Porsche 914 EV Conversion

FEBRUARY 18, 2007

Big thanks to Max at and all the other supportive engineers at HP for designing this circuit. I'll have to modify the circuit with a voltage doubler in the final stage to work with 8-volt golf-cart batteries for the 914 EV kit.

Golf Cart 147

Golf Cart Batteries Battery Kits 147

Porsche 914 EV Conversion

MARCH 23, 2007

After talking with some engineers at HP and mulling over some ideas, I came up with the attached schematics for an inexpensive battery balancer. The analog engineers at work are still designing the current/voltage limited step-down buck converter so that will be coming when I get their feedback. Any feedback you have is welcome.

Cheap 100

Cheap IDEA Convert Parts 100

Porsche 914 EV Conversion

MARCH 11, 2007

I spent yesterday (Saturday) disconnecting all the cables from under the car in preparation to drop the engine. I also drained all the engine oil and transmission fluid. My buddy Pete is providing some 2x4s later today to hold up the car so I can drop the engine this week. Yesterday was a bummer because I got really sick.

Oil 100

Oil Engine Parts Design 100

Porsche 914 EV Conversion

JANUARY 20, 2007

I'm working with an analog design engineer at HP to come up with a homebrew BMS system that does charge sharing similar to the PowerCheq systems, but for much cheaper, hopefully around $10 per battery instead of the $75 that PowerCheq units cost.

Golf Cart 100

Golf Cart Kits Conversion Volt 100

Porsche 914 EV Conversion

MARCH 8, 2007

A more effective system was designed by Lee Hart. My engineering buddies are looking into this now. The schematics and other info is located at the following link: [link] The major drawback of Lee's system is that it's expensive. The OEVA club is looking into this and I hope to cost reduce the system to be only $20 per battery.

Volt 100

Volt Purchase Batteries Battery 100

Porsche 914 EV Conversion

AUGUST 5, 2007

The RPM stays constant when I "coast" unlike a gasoline engine which tends to slowly drift back to "idle." I'm not sure how much current these golf cart batteries are designed for. Shifting was a real pain on city streets since the electric motor changes RPM very quickly during acceleration or regeneration.

Golf Cart 100

Golf Cart Volt Mariner Porsche 100

Porsche 914 EV Conversion

FEBRUARY 9, 2008

This included the folks at the Oregon Electric Vehicles Association, the motor control engineers at my work (HP), the communities at 914world.com, the other 914 EV conversion folks (Thanks to Randy, Ross, Roger, Matt, Paul, and many more.) I even received a few posts from Mike Brown at Electro Automotive, the designer of the kit.

Convert 100

Convert Kits Conversion DC 100