Converting an old VW Bus into a full electric car is a challenge, but by now we got a little used to this phenomena. The vintage white walled wheels have rolled more than 50.000 electric km’s, along highways and scenic alternatives. It all sounds like a good preparation for the 1600km’s of the WAVE trophy. So it seems from the perspective of a lowlander……..
Studying the road schedule of the WAVE carefully, we came to the inevitable conclusion that Switzerland has mountains, serious mountains……. My goodness, the stage of the Furkapass from Schwyz to Saas Fee goes 3000m up, and 2000m down……. So here’s our problem.
As die-hard-below-the-seelevel-lowlanders, we choose for a DC, non-regenerative braking, drive system, which is the most power for money you can get. The Old VW, nicknamed as the electric lovebus, still has it’s original breaking system, drum brakes, not empowered, ancient ancestors of modern disc brakes.
We thought that it was time to set up a boot camp, in dutch mountains, with roaring peaks just above 100m. Even than it is hard to find a more than 10% rate of increase. Luckily the “Holterberg” offers a small roadstrip of 500m, where the steepest part is 13%. After driving up and down a dozen times, the findings and conclusions where pretty clear:
- without braking, without pushing the throttle, in just 500m the car accelerates from 40km/hr to 100km/hr just by gravity.
- the drum brakes got smelly and burning hot!
- at 13% rate of increase, the handbrake is about to loose it’s grip
- a 10% rate of increase quadruples the power consumption at 50km/hr.
- Good brakes are needed……..
- No brake cooling will be lethal (or an regen. alternative)
- The hand brake needs assurance.
- 20km uphill at the Furka pass will take 40% of the traction batteries energy…….
Normally this is the moment to panic completely, fake some illness and call off our attendance for the WAVE. At Rebbl however, we sometimes do things different. In a small car we could consider an AC system, but this bus weighs 1800kg, and the only option is a liquid cooled AC motor, but we’re out of time for that option. So, back to basics, simplicity is our mindset anyway. First we considered forced aircooling, but some specialists laughed this plan away and calculated that this would need over 50kW of compressed airpower………. which leaves liquid cooling as the only option. A few jerry can’s, niples, a 12V fluid pump and small copper braking tubes are all we need for an experiment. It turned out that in 30min 45 liters of water, providing four small, but constant waterjets, for every brake. We will mount it on the bus the next few days. First pictures:
If this is enough for a smooth and steady Furka Pass downhill experience? There is only one way to find out….. mothers and children first.