Runtime.....question using 4s?

[SpEEdyBL]

My 8ight/Tekin 1900 gets 28 min on a 4s 5000 mAh pack on an indoor clay track. During a 15 minute main w/ practice laps, i used a 4000 mAh pack which took back less than 3000 mAh after the main.

With the same setup on a large outdoor dirt track, i get 19 minutes of runtime with a 4s 5000 mAh pack. During two 30 minute mains w/ one battery change the 5000 mAh packs took a combined 6200 mAh each time with 1st and 2nd place finishes.

Your motor choice will really make a difference. Before I ever raced I used to run the 2650 and it would drain batteries in 2/3 the time just doing practice laps.

[Rampokker]

I don't think you'll make 20 mins on that setup. I'm running the same setup with turnigy 4s 5000mah batts and get around 16 mins. I also don't think the extra 800mah from the 5800 batts are going to make enough of an improvement. You may have to look at a lower kv motor. Have a look at how much mah the batt takes after a 10 min race, and then you'll be able to work out how much more mah you need to get 20min.