[Duncan]

Hi
The basic choices are
DC - can be cheap and cheerful - and lots of power
New AC - expensive and a bit wimpy
Re-purposed AC motors - I don't think I have seen anybody manage this
Motors from an EV - probably the cheapest and most power

For a Midget I would either use a Series DC - brushes and no re-gen - but you can probably ditch the gearbox as well

Or try and fit a Leaf motor - I would try and get a whole crashed Leaf and use as much as you can

 

[Duncan]

Hi
That midget is far too nice to put that ebay motor in - not enough power not enough volts, I predict that it will be a slug

A Midget is not a sophisticated car! - it will be better with a DC motor and a decent bit of power

http://www.diyelectriccar.com/forum...dubious-device-44370p15.html?highlight=duncan

My forklift motor cost $100 - the controller was $600 and it was enough to remove the need for a gearbox so that the motor went were the gearbox would have gone and freed up the entire "engine bay" for batteries

I used a Chevy Volt battery - much much cheaper and better than using Chinese cells

 

[Duncan]

Hi
There is a thread on using forklift motors - worth a read

Basically there are two useful sizes - 9 inch in diameter and about 60 kg - and 11 inch - 100 kg
My motor in the forklift was 48 v and 200 amps - at that it would last forever

I started feeding it 144 v and 500 amps - that was good!
In something like Midget that would be able to break the rear tires loose and would give a top speed of about 80 mph

In my car with 55% of the weight on the rear wheels I have gone up to 1200 amps and 340 v
That is scary! - I drive at 45% current on the road - 540 amps

I would suggest
a 9 or 11 inch motor
The Paul & Sabrina Controller - $600 as a kit
Chevy volt battery - $2000

This will give you enough oomph to give anything else on the road a fright

 

[Duncan]

Hi
Try and fit the motor a lot further back - ideally where the gearbox normally lives
For weight distribution and for battery space
Batteries are bulky and you really want them as low as possible - in my car the whole "engine bay" is for batteries and I could not fit my whole Volt pack - I fitted 6 off 2Kwh modules and 2 off 1Kwh modules but the remaining 2Kwh module is sitting in my workshop

Forklift motors - you need to go to the forklift repair place with cash in hand - they keep motors "Just in case" then scrap them off - normally the day before you visit

I'm using the Paul & Sabrina - 350 V 1400 amp controller - I have a Beta version

 

[Duncan]

Hi
That is rated power - it is usual to slightly exceed those numbers in the search for automotive excellence

My 11 inch Hitachi is "rated" at 48 v and 208 amps
So I feed it 1200 amps and 340 v - it hasn't melted (Yet)

 

[Duncan]

Try your friendly local Forklift repair or motor re-wind shop
And go in person with folding money

You want to rob their "just in case" pile before they send them to the scrap metal guy

I have had zero success talking to them on the phone - but dropping in seems to work

 

[Duncan]

Talk to the guy you are getting these from
see if he still has the T shaped base plate

If you drill the spot welds off you get these nifty mounting plates

The ears on the cells go into one side and then a clamp plate goes down on the near side

These two were made with a bit of cutting and welding to make two to hold my two batteries in place

I'm pretty sure that the bottom plate and the clamp plates will just be thrown away

There are a LOT of spot welds - but IMHO it's well worth it

 

[Duncan]

I'm using the water cooling
I used three 48v modules and 1 24v module stacked together in a line and then another of the same way

I put the whole thing on end and used a hose to get it full of water and get the air out

 

[Duncan]

Hi
It's the Paul & Sabrina high power controller

My understanding (which could be wrong) is that one of the problems with using several IBGT's is getting them to share the current nicely
Paul's ingenious solution is to have each one with a length of cable of it's own before the three join together - this gives a small resistance and a small voltage - enough to balance the three IBGT's

On that point
What current are you using? - I have mine set to 1200 amps

 

[Duncan]

Hi
I have some switches on my dashboard
They put resistors in parallel with my throttle pot

For road use I drop to a maximum (full throttle) of about 45% - which is fine for the road

On some of the grass events I drop to 20% - and I'm still not pushing the pedal all the way down

100% is for the track

 

[Duncan]

Thinking about it with a midget back end you may want to change the software and drop that 1000 amps down a bit

I'm not sure that you ever want to put that much torque into that axle and suspension! Although tyre spin may drop the loads down to those the axle can live with