2WD advice

[BoogieMan]

Hey guys. I'm coming back to RC after about 15 years or so out of it. My new buggy should be together in the next week or so. :)

I'd like to run BL & Lipo but, I'm having a hard time finding the class rules for different off-road tracks in the area (or even out of area). Don't want to buy 4-5 packs of NiMH unless I have no other choice.

I'd appreciate any info (or where to find it) on what people can run at these tracks so I can decide on what motor and batteries to start off with.

Thanks:blowfoamo

[thekid]

i dont know of any off road tracks the alow lipos, but clint will know forsure,,

[bstull]

Boogie, this doesn't relate to your question, but I love the picture of the RC10. I still have my original one from like 1985.

[BoogieMan]

Boogie, this doesn't relate to your question, but I love the picture of the RC10. I still have my original one from like 1985.

LOL thanks. I still have that. In fact I took that pic a couple of months ago.

I also still have a conversion from back then of a RC10/JRX2 hybrid, called (cleverly enough) a RCX2.

[Judge Joe Brown]

Pleasanton is the only indoor track that I know that runs lipos in this area. They are oval though and not off road. Chillicothie has off road and some run at Hutcherson KS. Neither track allows lipos. As for Brushless, you can run them at either track I am pretty sure. It will be in the modified class. If you run at a ROAR race though, you must run a sensored motor. That means no Mamba. I hear Castle is working with ROAR to try to change this, but it probably won't happen any time soon. Novak or LRP would be the way to go if you plan on entering in ROAR events. Chillicothie has a couple of these types of events each year.

[UN4RACING]

I'm getting the urge.

[CRT.5Guy]

urge for what with this economy the way it is i cannot see spending 300.00 or more to have a car are truck set on a shelve collecting dust

[clintscreations]

joe is correct on his info............no lipo's at any of the indoor offroad tracks (that may change after the first of the year)
but if your going to just club race any brushless will do......mamba max 4900 is what i would recommend if you go the CC route.....plenty fast for any 2wd buggy
and as far as batteries go HT north sells SMC's 4200s for like $55-59 each thats all ya need and your good to go at any track you go to............i had mine for 9 month and they still scream

[UN4RACING]

urge for what with this economy the way it is i cannot see spending 300.00 or more to have a car are truck set on a shelve collecting dust

The urge to do some dirt electric this winter. And I can relate. Its becoming a rich mans hobby. Brushless lipo helps.

[CRT.5Guy]

uni next year will be different if chad gets his place up and running then i can see getting back into electric off road at least it will not cost 60.00 in gas to go somewhere to race thats all

[UN4RACING]

Hopefully we can run lipos there.?

[BluesFan]

I don't know of any track that bans the use of Lipos. The only scenario I know of that doesn't allow the use of Lipos is in a ROAR sanctioned race. Every indoor track I've run in I see Lipos being used. In our hobby where getting a good turnout is now very rare, I can't see someone being turned away to run if they have Lipos in their cars.

[Judge Joe Brown]

Do you run at Chilli and Hutch? I am told by the regulars there that Chilli is not going to allow till roar does.

[david alberico]

hutch and chilli are both roar tracks, and don't allow lipo's. From what I heard this weekend I'm not sure if lipo's will be legal next year. To be safe I'd go with NiMH cells...you can run them anywhere and you still get 10+min of runtime. I heard there is a safer lipo style battery coming out.

[Aaron P]

Hmmmm....I know a few people who will be racing this winter and will be racing at Hutch and Chilli, and will be running LiPo. For example, Dustin ran Lipo to practice at Chilli, and at the club race in Hutch back in Sept. No one said anything. Was it because they didn't realize it, or just didn't care? I know a few people who will be traveling with us this winter that only have lipo. Like Nick said, I can't see a racer being told, "Sorry, come back when you have some NiMh's" after they've just driven two hours to the track to race.

I don't see what the big deal is. I have never seen a problem with a lipo while at the track, and this last weekend in Hutch, four NiMh cells exploded. Can't say it's a safety issue, and if it's a ROAR legal issue, then Mamba's are out of the question. It will be interesting to see what happens the first time someone notices that people are running lipo.

[Judge Joe Brown]

I spent $100 on new NiMH this year because you guys told me I could not run Lipos at Chilli. I am not happy if that is not true. I would rather have gotten lipos.

[Aaron P]

Maybe it's a "Don't ask, don't tell" policy.:confused2 :D

[BluesFan]

Joe, I wouldn't sweat it for one season. Besides, if you want to run a ROAR race, you are set. It doesn't look like Lipos will be legal until 2009 (unless ROAR does another change in the middle of a season like they did a couple years back when they legalized brushless in the middle of a season). NiMHs are more than capable. All of our cars are too fast as is, especially for the tracks in the imediate area. Run what you have right now and get Lipos when they become the norm. No real sense in having them right now anyways. Its not like a lot of tracks have adopted 10 minute mains and up. That'll more than likely come along once Lipos have been legalized by ROAR.

I think the purpose of this thread was to get info. for club racing purposes. As Aaron reitterated, clubs shouldn't be thinking about what is and isn't legal to race. Clubs should be doing everything in their power to retain and grow their base of club racers. If a newbie showed up with a brushless stock and Lipo and tried to run in the brushed stock/NiMH class, I'd be shocked if Billy or the owner of Hutch turn them away. Certain rules may be 'encouraged', but shouldn't be enforced as rules when it comes to club racing. It'd be the same thing if someone showed up with a rtr 1/8 at Steve's track with a .28 engine and 150cc tank. It'd be ilegal for a sanctioned race, but why turn someone away for a club race when the out of spec equipment hardly qualifies as an 'unfair' advantage?

[david alberico]

:) :) :)

[Judge Joe Brown]

It was, and your point? :)
The starter of the thread wanted to know which batteries and motor to buy. Apparently there needed to be some discussion as to what you can and cannot run around here because you get a different answer depending on who you ask.

[CRT.5Guy]

ok sorry then i do now to me right now i not buying everything till i see what happens this time next year (chads) or i find a kyosho 2 wd before then

[Judge Joe Brown]

How can you stand to go that long without racing? About 2 weeks is all I can stand. Then I start to get the shakes. :)

[novelty rc]

As far as the insurance goes with ROAR, unless all the racers are a ROAR member, the insurance is null & void.....The weekly races would not be covered thru ROAR.....In '08 I will be allowing the stock brushless & li-po's on a weekly basis, and trophy races, unless of course it is a ROAR race.....Nick is right about getting and keeping racers racing at any given track.....Brushless & li-po's make for a much more relaxing day of racing, and the playing field will be more equal....It will be about who can drive the best, not who has the best motors & batteries.....And 10 minute mains would be very cool for the electric guys for sure

[Aaron P]

As far as the insurance goes with ROAR, unless all the racers are a ROAR member, the insurance is null & void.....The weekly races would not be covered thru ROAR.....What about the racers who ARE ROAR members? Would not the insurance cover them for weekly club races also? I'm not a ROAR member, so I don't know, just asking.

Has either Billy or Steve specifically said "No" to LiPo, or is it hearsay because they are ROAR tracks?

[UN4RACING]

How can you stand to go that long without racing? About 2 weeks is all I can stand. Then I start to get the shakes. :)

Get a coloring book. :leaving:

[Jeremy Blair]

I specifically Heard Steve at Hutch this weekend say NO LIPOS.
It may be different for club nights but I heard that out of his mouth this weekend.
I am sure they will not say anything for club nights but when it comes to a trophy race I think the answer would be NO.
later Jeremy

[novelty rc]

What about the racers who ARE ROAR members? Would not the insurance cover them for weekly club races also? I'm not a ROAR member, so I don't know, just asking.

Has either Billy or Steve specifically said "No" to LiPo, or is it hearsay because they are ROAR tracks?
Everyone that races at any given time has to be ROAR members for the insurance to be valid....If just one isn't, there is no insurance.....Any track can be a ROAR sanctioned track if they pay their yearly dues, but if the track doesn't require the racers to be members, then the insurance thing is only good for ROAR races that everyone has to be a member, or have a one event membership for that event.....
As a track owner, and racer, I have thoughts both ways.....I think most are thinking of the safety factor, they have heard bad things about li-po's.....I have heard about several 4200's in the last couple of weeks blowing up, but not one instance with li-po's.....I myself feel safer with a li-po stuck to my ear than a sub C cell....lol.....Any battery can be overcharged, which can cause problems....I'd say take a vote and go with the majority, or problably just try to keep up with the changing technology and go with it

[clintscreations]

i was standing there when billy said NO LIPO's
there was one or two there last year but no one knew about it

[david alberico]

Sorry, my bad on the insurance, I must have misunderstood it. Anyway, my advice still stands...go with what is legal. Off-road is mostly driver anyway.

I agree lipos are cool, and I can't wait to finally switch.

[Aaron P]

I think that this is going to cause both tracks to be down a few racers. I'm not going to be buying anymore NiMh cells(you can never get them when you need them anyway). I'm going LiPo after the first of the year, legal or not. I guess I will save plenty of gas and entry fee money not being able to run at the indoor tracks.

[BluesFan]

I was sorta thinking along these lines, but Jeremy said it: I would imagine that the only times Lipos wouldn't be allowed would be for ROAR races and specific trophy races. I would assume that is what both track owners of Hutch and Chilli would be referring to. If not....... well, I agree with Aaron. They'll be down a few racers. Like it or not, I strongly believe that many racers will be making the change prior to ROAR legalizing the cells. I've already seen it last winter. I'm new to this area for this winter racing season so I guess I'll be learning how it works out here, but all last season while I was in StL I didn't come across one track that turned away Lipo users unless it was a trophy or ROAR sanctioned race. Even some of the non-ROAR trophy races allowed Lipos. I also saw some experienced racers change over to Lipo besides a lot of the new people using them. Once again, it only makes sense to do it this way. If it was 10 years ago when clubs would draw 100 racers for standard club races, I'd understand maybe sticking with the rules..... but it isn't that way now and things need to change in order to keep people coming back out to race.

[novelty rc]

I'm also looking at the RC Rro Series rules for electric....Since last year they were legal in stock and mod, brushed motors it appears....If you have a BL and a li-po, then you would be in a seperate class, BL truck.....I think you have to look at both groups, some people are die hard ROAR, and it is the same way with the RC Pro Series.....I still think the main goal is to get more into racing, especially keeping them interested in running electric....Longer mains will help for sure....I myself would much rather race a 15 minute main in gas truck verses 5 or 6 minute main in mod truck....More track time....Just stands to reason why nitro is so popular.....David is right about off-road is all about driving.....He can take take a RTR and whip up on me no matter how much and what I have spent.....Drivers like him, and many others is what keeps the fire built in me, hoping some day to just stay on the same lap....LOL....

Forgot to mention the most important thing, having fun racing is what it is all about!

[david alberico]

Thank Novelty :)

Guys I try to get as much information I can. From what I have gathered, maybe not in this area but I have heard of not just exploding but fire from R/C Lipo batteries. I know everybody can say "I've never seen it" It has never happened to me." But it happens, and from what I have heard from different areas, quite a bit, and it's not just a loud pop...it's a fire. You know I have seen some videos of a small lipo pack exploding into a fireball, what if just one of these packs did that along the wall at the thunderdome? I mal-function of a charger, a defective battery pack? Everybody is talking about getting a lipo, but I have heard news of a mag-polymer pack coming out that is much safer, and chances are if this technology is safer with the same positive results of lipo packs then this will be the future and those that bought lipos????

As much as some don't like roar, stick to the rules...then after that stick to having fun.

Here is video for you entertainment...

http://video.google.com/videoplay?docid=5263883555163378025&q=lipo+fire%3F&total=36&start=0&num=10&so=0&type=search&plindex=6

[thekid]

[QUOTE=david alberico;34780] maybe not in this area but I have heard of not just exploding but fire from R/C Lipo batteries.
mal-function of a charger, a defective battery pack?
As much as some don't like roar, stick to the rules...then after that stick to having fun.
QUOTE]

gas can catch fire or expolde in the tank if some thing mal functions or something happens ,,, but i dont see people not drive cars becose of it,,

anything mis used or woren out can be danguras,,, just wondering what happens if you overcharge or smash a 4200,like they have been doing in all the online vids that are scaring some ppl???

charge at the right rate and dont run them down to far and all will be well

[CHRIS]

Heres my 2 cents take it or leave it , we allow both at my track and in the past year Ive seen more probblems with NiMh than the lipo's

[david alberico]

Kid- True, look at what happened to Hillbilly. I still think there is a greater risk with Lipos then even nitro, most Lipo accidents happen on the charger, following the instructions.

Chris - hope all stays well there, I really do. but it would just take one incident and I think it would change your world view...:)

all - not to start a huge debate or argue, If you are dead set on lipos I would seriously invest in the flame clothes they have out for charging them, I think it would be a good investment.

[UN4RACING]

Those kind of lipo vids have great impact for sure. Even though they are deliberate and controlled. You can be sure if it happens at a pit table it will be chaos. In order to keep control.
Do your selves some favors and think of what you would do if it occurred and be better prepared when or if it does.
I know every one ducks when a sub blows and usually followed by some one making a mad dash with a smoking pack in there hand out the door.

So I Googled Sub-c battery explosions and all I could find was safety data and no vids. I did conclude from a ton of reading that if you incompetently mishandle a lipo you will most likely do the same with Sub-c's.
I can tell you that the sub-c manufacturers are out to get lipos. It would be interesting to see the lipo manufacturers hit back with some vids of there own.
I even came across a company that will sell bulk. Be fore lipo that was near to impossible.

[UN4RACING]

And I will add that if forced to charge lipos in a bag and or have a bucket of salt water at the end of a pit table, it would be hypocritical to not require the same for a sub-c.

I have to say that prevention is the key to safety. If a man is willing to use lipo sacks and take every precaution then there would most likely be no dispute to the use of them.

As David has mentioned if this new technology is as good or better than the current we are set. And then we will still most likely be required to use the bags and sub-c will be just as exposed as lipos.

[UN4RACING]

I went back through and located the bulk one.
If you all want to do a group purchase you may check this out.
About 25.00 or 30.00..? a pack and at 35A discharge rating. Not bad

http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=2800

[UN4RACING]

Just one more log.

I found this on another site that I frequent.

The Norwegian Federation has taken the rather drastic measure of calling a halt to all races and training for electric powered classes following 3 charging related ‘explosions’ at a 1/10th scale National last weekend. According to the source on oOple.com, a lot of the failures have occured in the past with the IB4200 cell, however the most recent failures that prompted this ban on racing were LRP VTecs and Team Orion 4200 cells. All racing will stay suspended until January 2008, although I’m not sure what will be different from then until now, perhaps a list of approved cells?

and on the oOple forum:

Norwegian federation NMF closed today down all organized practice and all races with all electric classes due to battery problems.

Last weekend 3 (!) batteries blew up when charging in a 1/10 track national.
Due to this problem and similar problems around europe they choose to close down all events imidiatly.

rumors say that from april 1.st 2008, EFRA will change their battery list and none of todays batteries will be allowed in 2008.

Get ready for another NiMH vs LiPo thread...

[david alberico]

UN4RACING - I've seen some pictures of an exploding sub-c. Even heard one at the fall classic, point is, it exploded and that was it.....a Lipo is a huge fireball.

[UN4RACING]

UN4RACING - I've seen some pictures of an exploding sub-c. Even heard one at the fall classic, point is, it exploded and that was it.....a Lipo is a huge fireball.
I can only concede to that. Fortunately there hasn't been any issues yet.
Potentially a lipo is capable of a dramatic kaboom. Yet its said thats rare and has only been seen under controlled situations. In most cases I've read the pack only swelled. The huge fire ball has yet to be documented to my knowledge at any race events.
I would assume the lipo companies have not shown any vids of sub-c's blowing up due to the fact it would prove your point.
I will try to find a pic I saw a while back where a sub-c blew up and embedded itself in a wall.
Sneaking a lipo in under the radar to race takes away from the whole lipo racing experience. No one wants to hide there pack and would likely run where they can openly run it.
As for racing I plan that if I were to run this winter (off road) I will just run my 2 starter box stick packs and I bet I wouldn't even have an issue with run time. That is running brushless, we need to keep in mind the efficiency of those motors.
I plan that if I run I will just run a round cool down repeak and run each pack every other round. issue solved and on the cheap. Save the conditioning for at home. And I think that can be over rated some times (Aside from stock racing). And I would be willing to bet that it was stock racers trying to punch there packs out to 12 volts that were blowing up there 4200 packs. THOSE ARE THE GUYS I WORRY ABOUT. If they would have stayed with the Gp 3700's punch wouldn't be an issue. And we all know lipo is lacking punch in stock brushed motors. The gurus will need to carry an emergency medical team in there cases.

As for now Sub-c is safer in myth and proven to be even when the sudden
event occurs.

As for lipo they still have some proving grounds to acquire, but making ground fast.

[Hersh]

Wow! I'm honored to have started a thread with so many replies. :redpepper

BTW, this is my new user ID. I made "Boogieman" while I was drinking and decided to go with something more....me. (Also got myself locked-out in the process but it's fixed now :) )

Thanks for all the info, it helped me make a decision. For now, I'm gonna go ahead and grab some 4200 NiMH's so there'll be no worries (rule wise). Pretty much where ever I go I should be able to run. I also realized it might be a good idea to run stock for a bit, so it all works out. Now to figure out how many packs LOL.

Meant to come by P Hill today and watch, but wife kept me busy. :(

[UN4RACING]

Well the lipo battle will continue you can count on that. In the vids the over charging was manipulated by tweaking the charger. They never tell you how or what volts they did it at. Its probably the charge was done with a sub-c setting. And a Kokam can peak to 18volts before the big bang. So theres alot of hype on both sides of the fence.

I would expect lipo will be excepted soon enough at about any place you want to run them so I wouldn't buy more than 3 packs for stock, 4 would be better. And I would make sure you buy a good brand, they have been having trouble with the 4200's. I would call Eric at hobby town and purchase some Gp 3700's. He can also steer you on whats in the market as for quality. The best sub-c's I ever owned were purchased from Eric.
Call Steve at P-Hill he has some used 4200's in the glass. Cheap to. 4 packs sitting there and I know for a fact they were not used much. But they have been sitting there for a while.

[thekid]

So I Googled Sub-c battery explosions and all I could find was safety data and no vids.

http://youtube.com/watch?v=Xk00EvS25tQ

thats what i found,,,, and at the races last night some one behind me had 2 cells explode,, it was very loud and iam sure all that smoke was not helthy,,,
i would wather deal with fire than a bomb but thats my thought.

[cparks]

I don't see the advantage of lipo's. I was getting thirteen minutes of runtime in chilli a couple weeks ago, without discharging, no comm cutting. Oh, they were 3800. you can't take worse care of stuff than me.

[Aaron P]

...you can't take worse care of stuff than me.You must not know Keith "School Bus" Myers very well. HA!

[UN4RACING]

I don't see the advantage of lipo's. I was getting thirteen minutes of runtime in chilli a couple weeks ago, without discharging, no comm cutting. Oh, they were 3800. you can't take worse care of stuff than me.

Its in mod you will gain run time. The advantage is cost and longevity. The packs will out last a sub-c by about 4 times. And you only need 1 or 2 packs.
Approximately 150.00 and you can make them last 4 years. Thats the real advantage, cost. The next advantage is maintenance.
No conditioning no discharging. You can run a round or 2 repaek and finish the night, throw in the box and it will still be charged when you want to run it again.

They will hold a charge you can charge them 180 days before the race and show up and just throw down with out charging it. True.

In stock racing and even 19t sub-c is still really King. Unlike a lipo you can manipulate the charge rate to suit your needs.

Its considered the Lazy class. You would love it....:clinkmugs

[cparks]

I'm lazy. But I still can't ever venture from mod.

[UN4RACING]

I'm lazy. But I still can't ever venture from mod.
Trust me Lipo is a mod racers best friend.

[CRT.5Guy]

don't no about lipos love brushless systems o

[UN4RACING]

don't no about lipos love brushless systems o

Whatcha got?

[david alberico]

kid - you mean to say, instead of a quick pop from a sub-c you would rather deal with a fire that could burn down your house or track? seriously?

[thekid]

kid - you mean to say, instead of a quick pop from a sub-c you would rather deal with a fire that could burn down your house or track? seriously?

thats why i have a fire extingueser,, never heard of a bomb extingueser,, and it was alittol bigger than pop think mild m80,, iam sure that i can find someone having a sub c start a fire,, any thing can be danguras if misused, if any one dosint fell safe runing one fine thats more for me...

[david alberico]

find a video of a sub-c catching something on fire

...plus I think this magnesium polymer, is the future. It is safer than Lithium with the same run-time and similiar voltage.

[thekid]

...plus I think this magnesium polymer, is the future. It is safer than Lithium with the same run-time and similiar voltage.

i havint heard much on that stuff but want to see it,,,, but what ever they do i would kinda like to see it made in to sub c sizes that way you dont have to mess with the batt mounts on some and you can make the sadle packs,

[UN4RACING]

This is from a while back. I have tons of after the fact photos. I just don't have a vid of a deliberate over charge.


At this weekends **Allstar Shootout** at the Encino Velodrome, regular series racer Brad Muther was pulling double duty running in the B/L 10.5 Stock Car class and the 10.5 NASTRUCK class. The NASTRUCK class uses the older 3800 batteries so we have a class to use up 'old stuff'

After the days events were over on Saturday, Brad loaded up and headed off to Camarillo to stay with friends for the night before coming back for day 2 of our event... As he was truckin' up the US101 towards Camarillo he hear a LOUD BANG/Pop from the bed of his truck...then another...then another.

By the time he was able to turn to see what all the noise was, he saw BLACK SMOKE coming from the bed of his truck...as he swerved his P/U from the Fast lane to the RH shoulder....to find his Battery Case was on FIRE and his battery packs were exploding. (See below picture)

Thankfully nothing else was ruined..and NOBODY got hurt.

[UN4RACING]

Heres a photo of some cells that blew shrapnel into he ceiling.
That would hurt as bad as catching on fire.

[david alberico]

sucks to batteries short out like that.

[thekid]

wow look how bent that drive shaft is.. thats what he gets for line charging lol...

[UN4RACING]

Check these.
And after all the years of racing until Lipo, the controversy or safety was never an issue. Lipo comes along and we will ignore them both in the end as far as safety.

[UN4RACING]

This man is a battery Guru. I can link you want. This guys name is linger from another site I frequent.
Mr. Shawn Palmer hangs there to.

In the lithium ion/lithium polymer battery industry – the severe battery failures and battery fires are very well characterized. There are a lot of companies that make a living from failure analysis of batteries. I pick their brains on a regular basis and I get to plagiarize what they have taught me. All severe lithium ion/polymer cell failures can be attributed to one of the follow root causes:

1. External Thermal Damage
2. Overcharge
3. Overdischarge
4. External Short Circuit
5. Internal Short Circuit
6. External Mechanical Damage

1. EXTERNAL THERMAL DAMAGE – LiPo cells will get damaged by external heat. Most manufacturers recommend keeping the cells under 60 deg C or 176 deg F. In my experience, a cell will start to balloon up and the layers start to delaminate once the temperature rises above 90 deg C (194 deg F). If the temperature is extremely severe – the cell will go into thermal runaway and you will have a flaming mess. The thermal volatility is directly related to the cell chemistry. LiCoO2 is the industry standard and unfortunately, the most volatile. LiFePO4 (used in most power tools) is the least volatile and LiMnO4 Spinel (used by Apogee) is somewhere in between. Many of the responsible LiPo manufacturers are using mixtures and additives to LiCoO2 to decrease volatility at the expense of voltage output. Unfortunately, most manufacturers still use pure LiCoO2 since it seems to make the most power.

2. OVERCHARGE – LiPos are extremely non tolerant to an overcharge condition. A standard charge profile is CC/CV to 4.200V. Drastically overcharging a cell just once is a sure way to send a cell into thermal runaway. Overcharging a cell slightly but repeatedly is also extremely bad for a cell. For example, it you charge a cell to 4.300V, the lithium ions start plating on the electrodes forming lithium metal. Lithium ions are not flammable, but lithium metal is. Every slight overcharge cycle will plate more and more lithium metal resulting in a battery that is very prone to igniting.

The best way to prevent overcharging is to charge through a balancer and to avoid chargers that do not charge with the standard 4.200V CC/CV charge profile. At this point in time I do not recommend passively balancing the cell (matching the voltages while the cell is not charging) – I posted my reasons for this in another thread somewhere. There is an Integy charger with a 4.25V/Cell setting which allows for a slight overcharge. In my opinion, that charger should be banned.

3. OVERDISCHARGE – overdischarging by itself is not dangerous, but it will destroy the cell. Overdischarging below the recommended cutoff voltage will cause the copper to start dissolving in the electrolyte. The dissolved copper will then start plating on electrodes which may start an internal short circuit within the cell. The safety of the cell is compromised once this plating starts and the next charge/discharge cycle will be of concern (see internal short circuit).

Don’t store you cells completely discharged. All cells have a small self discharge when left alone and if the self discharge takes the cell down below its minimum voltage, then the cell will be destroyed. It is also a great idea to disconnect the battery from all electronics (remove from speedos, disconnect lipo receiver packs from regulators etc) since most electronics have a small current drain even in the “off” position.

4. EXTERNAL SHORT CIRCUIT – lipos have current capabilities that would embarrass NiMh. When these cells are shorted out, the extreme current drain will cause the battery to overheat. As soon as one section of the cell overheats – then the cell will go into thermal runaway resulting in a nice cozy fire. As far as I know, Kokam is the only lipo that designs the negative tab as a fuse.

5. INTERNAL SHORT CIRCUITS – this is mostly caused by contaminants getting into the cell. You would be amazed how many manufacturers operate in a nearly open air environment. One of my overpaid consultants uses a very simple tool – a magnet – and waves it over the exposed electrodes (prior to cell assembly) and it’s amazing all the metallic contaminants that little magnet picks up. Contaminants can poke through the separator over time. If you are lucky, the cell will just have a high self discharge rate. If you are unlucky, the microshort will cause a localized heat buildup and create a thermal runaway condition – and thus another cozy fire. Another source of internal shorts is the punching process the manufacturer uses to stamp out the anode and cathode electrodes. Most of the low end manufacturers use a low cost steel rule die that cost maybe a couple hundred dollars. The better manufacturers use a high end die that cost a couple orders of magnitude more. The problem with cheap steel rule die punch is that it tends to leave burrs on the electrodes. These burrs have a tendency to puncture the separator and create microshorts. This microshort will create an area of localized heat. In most cases, this will cause the cell to puff up. In bad cases, this localized heat may be enough to ignite the cell. Every time you charge a cell, the cell will expand about 5% in the thickness dimension. This expansion/contraction may cause the burr to eventually rub through the separator. The vibrations and shock from an RC car also rubs the burr against the separator. Most of the lower end manufacturers don’t perform a simple high pot test (apply a high voltage and check for current leakage) to check for small internal shorts during the manufacturing process. The big Sony recall was largely attributed to burr type contaminants as well as Dell’s non-standard pulsed fast charge technique during the CV part of the charge cycle.

What can YOU do to minimize the risk of this type of failure? - Not much actually. It’s not like we are able to audit every cell manufacturer and even if we did, most of the RC cell distributors hide the manufacturer information. Of all the factories I visited, Saehan Enertech had the highest level of quality control and cleanliness followed by Kokam. Enerland is passable though they lag behind Saehan and Kokam. I don’t think I am allowed to list some of the factories I visited that are downright dangerous.

As a distributor – if a lipo cell manufacturer claims that they can produce a custom size cell tooling for you under $2K, then it’s an indication that their electrode punching process is dangerous.

6. EXTERNAL MECHANICAL DAMAGE - it doesn’t matter if you have the highest quality cells in the whole world if you dent your pack. In order to understand how mechanical damage affects a lithium polymer battery – you need to understand how they are mechanically built. A lipo battery is made up of 20-30 layers of a very thin sheet copper anode, a thin plastic separator and a thin aluminum cathode. A dent will can create a microshort by making the stiff metal anode or cathode poke through the soft plastic separator. As I mentioned above – this microshort will create an area of localized heat. If you are lucky – the cell will puff up. If you are unlucky – you will have a fire hazard. Another repercussion of a dent is that some layers of the cell will become delaminated and thus inactive. This means that the working layers will need to work harder to provide current and thus generate more heat in a localized area. I’ve been a huge proponent of hard cases to protect the physical integrity of lipo cells. In my professional opinion, a hard case for RC cells should be mandatory. I cannot believe that there is at least one lipo battery distributor that is spreading propaganda that hard cases for lipos are not good. In my opinion, this is absolutely irresponsible. Toshiba had a recall on laptop batteries when they found out it would not withstand a drop test. The soft-shelled lipos don’t stand a chance in a drop test.

I’ve seen many postings on how XXX user has a soft shell pack that’s been ejected from the car and run over by another car and there was no fire and therefore hardshells are not required. Great – lucky you! Most of the time nothing will happen – but you don’t want to be around when that 1% of the time when something bad does happen. I’m surrounded by thousands of lipos everyday, but I wouldn’t pit next to a racer running a soft cased lipo.

What can you do? If you are a track owner/operator – insist on hard cased lipos.
As a governing body like ROAR – start specifying rules for the hard case. For example, the hard case needs to have a seam so that in case the cell expands, the case will pop open so that the cells do no build up any more pressure. In my opinion – Orion did a fabulous job designing the case (except that they flopped the + and – going from the 4800 to the 3200 battery) and I hope others copy it.

[david alberico]

Good info there. There is a lot of it.

no need to cause an argument. personally in off-road/oval. it really doesn't matter with the way races are run, if you make weight who should really care? When I talk to some of the bigger names in the industry I have to respect and take their opinion into consideration. All electronic devices have a risk of danger, I've seen laptop explode into a fireball (on the internet of course), in an envirnment that nobody can control, the laptop handles the charge and cutoff. Honestly will we ever see a lipo battery explode into a fireball in person, around here? probably not, but it doesn't mean the increased risk isn't there, will it be ROAR legal next year? there was a class for it at the nats. I guess time will tell. In the mean time since in oval/off-road it had more to do with driver and not really NiMH or Lipo I'll stick with what is legal everywhere, that was I can race everywhere. When the future is legal, I'll be the first to buy, which could be the MiPO or whatever and leave Lipo customers thinking "why did I buy these when they will never be legal."

[UN4RACING]

Ditto.
I'm not trying to argue though, hope its not coming off that way. I'm just defending the battery of my choice, and trying to share some of the stuff I know. Bottom line I run the rules and or just what ever is allowed. Its a discussion same as we would have at a race.
I just see the lure of lipos as so compelling theres no way to stop it.
Awareness is the 1st step to prevention knowing what to do and why it will happen and all that good stuff.
The truth is I don't even own a lipo right now. I have ran them though. My personal testing is done.

I'm not the wizard just trying to be.
GO FAST AND TRY NOT TO CRASH.!

Any battery is a potential hazard. Use caution.
The 1st step to prevention is awareness.

[Aaron P]

I just saw on Chilli's web site that they WILL BE ALLOWING LiPo's at the January trophy race in the MOD classes.

[david alberico]

that's awesome

[novelty rc]

I just saw on Chilli's web site that they WILL BE ALLOWING LiPo's at the January trophy race in the MOD classes.
Cool beens Aaron.....We were all talking about the 13.5's and lipo's after racing Sat......I really didn't think that from the conversations that Billy was going to allow the lipo's.....He was talking only allowing the Novak, but I'm glad he included the LRP also....Mark and Kenny are LRP guys, and I'm sure there are lots more out there too.....That way you can choose the brand you prefer....I did put a 13.5 on order yesterday with Horizon when I ordered....Showing to be here around the 20th this month....Made the right decision for once....lol....Several brushed items are ebay bound......No more need for lathe, motors, and so on.....You guys are coming back the 1st?.....I may not get back over til then.....I'd like to go Sat., but I'm taking off a few days for Thanksgiving.....

[Aaron P]

We're actually going to head up there again this Sat. so c'mon...you know you want to....:clinkmugs

[Judge Joe Brown]

Rex, are you saying we can now run 13.5 brushless in the stock classes at Chilli?

[Aaron P]

I think that it may be just for the trophy race.

[novelty rc]

Aaron, you're right, I do....Have to see if it will work out....Joe, I know on a weekly basis, I think he will allow it, or divide it up if there is enough to do so.....I don't think he will turn you down running it, but that is just my take on what was talked about last weekend after racing.....You know how it is sometimes, you hear what you want to hear....lol.....I know after this weekend, if I get to make the trip, I'm done with the brushed motors.....I'd just give Billy a call....I'd say the more racers who contact him and ask about it, I would imagine he would go with what most would like to run concerning the 13.5 thing....Here is his phone # if you don't have it

660-646-1120

[novelty rc]

As of now my plans are to be there....See some of you in the AM......

[Aaron P]

As of now my plans are to be there....See some of you in the AM......Sweeeet.

[CRT.5Guy]

has chili got smart and changed there start time yet (back to night)

[Aaron P]

No. They start at 2:00, which works out great for us, it's puts us home at a decent hour, rather than 3:00AM