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Old 10-27-2007, 09:41 AM   #16
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Since on road guys are now running 5 cells and off road guys don't use anything under a 10turn motor I'm sure that these things will cause you to lose power. If you still want to race stock class then keep dropping big money on nimh packs and brushes. The only reason stock and mod were seperated is because mod took more work to maintain back in the day. You should simply have a sportsman and a pro li//bl classes now.
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Old 10-27-2007, 10:02 AM   #17
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Not true at all! Mikr Truhe ran 5 cells at the worlds in Japan and finshed 5th over all. For off road 6.6 v is plenty of power.

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did you say these things are 6.6v ???
if so your still a nearly a hole volt down on power this is =top end speed.?

if this is true a 7.4v nicd will kick its ass......over 5 min race.
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Old 10-27-2007, 12:37 PM   #18
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What chargers are people using for these cells? Will an Ice charger work, or do you have to have the special charger from a123?
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Old 10-27-2007, 12:50 PM   #19
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There are a lot of chargers that can charge the cells. I'm sure you can program an ice to do it. However these cells are more durable then lipos and you can charge them at a 10 amp rate the entire charge period so a 3c rating is a true 20 minute charge.
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Old 10-27-2007, 12:53 PM   #20
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yes yes i agree the different motor combos in different cars with diff weight and FDR's and so forth will make a difference...

wot i was saying (meaning)is motor for motor bat bat if your racing a certian class of racing more allong the lines of stock racing a123 cant do as well...ive got nothing against a123 i dont know enough about them
hence my question....are they 6.6v
I have used lipo for over 6 years and pound 4 pound u aint gonna beet them for output.unless you plug in to the wall or its got a reactor.

volts = rpm
amps = tourque
give a motor 6.6v= rpm,,,,,,,,,,givit 7.4v= more rpm.
I race stock so thats the way may conversation leans(i did'nt make that clear, sorry)
go on dissagree with the principle's of electricty.
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Old 10-27-2007, 03:27 PM   #21
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+1 on what he said ^.^

li-ion (what a123's are) are punchier, so you can gear higher on the same motor. i can shove a half charged li-ion pack onto a 540 motor and it spins up faster than a fully charged ni-cd pack will do. and of course they weigh less, so you can gear even higher without the motor getting as hot (less weight to lug around).

so you will have less RPM but loads more torque, so you can gear higher to get the same speed, at a lower voltage. make sense?
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Old 10-27-2007, 03:39 PM   #22
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Unfortunately most lipo chargers don't let you adjust the "peak" or cutoff voltage. They are pre-set to 4.1-4.25v per cell cutoff... sometimes with a couple choices like the ICE.

But the A123 cells should be cutoff at 3.6-3.7v per cell. So a standard lipo setting will be overcharging them. Some guys actually do that... and the cells are pretty tough but that's not good for them.

Some chargers do have adjustable cutoff, like the TME Extrema... I don't have a complete list but a little searching would find out. I think the Thunderpower charger has it, and some of the e-Station chargers...

http://home.comcast.net/~truerc/Charge/chargers.htm
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Old 10-28-2007, 03:46 AM   #23
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the CDC 7.1 does lion,lipo vari cut off
its kinda close to the ice but 20amp discharge
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Old 10-28-2007, 03:54 AM   #24
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its just a matter of time b4 all lipo packs for cars will come stock reinforced and have built in chips to auto balance n stuff so that it is safer for the hobby and that people can be more casual and not cautious about it. look at nimh, they have a fairly good reputation and are pretty strong and you can throw them n whateva and they rarely blow up, but when they do go BANG, talk about it spreads like wild fire and people get overly scared about their own packs just blowing up. lipo is the same, but lipo packs seem to blow up more as they are only GEN 1 lipos and they are more prone to wrong usage. you could charge a nimh on nicd setting and most of the time its OK, but bad for the packs while with lipo charge on the wrong setting and bye bye pack and big bang with it.

i HONESTLY, find my lipos safer than nimhs because all the lipo BOOMS i've seen are from improper usage, while i saw 2 nimh packs, new, charged at 5.5A, infront of my eyes, go BANG.

like i said, give it time and all the companies will make all packs with hard casing when lipo racing because ROAR or whateva legal.
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Old 10-28-2007, 05:30 AM   #25
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Quote:
Originally Posted by d4_racer View Post
its just a matter of time b4 all lipo packs for cars will come stock reinforced and have built in chips to auto balance n stuff so that it is safer for the hobby and that people can be more casual and not cautious about it. look at nimh, they have a fairly good reputation and are pretty strong and you can throw them n whateva and they rarely blow up, but when they do go BANG, talk about it spreads like wild fire and people get overly scared about their own packs just blowing up. lipo is the same, but lipo packs seem to blow up more as they are only GEN 1 lipos and they are more prone to wrong usage. you could charge a nimh on nicd setting and most of the time its OK, but bad for the packs while with lipo charge on the wrong setting and bye bye pack and big bang with it.

i HONESTLY, find my lipos safer than nimhs because all the lipo BOOMS i've seen are from improper usage, while i saw 2 nimh packs, new, charged at 5.5A, infront of my eyes, go BANG.

like i said, give it time and all the companies will make all packs with hard casing when lipo racing because ROAR or whateva legal.
bingo! gotcha! hole in one! the battery technology is only 15 or so years old, and it's still in the early stages. ni-mh had 60 years experience to build on with Ni-cad, and lipo's are slightly more volatile than ni-mh because lithium is one of the most reactive metals on the planet! and nickel is fairly unreactive. to get more powerful batteries you must go for more reactive metals.
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Old 10-28-2007, 05:49 AM   #26
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more reactive metals to get more power? does that mean in like 50 years are RC will run on URANIUM cells? lol!

the new technology to go for perhaps is li-mn, lithium manganese. its stab proof and has the same power, plus its also pretty light. (i think)
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Old 10-28-2007, 07:01 AM   #27
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I know this is an offroad forum, but did anyone notice about 2 issues back in RC Driver they had a Tamiya TA05 IFS that was using a A123 battery pack. It was 2200mah I believe, and fit the vehicle perfectly.

There are also pics out there of packs for 1/18 scale scene, with one pic showing a A123 pack fitting a Mini-T perfectly as if it was made for it, and another pack that looks like it can work in a RC18T.

As for chargers, if I go with A123 I am looking at the top of the line hyperion to combo with my LBA10+ balancer. Hyperion makes some good stuff from what I am seeing and hearing.

As far as stock goes, I sent a message to the guys who run the track that has indoor carpet racing. They don't allow lipo which I can understand with its possible fire issues and its 7.4V, but with the A123 packs I am wondering if they would allow them since they are only 6.6V and don't have the fire issues. Would be at a disadvantage probably, but if it can generate interest in the packs and keep me from having to do the whole battery warchest and voodoo thing, I am fully for it as I would run for fun.

One thing that is curious is that even at the mah rating the packs are at, they seem to actually perform better than you would expect as far as runtime goes from what I am hearing. And since you can fast charge them in like 15 minutes I believe, this could really be a great thing for electric.

Now, if I can get a nice 6000mah (heck even 5000mah since they seem to run longer) pack that is similar in dimensions and close voltage (14.8V close I need) I'll put it into my brushless 1/8 scale buggy.

Finally, someone please post some pics of these buggies with A123 packs in them. I have seen 2wd versions where they cut down the tray, I am looking for 4wd buggies.
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Old 10-28-2007, 09:36 AM   #28
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Cain, if 13.2 volts is close enough, I have seen folks charging 4S A123's directly off a car battery with no "charger". Have you seen that? They just use some power cord as a slight limiter and they watch the voltage for when it is ready to top off. The charging is so fast that unattended charging is not required.
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Old 10-28-2007, 09:53 AM   #29
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Quote:
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Cain, if 13.2 volts is close enough, I have seen folks charging 4S A123's directly off a car battery with no "charger". Have you seen that? They just use some power cord as a slight limiter and they watch the voltage for when it is ready to top off. The charging is so fast that unattended charging is not required.
WOW thats dangerous. i heard it works for Ni-cad, but then they're like that. lithium requires a special charge sequence, which for the first 90% of the charge its fixed current, and the last 10% fixed voltage. so theyre only charging to about 90% anyway, as well as having basically a bomb! the car battery will be chucking 700 amps into them! thats alot of current! (and the wires will melt if you leave it for longer than a few seconds)

and D4, uranium isn't very reactive. one of the most is something like ceasium i think.
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Old 10-28-2007, 10:14 AM   #30
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You can build a pack w/out too much trouble. What I would do is use a standup motor mount that will mount the motor over the spur gear. Now go and take 4 cells and solder them up side by side just like any other 4cell nimh pack. Then build 3 more so you have 4 of these. Now go and wire these in parallel. You can also wire up ballancing plugs for these as well. then you can stack them in pairs and place two of them on each side. I'm sure that you could run a 13.2volt 9.2k ah pack w/out problem in 1/8th scale now couldn't you?
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