Quote:
Originally Posted by johnrobholmes
How many people do you know that would buy an HV car controller and use it? How many people actually have 12s setups or even the motor to use it? How about a vehicle big enough? The only production vehicle is the 5b.
His point is that there might be 100 people tops that would actually use it to its potential right now. That isn't enough to develop a new controller. If I made ESCs I wouldn't spend the time on a HV car controller yet, the market isn't there.
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Everyone already running 4s2p setups already has the car/truck to do it. The only reason to keep low voltage setups is to be able to use NIMH. More serious BL users move quickly away from NIMH anyway, so it doesn't matter.
What is missing is people's understanding of electrical power.
P=V*A
You can get power thru lots of amps (as in LV setups) or thru more voltage. Motor efficiency increases w/ voltage, and less amps also means less resistive losses. The motors are the same, just diff winds.
The net result is a better setup w/ HV. Less loss of power, less waste heat, and more TQ.
EX: my 5S2P A123 setup w/ MM/8XL
117A @ 14V=1628W peak
Now same pack, rewired as 10S1P:
45A @ 29V= 1305W (notice the lower V sag as well)
Yes it is less power, but due to efficency gains its
more power to the wheels. Its a bit unfair as the Hv motor is a Neu, but still.
8XL: 70-75% eff
Neu 1515/2Y (1100 kv): 94-95%
Lets just say 70% & 95%: (1305W*.95)/.7=
1770W
That would be the equiv power on the low-eff system. What you can also do is run cheaper XL motors and enjoy a reasonable level of eff and cool running on HV. Instead of a 8XL on 4S, run ~14-16XL on 10-12S. Instead of a 4S2P 8K batt, run a 10s-12S 2100 batt.
In the end the costs and weights are close (HV has an edge if done right) and you have longer runtimes as you are not wasting so much power. This is why all the planes and helis go HV for larger scale/higher power apps. There is a point of diminishing returns, but I don't think it is @ 6S.