At somepoint another ESC or MOTOR will deadshort causing a thermal run-away battery event or FIRE.

Personally I have already had two ESC go up in smoke. And thankfully I was able to pull appart the battery plug before the damage spread. (Faulty On/Off swtich, Overloaded BEC)

Would it be safe to start having Battery Quick Disconnects?

I have seen r/c dragsters use a Deans plug on the rear of a motor pod pointing out the back. A Female plug is wired in series on the positive battery wire. To complete the circut, a Pull Loop of Wire is solder to both terminals of a male plug. The loop is big enough to get a finger into and pull the plug disconnecting the circut. The disconnect was designed for the runaway car, should the micro switch weld on a closed circut on a dragster .With fires being more risky than a run-away car, this simple device could be adapted to keep the risk lower.

If that is too radical I guess a track could invest into a fire/blast chamger.
http://www.bombdetection.com/categoryimage/13.jpg

How about a simple fire extinguisher

My understanding is the F.I. will not work on a Lipo battery.

Well a class "c" or "d" type Fire Extinguisher would work

http://www.fireextinguisher.com/main.html

An ABC type fire extinguisher can put out a Lipo battery fire and whatever the battery may catch on fire. Problem is the chemicals used in these extinguishers will damge most electrical components they come in contact with, ESCs,Receivers,Radios,Chargers,Power supplys.

So the best Idea is to not Abuse your lipo batterys by overchargeing and closely monitor them while chargeing,charge in a lipo sack and be prepared to remove the battery to a safe area if it does ignite.

So the best Idea is to not Abuse your lipo batterys by overchargeing and closely monitor them while chargeing,charge in a lipo sack and be prepared to remove the battery to a safe area if it does ignite.


:thumbsup:

A fire container or a quick door exit may be a good way to keep the at risk car or battery from damaging other property. Such a device and/or safey plan should be instated before the racers show up.

IMO keep the battery from becoming a risk is the practice.

Smokey-the-Bandit says "Only you can prevent LiPO Fires"

http://www.larryrenfrow.com/bandit.jpg

http://johnstodderinexile.files.wordpress.com/2007/08/smokey-the-bear-classic.jpg

I guess someone finally caught my Smokey joke.

Well, having plenty of experience in this area. I thought I would post. I had a LiPo fire. OK several incidents really. The normal reaction of all persons in the vicinity when it started to make sparking noises was to run away. Boom. I approached with the extinguisher just before the second boom. There are always two on a two cell. Disconnect would hardly be helpful as everyone is running away. Also the speed control was not hooked up, just the charger. Other incidents I have had on the track had the car fully enveloped in smoke before I could get there. Looks cool with the wheel wells pouring out four smoke plumes about 30 feet tall. Very expensive cool. These were speed controls on fire. On a motor stall from a bad bearing all electronic components were ruined instantly from the dead short. I vote no on disconnect as I use plugs and a disconnect is not going to help except in a very unusual slow type of failure. It would not have helped any of my incidents.

ABC extinguishers work fine on a LiPo fire. Personal experience. Even a small spray can size is sufficient. None of the electronics that we use are succeptible to damage from the chemicals as they are more or less sealled. There is no problem with the Lithium as it is bound up in the electrode material. All of my electronics survived the fire and extinguisher with new wires exept the receiver which was melted.

The only advice I have is to use a Lipo sock when charging. Don't get lazy and charge the LiPo in the car.

Pic:RC10L2O after extinguishing battery fire. Battery was charging normally in phase 2 of 3 on this auto sensing charger. No user errors except no LiPo sock.

Hello Josh
John

That pic looks expensive!!!

I guess I point I was trying to bring home is, unless the hobbyist pratice safety with batteries, extremes like adding a battery disconnects will have be added.

Like you said John, Don't get lazy and assume everything will be fine. Charge the battery in a safe area, in a safe manner under supervision.


The intention of having a battery disconnect on the cars is to prevent property damage during a race not during the charging process. If the rear of the car was the desingated spot for the kill plug. For any reason a racer drops from the race and is unable to continue the turn marshal can quickly disconnect the battery. This practice will prevent several types of dangerous events: cars becomming run-away missles should the Fail-Sail be set improperly or signal interferance, Battery Fire from ESC or MOTOR shortting out due to thermal stress, Turn Marshals being injured when trying to locate ESC swtich (Burns, Cuts, and Pinch).

Many colligate and competitive events with batteries requries battery disconnect: Robotics, Solar Rayce, FormulaZero, Auto Racing ect..

My only point is that I had 4 real events. Three on the track. Where the battery disconect would not have helped. No sense guarding against problems that don't occur. When the motor stall happened the battery speed control and motor were all wasted in a matter of milliseconds. The two speed control fires were equally fast. Car stops, huge smoke before a man on foot can reach the car.
Our modern speed controls have two failsafe devices built in. One for overload (locked rotor) and one for high temp. Even these are apparently not fast enough to work properly.
John

I've have had speedos burn up, a disconnect will not prevent that. A dissconnect will only prevent further damage to property. If a charged battery is left in a dead short mode, it will be possibility that either the ESC, MOTOR or Battery will catch fire. At which anypoint there is a fire, there is a risk to everyone and the track.

If you have had 4 Lipo failures I would look carefully at what kind cells you run and how you treat them. 4 is no accident something must be causing this to keep repeating. Any idea?

..watching some of John's articles...I'd say PUSHING things to their edge maybe? ;) and a couple product failures..

We had 3 B/L ESC's go up in SMOKE last year, but I haven't seen one this year (Not that they may not have happened...I just haven't seen or been told of one)

I have seen 1/2 dozen LIPOs ruined. (One was one I had swell by discharging too far @ 35 amps) another with a charger that was in NiMh mode...the rest CRASHES that destroyed the packs (None of them caught fire, exploded or cause any other issues)

I thought I might list the failures and reasons. I started using lipos with the Scorpion LIPO which was the first put out for use in RC cars so my time with them is at least a couple of years where most guys have a few months experience. Here are the don'ts.

Scorpion LiPo- I dead shorted the pack with a human error plugging it in to the speed control. I resoldered it to the little PC board, put it in quarantine overnight. It shorted in the middle of the night in a pan on a stone surface. Don't try and repair this. Chunk the pack. I adjust my lead lengths now so plugging in backwards is not possible.

Apogee magnum (advertized as very fire resistant). The Astroflight charger which is auto sensing sensed a 3 cell LiPo when it was a 2 cell LiPo that had 3/4 to 4/5 charge in it. It puffed up immediately. We got it out of the car before it blew. It was sitting there all puffed up and ready to blow under a towel on the slab. I lanced it with the XACTO to make it safe. (The apogee guys are shown drilling one in their hand in an advertisement of its safety). It blew (very loud) and a fire destroyed the towel. Lots of smoke and flame. I got rid of this charger later (see below) and will never use an auto sensing charger again. I now use Scorpion chargers which will only charge two cells. You can put on the cell in any state of charge. No way to make a "user" error and select the wrong number of cells.

The same charger destroyed the MaxAmps pack in the Photo. I inspected the charger and it was on the correct phase. Phase 2 of 3. It blew all by itself. There was no known user error except for not using a LiPo sock. I suspected crystal growth from a few weeks of storage that penetrated the cell separator materials. These are weakened by heat. Don't heat your cells. Heating in the car can be tolerated up to about 140F. At this point they puff up.

None of these packs were abused by high charge rates or heating them up ahead of the run in the car.

Im not really such a dufus, I test this new stuff before other people do. Yes I use it hard on the track, but not in the pits, and report it in my threads. I make as many human errors as the next guy. Selecting the right equipment and avoiding reported bad procedures that led to failure helps other people not make the same mistakes. I currently have an oval thread on tuning over at RC-tech.
http://www.rctech.net/forum/electric-road/222869-crc-battle-axe-genxpro-10-1-10th-pan-brushless-lipo-4c-road-oval-tipsandtricks.html

So why don't I use Orion packs which are known to have the smallest fires. Well they are just not as fast.

Sorry to get off the subject of disconnect.
John