gholt13

iTrader: (8)

looking for a battery that will go for 20 min in race conditions in a rc8 with mamba 2200kv?

RMDesigns

iTrader: (7)

I can get that with my Reedy 5000mah 40c 4 cell.

lusifur

We run Thunder Power 3S 22C 8000mah batteries on the 2650 in 1/8 buggies and get over 30 minutes every run. A really, really aggressive driver would probably get 25+ minutes.

Cain

iTrader: (294)

Look for a 4S pack in the 6000mah range. The PolyRC 6000mah 4S pack should do it, or, you could do the Maxamps 6500mah pack, though, its more pricey.

scwrod

iTrader: (2)

You have to take more than battery capacity in account when trying to achieve a target runtime.
Gearing, ESC programing, Motor, throttle finger, Track size and conditions, etc.

I think you will find that as 1/8 electric develops into its own class the racetimes will be adjusted to suit the average batteries. This past weekend we had our first official 1/8 Electric class and it was great
Running with nitros has forced us to spend more money trying to make the long nitro mains.
I did see a 1/8 e- buggy finish a 45 nitro main w/ 2 batt swaps and actually place well.

kufman

iTrader: (6)

You are going to need 6000+ to make 20 minutes. Figure that you can drain about 80% of the labeled capacity from the battery. So if you have a 5000 you can use about 4000. I have run two different 2000kV motors (Meadusa 36-60-2000 and the Tekin 2050) on 4S and both have taken around 250 mAh/min. So 20 minutes would take at the very least 5000 mAh. Divide that by 0.8 and the total battery would have to be 6250.

R40Victim

iTrader: (1)

scwrod is right, you need to consider more than just capacity. I can run for 23 minutes on my rhino 4900 mah 4S 20C pack.(and I only spent $60 on it, not the $250-$300 that I'd have to spend to get a pack sold in the states) But I run on a tight, technical track. Many people run on larger, higher speed tracks, and use more energy. Also, when I let a buddy of mine drive my car setup the same way on the same track, his run time was closer to 15 minutes. He burned up an additional 8 minutes of run time because he can't stop blipping the throttle like a nitro. There's other things like that too. It only takes about 1/2 throttle to go full speed down the highest speed section of our track. I "could" floor it, but that wastes energy. Keep that in mind, because you may be able to save yourself ALLOT of money, and weight.

Edumakated

iTrader: (19)

Very track and driving style dependent but the only solid 20 minute main setups I have seen in a buggy are:

4s 6000 with a 1700-2050 motor
5s 5000 with a 1550-1700 motor (done it personally with this setup)
6s 3750 with a 1350-1550 motor

There is a big difference between racing a 20 minute main and just practicing on a track for around 20 minutes.

For a truggy, you will likely need to up the mah above by 1000 to make it as truggies burn way more juice than buggies.

Be careful, a lot of folks will claim 20 minute runtimes with dubious setups, but have never actually raced a 20 minute main.

b4maz

iTrader: (8)

I can get 20 min on a CC 2650 with a Thunder Power 4s 5000 mah 40c pack geared 14/50 in my RC8Be.

jmcvicker

iTrader: (2)

How much do you put back in after a 20 minute race - is it about 4000 mAh?

I think I can do about 13 minutes safely on a 3S 5000 Zippy 30C with a 2650kv on a larger track.

If the longest you ever run is 20 minutes, the 4S 6000 mAh idea is sounding the best but since 5000mAh are much more available from various vendors - that may work out too if the track doesn't suck the amps too much.

When in doubt, try it out. Try to borrow someone's 4S and see how it does for 10 minutes and extrapolate (ok, just double it) to 20 minutes and see if it would be right for you. You could also experiment with buying the lower-priced Turnigy packs from Hobbycity.com - you can just about buy a basic Turnigy 25C 4S 5000mAh for $50 or so and give it a shot. You'd probably want to race with a 30C or 35C battery.

b4maz

iTrader: (8)

Yea, I put back around 4100 mah.

gholt13

iTrader: (8)

i have the flightmax 5000mah 25c 4s and the best i can get is 16 min babying it mmm and 2200 geared 16 46 any suggestions .

jmcvicker

iTrader: (2)

The thing is, the 2200KV is a higher wattage motor than Castle's 2650 - so it will eat a little more power (but yeah, 2650 is also a battery hog). But only 16 minutes when others get more - could be gearing or track size. Have you run it with 1 less tooth pinion? Did you turn down any of your throttle EPA? Is it a big track?

Longer runtimes are easier with a lower KV buggy-specific motor. Such as the Tekin 1900KV buggy or a Neu 1512 1.5Y or 3D. If you go 1700KV, a 5S LiPo would work out leading to almost 25+ minutes of race-time possibly. To keep using 4S, and if you are turning down your EPA to baby it, you may want to jump to the 1900KV buggy motor.