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Old 12-14-2007, 06:06 PM   #1
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Default why are we still running sub-c cells??

why??
with the lipo on the market,what do we see good in nimh batteries,other than draining our pockets.i raced with them for 8 years and the day i tried a lipo pack borrowed from my friend i was sold on it faster cleaner cheaper trouble free and ...and....and.... so if someone knows somthing good about subc cells, share it with us please.thx
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Old 12-14-2007, 06:39 PM   #2
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LIPO to my knowledge is not ROAR aproved that is why it is not so wide spread and is used for club racing and bashing.
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Old 12-14-2007, 06:50 PM   #3
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I think its that and if your running stock you can punch them out to the higher voltages that you need. If I was to race stock I would run Sub-C.
I would guess that as long as theres a stock class the most competitive will want sub-c.
I don't care for any of the packs after the 3700 though, they seem to be awful sensitive.

I don't think we would we want to end sub-c? They are tried and true.
And its another product to play with.

If your looking for an edge sub's have the advantage.
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Old 12-14-2007, 06:53 PM   #4
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because there are still racers 'sponsored' by NiMh matching companies trying to sell their product....and there are still a lot of questions for a lot of people concerning LiPos.

Besides, it's hard to change to new things for some people...
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Old 12-14-2007, 06:58 PM   #5
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Originally Posted by UN4RACING View Post
I think its that and if your running stock you can punch them out to the higher voltages that you need. If I was to race stock I would run Sub-C.
I would guess that as long as theres a stock class the most competitive will want sub-c.
I don't care for any of the packs after the 3700 though, they seem to be awful sensitive.

I don't think we would we want to end sub-c? They are tried and true.
And its another product to play with.

If your looking for an edge sub's have the advantage.
I don't think you have all your facts straight. Lipo's are far superior in every way. punch, power, runtime , amount of charges you get out of each pack. The list goes on and on. Who really cares what roar is saying. Why aren't you guys complaining about brushless anymore? Because, now everyone knows brushless is superior to brushed in nearly all aspects of r/c.
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Old 12-14-2007, 07:01 PM   #6
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Lipo is not the holy grail. It's biggest limitation in my eyes is the 3.7v per cell. This makes it very hard to be adopted in 1/12, 4-cell racing in Japan, and 5 cell racing in Europe.
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Old 12-14-2007, 07:06 PM   #7
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as far as the 3.7 volts - with an open mind things can be done similar to what we are now doing with OVAL racing.

We are (in many areas) swtiching from 4 cell (4.8 volts) to a 2c Lipo, and had NOVAK create NEW B/L motors to achieve the speeds we were looking for...

This opens NEW things and concerns, but so far it's made our racing so much easier not having to BABYSIT batteries and cycle them 3 or 4 times nights before each race.
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Old 12-14-2007, 07:17 PM   #8
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Originally Posted by Juan Aveytia View Post
I don't think you have all your facts straight. Lipo's are far superior in every way. punch, power, runtime , amount of charges you get out of each pack. The list goes on and on. Who really cares what roar is saying. Why aren't you guys complaining about brushless anymore? Because, now everyone knows brushless is superior to brushed in nearly all aspects of r/c.
I hope this doesn't really start a battle, but I think this needs to be covered.
LiPo batteries are not superior in every way. Nor are they inferior in every way. They are just different technology and they will require a different set of rules that haven't been fully defined yet since they are not equal to NiMH Sub-C cells.

The one thing that keeps LiPo from being more widely accepted is their inflexibility in their voltage. At 3.7 volts per cell, you can't get back to the 4.8 volts needed for the current 4-cell classes, and we can't realistically bump these classes up to 7.2 (or 7.4) volts and still have them be drivable.

For the current 6-cell (7.2 volt) classes, I think LiPo is already being accepted at most club races. But, when the LiPo manufacturers finally address the voltage issues and come up with lower voltage cells to allow flexibility, we'll be changing again.

I am definitely looking forward to LiPo, but it isn't really an option for me in 12th scale. So, until that time, it's Sub-C cells for me.
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Old 12-14-2007, 07:19 PM   #9
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Originally Posted by Anthony.L View Post
Lipo is not the holy grail. It's biggest limitation in my eyes is the 3.7v per cell. This makes it very hard to be adopted in 1/12, 4-cell racing in Japan, and 5 cell racing in Europe.
It wouldn't be if someone would make a cutoff for 1/12.What is so hard about knocking the voltage down from 7.4 to 4.8
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Old 12-14-2007, 07:38 PM   #10
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It wouldn't be if someone would make a cutoff for 1/12.What is so hard about knocking the voltage down from 7.4 to 4.8
wouldn't that place a lot of stress on the voltage regulator?
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Old 12-14-2007, 07:53 PM   #11
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Hand out regulators just like motors....... It could work.
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Old 12-14-2007, 08:04 PM   #12
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The sad thing is this is still listed as a hobby, that means it should require a little effort.

Brushless, Li-Po, what will you guys want next cruise control.

Racing SHOULD be about what happens in the pits as well as on the drivers stand.
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Old 12-14-2007, 08:14 PM   #13
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Default Other options available are full of LiFe

There are other options available. We can start using the 3.3V batteries that powertools and laptops use. Most of these batteries are LiFe based. The best best would be LiFePO4. A123system makes batteries with up to 60C Burst, but there cell form factor is quite large sized for r/c.

Other companies make batteries in the 18mm x 65mm size or know in the idustry as 18650's with 1100mah most common. The 3.7V LiPO 18650s are reaching 2200mah but can not handle over 5C discharge. 18650 cells are the same diameter as a A sized battery but longer. Two of these in series would be a suitable replacement in 1/18scale but would amount to being the same size as a 4-cell 2/3A in stick form. For 1:12 and larger I would want a different sized battery. I was thinking batteries the same diameter as sub-c but longer, 55mm so users would not be confused if there were NiMH or Life. Getting two of these cells into a 1:12 scale would not be a problem, getting four would be. It would be same volume in cells of as a 5-Cell NIMH pack. Yes I know that 6-cells used to be in 1:12. In Sedan and Oval they would run a 2p2s battery pack.

Just to put this in perspective, running a 6.6V pack would be close to the new Euro standards as 5-cell. It would mean maybe speeds in 1/12 picking up but not as much as running a 7.2V pack.
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Old 12-14-2007, 08:20 PM   #14
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Quote:
Originally Posted by Juan Aveytia View Post
I don't think you have all your facts straight. Lipo's are far superior in every way. punch, power, runtime , amount of charges you get out of each pack. The list goes on and on. Who really cares what roar is saying. Why aren't you guys complaining about brushless anymore? Because, now everyone knows brushless is superior to brushed in nearly all aspects of r/c.
I may not but how much voltage can you get out of a lipo. If we are talking unlimited voltage then yes an 14.4 would smoke a 7.2

But a 7.4 will peak at 8.4 and a cheap stick pack will peak at 9.5.
I may not have all the facts but it seems to me sub-c is an advantage in that respect.
Now if we are talking unleash a 14.4 against a 7.2 yeah I will agree.
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Old 12-14-2007, 08:26 PM   #15
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I may not but how much voltage can you get out of a lipo. If we are talking unlimited voltage then yes an 14.4 would smoke a 7.2

But a 7.4 will peak at 8.4 and a cheap stick pack will peak at 9.5.
I may not have all the facts but it seems to me sub-c is an advantage in that respect.
Now if we are talking unleash a 14.4 against a 7.2 yeah I will agree.
Voltage peak under charge is irrelevant.

Cheap stick packs peak at 9.5 (I have some that peak at 11.0) because they have high internal resistance. That internal resistance cause voltage under load to drop very low, like 6.5 V at 17A for my packs. An equivalent (physical) size Lipo will hold 7.4 or higher easily under than same load.
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