New Batteries?

[mute]

New Batteries?

Have to agree with Ed here, by the sound of it your batteries aint kicking out enough current to stall your motors.

Micro Mute used to run two NCC-70 speedos on its motors, and we unfortunately current limited at the batteries. MM could easily draw well over 100A per motor (yes they were BIG motors), however the battery could only give out 100A max.

Dont rely on batteries current limiting because in a 5 minute fight they get VERY VERY HOT.... we lost 2x 24V 2.4Ah NiCad packs to over heating.

Micro Mute - the one and only battery cooker

[Mouldy]

New Batteries?

What good is all that power when you carnt stop before you hit a wall?

regards
Dave moulds
Team Turbine

[blazerbotics]

New Batteries?

in micro mutes case, in the pit!

[jamesb]

New Batteries?

had a custom made LiPo made for one of mine by a company that leads the world in the technology, and sent direct from Korea, but it never arrived.
been on to them and apparently its not safe to ship the way I wanted it (ie, cheap) in case it is knocked and cracked, it will explode....
asked how this is ok for robots and they seemed to confuse robot fighting with robot stangin there looking nice but doing nothing.

current, is limited by the size of cell, if you want more current get bigger cells, that was my plan, and I could have 45amp for 5 minutes (comprable to NiCDs we use in feathers). had to have special cell made, but is possible.

price, if youve got it flaunt it, if you havent... well.

at the end of the day, do what you want, but no offence to people who may show up with these in future, if you have a LiPo in your feather, dont expect me to allow you to run. Dont like exploding robots, and dont fancy wasting my fire extinguishers on a dead cert bonfire.

for now, ants seem ok, but until they can protect these lipos, I cant see them being safe.

BTW, arent they used a lot for electric flight with high current, high performance motors? Sounds like they can produce some useable power.

[ewan]

New Batteries?

My batt sponsor (http://www.countybattery.comwww.countybattery.com) has every type of battery you could imagine, exept Li-Po. They store their batteries in an air-conditioned warehouse and carry them around in or on crates by forklift truck. If a single small pack fell off a forklift truck,then boom! You could imagine a heavyweight bot with VERY large Li-Po cells come up against Storm II. The forces involved would almost definately leave the packs ending up in smoke...
Cheers, Ewan

[stu]

New Batteries?

- if a single pack fell off a forklift - then boom. I cant see a Nicad Pack going boom if it fell of a follift truck. LOL. Unless it was poorly made and shorted it self. Bit ott ther Ewan.

Ive never seen how a Li-Poly will react to if it got cut by a spinner from another ant weight or something - so cant comment on how safe they are etc. Nicads and Ni-Mh are bad enough. I see soo many packs in the pits with their wires hanging lose etc- i just wanna faint. LOL. Ive witsnessed many Nicad fires, even had to control one at Inspire. Nasty things when they do what they want.

Id REALLY hate to see something like Storm 2s nicad packs short them selves out or something. I know it aint gona happen too soon with all that 6mm and 12mm ti, but imgaen someone else with lots of nicads like that - wouldnt want to get too close to that.

Ne ways some people would call us sad speaking on the net on new years eve - bye all, im going to a party, have a nice Night. Cya.

Mr Stu

[ewan]

New Batteries?

I was talking about the Li-po packs going boom...
Cheers, Ewan

[storm]

New Batteries?

Ive played with Lithion Polymer packs - I dont know where the scaremongering is coming from that if one fell off a forklift theyre blow up.

Check your laptop, mobile phone, pda, mp3 player - I could go on. Li-Ion Polymers are everywhere. Theyre a safe non spillable battery type and physically theyre fine for RW

Why are they in things like laptops, phones and pda ? Because theyre good at giving a sustained low current output - hence why theyre also ideal for antweights. Sadly at present theyre just not up to the job of running a featherweight - theyre getting close, but its not there yet.

So no need to panic if your friend drops their mobile phone or laptop with Li-Ion battery - luckily its unlikley to explode !

Im off to a party too now - happy new year everyone !

Ed
http://www.stormrobot.comhttp://www.stormrobot.com

[ewan]

New Batteries?

I just know from expirence that you can never be to confident with Li-Po batts. (this IS a true story) One minute I was typing on my dads laptop, then the next, the battery port was smoking. It had fallen off my lap, and hit the floor, causing the contacts inside the battery to knock together. I quickly ran down stairs and got the fire-extinguiser from my workshop (in the cellar). By the time I got upstairs flames were visable but it was easily put out. If the flames had got a chance to get into the cells then it would have been a case of... Boom
The short-circuit had put to much stress on the battery causing the fire. Cheers, Ewan

[leorcc]

New Batteries?

Li-po packs in laptops and cell-phones are fitted with internal failsafe measures against shorting out. Fact is, if that countermeasure doesnt work they will heat up like theres no tommorow, en eventually explode. It does take a while to reach that point, its not a firecracker or grenade, but it will happen.

[blazerbotics]

New Batteries?

at AWS a Lipo pack got damaged (by a crusher i think), there was alot of smoke.

[ewan]

New Batteries?

If Li-Po packs do ever come to give out high enough currents, even for a heavyweight, Im personally going to stick to ni-mh and ni-cads.

[storm]

New Batteries?

Ewan - what sort of true story is that about batteries and how unsafe Li-Ion Polymber batteries

It had fallen off my lap, and hit the floor, causing the contacts inside the battery to knock together

Well duh - if you short any battery it risks explosion. What do you think the release vents are for in the top of a NiCad cell, to drain water ?

If the flames had got a chance to get into the cells it would have been a case of Boom....

WTF are you talking about Ewan ? Youre making out that Li-Ion cells are the only cells that can explode ?

Ive been trialling some Li-Ion cells and theres no indication that if you drop them they blow up. Theyre just as safe as NiCads. I dont understand why people are trying to make out theres this super-unsafe technology thats so unstable they could explode at any moment ?

Alan - watch a NiCad pack get crushed - lots of smoke there too.

Leo - Im sure you know that a NiCad pack has built in failsafes, which if they fail results in the cell going bang.

.... why are people making out that Li-Ion cells are different and super dangerous

Sounds like rumour and mis-information to me !

Ed
http://www.stormrobot.comhttp://www.stormrobot.com

[ewan]

New Batteries?

Its just all I know, Im not a battery expert, according to every source I have heard from, Its just the stuff inside the cells (the acid or whatever it is) that makes it more dangerous than other cells. I do admit that I havent witnessed any ni-cad fires myself, so for all I know, they could be just as dangerous.
Cheers, Ewan
P.S. Are ni-mh batts likely to provide enough current when short circuited to create a fire?

[Guest]

New Batteries?

Yeah, as are alkalines, SLAs, wet lead acid, lithium.....