Battery Equalizer Schematics Rev 1.0

Porsche 914 EV Conversion

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.

2007 141

Christmas Time!

Porsche 914 EV Conversion

On minor disappointment is that the cable supplied in the kit is #2 gauge cable. I suppose the AC kit doesn't require as much current as the DC kit, but I'll take all the efficiency I can get at this point. YeeHaw! The crate from Electro Automotive finally showed up.

2007 130

Trending Sources

Taking a Day off to see the EV Show

Porsche 914 EV Conversion

They run on 48 volts and the company sells them as a kit for about $3500. He built the DC version of the Electro Automotive kit awhile back and challenged me to a drag duel at Nedra next week.

2007 130

Routing Thick Cables

Porsche 914 EV Conversion

I've already added the 3-hole cap-plug provided in the kit. After cutting all the tape that bound the engine compartment cables together, I slid on the three-hole cap-plug from the kit and bonded it in place with silicone sealant.

2007 130

Trying a Different Transmission

Porsche 914 EV Conversion

I wish all the other 914 AC kit owners luck. I wish Ross the best in getting the second 914 AC kit on the road Last week Craig at Camp914 offered to lend me another transmission to see if I had vibrational issues. I drove out to Camp914 this morning.

2007 130

There are many paths to the same goal.

Porsche 914 EV Conversion

My 914ev partner-in-crime Randy (who purchased the very first 914 AC kit from ElectroAuto) e-mailed me some photographs of how he's wiring up his terminal blocks and relays. Excerpt from Randy's e-mail: I've also started on the wiring kit.

2007 130

Biting the Bullet

Porsche 914 EV Conversion

They provided an upgrade kit with lock washers and loctite to remedy the problem. Here are the pieces for the upgrade kit above one of the motor bolts. In short, a lock washer and flat washer replace the nylon ones that came with the kit.

2007 130

Hauling Lead and Confusing Connections

Porsche 914 EV Conversion

A modification of the prior strap is basically what is suggested in the DC kit instructions. It turns out that the only copper interconnect that fit right out of the kit bag was the completely flat bar with two holes. Tonight was an evening of heavy lifting.

2007 130

Finishing the Serial Cable and Testing the Fuel Gauge

Porsche 914 EV Conversion

For some reason, I had an extra cap-plug left over from the kit, so I used it to protect the cable from the sharp metal edges. I had a bit more time today to work on some other small projects. Here's the 914 patiently waiting for its rebuilt transmission from Rennsport Systems.

2007 130

Wiring up the Front Compartment

Porsche 914 EV Conversion

Here is the 9-in-1 wire for the AC kit pulled through the grommet between the passenger compartment and the fuel compartment. WARNING: the DC kit instructions call for 1/4"-20 x 1/2" bolts to hold on the DC-DC converter; however, the holes actually take 10-32 x 3/8" bolts instead.

2007 130

Dear Customer.

Porsche 914 EV Conversion

I received a package from Azure Dynamics yesterday with a field upgrade to the bolts on the AC24 motor for the EV kit. Apparently, the nylon washers weren't good enough to hold the bolts in under all conditions and some of them may get loose.

2007 130

More Wiring and ACK, It Doesn't Fit!

Porsche 914 EV Conversion

WARNING: The instructions provide direction for a different DC-DC converter with the "input" and "output" terminals swapped left-to-right from the DC-DC converter that comes with the AC kit.

2007 130

Motor Cables and High Current Posts

Porsche 914 EV Conversion

The instructions for the AC kit tell you to slide the motor speed control box through the two-inch hole that was cut in the wall between the engine compartment and the rear luggage compartment.

2007 130

Hacking the Regen System and Fixing Acceleration

Porsche 914 EV Conversion

In the original kit instructions, the regen relay turns on the brake lights when the AC controller is in regen mode. I recommend this alteration to anyone using this kit! Well, today was a good day.

2007 130

Hacking Big Cables

Porsche 914 EV Conversion

As I mentioned before, I'm replacing the #2 gauge cable provided in the kit with a thicker 2/0 welding cable. I'm still a cheapskate and will still use the #2 gauge lugs with 5/16" holes provided in the kit.

2007 130

Hacked Serial Cable Details and Bad Relay

Porsche 914 EV Conversion

A few people asked me about how I hacked together a serial port since AC kit people will need this in order to configure the controller correctly. I basically took three 16 gauge wires (smaller would be fine) and soldered on crimp sockets at the end of each one.

2007 130

Getting the Tachometer and Lights Working

Porsche 914 EV Conversion

The original kit doesn't use the red light and the green light is simply grounded. After receiving an updated.css file (ccShell config file) from Azure Dynamics for the DMOC445, I was able to access the EE1SpeedoDiv variable.

2007 130

Getting the EV Back to the Shop and Fixing Electrical Stuff

Porsche 914 EV Conversion

in the kit instructions), through a bolt connecting the large red wires, and then back to the ignition switch.

2007 130

Wiring and Rewiring - Getting Close!

Porsche 914 EV Conversion

I received an updated wiring diagram for the AC kit from ElectroAuto, and, much to my disappointment, many of the connections went between the battery caps. Ugh, I'm dehydrated, exhausted and mad at this inanimate object. I must love doing this conversion.

2007 130

The Suspension is Here!

Porsche 914 EV Conversion

The real gamble is how fast the rest of the kit shows up. Unfortunately, I'm betting that ElectroAuto is going to take awhile before delivering the remainder of the kit, so I'll probably hold onto these for a bit. I received the suspension parts from ElectroAuto today.

2007 130

Fun with Rivnuts

Porsche 914 EV Conversion

I still need to add the spring, cotter-pin and 5mm threaded barrel listed in the instructions, so I hope those come later with the remainder of the kit parts. Electro Auto shipped their first AC wiring harness to the first AC kit customer and it arrived today.

2007 130

We are Green for 12V Electrical!

Porsche 914 EV Conversion

The dangling white and green wire go to the ammeter shunt and the dangling black wire I think is not used in the AC kit. Whew! I spent the evening debugging the small sparking issue I ran into yesterday.

2007 130

Spaghetti Wiring

Porsche 914 EV Conversion

After studying the AC kit diagrams and reading the motor controller documentation from Azure Dynamics, I think I understand a little better what all these relays and terminal strips are for. Today was a day for really getting my brain wrapped around the initial wiring.

2007 130

Debugging, Debugging, Debugging.

Porsche 914 EV Conversion

The kit requires the 12V accessory battery to run the exhaust fans while the car charges overnight, so I altered the circuit to use an external 12V laptop supply instead so I wouldn't drain the accessory battery. Okay, things don't seem to be working too well. We have three issues: 1.

2007 130

Motor/Transmission Attached!

Porsche 914 EV Conversion

Note: the kit instructions mention that the bolts that tie the motor mount in the kit to the front Porsche motor mount are 3 1/2 inches long; however, I think this is a typo because I had to go back and purchase 2 1/2 inch bolts because the 3 1/2 ones were almost exactly one inch too long.

2007 130

Busy Day - Time to get your WooGah On

Porsche 914 EV Conversion

Note: The AC kit instructions don't say what to install the charger tray with. Whoosh! Despite being exhausted from yesterday, I got up early this morning and just cranked through a bunch of EV stuff on my day off. Here is the board that the charger tray mounts to.

2007 130

Closing up more loose ends.

Porsche 914 EV Conversion

One of the other 914 kit converters questioned why the accessory battery couldn't stay in the original tray, but I decided to remove it anyway and have the accessory battery up in the front trunk near the DC/DC converter.

2007 130

Starting the Wiring

Porsche 914 EV Conversion

The fifth wire called for in the AC kit instructions is supposed to be black with a yellow stripe for the rear brake lights. With the motor/transmission bolted into the chassis and all the mechanical shafts/cables attached, I'm starting the wiring.

2007 130

Wiring up the Controller Harness

Porsche 914 EV Conversion

Today, I installed the last kit piece that I have from Electro Automotive: the motor controller wiring harness. Here's the harness plugged into the controller and fed through the two-inch computer grommet from the last blog entry.

2007 130

Let My People Convert! - The A123 Challenge

Plugs and Cars

Use the existing and growing base of hybrids, offer kits to authorized installers, and give ZEV credit to the original manufacturer in exchange for not killing the car's warranty. Les Goldman wants you to convert (your hybrid.) Easy as 123.

2007 130

Still waiting for the Transmission

Porsche 914 EV Conversion

On a more positive note, Ross Cunniff got his 914 AC kit running recently and Bob has been making progress on his BMW 325i performance EV (see links at right). In the meantime, I'm helping other folks using the AC kits with the Azure Dynamics controller get their systems working. Well, it's been over a month since I've posted since the holidays are here and I'm still waiting for the transmission to get back.

2007 100

Plug-in Hybrid Bills in Congress Scare Auto Makers

Plugs and Cars

Calcars continues to work with the Electric Auto Association members to bring a do-it-yourself kit to hybrid owners with moxie. The Senate bill is known as the FREEDOM Act ("Fuel Reduction using Electrons to End Dependence On the Mideast Act of 2007"); the House bill the more prosaic "Plug-in Hybrid Opportunity Act of 2007." The Detroit News Autos Insider column today is reporting on Congressional efforts to promote plug-in hybrids and the backlash from the automakers.

2007 100

EV Toolbox

Porsche 914 EV Conversion

pre-made 24" battery cable with lugs (from NAPA) #2 philips/standard screwdrivers pliers small utility knife to cut insulation small 12V SLA battery to bootstrap the system if 12V battery dies Again, what would you add/subtract/modify in this kit? Before the accessory battery discharge yesterday, I wrote down a list of things to keep in the EV in case there was a breakdown out on the road. I came up with the following items. Any comments for additions or modifications would be welcome.

2007 100

Talking with Mike at ElectroAuto

Porsche 914 EV Conversion

Apparently I'm the only person with an operational AC kit currently, although several other people are hot on the trail to finishing theirs. Mike doesn't have an AC kit 914 back at the ranch. I just got off the phone with Mike at Electro Automotive. We chatted about the blown CCPower DC-DC converter and the engine vibrations. Since I fixed the DC-DC converter, we agreed that I would try to find out which conditions would cause it to blow again, if it does.

2007 100

An E-mail from Azure Dynamics about the DMOC445

Porsche 914 EV Conversion

I recently sent off an e-mail to Azure Dynamics, the maker of the DMOC445 AC motor controller in the 914 kit. Thanks Beth Silverman * From: Tim Kutscha [mailto:tim_kutscha@yahoo.com] Sent: Monday, September 17, 2007 8:34 PM To: Beth Silverman Cc: tim_kutscha@yahoo.com Subject: Re: tapping into the encoder signals to drive the RPM gauge Hi Beth, I hope you had a good two days off last week.

2007 100

More Delays

Porsche 914 EV Conversion

Over the past few weeks I've been trying to contact the folks at Electro Automotive to get the status of the EV 914 kit. They finally responded last night and apparently they're completely buried under the demand for EV conversion kits. He got one of the earlier DC motor kits for the 914 from Electro Automotive. 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.

2007 100

Two Week Commuting Report

Porsche 914 EV Conversion

With the motor out, I'm going to look into RPM kits for electric cars that use spinning magnets on the flywheel with a magnetic sensor to generate a signal. Since I don't work Fridays, this is the end of my second week commuting to work fifteen miles each way. Two things have definitely made the car more fun to drive. The batteries are broken in so I have more current to work with and more importantly 2. I've learned some of the tricks to driving the car.

2007 100

Measuring State-of-Charge on Lead Acid Batteries

Porsche 914 EV Conversion

The 914 AC kit uses 8V golf cart batteries and I'm wondering if different batteries like Hawkers or Optima Yellow-Top batteries would be better. The kit was specificially designed for the US-Battery model and the equivalent Trojan battery is just 1/8" of an inch larger in one dimension, so I'm guessing it won't fit in the battery cases provided by ElectroAuto (grrr.).

2007 100

Battery Boxes Have Shipped!

Porsche 914 EV Conversion

Since the contents of the Tuesday shipment are going to determine if I use the $200 in pre-built cables or not, I might take the weekend to lower the motor and replace the washers on the electric motor bolts that came in the upgrade kit from Azure Dynamics. Electro Auto e-mailed me again today to say that the battery racks and boxes have shipped and should arrive on Tuesday! I'm curious what else is in this shipment.

2007 100

My 2007 Dream Project

Porsche 914 EV Conversion

Since I live in Portland, Oregon, I went to a meeting with the Oregon Electric Vehicle Association and found out about several companies that provided drop-in electric conversion kits for existing cars. After doing some research, I found Electro Automotive out of Felton, CA and put down the $13,000 for one of their latest AC motor conversion kits for the Porsche 914. I hope everyone had a great 2006 and I wish you all the best for 2007

2006 100