Want to make 20 minutes with truggy..

[BrianG]

Just using a low kv doesn't necessarily mean an efficient setup if you gear high to compensate for low rpm. Also, efficiency does play a role in runtime amounts, but won't get you an extra 8 minutes to reach your 20 minute goal.

In your current setup, you say you get 12 minutes on 4s 5Ah. That equates to 25A average draw and 370w average power. Of course bursts will be higher, but that's average.

To get 20 minutes without changing your gearing/speed, you would need to run 6s on a 1300kv motor using 5700mAh cells. Adding in a little extra capacity to make up for the greater battery weight, I would go with 5800mAh. That seems a bit much for just 20 minutes in a truggy. Without looking at the vehicle speed, I would suggest gearing down if you can afford a little loss in top speed. Also, change ESC settings to tame those runtime-robbing huge current bursts: high punch control, low timing, etc.

[Kcaz25]

Originally Posted by BrianG

Just using a low kv doesn't necessarily mean an efficient setup if you gear high to compensate for low rpm. Also, efficiency does play a role in runtime amounts, but won't get you an extra 8 minutes to reach your 20 minute goal.

In your current setup, you say you get 12 minutes on 4s 5Ah. That equates to 25A average draw and 370w average power. Of course bursts will be higher, but that's average.

To get 20 minutes without changing your gearing/speed, you would need to run 6s on a 1300kv motor using 5700mAh cells. Adding in a little extra capacity to make up for the greater battery weight, I would go with 5800mAh. That seems a bit much for just 20 minutes in a truggy. Without looking at the vehicle speed, I would suggest gearing down if you can afford a little loss in top speed. Also, change ESC settings to tame those runtime-robbing huge current bursts: high punch control, low timing, etc.

Beautifully articulated sir! Good ole' math!

[nuz69]

Higer voltage, lower kV ===> better efficiency, 6S and 1300kV !

[malcster]

Think I am starting to understand this now
http://forum.teamtekin.com/phpbb3/vi...hp?f=38&t=2411
this chart is great and shows average power used which Brian worked out before so I can see that I use a bit more than the average of 330 on chart on 4x cell and can see by chart how much more efficient 5 and 6 cell are and that with a few tweeks to me and ecu I need about 4200mah for 6 cell using there average..so a Turnagy 5000mah 6 cell would be fine and 5800 mah for 5x cell so a Hyperion 6500mah 5cell would also be fine..if my maths is correct..correct me if I am wrong... so have answered some of my questions..still dont know if I will go 5 or 6 cell though

[malcster]

I have settled on the 6 cell/1350 Tekin set up as want to try a sensored system and will get some 5000 Turnigys from Hobbyking and with a few changes to ecu and me should get my 20 minutes.