Super Capacitor Accumulator for Racing Gocart
I am on an engineering team working on an electric go-cart for the E-Velocity competition. We are trying to figure out how it would be possible to build a super capacitor accumulator to give us an advantage.
The theory is that because the competition is limited to 2kw of battery draw that when we are not using the throttle (eg cornering/breaking) we would be able to store the energy in a super capacitor in order to use it later as a 'boost'.
Any help is appreciated as this is a problem of implementation.
8 Replies
The competition has max voltage of 60V fully charged so I was looking at capacitors like the 63V 15F capacitor here:
https://a.aliexpress.com/_m03RRG9
Quick calculation says that from a voltage of 60V down to 40V there is 15000J of energy and that if we wanted a 2kw boost, for a total of 4kw of power (super cap + battery), it would give us 2kw for 7.5 seconds for each capacitor.
The biggest issue we have at the moment is how to limit the current into the capacitor from the battery so we can stay within the 2kw battery draw limit, resistors seem like a waste of energy. I was thinking something like a high power MOSFET with closed loop control using a current and voltage sensor. Not sure if that is a sound/efficient/safe idea.
PWM with inductor in series and diode snubber.
I apologise for the novice reply but I don't really know anything about inductors. Ive only ever seen them in 'low power' electronics. I assume you mean something like this https://www.coilcraft.com/en-us/products/power/shielded-inductors/high-current-flat-wire/agp-ver/agm2222/ but I would need help figuring out what spec we would need.
On another note, what does the inductor do? Does it just smooth out current spikes?
If it's needed to drop the voltage that may not be needed because we will have a 60V battery and the capacitors I've found are rated for 63V
Again, apologies for the novice question it's a very new field for me.
I will not teach electrical engineering by discord.
Capacitors impede voltage changes, while inductors impede current changes.
Internet searches for "current limiting" or "constant current",
along with "inductor" and "PWM" yield plenty of matches.
Im not the most smart with electrical, anyways to increase power would be good.
But honestly for those competitions its the mechanical aspects that will get you the win
Lightweight carbon fiber rims, tall not wide tires. Lightweight frame, aluminum everything. Skinny driver
Get someone to tig you a aluminum frame
It will be worth it
And a short gear ratio, you dont need anything above 30mph i dont think.
Ceramic bearings
And an experienced driver
We weren't sure how difficult aluminium is to weld and out teachers keep telling us it's very difficult. We also have a lot of steel square tube laying around witch is a convenient shape aswell.
As for wheels we don't really know what other options there are other than gocart tires, we really want to have small (diameter) tires to keep us lower to the ground but as I understand it the width of the tire will increase rolling resistance. Just need to find some thinner tires.
Tig is one of there harder things to do yes
We are looking into aluminium, we are organising for a real welder to come and teach us.
No offence to our teachers
Carbon fiber rims? Like wheels?
That's likely, the highest speed we have reaches so far this year is 42kmph(<30mph)