4s vs 5s and gearing

[tc3_racer_001]

any way tat you could run a slightly bigger spur?

hv is only good when your aiming for the same speed. a 6s which goes 35-30mph will be much more efficient than a 3s which does the same speed... id suggest trying without brakes, adding a smaller pinion and go from there... easier and much cheaper than putting more money down for a motor which may not be warrented (if you do change the motor, your 4s pack will be slower, whereas if you keep the same motor its as easy as changing out the pinion beofer your next race!!

this make sense?

[lutach]

Higher voltage = lower AMPs used to get the same power of a lower voltage set up. Lets say your properly geared vehicle is making 1200watts peaks with 3S then the system is peaking at around 108A+- a few. Now on 6S your system will peak at 54A+-. Now we all know a lot of system will peak much higher, but the average A will be lower with the 6S then with the 3S (In my case it is ). I still haven't run my 1521/1.5Y with 10S in my BPP truggy as I'm having some fun with the 1521/1Y with 6S, plus I'm still testing how good the Kong Power 5000mAh 3S packs are.

Originally Posted by tc3_racer_001

any way tat you could run a slightly bigger spur?

hv is only good when your aiming for the same speed. a 6s which goes 35-30mph will be much more efficient than a 3s which does the same speed... id suggest trying without brakes, adding a smaller pinion and go from there... easier and much cheaper than putting more money down for a motor which may not be warrented (if you do change the motor, your 4s pack will be slower, whereas if you keep the same motor its as easy as changing out the pinion beofer your next race!!

this make sense?

Yes it's a good idea, but i real want to keep the mechanical brake. I don't want to brake with the controller, because i want to remove more stress of possible on the controller (and you know like me that MGM controller seem to be very fragile) and more, use the controller to brake pull lots of curent of the batterie, and cut on the runtime.

But, if i've not choice, i'll remove brake and use motor to brake, and use smaller pinion to run on 6s.

But a last question, if i use 6s but i'am geared to keep the same top speed than my 4s setup, is the 6s will be more powerful, with harder acceleration???

[othello]

I think it is a good idea to keep mechanical brake with the MGM ESC. My buddy uses the brakes of his MGM ESC, but experiences braking problems in his MBX5T.

>use the controller to brake pull lots of curent of the batterie, and cut on the runtime

Actually, braking with the ESC regenerates energy back to your battery pack, thus runtime will be longer. During braking with the ESC current flows back to the battery and therefore you see some amp spikes resulting in a rising voltage (can be compared to charging your battery pack). This puts additional stress to your ESC and it will run hotter.

I would not recommend running your Neu 1515/1Y (2200kv) with 6s. RPMs could exceed 50000rpm. 5s is more then enough and would give you around 40000rpm. This seems way more reasonable and as i already posted does work in a MBX5T and gives you very good acceleration and top speed (with a good battery).

With a good battery 5s could definitively give you better acceleration (if you have enough grip). Let's assume your actual 4s flightpower pack is able to pump out 150A@3,5V x4s = 2100 Watt. The same 5s battery pack would be able to generate 150@3,5V x5s = 2625 Watt. More Power means you could gear it for higher speed and you won't accelerate any slower as you have more power at your fingertip. On the other hand if you use more power, runtime will come down and your components will run hotter.

If you want to benefit from higher voltage (and thus using less amps) you have to gear accordingly. Meaning: If you switch from 4s to 5s, you have 25% more voltage (theoretically 25% more motor rpm), therefore you have to change gearing by almost 25% (for example from 1:14 with 4s to 1:17,5 with 5s). The car will have about the same speed. Amps will drop, as will temperature of your components. Thus leaving more room to gear it for more top speed (if you want to).