#6) Project ForkenSwift electric car: LED battery gauge

http://www.ForkenSwift.com - One of the challenges of driving an EV with old or mismatched batteries is that you'll murder the weaker ones if you don't keep an eye on their state of charge. This "new to us" LED battery pack gauge will help to ensure we don't send any batteries to their graves ... uh, to the recycler ... prematurely.

Schematic available here: http://www.evconvert.com/article/led-bargraph-battery-monitor#c002474

Here's the full text from the video:

- May 7, 2008
- Testing out an LED battery pack monitor.
- Background: the ForkenSwift runs on used batteries
- Graciously donated by other EV owners.
- (Thanks, Fred!)
- (Thanks, Allan!)
- But there's a problem with older, mismatched batteries.
- They have different capacities, so they run down at different rates.
- So, just watching the pack voltage with a multimeter isn't good enough...
- ...because it won't tell you when an INDIVIDUAL battery is out of juice.
- And if you keep running the weakest batteries down too low...
- You'll soon have a growing pile of dead & damaged batteries.
- Ask me how I know this :-)
- The solution?
- A display that shows the voltage of each battery in the pack at a glance.
- (Eight 6 volt batteries in the ForkenSwift)

[Next subtitles shown while driving, showing the LED gauge in action.]

- Stopped. Accelerating... Changing gears. Accelerating... Changing gears. Accelerating...
- Batteries #1 and #6 (left to right) are weakest. #2 and #4 are strongest.
- Coasting...
- The lowest LED in each column lights up at 5.25 volts.
- Going below 5.25v risks damaging the battery.
- The display shows why the weakest battery in the pack is the limiting factor for range (and power).
- It was made by a clever EV owner in the UK. (Thanks, James!)
- Cool eh?
- The display will make it easier to finally sort through the batteries...
- ... identify the duds, and put together an "A pack" and
a "B pack".
- Nothing like a rolling load tester!

http://www.ForkenSwift.com

Category:

Autos & Vehicles

Tags:

• EV
• electric
• car
• vehicle
• conversion
• NEV
• LSV
• Auto

[beatsanz]

congratulations!!!!!

how do you do with brakes and stopping since ya dont have booster

[ForkenSwiftDotCom]

The brakes were upgraded: the larger rotors, calipers and pads from the 4-cylinder version of this car were installed.

They take more effort to press, but they work fine.

[r3di2watch]

I wonder if you can get some kind of computer or micro-controller to average the voltage over time and give you a simple readout on the battery.

Battery #1 seems to be going too high as well as too low, so it has a bad cell and the electrons are saturating the plates on the other cells.

Are you going to match your cells for increased range?

[ForkenSwiftDotCom]

It can certainly be refined, but what you see is what you get with this car! The used batteries shown in this clip have since been replaced with slightly less-used ones, so the pack is more evenly balanced now; better for range and individual battery health.

[xINJUNx]

very impressive especially the budget,could u please tell me more about the motor,single phase?,3 phase,voltage,hp,what is top speed and top distance on a single charge,tia

[ForkenSwiftDotCom]

Thanks. Google "1993 Geo Metro ForkenSwift" and go to the top result for more info.

[drdhdmd]

That is a very old "wive's tale".  It is just not true.

[WorldStove]

too cool for words

[jeepers2655]

how many batteries does a fork lift have?......use those ? or are they too heavy?.....they seem to work on a lift truck?

[wuiloby]

Nice device for my car, thanks....

[aleon1018]

So easy, even a Canadian can do it ! lol

[ubergnar2808]

very cool

[drdhdmd]

Your display is very similar to mine. I just put mine in a nice box. ;-)

Your music and video are very nice.