2S vs 3S run times?

also you have to remember that the 3100mah 3s battery has 34.41 watt/hours of power and the 2s 4200 has only 31.08.

which to me means if you were to gear down so that the top speed was the same with the 3s pack and you were not running the motor at too high an rpm as to the extent of not effecting the efficiency of the motor significantly then i suggest that you would get an increase in runtime with the 3s pack.

[GO-RIDE.com]

Originally Posted by chilledoutuk

also you have to remember that the 3100mah 3s battery has 34.41 watt/hours of power and the 2s 4200 has only 31.08.

which to me means if you were to gear down so that the top speed was the same with the 3s pack and you were not running the motor at too high an rpm as to the extent of not effecting the efficiency of the motor significantly then i suggest that you would get an increase in runtime with the 3s pack.

This is what I was wondering. Essentially, the 3100mah x 11.1 volt battery does store a slight bit more energy (123,876 joules) vs the 4200mah x 7.4 volt (111,888 joules).

So, if you took two equally efficient "S" can motors that had the appropriate KV rating to top out at around 35,000 rpm (4730kv = 2S and 3153kv = 3S), and the same pinion then you should have very similar run times between the two systems?

I'm then guessing that if you choose to go for more punch and use an "L" can motor with a larger pinion on the 3S system you will start to see reduced run times?

[lincpimp]

Load will be the important variable in going from a S can to a L can. If you can gain effecientcy by using the higher torque of the L can you would see a difference between the two. If you vehicle is only going to load the motor to a specific output, finding a motor that can produce that amount with the highest effecientcy will be the only method of increasing runtime.

From personal experience, the higher voltage systems appear to produce more power when under heavy loads. This is most likely from the battery being able to cope with the power needs better due to less amp draw with higher voltage. Voltage does sag under load, and a lower voltage battery will require a large capacity to be able to produce the necessary power and hold the voltage level.

Vehicle weight and application will determine the best motor choice, however a cheaply made motor will continue to heat up during use and lose effecientcy during that time. Plus a higher end motor will produce more power and torque.

You will find that a higher kv motor such as the feigao s can will heat up faster on lower voltage than a lower kv motor on higher voltage. If geared for the same top speed and both motors running at the same rpm the higher voltage system will react better. I say this with the current battery technology, as even the best batteries operate better at lower current draws.

In order to maintain the same weight the number of cells must be balanced with the weight of each cell. This usually leads to the use of lighter, lower capacity cells to make up the higher voltage pack while retaining the same weight.

The main concern I see with Brushless is heat. And higher voltages just seem to produce less heat.