Electric Bike Review

I think they like it.

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Supersonic27 said...
Looks and sounds awesome actually, 500,000 kms before battery performance drops to 80%, did they say that!

They did and I don't believe them.

Everything I have ever bought, including an electric bike, using batteries of any sort, including lithium batteries, does not live up to the sales blurb on the battery life. Mostly the battery life doesn't even come close to the claims.
Within a year or two the performance is noticeably degraded.

500,000 km would take ten years of heavy use and I thnk the battery would be totally knackered before then.

And even if someone used it non stop, and the miles was as claimed, (which I don't believe either) that would need around 1800 full recharges.

I think the 171 miles range (275km) would be under ideal conditions; flat road, no wind, light rider,..light throttle,..

Just going on the figures quoted it would have to be because,.. battery capacity is 14.2KWhr.
Even if the motor was 100 % efficient, that would give 19 hp for just one hour flat out to give the top speed of 102mph.
1 hour at 102 mph gives 102 miles, not 171 miles.

Apart from the fact that 19 hp will not drive a bike at 102mph under anything but the most ideal conditions, (downhill and with a strong tail wind,..) , the efficiency will definitely be far less than 100% at that power output.

The bike is probably way better than previous models but not as good as the specs claim.

If they would like to lend me one for a few years I can test it for them and report back.

yeah sorry,..

Although I don't know what conditions they would need to get 500,000 km out of the batteries.
Maybe a veeeeeery looooooong hill?

Plenty of electric push bikes that out perform this in all aspects including top end, if us back yard hacks can do it I'm sure it's not hard with the right engineering. The battery life sounds a stretch but half that should be possible but the quality of the BMS will determine that more than anything. I clocked 14000 km on my near new A123 cells with 400 chargers around 60% DOD and no loss of capacity at all. Remember every time you squeeze the happy handle on a stink bike you blow 60 - 70% in noise! vibration and heat with the rest trying to move you along.

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jn1 said...
pweedas: Not sure where you got 19 HP from ?.. The web site is quoting 54 ponies (I assume from the back wheel ?). Yes, I agree with you about the L-ion batteries. Their capacity decays as soon as they are manufactured, unless Zero have a special manufacturing technique that prevents this ?

No. I think they have a special advertising campaign that prevents this.

So where did the 19hp come from?
I ran through a few figures at variious power settings to see how realistic the stats quoted in the videos were, considering the capacity of the battery,.. I didn't say it all because most will glaze over and not bother with it,. but since you ask,..

Here are a few details.
Firstly, the figures I take as accurate are the battery capacity because it's easy to read off the label on teh battery and quote it, and although it's also usually overrated, sometimes it's accurate, so lets say it is.
They say it's 14.2 KWhrs.

Secondly, the quoted maximum engine power of 67hp equates to 50 kilowatts and would be the power consumed by the motor, not the power output of the motor. They usually rate electric motors that way rather than state the power output. Thus when they say a 50kw motor you can take it they mean it draws 50kw, not that it will supply 50kw.
It would only output 50kw if it was 100% efficient. I discounted that error and thus continued on the basis of a 100% efficiency.

so,..Take the case of a flat out run at the stated 102 mph.
Flat out the motor draws 50kw out of a 14.2kWhr battery.
Thus it would last 14.2/50 hours = 0.28 hrs @102mph gives a distance of 30 miles (= 47km total) .
With a good lithium battery you can discharge it in 15 minutes but it will get quite hot and it degrades the battery if you do it often. I think the instructions would advise against it.
Thus a range of 30 miles is the worst case conditon.

However, you can realisticaly drain the whole battery in 1 hour without damage to the cells so I used a 1 hour discharge rate.
14.2 Kwhr used over 1 hour is obviously a 14 kw motor power draw, which equates to 14.2 / 0.746 = 19 hp.
I was then very generous and said that under ideal conditions, since they claim a top speed of 102mph, lets say they achieve that with just the 19hp (14kw) power. Since that was for 1 whole hour then that makes total distance of 102 miles, which is still a long way short of the claimed 171 miles even using the most wildly optimistic figures.

So,.. let's be a bit more realistic.
I think 14 kw under no wind and flat road and small rider lying flat on tank, would give a speed of about 65 miles per hour. Thus the range of the bike at 65 miles per hour would be a lot closer to 65 miles than it would be to 171 miles.
If someone says you could get 75mph out of a 19 hp motor, that still only gives a range of 75 miles.

Next off,..what conditions might result in a range of 171 miles?
We can try an educated guess here,..
With a power draw of say 3.25kw you could expect a speed of around 40 mph, and the battery at that rate would last around 4.4 hours.
4.4 hours at 40 mph would give a range of 176 miles.
These are ball park figures and they still assume a 100% efficient motor.
They also assume no start/stop driving, and very easy throttle application,.. which no-one actually does in practice.
But yes,.. around town at 30 to 40 mph and very easy on the throttle, and a new battery, you could probably get the 171 miles stated. But who's going to do that?