2013-08-05 20.28.18 sml-crpdThis 1993 Honda Del Sol is an interesting part of EV history. Greg Solberg bought it to convert to electric in 1995. The lead-acid battery powered car became known as the "Del Sol-berg" in the bay area, California. It was built with features for testing a new motor controller product that Greg and Otmar Ebenoech (EV Components & Cafe Electric) had teamed up to design. The result was a fully programmable, water cooled, Sep-Ex controller that is still running strong today. Greg went on to become the early controller engineer at Tesla Motors and Otmar continued to develop and manufacture record setting Cafe Electric "Zilla" controllers.



Sep-Ex is short for "Separately Excited" (or magnetized) referring to how the field and armature of the motor are separately fed power from the controller. In the mid 1990's, most DC motors in this power range were "Series" type, where the field and armature are magnetized in series with each other through a brush connection. The Sep-Ex design promised distinct advantages over series, such as a more broad power band and linear controlled regenerative braking. Drawbacks include shorter brush life and increased heat. Otherwise, this controller model would have gone into production.


Under the hood of the Honda Del Sol -bergInterior of the Honda Del Sol -berg

When we got the car, we removed 24 lead-acid batteries (1054 lbs), located in two boxes under the hood, one box behind the seats and another box where the gas tank once was. We replaced the lead-acid batteries with 44 100Ah GBS Lithium cells (LiFeMnPO4). They are monitored and protected by an elithion battery management system (BMS). The BMS is located in a compartment behind the drivers seat. The new GBS battery pack weighs 287lbs and fits nicely under the car where the gas tank was. The interior behind the seats have been returned to a stock configuration.


The new battery pack provides >50 mile range per charge. Pack state of charge (SOC) is displayed accurately on the stock fuel gage on the dash. There is room under the hood for more batteries if upgrading to a 100 mile range is desired. Our daily driving has never used a full charge in one trip. We keep it plugged in when it's not in use, so it's always ready to go.

New GBS Lithium (LiFeMnPO4) pack for Honda Del Sol -bergThe Sep-Ex Zilla controller (green box) was originally located near the front grill where water may have eventually caused a problem. We inspected the inside and found it to be spotless. Following an external makeover and a new lid -courtesy of Cafe Electric, we moved it into the protective black box pictured. The 9" Advanced DC (ADC) motor is also modified (from series to Sep-Ex) using standard parts, but a unique configuration. A custom mount allows the motor to rotate, applying it's torque against a load cell (currently not installed) for gathering real-time torque data. With the lead-acid batteries gone, everything is visible under the hood, making it easy to see and discuss the EV parts. 

 Other details:

  • The car has 88k miles on it. Only 3k on the new battery pack.

  • It drives almost like any other car with a five speed manual transmission. Conveniently, first gear does not "need" to be used, and using the clutch for a stop or take-off is optional but unnecessary. Honda Del Sol -berg J1772 inlet

  • Cost for a full recharge (>50 miles of driving) is $1.35. That's $8.10 for 300 miles of driving.
  • Charges at Public charge stations (EVSE's), RV parks, and home.
  • The car easily tows behind an RV or pick-up. Tow bar (included), stows in the trunk and hooks up to the front of the car in about two minutes without tools.
  • Stainless steel grill plate is easily removed with one pin, located under the hood.
  • A 2500 Watt Elcon charger is capable of recharging in 5 hours. Less discharge requires less time. An upgrade is available to reduce a complete recharge to less than 2 hours.
  • Del Sol's have a built-in rack for stowing the targa-top in the trunk area. When the top is in this rack (as pictured) a release lever and gas shock lets it lift up for easy access to the trunk area.

  • Electric heat warms up instantly. There's no waiting for a gas engine to warm up water.
  • The stock spare tire is under the trunk floor and the jack is stowed in the trunk wall.
  • All electric windows, including the back window.
  • Electric Mirrors
  • Tall drivers & passengers fit well, with the targa-top on.
  • Top speed is somewhere above 80mph.Del Sol -berg trunk and charger
  • Acceleration is slightly better than the gas version.
  • Vacuum assisted power brakes.
  • Light trailer hitch: 2000lb max gross weight, 200lb max tongue Weight.
  • New stereo system

  • New tail lights

  • New shocks
  • New coil springs with adjustable height
  • New brake pads
  • New bigger wheels
  • New low profile Hankook tires
  • New torque rod (motor to chassis)
  • Advertisements on the car are Vinyl, and can be easily removed.
  • Imagine, no spark plugs, no motor oil, no air filters, no carbon monoxide, no stinky gas station lines.

electric del sol -berg front view lights onFeatures you don't have to use, but are useful for service or experimenting:

  • Linear control of regenerative braking is applied with a simple twist of the emergency brake grip.
  • Elithion Battery Management System (BMS) settings and data are accessible through a USB port. This is where battery protection is programmed to monitor and protect the battery pack.
  • BMS controls the fuel gage to accurately provide State Of Charge (SOC).
  • Manual switch for Economy Mode or Power mode.

 Curb Weight:

  • 2295 lbs: stock curb weight with manual transmission, according to Wiki.
  • 3400 lbs: with lead batteries (as we bought it) - according to local truck scales.
  • 2550 lbs: after we finished, with forty-four 100Ah LiFeMnPO4 cells in series (14 kW/hr).


Dash of the Electric Honda Del Sol -berg

electric del sol -berg rear view