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-   -   EXPLODING BATTERY CELL !!! (https://www.rctech.net/forum/australian-racing/139928-exploding-battery-cell.html)

Swamp Rat 12-10-2006 09:48 PM

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 ??

heavy 12-10-2006 09:50 PM


Originally Posted by Swamp Rat
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 ??

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

Swamp Rat 12-10-2006 10:01 PM

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:

SSS Racing 12-10-2006 10:11 PM

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

Swamp Rat 12-10-2006 10:14 PM

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

ozoner 12-10-2006 10:17 PM

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

Swamp Rat 12-10-2006 10:21 PM

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).

pardypooper 12-10-2006 10:24 PM

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.

cannon 12-10-2006 10:29 PM

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

Andrew Barr 12-10-2006 10:29 PM

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.

cannon 12-10-2006 10:40 PM

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.

Swamp Rat 12-10-2006 10:44 PM

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


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

Andrew Barr 12-10-2006 10:53 PM


Originally Posted by cannon
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.

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.

zacabrandy 12-10-2006 10:56 PM

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.

cannon 12-10-2006 11:11 PM

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


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