How was the solar van built and how does it work?

The dashboard AC upgrade in progress left, and finished above! I added quite a few health and safety stickers and information notices around the vehicle this time in case I ever sell it on.

With hard work over a period of over five years! I started with a basic Bedford Rascal van with a blown engine, and spent the first year stripping it down and repairing it. Once I had a solid base, I researched and installed the various components required to turn it from an internal combustion engine powered, noisy, smelly, gas guzzler, into a silent, clean, electrically driven head turner.

The solar van is in reality quite simple from a technology point of view.

1) Electricity is stored in a large capacity set of Li-Ion batteries. The batteries are designed for repeated cycling, that is charging and discharging. The 28 batteries in the ventilated secure container are "Thunder-Sky" Li-Ion types of 3.6v 200ah capacity. This battery pack stores about 20kwh of electricity. The batteries are connected in series providing 100v at 200ah capacity. The batteries are managed by a series of individual balancing and sensing circuits on each cell, designed by Cedric Lynch of "Lynch Motor" fame, which detect over and under voltage. These signals are presently used to control the charger and inverter to prevent battery damage.

2) The batteries are charged from a variety of sources at every opportunity. Solar power currently provides about 10% of the daily energy (based on my 26 mile daily commuting requirement) and as the 200w "Solara" solar panels are fixed to the vehicle, they charge the batteries at varying levels during all the hours of daylight. Power is also fed into the batteries by an onboard mains powered Zivan NG3 3kw charger with a small charging socket behind the old petrol filler cap! The addition of a small "Air-X" wind turbine which produces up to 400w could render the vehicle independent of any mains power. An off board home made 50A 6KW charger can also be used for quick charging!

3) The motor is a brushless 3 phase low voltage AC induction motor made by "Best Motors" in Italy. It is rated at 96v 12kw continuous power and can produce over 300nm of torque at low rpm.  I opted for range and relaxed cruising in my design not speed. The motor is mounted in a similar position to the old petrol engine, and is connected directly to differential using a custom prop shaft.

4) The motor is controlled by a "Zapi" 96v 450A electronic AC 3 phase regenerative inverter. This very clever box uses big mosfets to convert the 100v battery supply into a smooth 3 phase AC supply, with total flexibility over speed and power through numerous console programming options.

5) The vehicle has no gearbox as the motor has very high torque at low speeds, and reversing is accomplished by simply changing the direction of current flow through the motor.

6) With the old engine gone some things like a 12v supply for all the lights and ancillaries, vacuum for the brakes servo etc, have to be found in alternative ways. The 12v normal car supply is provided by a small efficient dc-dc power converter which changes the 100v of the main battery pack to the 12v required, this charges a 15v 56 Farad Maxwell Supercapacitor, and then in turn provides all the power required. The brakes use a servo assist unit which relied on the induction vacuum from the old petrol engine. Luckily neat 12v electric vacuum pumps are available which simply connect directly to the servo and pump as required.

7) The old dashboard has been replaced with a collection of digital meters which provide information on various vehicle parameters. I intend to replace this with mk2 of by own BMS and PC display system when I get around to it!

8) Safety is an important factor with any vehicle, and an electric one is no exception. A big red "Albright" lockable emergency disconnect switch is mounted on the centre console between the front seats, and serves as a safety cut-out and means of isolating the electrical circuits for maintenance etc. A 300A fuse is also fitted into the main battery supply. A multitude of other fuses and relays protect various parts of the charging and auxiliary power circuitry. A dry powder fire extinguisher is also carried.