Project: The Electric Booger (budget EV conversion - '92 Mazda MX-3)

[Daox]

Originally Posted by mechman600

Clark Griswold style!

Haha, I just watched that the other night too...

I do know a friend who has a 300V Neon who is using individual 10A chargers. He used several large power strips to charge up his car. He has to charge in stages because I think he has 24 chargers total, and that would blow normal breakers. Seems to work well for him.

[mechman600]

Your buddy could probably do 240V with his same chargers. Hook half up between to the white and black and the other half to the red and white (backwards 120V through a different breaker) to "cheat".

[mechman600]

Here are some pictures I took of my rear battery pack today.


Note my "Battery Pack Restraint System" in case of a crash.

And my ridiculously large "charger array":

There's two more under the hood!

Today I scored a free sheet of black plexi-glass and cut it to size to make my battery cover:


This weekend I will properly fasten this cover to the rear seat frame...maybe. Actually, it really doesn't have anywhere to go so it doesn't really matter for now.

[Xist]

Awesome!

[mechman600]

There seems to be a charger theme in this thread as of late. But I plan on getting it right, so I shall continue this theme for a little while, anyway.

My recently purchased six individual chargers are a temporary solution to avoid murdering my brand new batteries. Series charging my pack was doing just that - undercharging some and overcharging others - because of varying internal resistance within my pack.

According to Canadian Tire's website, the return policy for these charger is "90 days in the original packaging". So I have 82 days left.

These chargers are old school transformer based chargers. Very very inefficient. So inefficient that I am embarrassed to enter fuel log data.

During the bulk charge when batteries resistance is low:
Input power: 160W
Output power: 10A*12.8V=128W
Efficiency: 80%
Once the battery voltages go up and resistance increases, the charger output current drops significantly while input current drops much less:
Input power: 125W
Output power: 5A*13.5V=67.5W
Efficiency: 54%

Since the current slows down at higher charging voltages, most of the charging time is spent in this stage, where efficiency is quite low.

But I knew it would be like this with these chargers, and I have to keep reminding myself that this is temporary.

So....for my [hopefully] final charging solution I have ordered.....(insert drumroll)..this:
Alloy Shell 240W LiFePo4/Li-Ion/Lead Acid Battery EBike Charger - BMSBATTERY


Six of them. 12V*10A. Configured for 14.4V max output to match my AGM battery constant voltage charging spec of 2.30-2.43 VPC. Tiny (170mmX90mmX50mm) and light (1kg). PWM controlled (instead of transformer/resistance "controlled").

[Daox]

Sounds like a good solution. It'll be interesting to see the efficiency results.

[mechman600]

Thanks for the sticker, Darin!

What do you think? Keep it?

[MetroMPG]

No prob! Thanks for the tour of the car, and the demo drive.

The eBooger is what the ForkenSwift wants to be if it (the FS) ever graduates from kindergarten! The 48 Volt ForkenSwift would be steamrolled in the "real" traffic that you drive in.

Cheerleader's car or not, eBooger is a one of a kind practical runabout, and it's always great to get a ride in another EV.

[bennelson]

Looks good! Keep the sticker!

[mechman600]

Hey Ben, another thing we could do if we lived closer to each other is have a 72 volt race. That would be EPIC.