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Old 06-21-2008, 12:24 AM   #1
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I was wondering about some setups for this 27turn class that has no weight restrictions. Lipos are not allowed for some odd reason. I have some batteries that I can choose from.

1. 4200mah that has about 8.5V at full charge. weight of 450g
2. 2400mah with avg volts of 8.30 at full charge. weight of 300g

The 150gram weight savings from the 2400 seems big, but are there any other factors that I should consider? the race is 7min long.
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Old 06-21-2008, 09:19 AM   #2
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Originally Posted by redbones View Post
I was wondering about some setups for this 27turn class that has no weight restrictions. Lipos are not allowed for some odd reason. I have some batteries that I can choose from.

1. 4200mah that has about 8.5V at full charge. weight of 450g
2. 2400mah with avg volts of 8.30 at full charge. weight of 300g

The 150gram weight savings from the 2400 seems big, but are there any other factors that I should consider? the race is 7min long.
Well, the 2400 may or may not make it through that race. If you gear conservativly, sure. But IMO, i would run the 4200.

Perhaps there is an optimal setup that could take advantage of the 150g less weight, but it might not make it through the race.

my 2 cents...

Cheers!
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Old 06-21-2008, 09:36 AM   #3
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Test and find out!

150g is a significant weight saving (10% on a typical tourer), but the 2400s will have less voltage under load than the 4200s (charge voltage is irrelevant, it is the voltage under load that matters, and the latest race NiMHs are all a lot better than the 2400 NiCds in that respect).

Also the lighter cells will affect the cars weight distribution and handling, although it may be faster it may handle less well.

Could go either way basically.
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Old 06-21-2008, 11:48 AM   #4
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thanks for the input guys

I tested the car outside my house, and the car is more punchy with the 4200s(duh). But the car is much more nimble with the 2400nimh. Not sure if anyone tested, but is there an optimal weight for TC for the type of tires we use(asphalt with sorex36)? If it is too light, there won't be enough weight to maximize the contact patch. Maybe a 3000mah batt is better for overall balance(weight, power, runtime). BTW, the car weighs 1380g race ready using the 2400s.
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Old 06-21-2008, 12:04 PM   #5
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I tried something similair to this in last years tamiya series.

Rules=1500g min

With 4500mah packs my car weight aprox 1560g. With 2400 nicads I had to add about 80g of lead to just over 1500g.

The car handled a little better but accelleration was noticably less. Speed difference was most at th start of the runa nd towards the end I started catching people up again but it wasnot enough to be an advantage.

If I had not had to put the weight on it might have been an advantage but I think probably not because you would still have to overtake people later int he race.
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Old 06-22-2008, 12:59 PM   #6
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If the rules are fairly laxed, go 5 or 4 cell with some good 4600's. Your top speed will be a little lower, but your out of the corner rip will be better.

The new 4600's weigh like 75g a piece.
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