Firefly Electric Conversion

[Stubby79]

Gave her a full brake service & check over this morning. Something I always do when I get a new-to-me car...but that's assuming they're working and don't have more important issues to resolve first.

De-glazed/de-rusted the front rotors and pads, lubed up the pins. Same idea on the rear, with the addition of checking the wheel cylinders weren't leaking.

The fronts appeared relatively recently re-done. Lots of meat on the pads, rotors were flat/not lipped, though it looked like the right side had been working harder than the left. The rears hadn't been off in forever. Lots of dust and rust. All better now.

I can now stop the car without the booster. Much better.

Previously, it took...a long distance - like 30-40 or even 50 feet to stop it from 30km/hr. Down-right dangerous. I can now make normal, forseen stops without much effort. If I stand/jump on the brake pedal, I can lock up the wheels - with their under-pressured tires- on wet pavement. There's the sensation of actual deceleration now...enough that when you are braking hard, it helps by throwing your own weight against the brake pedal.

I'll probably want more braking power if I am carrying any weight, but for now, I can jump ahead to some more realistic driving tests.

Oh, I forgot to mention...with the front end off the ground, I opted to wear in the brakes a bit. The motor had no problem, in first gear, overpowering the brakes (though I didn't stand on them).

But, more important to me was checking top speeds in first and second, unloaded. 35km/hr in 1st, and 65 in second. the difference from first to second is a rather large 1.8:1. Anyway, 65 means I can go about everywhere in town in 2nd gear. But first I need more torque, as even with working brakes, I didn't get much over 35 in 2nd gear. Thus field control is next and foremost on my list.

[Stubby79]

Holy gazillion electrical connections to make, Batman!

Was going to install the Kelly mini motor controller (was Mechman's) for field control, but it wasn't set up how I needed/expected...and low and behold, after screwing around for an hour to get the serial-to-usb cable working, the controller appears to need an adapter to communicate with it. My other Kelly controller (not part of this project) communicated fine. At least I verified that the little bugger worked at last. Wires, clips, and more wires to do that.

So I set about - and eventually finished - installing the LED panels for the brake lights and interior light. Not sure I'm content with how yellow the interior light is. But they're in and work; job done.

The wires come in while the glue way setting. Figured I should get around to properly installing the LiFePO4 auxiliary battery. This meant hooking up the BMS fully, not just for charging, and "waterproofing" it while I was at it. Wires, solder, wires. Which also mean putting a quick connect plug for my charger on it...and one on the charger too! Wires, solder, wires.

Oh and wiring together a flyback diode for the field coils...no more trying to weld battery terminals when disconnecting it.

While it is important to do it all right and not just slap it together any old way, it sure gets old after a while...

[Stubby79]

I have photos this time for the literacy-challenged!

Don't worry, I have a short attention span too.

I just went down to put the SLA temporary accessory battery on charge, and ended up spending a few hours getting the real battery installed properly instead.

Battery with PCB/BMS and shunt, finally ready to install in the Firefly:


In it's final resting place...hopefully. Maybe not those ugly straps though:


Shunt still accessible for meter hookup:


Meter goes in next, after xmas. Still need to decide where it will go. It fits well in several places!

Amazing how long one can spend on just one little battery...sticking with lead would have been much simpler.

[Stubby79]

I have photos this time for the literacy-challenged!

Don't worry, I have a short attention span too.

I just went down to put the SLA temporary accessory battery on charge, and ended up spending a few hours getting the real battery installed properly instead.

Battery with PCB/BMS and shunt, finally ready to install in the Firefly:


In it's final resting place...hopefully. Maybe not those ugly straps though:


Shunt still accessible for meter hookup:


Meter goes in next, after xmas. Still need to decide where it will go. It fits well in several places!

Amazing how long one can spend on just one little battery...sticking with lead would have been much simpler.

Edit: Just remembered why I spent as long as I did on it this morning...I started off getting the reverse lights back up and running again.

I pulled out the old harness, cut it open to follow the reverse switch wires, only to find they terminate at the main engine connector. So I Went and looked for matching wires at the main body harness by the battery, located them, tested them, and then cut off the three extra feet of wire from the connector and soldered them up. Dead easy. Pissed away more time cutting the old harness apart than it took to actually reinstall the plug.

Why they felt the need to run the wires all the way around the engine when they could have gone straight to the main harness, I'll never know...

[Daox]

Originally Posted by Stubby79

Why they felt the need to run the wires all the way around the engine when they could have gone straight to the main harness, I'll never know...

But they never give you the extra 2" when you really need it!

Awesome work btw, loving the thread.

[MetroMPG]

Originally Posted by Stubby79

I have photos this time for the literacy-challenged!

Music to my eyes!

PS: straps are very festive.

[Stubby79]

Originally Posted by MetroMPG

PS: straps are very festive.

Hadn't even clued in to the color theme! (These would be the only decorations I've put up this year)

[Stubby79]

I'm still pondering the second battery location. There are pros and cons wherever I look.

Currently the front of the car is ~100lbs heavier than it was before. The center of gravity of the weight in the front is only slightly ahead of the front wheels, which I am content with. It's also more off to the passenger side, so it should offset the weight of the driver, ending up with pretty good weight distribution...except for the particularly light back end at the moment.

I basically have 3 locations I can put the second battery pack:

1. Over the radiator support/right in front of the motor.
2. Where the gas tank was.
3. In the spare tire well.

Pros & Cons:
1. Rad support, Pros: All batteries in one location; short power cables; easy access. Cons: Weight even farther forwards; batteries blocking motor and taking up space where I might want to put add-ons.

2. Gas tank, Pros: Best weight distribution possible. Cons: Damned difficult to get at batteries, or else have to cut floor pan for easy access; Long power cables.

3. Spare tire well, Pros: Very easy access, perfect dimensions for pack. Cons: Very long power cables; weight is past rear wheels; batteries are now inside passenger cabin.

Then there's the added complication of the idea of carrying around the 6x 12-volt, 30amp-hour lead acid batteries I have as "backup" power and or as auxiliary power for the heater and such. They need roughly the same space as the second pack and weigh just as much. If I use them regularly, they'd probably be worth carrying. If not, they're just dead weight and taking up room.

So. If I wanted them in, I could put them in place of the gas tank, and the second/real battery pack over the rad support. They're less fussy, so I don't need to monitor them much compared to the LiFePO4s, so not being able to get at them is no real big deal. I still lose out on the useful space in front of the motor though. Which I'm not even sure if I'll put to use any other way.

Or the real pack goes in where the gas tank was, and the lead goes in to the spare tire well, where it can be easily removed if not being used. Same goes with the lead going in the rad support area. Weight too far forwards or too far back. At least they're removable there. That might be important. Or not if she performs well.

Maybe I need to experiment a whole lot more before settling on what I do or don't need. I'd be out doing it right now, but I'm stuck at the inlaws for xmas with nothing better to do than to over-think things.

I need to seriously figure out how to go about cutting the floor pan under the rear seat and making it work if I am going to go that route. I don't mind, really; that's why I started with a cheap/rough condition Firefly. I don't feel bad chopping it up to make things work.

Time to stare at EVMetro's photobucket for a while.

Nothing there to clue me in. Hmm. Maybe if I cut just the hump between the rear seats open, it would give me "easy" access without doing anything drastic...

[Stubby79]

Looking over my charts, the controller's continual output and what it takes my gas Firefly to make it up the hill on the highway, it looks like I'll need to run 100v/225a @ 5000rpm to do the same thing.

My EV power calculator concurs. I'd have to lose a bunch of weight and get the aero .cd way down to pull it off on 72V.

Good to know. Still need some real world tests to see if I can get more amps for the few minutes I would need them to climb said hill.

Merry xmas?

[Stubby79]

Happy flippin' 2017, fellow nutters!

It finally warmed up to freezing this morn, so I got off my butt, slapped the wires I made to run to the field connections, and did some brief tests with 36v on the field.

The extra torque/acceleration was nice, but it didn't solve my issue. I finally remembered to watch my battery voltage. It was sagging down to 65v -- where the controller automatically scales back battery current to prevent over-discharging the battery pack. It's set that way from the factory, and nothing much I can (or want to) do about it. This had occurred to me more than once over the past weeks, but, alas, every time I would climb in and boot about, I'd forget to watch the battery voltage. Ooops!

My batteries should be able to keep up. My guess, followed up with a bit of research points to them being too cold to perform worth crap. That's better than them just sucking really bad.

I will have to consider a battery warmer if I am driving it next winter. Or at least insulation.

Not much for it at the moment. I either need warmer batteries, or the second half of my battery pack in there to make up for the lack. I'm just about ready to start in on that anyway...