Electric car conversion: Project ForkenSwift

[MetroMPG]

No rack progress to report (that'll be wrapped up this weekend), but I keep risking getting busted by driving the car around.

I used it 2x this week - which basically means it was raining when I needed to get somewhere. I bet if I checked, there would be something like 75 additional km on the odo since we pulled the ICE.

[MetroMPG]

Got the rear rack done, secured, and full of batteries:



Did a few other minor repairs that are on the list of things needing to be done before I bring the car by my mechanic to get his "it's an electric car" inspection letter.

This week will work on getting the batt cables shortened/routed/tidied up.

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I'm so going to get busted if I don't get it legal soon...



I checked, and the car's got over 100 electric kms on it already.

[MetroMPG]

Bruce chimes in late...

Did you keep the tranny or what did you do for power transmission between the engine and the wheels?

I'd be OK with a reference to an earlier post #.

No prob.

Kept the stock tranny... we need it, since our setup doesn't have much power - 225A max when the golf cart controller is cold; less as it heats up (which is fairly quickly). I've been driving in 1st & 2nd gears, upshifting around 3000-4000 RPM.

Technically, the closest car to the old ForkenSwift is the old CitiCar/ComutaCar:



Same voltage (48) & number of floodies (8).

These cars are direct drive through the differential, but it also has much more oomph because it's got a straight contactor controller (in stock form), so with your foot on the floor, there's a direct connection from the batts to the motor @ 48v. These cars apparently go 40-45 mph, and can drive in normal traffic. Though they are also 500 lbs lighter (1400 vs 1900 est.)

The FS can't do that. I have to stick to side streets because it just can't accelerate at a "normal" rate, even with shifting.

To solve this, ultimately we'll put in either a more powerful controller, or a contactor bypass. Even with more power on tap, to maximize range I'll still accelerate like a granny on valium when nobody's around me though. And I'll still shift, because it's more efficient (I think - could be wrong).

[MetroMPG]

Well, the car isn't moving any more until I get to work on the cabling tidy-up & connector-making. I cut one of the battery cables this evening to plan my approach - and I don't have any extras.

[MetroMPG]

Re: shifting...

It's just GOTTA be more efficient, huh? But I don't have any ideas what revs you would be shooting for...

I've read in several EVDL threads that around 3000 rpm is a good target for e-motor max efficiency. But the only way to know for sure is to test it. Fortunately, it's not too hard to do.

[MetroMPG]

Futzed around some with the DIY cable lug idea I had, which was this:

1. get some copper tubing with a slightly larger diameter than the 4/0 cabling.
2. cut about a 5 cm length of tubing
3. hammer one end flat, creating a "blank" cable lug
4. in a vice, heat the open end with a torch, and fill it half way with solder
5. insert cut end of cable into molten solder
6. after cooling, drill hole in the flat end (for the battery connection - the floodies have threaded terminals)
7. tin the flat end with solder for oxidation protection

... and voila, cable connection on the cheap.

Unfortunately it didn't work out that way. The main problem being the fine stranded cable seemed to prefer to wick up the solder very efficiently, rather than leaving enough in the tubing "receptacle". I tried it a few times and dissected the results with a cutoff wheel - wasn't really happy with the way the inside of the connector looked. Not enough solder filling the gap between the cable and the tubing.

I may try again (lots of variables to play with - preheating the cable or not, how much flux to use or not, how much solder to melt into the open end before adding the cable, etc.).

Otherwise, I'll call up the forklift place and find out how much their lugs are, and how much to get them to crimp them on for us.

[MetroMPG]

One of my first thoughts was to bend up a bunch of copper tubing and make buss bars for the interconnects for the batts that are grouped close together. But the impression I get from the EVDL is that solid buss bars are failure prone / loose prone, and that steered me off that path.

[MetroMPG]

Suggestion:

Can you tin the cable before you put it into the lug? Might keep it from wicking up so much of the solder in the lug.

Great minds... I just came back from the garage and had tried just that. It seems to work better.

Not perfect, but I may be able to refine the process - I have to keep the heat from building in the cable or it just starts wicking the solder away again. Might be a multi-step process to let things cool down in between.

[MetroMPG]

I snuck out and made another couple of test lugs & connections with more judicious use of the heat as suggested.

Revised process:

- cut & trim cable
- flux & tin cable bottom 1 cm
- while cable cools, make lug: cut copper pipe, heat & flare open end, flatten the other end
- flux & fill open end of lug about half way up with molten solder
- briefly heat tinned cable end, add a bit more heat to lug & insert cable in molten solder

The solder that gets pushed up out of the lug when I insert the cable isn't making a good join (cold joint) up high around the "collar" of the lug, but I dissected my last attempt and it looks OK deeper in the lug.

But I'm waiting to hear back from the forklift place. Which way we'll go from here depends on how much money they want to sell us "proper" lugs (and if they'll lend us their crimper).

I'll post some pics of my lug attempts later.

[MetroMPG]

Heard back from the forklift place. $7 CAD per lug - yikes!

I found similar ones on evparts.com for $3.60 US each, however there's shipping and currency exchange on top of that.