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Old 06-13-2009, 03:31 AM   #1
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Default Lipo's in 17.5 class

With so many different brands sizes etc of lipo's I thought Id ask everyone for some indepth advice too help me too decide which ones too buy.

Is a bigger c rating better/or usable in stock class (17.5).
Or is a bigger mah better?

Which brands are better and which ones do i steer clear from?

eg: 5000 20c and 5000 40c is there a noticable difference in said 2 batteries if same brand etc?? in stock class (17.5)

Cheers in advance
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Old 06-13-2009, 04:37 AM   #2
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I have been using the Intellect 5000mah 30C packs and they are great, and the new 40C version is looking the goods as well.

The bigger capacity is definitely good as it is able to maintain a higher voltage across the run, as voltage curve does not drop off as quick as with a smaller capacity pack.
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Old 06-13-2009, 07:01 AM   #3
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I have been using the Intellect 5000mah 30C packs and they are great, and the new 40C version is looking the goods as well.

The bigger capacity is definitely good as it is able to maintain a higher voltage across the run, as voltage curve does not drop off as quick as with a smaller capacity pack.
5000 and 40c is noticeably better than any other configuration I have used. Although I don't think the 17.5 can draw 40c, I am told that they have a higher nominal voltage over a lower c rating which gives you more punch.
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Old 06-13-2009, 07:46 AM   #4
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Ive been using the ThunderPower 5000 40c and it works great!
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Old 06-13-2009, 07:04 PM   #5
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Ok so has anyone actually been using say a 20c then upgraded to a 40c and noticed any difference too speed or lap times etc? (same mah) in 17.5 class

does it increase heat levels in the motor etc?
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Old 06-13-2009, 07:25 PM   #6
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Ok so has anyone actually been using say a 20c then upgraded to a 40c and noticed any difference too speed or lap times etc? (same mah) in 17.5 class

does it increase heat levels in the motor etc?
they say you cant tell in a stocker you cant tell a difference in speeds and power. I ran a trakpower 4900 25c and it sucked. no power at all. ran a orion 3800 30c and it had a ton more power and was faster and jumped better. in the end go with the higher c-rating because you may need it in the future and it will make a significant difference on the track. also it was a lower mah. 40c all the way
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Old 06-13-2009, 07:38 PM   #7
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Well I am going to say the opposite but only because its been my own experience so far...

I have an Intellect 4200 30C and a couple of Harris RC 3200 20C and for punch with a 17.5 I would run the 20C packs any day over the 30C Intellect pack...

Whether that's a reflection of the performance level of the Intellect pack or the freaky power of the Harris packs, I cannot say but I am not the only one in the club I recently raced at that has had a similar experience
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Old 06-13-2009, 07:48 PM   #8
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In 17.5 I use a 24C SMC, 13.5+ I run 40C. I can't tell much difference in performance between the 24 and 40C's in 17.5 racing. In fact I get a little quicker midrun on with the 24C heating up a little, the 40C stays cooler so it stays the same voltage, a flatter curve. The 24C seemed to go up a little in punch as the pack heats up during the run due to the 17.5 pushing the LiPo's discharge rating. And as everyone knows the more heat a LiPo has the less IR thus more punch.
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Old 06-13-2009, 07:51 PM   #9
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But, some professional racers say their cars are faster with the lower c-rating packs and some say the opposite, the weight of the packs can be a factor or the packs might not have the true c-rating. Like some say you cant tell the difference in c-rating of batteries.
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Old 06-13-2009, 09:03 PM   #10
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I use a 25c 2s 4800 Saddle pack lipo in our VTA Class with a 21.5 Bl and im just as fast as someone that has a higher C-Rateing. the speed/Lap times are all based on driving skills and setup/gearing
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Old 06-14-2009, 12:44 PM   #11
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well if anyone has seen the new Xtreme RC CAr mag for this month they have a very good article about lipos, and the tested a 17.5 brushless with three different C lipo with the same mah and the 20C had a 16.76mph while the 40C had a top speed of 18.28mph. So there is a difference and a 6.5T had a difference of 5 mph. I hope this helps some
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Old 06-14-2009, 02:17 PM   #12
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take the maximum amp draw that you get from your setup and add ten amps for overhead. that will give the discharge rate you want to look for. then look for a high capacity.
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Old 06-14-2009, 02:24 PM   #13
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well if anyone has seen the new Xtreme RC CAr mag for this month they have a very good article about lipos, and the tested a 17.5 brushless with three different C lipo with the same mah and the 20C had a 16.76mph while the 40C had a top speed of 18.28mph. So there is a difference and a 6.5T had a difference of 5 mph. I hope this helps some
I don't see how the C rating effects top speed. C rating is a discharge current. For higher top speed the voltage has to be increased. The only thing I can see the C rating effecting is acceleration. But I might be wrong.
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Old 06-14-2009, 03:30 PM   #14
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C rating effects everything. Electric motor's take all the power they need. So if a 5000 mah 20C only provides 100 amps and a 5000 mah 40C provides 200 amps. And if your motor can take 150 amps then the 20C is simply not enough to get the most out of your motor. Plus the more amps you battery can put out the less voltage drop it will have. Correct me if im wrong anyone
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Old 06-14-2009, 05:37 PM   #15
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Also, take into account the voltage drop along a run of wire and what resistance the connectors (if any) have.
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