Porsche 914 EV Conversion

SEPTEMBER 8, 2007

volt power supplies from HP inkjet printers and hooked them up in series. It looks like we have a period of 30us and the power supply for the SG3525A is 12 volts. Without any load, the voltage swings on the FETs are twice the input voltage (about 312 volts) plus any ringing from inductor kick-back! In essence, I took five 31.2

DC 100

DC Volt Convert Supplies 100

Porsche 914 EV Conversion

FEBRUARY 18, 2007

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. By clicking on the images, you can get a much larger version of the pictures. Any feedback on how to improve the circuit would be welcome.

Golf Cart 147

Golf Cart Batteries Battery Kits 147

Porsche 914 EV Conversion

FEBRUARY 14, 2007

volts down to 0.2 volts overnight. On a more interesting note, I prototyped a battery equalizer with two 12V UPS batteries earlier this week. The circuit seems to work just fine and I was able to get the voltage difference between two adjacent batteries from 1.0

Volt 100

Volt Installation Batteries Battery 100

Porsche 914 EV Conversion

AUGUST 24, 2007

volt drop from the wire resistance going to the back of the car and front again. volt drop from the long wiring and the 12V system is much happier. Unless I come up with a better idea, I'll probably tie the hair-dryers directly to the 144 volt system through relays controlled by the rear-defroster pull-knob.

Volt 100

Volt DC Light Electric 100

Porsche 914 EV Conversion

AUGUST 5, 2007

The battery voltage sunk from 152 volts at rest down to 132 volts after awhile during heavy acceleration. If my ammeter from West Marine is correct, then just cruising takes about 50 amps and every time I accelerate even slightly, the current goes up over 200 amps.

Golf Cart 100

Golf Cart Volt Mariner Porsche 100

Porsche 914 EV Conversion

JANUARY 20, 2007

Besides, the PowerCheq units only handle 12 volt batteries and the ElectroAuto kit is designed for 8-volt golf-cart batteries, so a homebrew system will be required.

Golf Cart 100

Golf Cart Kits Conversion Volt 100

Porsche 914 EV Conversion

JULY 19, 2007

Since the positive terminal of the auxiliary battery is tied to the unswitched 12V rail, the negative terminal of the battery is at zero volts. of the DC instructions, it drives the keyswitch relay coil instantaneously with 12 volts, energizing the coil. When we attach the black wire in step XXV.R

Green 100

Green DC Volt Installation 100

Porsche 914 EV Conversion

AUGUST 23, 2007

The hazard signals started flickering and nothing would turn on. After pulling over and checking the voltage on everything, the pack was nicely up at 150V but the accessory battery was down to 10.5 With the key on, the DC-DC converter light was on; however, when I checked the DC-DC fuse, it was blown.

Batteries 100

Batteries Battery DC Volt 100

Porsche 914 EV Conversion

JUNE 5, 2007

After much time on the phone with UPS Freight, the 8-volt golf cart batteries finally showed up today! Although the Bill of Lading clearly stated that this was a residence requiring a liftgate, UPS seemed to overlook that part of the order. Here's the semi that showed up at my doorstep to block off the street.

Golf Cart 100

Golf Cart Batteries Battery Volt 100

Porsche 914 EV Conversion

MARCH 6, 2008

The batteries are 8 volts apiece and the serial port dumps tenths of a volt (scale on the left edge). The PakTrakr logs voltage for each battery and then dumps it out a serial port in.csv (comma separated) format for MS Excel. I captured the above graph from the chart that MS Excel generated.

2000 100

2000 Miles Volt DC 100

Porsche 914 EV Conversion

JULY 26, 2007

volts per battery. It looks like the controller is getting 12 volts, but there must be something holding back the controller from spinning the motor. Here is the voltage measured at the AC controller. Looks like we have about 8.4 Of course the next step was to get out the fire extinguisher and turn the key on. Guess what?

Volt 100

Volt Motor Motors Motoring 100

Porsche 914 EV Conversion

AUGUST 24, 2007

volts so I'm guessing the 12V battery was mostly dead. The car is still stranded at Krista's place. I brought over jumper cables and tried to charge the battery with my ICE vehicle. The voltage drop across the 300amp jumper cables was 0.8 Since this is my day off, I might take a risk, charge it up some more and try to crawl home for repairs.

DC 100

DC Convert Volt Plug-in 100

Porsche 914 EV Conversion

AUGUST 24, 2007

Since the FETs are rated at 16 amps and the fast-acting input fuse was rated at 5 amps, I suspect the FETs sustained damage from a high-voltage spike that went past their 400 volt rating. volts to charge up the accessory battery. I'm glad I wasn't around when it blew!). The DC-DC seems to be working fine again.

DC 100

DC Convert Volt IDEA 100

Porsche 914 EV Conversion

AUGUST 12, 2007

They run on 48 volts and the company sells them as a kit for about $3500. This was originally just a human powered vehicle made in Belgium, but the owner added an electric motor to power the rear third wheel to get up the hills in Portland (of which there aren't many in Belgium). Not bad for something that has a top speed of 50mph.

Portland 100

Portland Belgium Kits Neighborhood 100

Porsche 914 EV Conversion

OCTOBER 14, 2008

volts which is a very bad sign. I was able to "jump-start" the car by using my 12V fan-power transformer to activate the DC-DC converter relay. This enabled the DLS-45 DC-DC converter to quickly charge the 12V battery off the main pack. Unfortunately, the 12V battery had drooped down to 3.2

Porsche 100

Porsche Batteries Battery Deep Cycle 100

Porsche 914 EV Conversion

SEPTEMBER 14, 2008

It shouldn't be too surprising since 200 amps going through 10 milli-ohms will cause 2 volts of drop, indicating a bad battery. This experiment tells me that the fusible link has enough resistance to confuse the PakTrakr into thinking that a battery is failing.

Miles 100

Miles Volt Batteries Battery 100

Porsche 914 EV Conversion

SEPTEMBER 11, 2007

Here goes: "The converters have been manufactured for over 20 years and we have 10,000+ units operating in South Africa at 120 volts, all using the same build, without any problems. I prefer not to comment on it but simply wish to pass it on to others who might have wondered what the manufacturer said.

DC 100

DC South Africa Power Powered 100

Porsche 914 EV Conversion

MAY 28, 2007

I should be getting the 18 8-volt golf-cart batteries from American Battery Company early next week. I've sent three e-mails and one phone call to Electro Automotive asking about the status of the battery racks/boxes and received no reply. As you might imagine, I'm a bit frustrated with this and don't really know what to do next.

Golf Cart 100

Golf Cart Volt Auto Batteries 100

Porsche 914 EV Conversion

AUGUST 1, 2007

Mine was set to 136 volts. It turns out that if the voltage coming from my batteries fell into the 136 to 149 volt range (EE2NoAccelBat + EE2AccelRamp = 149), then the controller would linearly limit the power going into the motor down to zero when the voltage reached 136.

Kits 100

Kits Volt Light Plug-in 100

Porsche 914 EV Conversion

AUGUST 30, 2007

Next week I plan on taking five 32-volt isolated supplies (2.5 It fired up the DC-DC converter, but the whole thing was moving up and down at 60 Hz, it was darn near impossible to look at things with an oscilloscope. amp) and hooking them up in series to form a 2.5

DC 100

DC Convert Supplies Volt 100

Porsche 914 EV Conversion

MARCH 9, 2007

Method of connecting 12-volt gel-cell to fuel pump to dump fuel into gas can. The empty fuel tank with separated expansion tank (to remove the fuel guage plug). Note the two hydraulic jacks near the wall. Having two jacks makes dropping the engine much easier. Rear trunk lid removed. The front and rear trunk lids, removed.

Volt 100

Volt Fuel Gasoline Engine 100

Porsche 914 EV Conversion

FEBRUARY 20, 2007

If you hadn't read before, the 18 8-volt golf cart batteries add 800 pounds to the weight of the car, so the suspension needs upgrading. I received the suspension parts from ElectroAuto today. It looks like I got new springs(blue), torsion bars (red) and two sets of matching shock absorbers (white/silver).

Golf Cart 100

Golf Cart Kits Volt Batteries 100

Porsche 914 EV Conversion

MARCH 21, 2007

Instead of the $150 Vicor BatMOD module, I'm using a free 100-watt 32-volt isolated power supply from an HP printer and making a current controlled buck converter to step down the voltage and charge the batteries (about $10).

Batteries 100

Batteries Battery Convert Volt 100

Porsche 914 EV Conversion

MAY 5, 2007

It turns out that the positive wire to the horn is also tied directly to the positive terminal of the 12-volt system. If I really get impatient, I think I'll line up the 18 8-volt golf cart batteries on the floor and run two battery cables into the controller just to see if I can get the motor to turn.

Golf Cart 100

Golf Cart DC Kits Lead Acid 100

Porsche 914 EV Conversion

AUGUST 26, 2007

The CCPower website only has the input voltage of their DC-DC converters listed as 80 volts so, although these are designed for EVs, the underlying design may not be able to handle the higher voltage, especially with spikes from regenerative braking. I'll have to double check to see if the inductive kick-back diode is properly functioning.

DC 100

DC Convert Volt Plug-in 100

Porsche 914 EV Conversion

JUNE 30, 2007

The 8-volt golf cart batteries arrived over 24 days ago and have just been sitting on the garage floor, discharging. This is inside the driver-side fuel compartment looking forward. The two one-inch holes will get grommets for the high-current battery cables connecting the front batteries with the middle pack.

Golf Cart 100

Golf Cart Batteries Battery Connect 100

Porsche 914 EV Conversion

FEBRUARY 7, 2008

The 12V voltmeter in the center console never dropped below 12 and stayed at 13 volts most of the time, even with the headlights on. Okay, the first test drive with the new converter was very successful. I turned on all the lights, including the fog lights and drove around for about 20 minutes. The new converter is dead silent.

DC 100

DC Installation Parts Convert 100

Porsche 914 EV Conversion

MAY 1, 2007

Both US-Battery and Trojan have 8-volt golf-cart batteries. After researching different battery types, it looks like the Hawkers and Optimas can put out more amps for more torque and are more rugged, but the golf-cart batteries still rule in terms of capacity per weight and size.

Lead Acid 100

Lead Acid Golf Cart Batteries Battery 100

Porsche 914 EV Conversion

JULY 23, 2007

These high-capacity 8-volt golf-cart batteries are 70 pounds apiece. Tonight was an evening of heavy lifting. I'll definitely take some ibuprofen before tomorrow. Here are the batteries in the front box. The fuel compartment box. And the rear box.

Connect 100

Connect Connected Golf Cart Kits 100

Porsche 914 EV Conversion

JANUARY 28, 2008

The added output current should also provide some extra amps for powering a 15-amp 12-volt cabin heater if this cold weather keeps up. The technical support person at Iota was extremely responsive and provided accurate information. I ordered one and it should be here later this week.

Kits 100

Kits DC Google Convert 100