If you put a powerfull mod motor in your TC5 you will want to upgrade your plastic rear diffs to Aluminum. Here are some links. The front you will upgrade to aluminum diff or a spool. The best spool is described in my previous post. I am getting great service from it.
What happens to the plastic diff is first of all it does not retain tension very well. The plastic flows away from the pressure of the screw. As soon as it slips the plastic will melt with a powerful motor. If you are using this plastic diff check that tension once in a while.
Hi John: quick question on LRP Sphere TC speedo...would you happen to know the Lipo voltage cut-off set on the Sphere TC? Some are telling the Sphere doesnt have such a thing, other are telling it does but dont know what its set at? Hopefully at least at 6v?
If mode 1 is set to value 1 then the sphere comp tc edition will have a proper LiPo cutoff. The voltage is not stated, but it should be OK. Value 2 is for NiMH use. Value 1 is the default mode when the control is new.
This is from the web site.
Two adjustable settings for the Ni-MH-Li-Po adaptation:
#1: Ni-MH/Li-Po automatic adaptation
#2: Ni-MH 4-7 cell racing mode
I would just leave it in value 1 all the time except for 4 cell use.
John
Last edited by John Stranahan; 05-20-2008 at 01:09 PM.
Wow, I just found this thread on another forum while searching Gen x 10 stuff and brought me back to this thread. John what type of fire extinguisher would you recommend having on hand, this is scary stuff here. I know this is old news but something to keep in mind when working with lipo batteries and staying safe.
Quote:
Originally Posted by John Stranahan
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.
Firstly you should take the battery out of the car and charge it in a LiPo sock. This is a soft package made of NoMex fire resistant material like a racers driving suit. If the battery goes off in the sock only smoke escapes. Secondly I recommend a charger like the Scorpion Charger From FMA direct that will only charge a 2 cell LiPo. That way you cannot make a mistake with a wrong setting. I have had several of these incidents while learning what works and what does not. I feel that packs are also a bit safer now than they used to be as they are required by ROAR to be able to withstand a bit of overcharge. I have had only one incident that was not caused by user error (hooking it up backwards) or charger error (not sensing the correct number of cells in a partially charged pack). The one incident was resurrecting a pack from long term storage. I don't recommend this either.
There are plenty of incidents these days with NiMH cells exploding. This is a very high energy type of explosion with high speed projectiles usually. I have seen the result of a NiMH explosion of a tiny receiver pack in a Nitro car. It was equally devastating to the car as a LiPo fire. It broke bulkheads and burned up the fuel tank and front plastic parts. Fortunately there was no fuel on board.
Suitable extinguishers are ABC. Even a small aerosol sized can is sufficient. We are talking about a teaspoon of flamable solvent inside the pack. I put the above fire out with 2- 1 second bursts from a medium size extinguisher supplied by the track.
John
Last edited by John Stranahan; 06-12-2008 at 02:35 PM.
Thanks John, my lipo sack arrived 2 days ago and had no plans on charging my lipos until I got this protection. I will pick up a small extinguishers to have right by my side at track side.
The Associated springs are .515 inch ID. A spring with this inner diameter or a little bigger should fit. I don't have a tamiya spring to test this. Anyone?
John
Thanks John, my lipo sack arrived 2 days ago and had no plans on charging my lipos until I got this protection. I will pick up a small extinguishers to have right by my side at track side.
make sure you get one for lithium fires or you may create more problems then you think.
The fire is not really a Lithium fire. There is a small amount of solvent as the electrolyte. This solvent (like a gasonline fire) is what burns along with the plastic in the separators. A small ABC extinguisher is sufficient to kill the fire as the amount of solvent is low. The track should have a couple of 5 lb extinguishers present. Fire is also a problem with NiMH explosions in the car. I saw one Nitro car completely burned up in the front as the receiver pack, blew, then shorted, then ignited. Fortunately there was no fuel on board. Just use a sock for LiPo.
John
Here are some dimensions
Spring relaxed length 27 mm
Shock fully extended end to end 60 mm
There is a maximum diameter tire that are legar for TC use. I'll check.
Maximum tire diameter 67mm
here is a pic of the rears correctly assembled to the shock tower.
when using the correct short ballcups my shocks are roughly 62mm end to end.
When running the LRP Sphere TC Comp, 27t Brushed motor and a SMC 5000 30C Lipo what runtimes should I be expecting? I am running Foam on Carpet (pretty short track). Im asking because I have no idea and you will probably know.
I havent tuned the TC5 at all yet so its completely stock. Can you recommend anything I can do to make it any better?
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