Hurry up and weight

Keeping weight down to minimum is always high on the agenda when building a pure race car, but I’m wrestling with trying to keep the Flux Capacitor as normal looking (and street legal) as I can. Ok, ignoring the stance, wheels and 4-foot wheelie bars.

Originally the Enfield had a single electric motor with 8hp and eight 12-volt lead acid batteries (weighing over 300kg!) making 48-volts. The car weighed 975kg and did 40mph top whack, with a maximum range of 55 miles.

Compare the 6KW and 150 amp output of it in 1974 when this chassis number 003 Enfield left the Isle of Wight factory to the 600kW it has now. The Flux Capacitor will be able to unleash up to 2000 amps at over 300 volts, which could be in excess of 1100lb-ft of instant torque.

It’s come from this in ’74…

To this in ’14…

Before adding the lithium-ion batteries Hyperdrive Innovations corner weighed the Enfield. We’ve shed bulk here and there, but added in other places – most notably safety stuff like the roll cage. 711kg.

There’s 319kg at the front axle and 392kg out back. This is before the battery pack, which looks like it will be the best part of 145kg including the enclosures, cabling and Hyperdrive Battery Management Systems.

It’s a tad heavier than I was originally aiming for, but the batteries are set to give far better range than I planned – 60 to 80 miles depending on driving style. At full power we could achieve 5 to 6 runs on the quarter mile strip. Plus, we can always shave weight once I’ve started getting used to the car.

As he’s been utterly instrumental in his expertise throughout the build I consulted Olly Young at Current Racing about where we should locate the batteries. I sure as hell didn’t want them inside the passenger compartment with me, so it was a case of front, rear or under floor.

This will be a drag car first and road car second, the priority is for it to grip and run as straight as possible on the quarter mile. With this in mind Olly has recommended as the batteries go in the main ‘engine compartment’ under the bonnet, as this would give 60% front and 40% rear weight. Says Olly ‘That is the ideal dragster distribution, as this helps loading up the four-link rear suspension correctly off the start line’.

I’ll be showing off the Enfield’s finished battery enclosure next week, but here’s a build shot of the 3 segregated packs.

In the meantime here’s some stats to digest:

The Flux Capacitor has 144 cells connected in 2 parallel and 72 series. These are split into 3 battery packs, all living in the front bay. Here are six of the 144 cells.

Voltage 266.4 nom. Max 302.4 volts. Current 31A x 2 = 62Ah cells, so pack energy is 16.5kWh.

Nominal discharge rate will be 2,480 amps at 266 volts, which is approximately 883hp. Or max discharge is 2,480 amps at 302 volts is approx 1,003hp of potential power. That’s up to 1003hp and a projection of some 1,100 lb ft of torque. Zoiks!

Thanks must go once again to Hyperdrive Innovations for their involvement in the project, not to mention my sponsors Adrian Flux Insurance, npower and Red Maple IT consultants. Cheers for sticking with me.

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