or 3 years. You've kind of moved a consummable cost away from the gas pump and over to the battery store. If I could get 10 years, or better 20, then the $10K is part of the capital expense of the vehicle incurred when I was all excited about doing the vehicle.
Along the way, any way you engineer it, if you do it properly, you wind up with an 80 mile range instead of 30, which I find to be all the difference in the world. And the car drives like a normal car, instead of like a lumber wagon from the weight of all the lead.
Because of this, we think that these LiFePo4 cells, which we've only been able to buy at all just in the last three years, make electric car conversions, which have been around for decades, suddenly into a NEW and VIABLE thing, instead of an expensive demonstrator toy. It is now USEFUL as a REAL CAR you can use as a car with really very little limitation.
If you drive 200 miles a day, still not for you. But you are spending 4 hours per day behind the wheel, and it's a life I would not have anyway.
For 90% of us, it is real and it is here, and it is now. Unfortunately, it's still a little expensive.
On the other hand, go price an ordinary aluminum jon boat, motor and trailer. They're not what they were either. Picture $18,000. If you want to get fancy, it gets worse.
Jack Rickard
I must not really understand the issue, are you saying that you can't overcharge a pack that doesn't have a BMS? Overcharging is overcharging, regardless of BMS (or lack thereof).
ReplyDeleteOf course you can overcharge a pack that doesn't have a BMS. Why would you want to? And if you have your charger set correctly, it just doesn't seem to happen.
ReplyDeleteIn this case, they insist it was not charging. But they did have a BMS connected to the cells.
Jack RIckard
I just watched your latest show (friday March 25th), and noted that in your conversations they said that the BMS control box was not turned on. Question: If you have your charger setup for control with the elithion bms to have the stop charge under the BMS control box, but the control box is turned off, does the charger fail to start charging or does it fail to stop charging? I would hope that it fails to start, but if it is the latter, and somebody eager to get the car ready for the first test drive plugged it in to charge the batteries, it would just charge to destruction.
ReplyDeleteI really hope we get some real answers from this as we all need to get on the same page on these fires.
Michael
From Toyota -
ReplyDeleteIn fact, one in every four fires is a car fire and one in every eight fire deaths are caused by car fires. Each year, car fires alone kill 550 people and injure 3,300 more. There are more than a quarter of a million car fires annually- and the number is rising.
All but a couple of those do not have a BMS fitted - What makes you think that just because the gas tank and engine have been removed and replaced by an electric motor and battery pack that an EV is immune from all of the miriad of regular causes of car fires ?
Hi Jack,
ReplyDeleteHere is a pertinent video from Steve Chunn: http://www.youtube.com/watch?v=egE0VbNabQ0
He was trying to revive some damaged LiFePO4 cells with a 12V "dumb" charger and forgot the charger hooked up to them. They had no BMS on them but it does show, as you know, what happens when they get over charged.
I can't imagine anything but an overcharged cell causing all these car fires.
David D. Nelson