Electric car conversion: Project ForkenSwift

[MetroMPG]

The charger didn't automatically shut off last night. This is the first time this has happened since I repaired it a few months back.

Recall that I'm charging the 48v pack with a 24v charger by splitting it (the pack) into two strings and paralleling them.

I checked each battery's voltage under charge, and two (one in each string) weren't coming up enough to trigger the charger's voltage based shutoff timer.

I need to:

1. check the water levels (I'm embarrassed to say I haven't checked in probably two months); and if that's OK,
2. swap out those two batteries and see if I can get better performance out of two randomly chosen others that we have sitting on the sidelines.

[MetroMPG]

While I'm oon the topic of ruining batteries because I'm not monitoring their relative voltages closely enough...

Last fall, a fellow EV owner in the UK sent me a portion of his hand-made LED battery monitor that he'd designed & assembled for his Metro EV. (Rover Metro - not at all the same car )

Here's what it looks like.

(Note: the height of each LED column is about 3 cm.)




His EV obviously used more batteries than the ForkenSwift - so I only have eight segments from this setup.

It works simply enough: each of the 10 separate LED's in a column represents about 6% from "full" to "empty" for each battery.

Of course, I haven't installed it yet. Winter. You know how it is.

He replaced his home-made setup with a relatively new commercial battery monitor called the Pak-Trakr.

Unfortunately, disaster struck his car: it caught fire and was ruined on New Year's day.

[MetroMPG]

So... the ForkenSwift may be slow, but it's apparently powerful enough to overwhelm a commercial web server.

The Ecomodder Blog post about the car went to the #1 position at digg.com yesterday, and promptly became a victim of its own success. The surge in traffic/viewers knocked out the server, and the hosting company disabled Ecomodder to protect its other customers' interests (whose websites resided on the same machine).

We immediately switched to a new hosting company who promised they could handle the traffic, but as those of you who deal with this kind of thing are aware, it takes some time for the DNS change to propagate across the 'net, so for all intents and purposes, Ecomodder was down and out, and the blog post was inaccessible.

It was kind of like winning the lottery, and then losing the ticket. What might have been fifty to a hundred thousand readers was cut short at 15 thousand.

On the bright side, that's 15,000 more people who now know about EV conversions than there were the day before.

I predict that if the blog post could have been seen by the full onslaught, today would have been a very good day to open a used forklift business.

[MetroMPG]

We've been bad to the badderies.

I checked the "water" level, and they were all low-ish. More than a couple had (slightly) exposed plates in at least one cell. I added about 6 L (~ 1.5 gal.) of distilled water across the entire pack.

Must make it a monthly maintenance thing.

[MetroMPG]

I drove the ForkenSwift out to the local Toyota dealer yesterday afternoon (to scope out Prius rear underbody aerodynamics... long story). None on the lot, and none expected until March. (Apparently they're sending them all to California and British Columbia.)

Funny story: on the way back, a train was blocking ALL FIVE level crossings in the city, and I needed to get across. There are two railway overpasses on major roads, but they're too steep for the ForkenSwift to climb at anything other than a walking pace in first gear! (Unless I had about a half a kilometer run to get the speed up to max before hitting the climb - which I didn't). So - not an option in busy traffic at 4:30 in the afternoon.

I had to sit and wait for half an hour at one of the level crossings.

[MetroMPG]

Also: in 4 of the past 5 recharge cycles, the charger hasn't shut off automatically. I need to swap out at least two batteries that won't come up to full voltage. They're preventing the total pack voltage from reaching the threshold needed to trip the charger's shutoff timer.

[MPaulHolmes]

Hello! Ya, the email from ecomodder kept getting thrown in the garbage on my email. that was the problem. Do you know if leaving out the resistor is bad for the controller for the caps to get charged so fast? Is it only bad for the batteries to have a high current burst?

[MetroMPG]

Hey Paul - glad you got it figured out.

The precharge resistor isn't for the batteries' sake - it's to protect the controller's caps, as you said. The Yodas on the EVDL say you really need it. It also saves wear on the main contactor & go pedal contactor, since neither of them are responsible for closing the circuit and carrying the current that recharges the caps.

[MPaulHolmes]

I found a really good deal on a possible adapter plate, but it's 11-7/8" x 15-1/4". Is the 11-7/8 going to be too short? How big is the bell housing on a metro? I don't have my car yet, so I can't go outside and measure it. Actually, It will be either a rabbit, geo, swift, justy, or some other tiny car.

[MetroMPG]

Hi Paul - I'll measure my adapter plate tomorrow and let you know.

Bad news!

Tonight I did something I've never done before - I "hit" another car. And it was the ForkenSwift I hit.

I was taking my nephews snowboarding at a local hill in my brother's van, and I misjudged how much room I had to get by the FS. Scraped the side of the van on the back corner of the car. Damaged both.

Surprisingly, the FS seemed to get the worst of it - I "beveled" the formerly round corner of the hatchback and cracked the tail light. The van just seems to have some deep scuffs above the rear wheel arch.

Nothing that can't be fixed, but my until now unblemished record can't be buffed, bondo'd & repainted!