Rules thoughts

[sjslhill]

I matched thousands and thousands of NIMH cells and used them for years, never seen one explode or burn. I have seen LiPoly swell and burst into flames and burn into the asphalt it was sitting on.

There is no doubt that LiPoly is the best power source on the planet at this time, no argument there. It's also the most dangerous hobby battery ever allowed into the public's hands. I am glad that nobody has ever died yet from a fire. I know there has been fires at NAMBA events, you guys have done a good job of being quite.

I may be crazy but I feel safer letting my trained 12 year old shoot guns rather than charge LiPoly batteries.

[sjslhill]

I saw an image of someone charging a 2s 720mah pack in a coffee can on the stove, it caught fire and shot flames up into the vent and melted the fan. These things are highly dangerous. Yes, they have been used safely but it only takes one accident. There are all kinds of videos and images out there on the Internet. Houses, cars and other fires.

Doug,
How the heck did you detonate the batts??

...These lipo sacks IMO are giving people a very risky and false sense of security... That's precisely why I asked about them

Proceed with caution... I always do, that is one of the reasons I backed down on the charge current. I'd rather wait a little while longer than deal with the alternative.

How bout putting the batt in one of these while it's charging... http://www.sentrysafe.com/Products/1/1100_Fire_Chest - Yes I realize the idea is to protect the contents in case of a house fire; but it seems to me that if they can do that, then they should be able to keep the contents contained as well. Just a thought...

[DPeterson]

JW-Pepper,
I had a bunch of old RC Lipo 4S and 2S packs that were in suspect condition. I charged them up, lined them up outside and shot them with a 22 rifle. Wanted to see what would happen and had a lot of fun at the same time. 50% of them just kind of fizzled. The other 50% shot the flame out between 8-10 feet intensely for about 60 seconds.

Your not going to put out a lipo fire. You can only try to direct where the flame throws and then try and protect the surrounding area. The lipo sack does not direct the flames in a controllable direction. I personally consider the use of Lipo sacks to be highly dangerous. I see them on pit tables with the flaps facing either the racer, his equipment or his buddy siting next to him. Furthermore - lipo sacks are made from fireproof material. The same material oven gloves are made of. I believe this material is good for like 350-400 degrees. Way below a lipo flame out temperature. This is why most lipo sacks has a specification rating of up to 3S. The suppliers have their liability exposure covered.

On the other hand I have not seen a lipo flameout ever from being on a charger. Not sure how this could happen using a proper charger with balancing taps on. All the lipos fires I have seen were in the boats and were caused by some sort of damage to the cells. I have even witnessed many lipos being short plugged by accident and all I have seen was the unsoldering of the wires. So IMO it is the suspect cells and the damaged cells you have to be extra cautious about. Pull them out of your inventory and discard them.

Oh - Disclaimer - I do not represent any organized racing association.

Doug

[Doby]

JW-Pepper,
I had a bunch of old RC Lipo 4S and 2S packs that were in suspect condition. I charged them up, lined them up outside and shot them with a 22 rifle.
Doug

Classic....must have been a slow cheese day.

[kwiktsi]

JW-Pepper,
I had a bunch of old RC Lipo 4S and 2S packs that were in suspect condition. I charged them up, lined them up outside and shot them with a 22 rifle. Wanted to see what would happen and had a lot of fun at the same time. 50% of them just kind of fizzled. The other 50% shot the flame out between 8-10 feet intensely for about 60 seconds.

Your not going to put out a lipo fire. You can only try to direct where the flame throws and then try and protect the surrounding area. The lipo sack does n. direct the flames in a controllable direction. I personally consider the use of Lipo sacks to be highly dangerous. I see them on pit tables with the flaps facing either the racer, his equipment or his buddy siting next to him. Furthermore - lipo sacks are made from fireproof material. The same material oven gloves are made of. I believe this material is good for like 350-400 degrees. Way below a lipo flame out temperature. This is why most lipo sacks has a specification rating of up to 3S. The suppliers have their liability exposure covered.

On the other hand I have not seen a lipo flameout ever from being on a charger. Not sure how this could happen using a proper charger with balancing taps on. All the lipos fires I have seen were in the boats and were caused by some sort of damage to the cells. I have even witnessed many lipos being short plugged by accident and all I have seen was the unsoldering of the wires. So IMO it is the suspect cells and the damaged cells you have to be extra cautious about. Pull them out of your inventory and discard them.

Oh - Disclaimer - I do not represent any organized racing association.

Doug

I have done the same thing with my .22 and .380 lol. I crashed a plane at the field one day and bent the pack to hell. It got warm but never burst. Being a little concerned about it being in the car for the trip home, it got the .380. Flamed out, waited for it to cool and chucked it in the a box. I have also done several with a hammer and screwdriver before chucking them- they hiss for a bit then flame up. They are not the violent ticking bombs many would have you believe. Sure, they are volatile, but you get plenty of warning. They should be treated with proper care (as should any battery...) but are notwhere near as dangerous as many on the net would have you believe. Respect them and what they're capable of and you'll be fine :-).

Oh yeah, dead shorted a couple myself as well and as you said, worst that has ever happened was a wire came unsoldered or it burned the aluminum tab off the cell. No mushroom cloud or spontaneous combustion.....

[blowNover]

Key points I'd like to hit on. Mr. Hill. You said your children are trained around guns. Why can't you train then for lipos?
Second kwiktsi said something about there being warnings for a lipo that is getting ready to burn. There's not much warning when a Nimh is going to explode! It just gets hot so unless you are constantly tracking or checking for heat you will never know when one might go.

[blowNover]

So I guess what am saying is if you hawk over either type of power sorce you may never have an incident with either.

[T.S.Davis]

I've had NiMh burst their cans and puke their guys out but not actually spit debris. I believe Mike, just never happened to me.

At the cup last month I had a stuff that turned yard sale. Everything was everywhere. The batteries came out of the boat and were dangling in the water by the wires. The cells were buzzed by the prop before all was done. Looked like a shark attack. I was expecting a thermal nuclear discharge. Didn't happen. No clue why.

[T.S.Davis]

So I guess what am saying is if you hawk over either type of power sorce you may never have an incident with either.

That's the most sensible thing out of this entire thread.

Pay attention and learn what you're doing and you decrease the potential for disaster dramatically.

[kwiktsi]

As mentioned earlier- I have had Nimh damage boats and one let loose while charging off my car battery. The car was outside in the driveway and pieces of the battery were scattered all over the garage and even scratched up the door going from the garage to the house- 20' away from where it blew!! I know there are shrapnel pics somewhere but these are all I could dig up right now. We were in the house and it sounded like a gun went off outside followed by the sound of stuff hitting the door. We literally thought some yahoo fired off a shotgun into the garage by the sound of it! I have NEVER had a lipo do anything even remotely like this- and I have NOT been overly cautious with them over the years. Even when I TRY to get them to blow, it is nothing like a Nimh going off!!

[Darin Jordan]

Back to the original topic... I think the NAMBA rules DO need to be revised... the voltage specified should NOT be a "nominal voltage"... it should be a MAXIMUM voltage allowed. Super easy to tech, as well as chemistry independent.

To be reasonable (something very tough for many to do these days... ), one would have to base the maximum voltage on the most popular/recent/available technology available when the rule is written, in this case, obviously, that would be LiPo....

Require that boats be teched OUT, as opposed to after the run.

Pretty simple...

As for safety... Anything can be dangerous in the wrong hands... Respect for the technology, just like everything else.

[Brushless55]

Back to the original topic... I think the NAMBA rules DO need to be revised... the voltage specified should NOT be a "nominal voltage"... it should be a MAXIMUM voltage allowed. Super easy to tech, as well as chemistry independent.

To be reasonable (something very tough for many to do these days... ), one would have to base the maximum voltage on the most popular/recent/available technology available when the rule is written, in this case, obviously, that would be LiPo....

Require that boats be teched OUT, as opposed to after the run.

Pretty simple...

As for safety... Anything can be dangerous in the wrong hands... Respect for the technology, just like everything else.

good stuff...

[fox88gt]

It amazes me that people still don't believe in LiPo technology. I can't claim to be a battery engineer, chemical engineer, battery expert, or anything like that. All I can claim is being an RC hobbyist and racer for about 5 years. In my experiences at the track, the only batteries that I have seen go up in smoke, fire, fizz, or fail in any way, are the NiCD/NIMH cells. Treated properly (meaning correct charge rates, no over-discharge, charge them in a Lipo charging sack, etc) the Lipo technology is safe. Why on earth would RC tracks let you charge them on their premises if they weren't at least somewhat safe. 2S lipo is going to beat 7cell NIMH any day.

Apparently the cell phones we hold to our faces aren't safe either then, because they use lithium technology. Sub C is dead. The facts are the Sub C are being made cheaper and cheaper by the day because the technology is dead and that (to me) is more dangerous than using a quality Lipo pack.