Thread: Goingbush's Electric Vehicle project

It's true that just because the vehicle is travelling slowly doesn't mean the engine is turning over slowly.

However, I was envisaging the sort of off-road, low range driving where delicate application of the throttle is all that is needed. In that situation, the revs would be quite a bit less than the revs at normal highway speed.

While the revs aren't necessarily lower in low range, often they would be.

Originally Posted by vnx205

It's true that just because the vehicle is travelling slowly doesn't mean the engine is turning over slowly.

However, I was envisaging the sort of off-road, low range driving where delicate application of the throttle is all that is needed. In that situation, the revs would be quite a bit less than the revs at normal highway speed.

While the revs aren't necessarily lower in low range, often they would be.

did you see this video, bit of an eye opener

ZookEV Electric Suzuki Samurai at Barrett Lake Trail ep15 - YouTube

Well that worked , I took 6mm off the end of the motor shaft , 7.5 mm off the rear face of flywheel adaptor and bored the shaft hole right through the adaptor, (about 6mm removed)

Now the flywheel sits only 2mm reward of where it lies in the Petrol engine location, I should be able to take that up with clutch adjustment only, ( slave cylinder rod)

some interesting formulae here.

EV-calculations

One sentence in that article seems to me to confirm my feeling that low range work might not extend the range as much as you would expect.

A 5% grade requires twice the power that is needed on level roads.

As I tried to point out, hill climbing will use the same amount of energy regardless of speed. As long as there is enough torque available at the wheels to climb the hill, it will make no difference to the energy used whether you use low range or not. As aklways, the rate of energy consumption is proportional to your speed.

The only advantage of low range in extending range is that it will enable you to travel slower - but once your speed is below about 40k, the advantages diminish rapidly, as below this speed the losses aerodynamic losses become small relative to rolling resistance, and as pointed out above, energy used to overcome rolling resistance is proportional to distance travelled, with speed not a factor.

One point to note, is that if we are talking about a Series Landrover, low range means you are in four wheel drive - which means rolling resistance increases due to the 'locked' centre diff requiring the different distance travelled between front and rear to be accommodated by tyre slip.

Some interesting simple tech low budget build here that might help a few
Electric(EV) Suzuki Samurai on the trail in Dresser WI - YouTube

The rate of battery discharge would be the biggest factor (apart from aerodynamic drag) in extending driving range.
The slower you discharge a battery, the greater apparent capacity it has. i.e. draining a battery in 1hr that gives you 3ah, will give 5ah if drain it over 20hrs.
So yes your range should increase greatly, the slower you drive. Even once you get below a speed where aerodynamics are an issue.