EXPLODING BATTERY CELL !!!
 

Had the experience of a intellect single cell explode over the weekend.

Sharing a pitt table with another competitor in a room with another 20+ people, the cell self exploded on our table while working on cars.No one was injured.

We had just returned from our heat and started working on the cars when we noticed a battery pack (that had been charged and placed in a non conductive battery box)starting to smoke and sizzle (something that i have seen before, but only on charge or in a equal' tray) Picking up the pack it fell apart from heat. Thinking that was the end of it, some 3-4 minutes later a single cell let off a bomb like explosion as load as a shotgun.

From this experience if anyone witnesses this sort of over-heating activity of a battery pack i would recommend you to place the pack (or cells) into a strong case or container such as a transmitter case and then remove them from the pitt area.

The pack had only been chagred at 6 volts and with a heat sensor, the pack must have shorted out some way?

wow,
thats scary :eek:
and i thought that we only had to worry about the new lipo cells desintergrating :(
thanks for the heads up and will pay closer attention to them in the future :)

Yeah this happened at the Off-road Nats this year. Someone finished charging a pack and put it back in his battery box, a couple of minutes later it started smoking and then at least one cell blew.

Here are some pics:
http://www.rcracephotos.com/displayi...album=7&pos=44
http://www.rcracephotos.com/displayi...album=7&pos=46
http://www.rcracephotos.com/displayi...album=7&pos=42

As for putting them in a box, you can do it, but I think its just one of those rare things that happens. I won't be changing my charging habits because of it.

Not to mention scaring the crap out of everyone in the building and the Drivers on the stand waiting to start the A main.....

IMO It is scary...make me think Nitro might be safer.

Just ask z-mann about them, he is the SMA expert at exploding cells......:lol:

:lol: :lol: :lol: :lol: :lol: :lol: I was there on both ocassions and my ears are still ringing.

Temperature guages are a must when charging, also more and more racers tend to recharge packs without giving them time to cool down after a heat or discharging. Also, some people set their peak delay too high to avoid false peaking.

I think we need a few hard facts about this incident.

How many times was it repeaked trying to find some heat ?
What type of charger was being used ?
What was the peak cutout set at ?

I've heard a few stories in answer to these questions which throw a bit of doubt on the statement that started this thread.

QUOTE "The pack had only been chagred at 6 volts and with a heat sensor, the pack must have shorted out some way?" UNQUOTE

Presuming that should be 6 amps not volts - what temp was the "heat sensor" cut out set at ?

It's important that we have all the FACTS !

Sorry Heavy about the amps/volts thing, all i know is that it had a heat sensor on it while charging and that it had been charged at 6 AMPS when fully charged it was put in a battery tray. Not sure if it had been repeaked or anything. I just want to let people know if you see batteries act like this, to take immediate action, from this experiance.

Heavy
4200 Worlds cell on a muchmore cellmaster set at 6 amps. Battery was peak charged with no temp sensor. cut of set @ 18mv. I think sonny charged it in a corally Battery box second slot in. The cell was disconnected then another cell placed on charge in the outside slot. The heat from this cell may have transfered to the problem cell. the pack overheated and was removed from the box in bits. one cell was so hot it started to melt the PVC table.

Sonny was a very lucky guy as the positive cap shot out putting a hole in
a oil bottle before hitting the back wall.

If it was pointing at him it would of hit him in the chest.

I'm not trying to question anything Shayne or Nigel are saying just trying to get the facts. i think we are all getting a little too casual about our battery charging - what we are setting the cut off at - how many times we are re-peaking etc etc.

For example if it was charged on a Much More then the cut off should have been set at 03 not 18

I need to get on to Sony and find out exactly what he did so we can make sure people are aware of how to avoid these kind of problems before people get hurt. This is on the eve of Lipo being available to the general RC public which have much more potential for problems.

lets get the facts out and have a re-look at what we are all doing - right or wrong.

If you don't think it's serious have a look at the photo below and imagine if that was a vulnerable part of your body

Fromr the Feral site
"Feral batteries have been packaged with a small amount of charge left in the battery. This helps to maintain the cells before use. After assembling the pack and before the first charge it is recommended to put about 200 seconds of charge into the pack and then discharge down to 0.9 volts. This will help activate the cells and possibly avoid any venting on the first charge

The new generation NiMh cells have similar characteristics as far as the charge technique is concerned. You should use the following settings:

6 amp charge for best voltage
3 or 4 mv cutoff per cell (18-24 mv per pack)
It is essential that you have a good quality charger. You have good cells so why destroy them with poor quality chargers"

6 x 3mv = 18mv per pack ??

At SMA theres a member whos had a few packs blow up, the best part is knowing when one is going to blow and then seeing it blow!! :nod:

Not to be mean but it is halarious to see what carnage follows eg. it blew in a mini once the body landed on race control :lol: and i had a cell casing land on my table. Another one blowing and then after being remove another cell hissing and smoking then BANG! i have pics on my phone of the burn marks on the bricks!!!

I think some people just need to take care of their packs better, when my packs vent i don't touch them, it just seems too dangerous to me!!

Although that being said is it a specific type of cell? My dad brought 2 4200 fantom packs for a challenge cup and probably not even 6 months after both packs had venting cells!!

Swamp Rat .... Heavy is asking whether the Much More charger was set at 3 or 18 on the charger as the charger has cutoff displayed for single cell which means you put in 3 mv in the setup which equates to 18mv per pack. If you put in 18mv on the setting you were using 78mv per pack which would explode the cells.

It is vital that racers understand their battery chargers settings. I have asked a lot of guys numerous times what settings they are using to only be replied to with blank faces !!!!!!! Learn whether your charger displays voltage cutoff as a single cell or pack measurement and set accordingly ....3mv per cell or 18 mv per pack.

Also be careful of repeaking as stated before with a long lockout. Most packs will repeak successfully in around 4 minutes If you have a 10 minute lockout set on your charger, it will continue to charge despite the voltage drop....the result can be a bomb !!!!!!!!

Can we have some feed back from the battery guys . Ferel / Harris

i have four sets of 4200 (2 of them worlds)1 from harris and 1 from ferel

they are both charging hotter than the standard 4200's

why is this ??

it was set at 18mv

the reading should be 3mv is that right??

voltages are per 6 cells ??

Most guy muchmore setups i've seen use 18mv ??

Well whatever you think Shayne. There is some confusion around whether the setting is per cell or per pack but for my money I'll go with the Much More handbook which recommends it be set at 03mv. I've been using 03 for 2 years and the packs always finish nicely warm and never venting or blowing up.

Maybe there will be a technocrat who will come on and explain it - until then I'll stick with the charger manual recomendations.

oops- crossed post with cannon. Shayne Cannon is Feral (in so many ways :lol: :lol: :lol: :lol: ) so he should know. The much More setting is per cell 6 x 3 = 18

From Muchmore

***Keep in mind that the MMR Cell Master utilizes different (lower) delta peak cutoff settings than other chargers due to its super linear current. A value of ?05? on the cell master equals .005v or 5mV, NOT .05v (this value is for the entire pack, not each individual cell). Therefore, the values below are representative only to the Cell Master. It is recommended to use a .02 or .03v delta peak setting on other chargers.***

What does it all mean ?/? :confused: :confused:

Unfortunately 18mv on Much More is a big no no and asking for a loud bang to go off...

A setting of 03 is around the mark for 4200's

Check out the Nexus Racing site for a good explanation as to the difference and correct settings for Much More charger.

http://nexusracing.net/newsdesk_info.php?newsdesk_id=29

Temp cutoffs are really a great backup and i make sure to always have the sensor attached to the pack just in case

Ryan

I know cannon is ferel. i was repling while he was posting
Time delay it's a problem

Most chargers use per-cell cutoff. 03 on the muchmore = 3mv.

If you don't know which one your charger uses, set it at 3mv, NOT 18mv - better to undercharge your pack than overcharge it.

-Scott

Even more Confused :confused: :confused:
Quote from site

"Setting Delta Peak on the Cell Master:"

Now that you've read the technical information concerning why the Cell Master utilizes lower delta peak settings, perhaps you would like to know how to actually input the value.

In the setup menus for each charging profile, there are two digits for setting your delta peak value. This setting is in terms of millivolts (mV) for the entire pack. You can think of your setting here as 0.0##V.


So, a value of 06 (as in the above pictures) is equal to 6mV or 0.006V (for the entire pack).

***There is no setting on the Cell Master for mV per cell. A 06 setting (0.006V or 6mV) for a 6 cell pack is equal to 1mV or 0.001V per cell (calculation: 0.006/6=0.001).

Haveing seen one explode I think we'd better get serious about this these things,it could be potentialy fatal, apart from loosing a good friend what would it do to our hobby.

Shane ,

As I said on my website, use 3mv per cell or 18mv per pack. However, according to your Much More information, the 18mv per pack on most chargers is equal to the 03 setting on the Much More.

THere is a motto " If all else fails read the instructions" :lol: :lol: :lol:

Shane, seriously, you were lucky you didn't kill yourself. All racers should read the instructions for their chargers to see the manufacturers recommendations. Much More seems to have made it quite clear that there settings are different and their setting of 03 or 05 is similar to the .02 or .03v settings on other chargers

What would be an appropriate peak delay setting as this could be the root cause of most battery blow ups (but not this one). I set mine at 1 minute, yeah i do get the occasional false peak, but it is better then blowing up a battery.

Andrew,

On my CDC it takes about 4 minutes to repeak a battery. Therefore if you set the lock out to say 3 minutes it will not interfere with the voltage drop detection if you are repeaking.

Don't get me wrong i know its very serious

But why would much more have a possible cut of delta peak of 99mv

thats the highest setting

i'll be charging at 03 in the future but if much more cant get there instructions right what chance has any one got with this time BOMB

from muchmore

does this mean 1mv per cell = 6mv on the muchmore
if so 3mv per cell = 18mv or 18 on the muchmore

My CDC and ICE chargers are set up identical, however the ICE charger tends to false peak ocassionally. The CDC never has. The false peakings dosent not overly concern me as i never leave the charging batteries unattended (joys of having young kids). However someone who may not like it, may set the peak delay considerably higher.
This is a really good thread and i am sure everyone who has read it will now go back and check their charger settings (me included). In my first year of racing i went for eleven months and did not see one exploding battery, but in the space of two weeks, i have seen (and heard) two. All it takes is one person to get hurt and the offending club may as well pack their bags and go home.
What is even more scarier is lipo's are more popular and have a tendancy to explode with a bigger bang.

Holy Bat crap Robin! I was standing off to the left of Sonny and Nigel when this thing went off, I almost caught the Silicon Oil bottle that got thrown onto Andrew's pit table.

After cleaning up the oil, which was everywhere and once Sonny and Nigel had been able to calm themselves, I asked Sonny what he had the temp set at on the charger, the reply was he was advised to set it at 60 deg, Now I dont know about you guy's but to my 60 is a pretty hot battery, I always have mine set at 48 deg celcuis althoug I must admit I was confused about the mV cut off thing and had it set at 18 on my Much More. I have now reset it back to 3.

I guess one way of making sure everyone has a good understanding about battery care is to have the respective committees from the clubs advise their racers of the appropriate setting etc and enforce them for safety reasons.

Sonny and Nigel escaped with no damage this time but what if someone had been inspecting the battery when it went off.

I think all racers need to realsie that with todays cells being as high as they are, run time is no longer and issue and although there is the punch v linear power through charging debate it is not that much of a difference to risk your health.

Maybe the manufacturers could set guidlines so that ALL chargers manufactured can only take batteries to an acceptable heat, peak and mV cutt offs that are not changable, at least not increasable and then the battery manufacturers could make batteries accordingly.

I dont think any one did anything wrong yesterday, it was just an unfortunate but timely reminder of the potential dangers of this sport/hobby.

With so many champoinship meetingsso close to each other, it's no wonder these things start to happen when battery packs are being subjected to some real punishment on a more regular basis than they would otherwise be if just racing club meetings.

Just my 2 cents but I dont think anyone can be blamed or have one thing picked out as the problem, it's just been a good, albiet exciting wake up call to those PECKER HEADS that charge their batteries at ridiculous rates. Your not just wrecking your batteries fellars but you endangering those around you.

6 amps, 3mV cut off, Max Temp Cut 48 deg C and I have never had a battery even look like going nuclear on me.

Another area that a racer should check is that when using a discharger that they get a good contact on ALL cells before starting a discharge. I haves een a acase where contact was not obtained on a single cell. This effectively meant that 5 cells were flat but one cell was still heavily charged. The result when next charged was one cell that overcharged ... and landed 30 metres away.

So lesson is ... when using a discharger make sure you have a good contact on all cells. Some dischargers like the Wave discharger have inbuilt voltmeters. I always put the discharger on to voltmeter reading before discharging to see that I have a good contact with all cells.

Hope this helps

Exactly the reason I am trying to find out the FACTS of what happened is so I can put something out to the clubs through the Interclub committee so members can be advised.

No one is trying to blame anyone

Quickly reading thru the posts here.

Some revelant points to chargeing have been brought up and should be adhered too I guess some of us(Battery Guys) just do things that we assume others do and take this for granted that every one knows what to do and what not to do when chargeing/dischargeing these cells.

As Greg and others have pointed out.YOU MUST READ and UNDERSTAND all instructions that are provided with anything one purchases or uses. If in doubt ASk..

Picking up on two points here that would be revelant to the outcome of both these incidents thathave occur and i couldnt see where anyone has mentioned this..

Yes your mv settings are important BUT also When a battery is charged it builds up heat which changes characteristics of the materials used in its construction.. In simplicity the hotter it gets more gas is generated until the pressure build up causes it to vent( In most cases this venting doesnt occur and when the cell starts to cool the gas is absorbed back into the cell material.

When a cell has charged the internal heat is still greater than the exterior, therefore it will still heat up after charge until this is dispersed threw the outer case.

The battery in this case as stated was placed back into a non conductive battery case{was this a foam lined box( as was the other pack that expoded)} This alone would act like a minature oven and most likely generate more heat again...Causing the battery to produce excess gasses than what it would if left on a bench in a ventilated area. This would in effect creat a pressure container??


Not only do we need to be educated in the proper use of Chargers/dischargers but in general the proceedures of manageing the cells after the charge process.This also can occur in reverse with severe discharge with high loads(current draw)

this is why i asked the question.

we have all got bombs ready to go off.

you can read all you want but if you ask the right question from the wrong person you will get a bad result.

how many chargers are set wrong.
i saw at least 5 muchmores set at 18mv on sunday ??

How Many More Chargers are set to be BOMBS
:sweat: :sweat: :sweat: :sweat: :sweat: :sweat:

Just to clarify, with the Muchmore CTX chargers only - the delta peak cutoff setting is for the entire pack and not the individual cell like most other chargers. As like what others have stated before, with the MuchMore CTX chargers, only use 03, 04, 05 and 06 as values and do not go higher than this. As a guide, use the ambient temp of the room as a guide if the ambient temp is low (under 25'C - ie. night time racing or a cool day) then use a higher value like 05, 06 if it is above 25'C use 03 and 04. Make sure the thermal sensor is used and the temp cutoff is set to 47-48'C.

These are just guidelines which when I was using MuchMore CTX Chargers worked quite nicely. I hope this helps.

I am glad to hear that no-one was hurt or injured by the exploding battery.

Leonard.

In my opinion charging in a battery box or any kind of box is crazy.

Surely natural air circulation around a battery pack is a must if you dont want it to overheat. Packs already get hot enuff as it is during normal charge at 6 Amps and the foam in a battery box will act as an insulator to hold more heat in the cell.

I wont even put a pack in the box after charging to ensure it cools down properly.

IE i charge a couple of packs before heading to racing to ensure i am ready to start, so when i travel to the track i usually put them on the floor of the car to make sure they are still able to cool down.

Anyway just my opinion....

so setting the temp probe to 48 degrees, what happens on a 40 + deg day
when the battery will get to round 60 deg u end up with an undercharged pack. just stick to 3mv setting and set temp to 60 deg havn't had a problem with mine using this method

Dont leave your batteries in the sun or charge them in the sun. Make sure they sit in the shade :)

CANNON.

To avoid the heating problems and venting blah blah blah, would placing the packs on an ice pack or in a cool esky do any damage to them. This would be before charging them and maybe if a hot enough day, whilst doing the intitial charge prior to re-peak

The reason I asked is I placed one of Sonny's battery packs (Johnny's) on some ice rapped in a cloth I had left over from a drink. The batteries when I noticed them were at about 55 deg, after placing them on the ice they went down to 44.5 and stabilised, this is whilst charging them. They were also placed behind the Much More charger so the fan was also blowing on them.

As for the comments regarding the IB World cells, they do seem to get stupidly hot as the pack mentioned above was being charged right after the explosion and this pack was getting very hot also.

Thanks in advance

Just one note that i dont think was mentioned. After charging, the batteries keep generating heat for up to 30 mins after the charger has been disconnected. I would strongly advice against putting the battery into any type of storage container for up to 1 hr to ensure the batteries chemical reaction has finished.

The charge in a rechargable battery comes from this chemical reaction... an example of this can be as: my charger is set to 47 degrees temperature cut out, my charger sensors this temp and shuts down the charger. After about 5 mins the pack temp can be upto 58 degree.... mmm up by 11 degrees.
Outside cooling ie: fans should not be used to cool the battery as this only gives a false temp reading on the outside of the battery. The temperature is generated from within, thus this can lead to problems.