Please help a lost nitro guy convert to BL!!

[jhautz]

Originally Posted by bluonyx

I have a questions for people runnning 5S or 6S lipos? Do you take into account the weight or just go for a more efficient system?

All I do is bash, 3' to 7' high jumps most of the time. Do you 6S guys do that? Just wondering.

45min to 1hr runtimes are a must, so far I found 4S 8000mah's do really well for my needs.

You can get the same run time on lower mah packs when you go up in voltage. You use a lower kv motor so the system put out the same amount of power over all, but more of it is generated with volts rather than amps.

Heres how I figure relative run time for 4s to 5s to 6s... Multiply the nominal voltage by the mah of the pack and that gives you a total potential energy for the pack. A 4s system with a proper motor and gearing with a total potential energy number similar to a properly set up 5s or 6s system using a battery with a similar total potentail energy should give you similar run times and the pack weight really should be close to the same as well.

4s 8000mah= 14.8V * 8Ah = 118.4 Watt Hours
5s 6000mah= 18.5 * 6Ah = 111 Watt Hours
6s 5000mah= 22.2 * 5Ah = 111 Watt Hours

The difference is rather than running the same motor and spinning it faster you should be choosing a lower kv motor for the higher voltage and spinning it about the same total rpm (or manybe even a little less since the higher voltage with provide higher torque that would allow you to gear up a bit) so you can creat about the same averall speed and run time. The diference is you are creating more of the power with voltage rather than amps.

remeber V * A = Watts (power)

Not sure if I did a great job of explaining this, but I think you will understand what I'm talking about.