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Old 09-01-2007, 12:18 AM   #166
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Originally Posted by John Stranahan View Post
Dan-Thanks.
Verndog-Thanks and thanks for clearing up the chassis thicknesses. The ITF chassis must be misadvertized at several retailers as a 2.5 mm chassis.
John
I've been following the TC5 thread and that was posted in there from Brent of Team Associated. I had a chance to meet the team members
at the ROAR Nats here at SIR this summer. I noticed several of them were leaving the mount screw, on right side of motor, that ties the
motor mount to the rear bulkhead OUT,That surprised me and asked why...I guess they feel that is a bind point that keeps that
side from reacting like the other side. They said either leave that out or one of the chassis side screws under the car to help release it.
That was with the ITF chassis on an asphalt track.
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Old 09-01-2007, 12:19 PM   #167
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Verndog-Thanks for the extra info on chassis flex. One reason why I put extra holes on the left side of the chasssis was to make the chassis more the same left and right as far as flex goes. This is probably not something I can feel on the track though. I'll keep that motor mount screw tip in mind.
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Old 09-01-2007, 06:28 PM   #168
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Another LiPo Fire

I had a batterry fire today. Makes life exiting anyway. Here is what not to do. I took an older MaxAmps LiPo which had about 50 cycles on it. At this point it was down to 2950 mA-h at the last test from a high of 4050 or so. It had been out of service for only two months, but charged every couple of weeks. They have a low self discharge rate. The battery worked the motor fine on the bench. It seemed to charge fine 2c1, then 2c2 was fine, I last inpected it at about 1250mA-h. No puffiness. Nothing unusual. Put the TC5 down just long enough to find out 3.5 degrees was too much rear toe for our track. It completely disconected the back. Got back to where the fire estinquisher was and got a notice that my battery in another car was acting up. Shortly after ward it was on fire. I grabbed the extinguisher, half way to the table the battery (probably the second cell) shot out a big aerosolized jet of vapor which immediately ignited into to quite a spectacular fireball. They said it was loud. As I was closer to the action, this time, I did not hear it. The flame was 2 foot high shot all the way to the edge of the second table that was side by side with this one so 4 feet long and caught the bag, which I thought was out of reach, on fire so maybe 2 feet wide. A couple of squirts with the fire extinguisher and it was out. No faster action could really have been taken on our part because if I was at the battery, I would then have had to run to the fire extinquisher and back. So here are the losses.

In the car- The receiver is melted, the fan on the speed control is melted, the car stand is melted. The setup board has melt damage. It was not under the car but beside it. Chassis is probably OK.
In the bag. The big Nylon bag caught fire and melted off the body of my other pan car. Melted two stopwatches and a voltmeter inside. And there is probably hidden damage. Here is a pic. I have some pics of the scene of the crime coming, I'll post one if it comed out.

Would the battery sock have prevented secondary damage. Probably most. The explosion may have been bigger though, someone did unplug the chargers. I supect the sock would have jetted out a flame quite some distance from the type of fire I saw. Aerosolized vapor already at the flash point jetted out under some good pressure.

Just a report here. Typical procedure. Chunk those weak packs.

John
Attached Thumbnails
Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks-batterry-fire-resized.jpg  

Last edited by John Stranahan; 09-09-2007 at 04:39 PM.
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Old 09-01-2007, 06:45 PM   #169
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That's really sad news, John. Is the motor OK? Servo? Tires? Did you charge the lipo pack w/ that same charger you complained about a few posts back which you said made a mistake in recognizing number of cells?
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Old 09-01-2007, 06:51 PM   #170
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John, was this the Astroflight charger?
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Old 09-01-2007, 06:53 PM   #171
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I used the same Astroflight charger but I did check it to make sure it was on the correct profile. It was. The problem was in the battery probably from an internal short on charging (age related). Would have happened with my other charger probably. I had a similar failure that puffed up on an older cell of a different brand Apogee. There is a lot of wire damage at the receiver. The car is too stinky to work on yet.

(The only good news of the day was the Ford Focus pulled .98 g's with the Motegi rims and Azeni tires. It took a little tweaking of the tire pressure 32 front 25 rear.)
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Old 09-03-2007, 02:17 PM   #172
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We have had some rain so testing is postponed.

LiPo Corrective Action
This is the first real damage from a LiPo other than the pack itself that I have experienced. I have been using lipos for 1.5 years. I have had several fires (in the mortar tube) all caused by a mishap of one kind or another (over charge, reverse polarity, charger misreads state of charge). This was the first fire with no mishap and nothing abnormal except a well used pack. I plan to take some corrective action. I will charge the cells in a LIPO sock or mortar tube. (metal pan with high walls to deflect the blast upward). I'll keep my pit bag under the table. I am just starting to clean up the mess. The servo will need a new harness as well as the speed control. The tires were a sticky muck and needed to be disposed of. The chassis and shock are OK. I'll need to replace some plastic bits. The motor is OK. I plan to discontinue use of the Astroflight charger as it has killed two cells now. This one I don't think was the charger. There is very little ash left from this MaxAmp Cell. It was very efficiently combusted almost completely or blown away by the fire extinguisher.
On a scale of 1-10, I rate this fireball a 10. Probably as big as possible with only this amount of material. The Apoggee Lithium Manganeze was about an 8. Much louder, though The fireball was somewhat squelched by a small towel over the cell which was consumed. You can tell how loud it is by how far people come from to see the mess. I did not hear this one as I was near on top with the fire extiguisher when it blew. Tachi-Pshychia I believe its called; the lack of hearing during a crisis.
John

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Old 09-03-2007, 02:31 PM   #173
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Well shoot, that's tough luck. You just convinced me to buy some proper charging safety devices. I used 2 lipos for about 1 year, never had a problem, but it's that ONE time without safety that I will regret it. BTW I received my TC5 friday and had it assembled saturday. I am watching this thread very closely also, as your posts are VERY informative, and being that I will also have a very similar setup, this is very helpful info.
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Old 09-04-2007, 10:34 PM   #174
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John S: You said you had a Lithium Manganese Apogee pack go up on you? What were the circumstances? Reading that is a bit discouraging since I thought the LiMn packs were supposed to be safer.

As with the other poster, your story certainly has me thinking about my lipo habits with my 1/18th scale stuff.
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Old 09-04-2007, 11:42 PM   #175
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Kcobra-Here is a pic of the Apogee magnum fire. It is described in detail on the Pantoura Thread. Briefly, I took this pack off the Scorpion charger and placed it on the Astroflight charger to finish up. The astroflight misread the number of cells and started charging for a 3 cell pack. In much less than a minute it had puffed up. I got the batt out of the car put it on the concrete slab covered it with a towel and I lanced it with the X-acto to make it safe. Their video showed a guy drilling it after all and then holding it in his hand. In 10-15 seconds it blew with a huge noise, large mushroom cloud and plenty of red flames. Not as much as the Max Amp flames. Had Apogees video battery blown like mine he would definitely be changing his pants. Maybe his was not charged much.
Now I have got a picture like this for every brand of LiPo that I have tried extensively. I have seen overcharge test results that show even safe brands spewing some fire on overcharge. It is not really the fire that will change with brands just the size of the fire.
Previous to this Max Amps pack blowing there was always a charging mistake or bad procedure involved. You can consider changing chargers before the battery is full as a bad procedure for this type of battery.

It might be a good time for me to stick those Li Ion NanoPhosphate batteries in the TC. We have added a shortcut to our track to run some 1/18 scale stuff. It might work good for that shortened track. Running it light does not seem to be particularly helpful on my long track. It is not really hooked up that well (note this problem was fixed with a better setup later on). I had similar problems running stock pan cars light. If I had more traction it would be hooked up well. The TC is still not well suited to the long track even with 1 years more worth of development on the motors and speed controls. Same problem of blowing up arms or overheating. Take your pick.
These nano phosphate batteries are not as finicky about over and under charge and will not burst into flames from what I have read. I predict that they would be a good equivalent to 5 cell on a TC sized track. I plan to order some tomorrow from Horizon and run them in the TC5 on the short course. This course still has a fairly long straight by TC standards.

I will still run the Pan Car with LiPos on the full track as it is quite enjoyable.
I have a lot of high tech stuff in shambles at this point, though. X11 is blowed up. Novak GTB is melted, AmpMax is burned up. A Titanium gear servo is having a really hard time although it works quite well. I broke the ears off in a horrific 50 mph crash. Replaced the case. Now it has the lead wires burned off. The Spektrum receiver looks like a chocolate bar shape and color.

I agree to improve your charging procedures just a bit to save your stuff. This took hundreds and hundreds of runs before I destroyed some stuff other than the batts, but it seems like it might be inevitable.
John
Attached Thumbnails
Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks-apogee-magnum-fire-002-resized.jpg  

Last edited by John Stranahan; 09-10-2007 at 12:56 PM.
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Old 09-05-2007, 06:45 AM   #176
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Wow John, that really sucks, I feel bad for you but I am glad the damage wasn't worse like your house getting burned down.

I won't ever trust a computer auto-detecting lipo charger now, that is for sure. I wonder if you just left it on the scorpion 2s if it would have still done this? I don't think so because the scorpion would have continued to treat it as 2S. I have the balancepro hd from FMA and this charger doesn't auto-detect either because I have to hook up the balance taps, so I am glad about that.

After seeing all those lipo fires on youtube, I have been storing and charging all my lipos in a fire safe lately, or charging them in a plant pot.
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Old 09-05-2007, 03:14 PM   #177
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Mattnin-This latest incident on the Maxamps pack was not caused by the charger in my opinion. It was charging normally on the correct program for 2s1p. I think it would have blown on the Scorpion charger.

The Apogee pack whose destruction I described near the middle of the other thread was caused when the Astroflight misread a partially charged 2s pack as a 3S pack and proceeded to overcharge it quite rapidly. Here is a link to the Apogee fire post. I suggested at that time not to buy this kind of charger for RC car use; the kind that autosenses the cells in series. The reason is that for racing you don't aways deplete every pack that you charge. I tend to keep a spare battery pack charged up in case one does not peak on time. Even during a practice session I don't always get to run every pack that I charge. Sometimes I need to charge a mostly charged pack. I usually discharge it for 1 minute at 30 amps on the very nice discharger made by Integy: Discharger 30
It is not good to do this on a discharged pack as you may go below its low voltage limit.

I ordered the Li ion nanophosphate stick pack and 123 charger from the shop today. Should be here in a week or less. How about Li nPO4 for a short name. The little n (nano) is important

Last edited by John Stranahan; 09-05-2007 at 03:35 PM.
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Old 09-05-2007, 04:44 PM   #178
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hello john,

greetings from uk.

I have been following your thread with interest... hats off to you mate, your both a scholar and a mad scientist.

Here are some piccies of my beasty


i found that using the TC sphere speedo to run a brushed stock motor was pretty awesome for a few reasons.

1 . it was more balanced when using 6 cell (as you may know we run 5 cell mod here in uk) if not you do now :P

2. found it very smooth even on the highest brushed setting...

My TC5 has titaniuam racing sppol, driveshafts, layshaft and rear diff. this has helped take 50g out of the drive chain.


the car is very free, could be better if i played with bearings but cba atm.

In addition to the TR parts, I have the cool can fan DCCF and the speed passion 13.5 brushless to be tested this weekend at my local track.
Eastbourne

after my last trip out at a large track i found running same springs and oils allround aided my handling and cornerspeed, rather than heavier oils and springs on the front end.
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Old 09-05-2007, 10:47 PM   #179
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OoliganRC-Thanks. Thanks for the pics. Nice work. I found as well with a locked front diff that my TC3 and TC4 liked blue springs all around and similar shock damping front and back. I don't have my perfect setup yet on the TC5. Rain and fires are impeding my progress. I put a Novak 3.5R in it and set it up a little softer to try on our shortened course. I think I had mine. too stiff. The track was wet today. Tell us that titanium racing spool holds up. I guess those sway bar mounts do dress up the ends of the bulkheads even if you don't run the bars. I have thought about doing that.

Nice track. I like the curbing and the grass.


John
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Old 09-06-2007, 07:06 AM   #180
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Quote:
Originally Posted by John Stranahan View Post
OoliganRC-Thanks. Thanks for the pics. Nice work. I found as well with a locked front diff that my TC3 and TC4 liked blue springs all around and similar shock damping front and back. I don't have my perfect setup yet on the TC5. Rain and fires are impeding my progress. I put a Novak 3.5R in it and set it up a little softer to try on our shortened course. I think I had mine. too stiff. The track was wet today. Tell us that titanium racing spool holds up. I guess those sway bar mounts do dress up the ends of the bulkheads even if you don't run the bars. I have thought about doing that.

Nice track. I like the curbing and the grass.


John
the TR spool holds up very well...the centre piece is alloy but the outdrives are delrin with allow sleeves. as is the rear diff so rotating mass is reduced as much as possible. I ran mine with a 4.5 orion and it handled it better than i did.

most of the uk tracks are like eastbourne, although most are bigger. Eastbourne is a very technical track.

As for your combustion issues, how many charges had the batteries had, did they go below threshold? the UK has the select few chanting "we want lipo!" for our nationals, but the governing body BRCA, has yet to allow them.

As we run 5 cell here, until a 6v lipo is available and reliable and safe, we here will be nimh powered.

just for info the itf chassis is 2mm thick.

i just looking for a one way unit to fit the car now, I know the yokomo BD fits but the outdrives are too small for standard drive shafts, although tc3/4 ones I have heard work.
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