Ben Nelson's Electro-Metro Build thread

[MetroMPG]

I'm looking forward... to the spreadsheet.

[Planecrazy]

Hiya, Ben!

I have spent the last three days reading through your EV exploits from start to finish, this a result of having seen your instructable. To say I'm impressed is a major understatement! It's impressive enough to undertake what you have and complete such a project (to the point that you have) in so little time with so little money invested, but to do so (and succeed) in the brutal weather we both experience here in the upper midwest is truly commendable!

I see you have made the trek into IL a number of times to attend EV and alternative energy events. The next time you find yourself headed for the Chicago area I'd sure love to know about it so I can check out the Electro-Metro! My best friend (who lives in Zion, just south of Kenosha) is intent on building an EV recumbent bike (which I'll help him weld up) and I'm sure he'd also love to check out both of your EV machines!

I had a thought regarding your defrosting challenges for winter driving. It occurred to me that if you were to build a removable shroud that captured the heat coming off the motor (and perhaps utilized the airflow generated by the integrated fan) you might be able to get a nice constant supply of fresh, heated (even if it's only slightly heated) air funneled to your defroster vents. A side benefit (at least during the winter) is that such a shroud MIGHT also help to muffle some of the "futuristic cougar" noise coming off the motor and make the Electro-Metro even quieter than it already is. I suspect that the amplitude of your EV isn't an issue at all, but it would be cool to make the "cat" even slinkier than it already is, hehe!

I know you've mentioned that the motor generates almost no heat, but I suspect that with the increased voltage (and even at the lower 72 volts) that fan is (or will be) probably moving a meaningful amount of warmer air. Wouldn't it be great to be able to use that excess "free" energy to keep the windshield clear without losing any electrical efficiency in the process? I realize this doesn't solve your overall heating problem in the cabin, but it does provide one possible solution to the biggest problem you've had driving the EV in the winter ... seeing out the windshield!

Another possibility would be to suck warmer air out of the transmission housing (using the access hole cut into the bottom) to perform the same task. This assumes two things that may or may not be true ... First, that the operation of the EV causes the tranny to heat up enough so that you can use that excess energy and second, that any heat built up collects inside that housing such that you can use a small fan to blow it into the defrost vents. This solution would, of course, require you to add a small electric blower to the equation, since the tranny doesn't have an integrated cooling fan like the motor does. However, if the tranny gets warm enough during operation it might be worth the trade-off to harness that heat energy.

I also have an observation regarding the question of the Electro-Metro's gross vehicle weight (GVW) capacity. You've been basing your plan to either use or dump the back seat based on GVW figures for a stock Metro, but just like a full sized pickup truck can be bought with several different load ratings (mostly based on suspension differences) you've substantially changed/upgraded the Electro-Metro so that those original figures don't necessarily apply anymore. The combination of beefier springs from the Explorer/Ranger combined with the addition of a sturdy battery box in place of what was originally contoured/flat sheet metal in the body has hypothetically upped the structural integrity/load carrying capability quite a bit.

I would argue that if you added a few well placed pieces of square tubing to the equation (to tie the battery boxes and frame pieces together in addition to the sheet metal that already does this) you could confidently carry a much heavier load than what the original specs dictate. I'm not, of course, suggesting that you go out of your way to overload the vehicle, but I want to make sure that you realize that you've probably added quite a bit to the vehicle's GVW capabilities. In short, I'd keep the back seat simply because you never know when you might wish/have to squeeze a few extra passengers into the vehicle, and I believe it is more than up to the task of handling the increased load, at least for short hops.

Hope these ideas are useful! I've truly enjoyed following your progress, and look forward to someday meeting you (and the other EV guys/gals) and seeing the projects in action!

Regards,
Steve

[bennelson]

I got all my used gel batteries back from the battery shop.

The bad news is that most of them are in poor condition.
Two came back with a giant BAD magic markered on the top.
6 of them are really usable. That leaves 10 that ain't so good.

I sorted out the 6 best to put in the Metro.
It looks like possibly the best way to go is to keep the car at 72V right now. I am not sure how much better range I would get by adding 6 more batteries of poorer quality, especially since I don't have individual battery monitoring.

Maybe I start saving my money for a set of 12v deep cycle boat batteries at some point in the future.


Last night, I took the Metro to the Urban Ecology Center in Milwaukee. I, Swee, and Mike Mangan all gave short presentations on our vehicles, and then had them on display for show and tell afterwards. Mike's electric Harley Sportster was very popular.

Also, I got an e-mail from a new Alt. Vehicle friend I met a few weeks ago. The closest highschool Electrathon team to me is having their final competion out of town this weekend, and their ammeter just blew out. I am going to grab the one out of the Metro to loan to them. Their last "build day" before they leave is tonight. I might take my motorcycle out there to show off to them while I'm at it.

[Daox]

Well, to be optimistic about it, when/if you get new batteries, your range should increase a fair amount.

Oooh, and snap a few pics when you are at the highschool thing if you can.

[MazdaMatt]

alternatively... why not just pinch pennies and deal with the 72V for however long it takes to buy a "premium" battery pack? Ongoing/lifetime costs are allegedly less.

[bennelson]

By "Premium" battery pack, are you referring to Lithium, etc.?

This whole vehicle project is one big low-budget experiment.

I doubt I would ever put any truely expensive battery pack into it.

I might choose to go to a purpose-built vehicle, such as an all-electric XR3 if I ever put that much money into a project.

I think I am sticking with lead for the foreseeable future.

On a side note. I put my motorcycle's Optima Yellow Top AGMs in the Citicar for this weekend and WON BOTH DRAG RACES! Some variations of lead-acid are still pretty nice.

[MazdaMatt]

Yes, i was referring to that. I understand you've created the beast on a low budget, but everyone on DIYElectricCar and EVDL is screaming foul when people claim that lead acid is cheaper... you'll get lower long-run costs with a premium pack... hence the "pinch your pennies and deal with 72V for now" comment. And heck, once you've got 144V of lithium or lifepo or whatever, you can always put them into your next car when the wheels rust off your metro.

[Planecrazy]

...not to mention, Ben, that you'll be better able to deal with the additional power draw a "winter" solution (like some of the ones I mentioned above) will require in order to use the vehicle year-round without suffering, hehe!

Regards,

[bennelson]

I got a radio installed today.

OK, mostly it was Chris, one of the EV build buddies, who did almost all the work. I still have to get it physically mounted right, the wiring is all done up and working.

It was the cheapest stereo available at the big-box store, yet it has plenty of bells and whistles, including MP3 playback from CD, SD card, or USB.

You know the first thing I had to do was test some sound effects....
I already had some motorcycle sound effects handy, so I loaded those on a memory card and plugged it in. Sound effects were every bit as good in the car as they were on the motorcycle.

I am taking the car to the MREA energy fair in two weeks. Last year, I lost my voice talking to people about my motorcycle. Perhaps this year I make a recording of myself tallking about the car and play it repeating on the stereo?!

Looks like I will have to find the George Jetson flying car sound effect to use in the Metro...

[Planecrazy]

Good Deal, Ben - Gotta have "tunes" (and George Jetson's flying "car")!!!

Regards,
Steve