Mini perfomance test

[Footie]

Up to now I have limited my travels to the town and Tesco’s.
My fitness has steadily increased since I started riding my ebike. So today I decided to venture out of the town to a nearby small village. The terrain is moderate rolling hills (no steep ones). I wanted to test the bike as a “road bike” to see how it behaved. I thought this test would prove useful to those who are comparing speed, performances, etc.
Personally, I was not disappointed with its performance; in fact I was very pleased with it. It should be remembered that I live in an area with long steep hills and this reflects in my choice of bike. There is substantial rider input on the hills (I have to peddle to get up the hills, long and steep). The bike is a Cougar Mountain Electric Bike, now eight months old, it has a 36v SLA battery and weighs in it 38kg including the battery.

Down hills = No power, 6th gear – (16-21mph)
Flat = No power, 5th & 6th gear – (12-15mph)
Flat with headwind = power, 4th & 5th gear – (12-14mph)
Up hill = Power, 3rd, 4th & 5th gear – (10-14mph)

The stats from my Cateye Vel08 were as follows:
Distance= 6.42 m
Time: 28 min
Avr speed: 13.7 mph
Max speed: 21.2 mph
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[Footie]

OK, I now know two things.
One – I can ride my SLA bike with a flat battery – at least for 2 miles
Two – I think I have a problem with my battery over long distance.

Just been out for a second “road test” and I have had some disappointing results.
At 7.5 miles my battery cut out and then repeatedly cut out after a few seconds use. The power lights were showing two or one. The empty light never lite up.
It was the same route as before only with a bit more road. There was a strong head wind and I had to use power almost all the way.
These North Cornwall hills really take their toll on the poor old batteries. Although, I’m surprised they only lasted 7.5 miles, I would have accepted at least 12 to 15 miles.
Am I asking too much from my ebike
From this, I assume, I can either restrict my cycling to very short distances – 7 mile there and back or look at replacing the SLA batteries with new ones and hopefully get more distance - but will I?

The stats from my Cateye Vel08 were as follows:
Distance= 9.16 m (7.5 m on power, 2 m without power)
Time: 42 min
Avr speed: 13.1 mph
Max speed: 23.4 mph
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[flecc]

That does seem a short range, though I don't know what capacity batteries your bike uses. Ranges can vary enormously, the Currie SLA bikes able to turn in as little as 10 miles with their 24 volt standard batteries, while Powabykes can cover around 22 to 35 miles, depending on territory and assistance levels.

Do you know the battery capacity, A/h ?
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[Footie]

Do you know the battery capacity, A/h ?

In a word flecc, no.
No details at all, so they could be anything.
The range was quoted as "Approx 10-25 miles" - 7.5 mile seems well on the low side (too low).
It was also a rushed replacement, with my original having to go back with buckled forks.
Can't do any more now, as I have to go to work, but tomorrow I think I might open the battery box and have a peek inside.
Any idea what should they be?
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[flecc]

Could be anything from 7 to 12 Ah on each of the three batteries in the box.

If they aren't marked, just measure the three dimensions of one battery in millimetres and we can tell from that.

Those hills are wicked, and in combination with the bike weight will certainly account for much of the problem if they give the start point of the range as 10 miles, since suppliers are usually optimistic on range. Your own weight will also be a factor of course.
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[Footie]

I have had a peek inside the battery box.
Unfortunately I can’t get the batteries out - very tight and I don't want to bugger anything up.
They are 110mm x 85mm x *100mm high
(*estimated by measuring all three in height and dividing by 3)
Everything is in ~#^&*&^$ on them except the following:
XK06 - 044 - 00367
5110410307240
There is a round sticker with the following numbers on it - 1105293
They are green with a black top.
Is that enough information to work out what they are?
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[flecc]

You've measured very accurately, that is a standard SLA battery size, and usually 7.2 Ah each, so that's your batteries capacity overall since only the voltage is additive in series.

So given your hills and the fact that motor seems to have plenty of power, that short range is possible. Unfortunately an e-bikes hub motor is at it's most economical at near to full speed, and when climbing a hill at around 8 mph or less, the consumption is at the maximum. Therefore there are large differences in range between someone in a fairly flat area and in a hilly area. Hence the manufacturers span of indicated range, 10 to 25 miles.

The important factors are weight, hill steepness, your contribution which you've said is high, and wasted kinetic energy. That last one is keeping your speed downhill slower by braking. My main bike probably isn't much faster than yours, and I'm in a very hilly area, but my average speed over time even without pedalling most of the time is 15.3 mph, and it can rise with the usual full time pedal assistance. Part of the reason for that is letting the bike have it's head downhills, 24 to 38 mph typically depending on hill steepness, the speed then carrying the bike a long way over the following stretch, all of that distance gain without battery use of course.

That's obviously ok if you feel comfortable and the bike seems safe at that, but safety must come first of course.

At 8 months old your batteries could be getting on for half way through their life, and capacity deterioration is continuous from the start, so the 7.5 miles is possibly not far off a reasonable expectation in those conditions with a heavy bike, but without knowing the technical details of the motor I can't be more precise.
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[Footie]

Thanks flecc for the help.
Not a lot more to say then.
Basically I’m at the limit. My fitness may improve (some more) and I suppose a bit of weight lost won’t do me any harm. However, fitness will be limited as I have a heart condition, which limits what I can do at high-level exercise.
That’s unfortunate as I wanted to use the ebike further a-field but it appears the North Cornwall hills have screwed me on that one
Looks like this area is not so good for ebikes after all.
I’ve looked on the Internet and I can’t find any the right size, that are 7.2 Ah – found some 5 Ah (£26 each) but that’s going the wrong way. Not a lot of point re-newing the batteries anyway, as it looks like I have hit the limit of my ebike usefulness – Tesco’s and the pasty shop all under 7.5 miles round trip.
Have to get my Kawasaki VN800 out of the shed if I want to go further

PS: Maybe it's time to drag the old none-electric mountain bike back out of the shed and pump up it's tyres. At least I wouldn't have to drag a dead cycle, if I go further than 7.5 miles
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[flecc]

The Kwaka's the easiest option.

This North Cornwall and Devon problem of the hills has often cropped up in here from the beginning, and the popular option is the bikes with the Panasonic power unit. The old Lafree Twist series bikes would still do between 15 and 20 miles while climbing just about anything, and the Kalkhoffs with the higher capacity battery and increased efficiency of the new unit could easily do at least 30 miles. They are slower overall though, more like 12 mph average in those conditions, and of course the price.
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[Footie]

Just had a thought.
Would it be worth replacing the SLA batteries with Lithium Batteries?
I am thinking, this would mean less weight and possibly more powerfull batteries?
I have emailed Powabyke as they have a page on their website about lithium battery replacement.
Anyone know anyone else who would be able to do this? - I would obviously need a new charger too.
I'm not ready yet to give up on my ebike
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[flecc]

Frank Curran tells me the Powabyke lithium battery is much smaller than the casing, so it should fit in yours. You may be able to fit it yourself as it would only be a matter of connecting the two output wires and mounting it so the charger socket was accessible. Using their charger would mean it would be safe.

The only thing is that you'd be spending more than the bike probably cost in the first place.
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[fcurran]

Hi footie, I think I replied to your email earlier. Powabyke's lithium batteries come ready made into our cases specifically for our bikes however it could be worth contacting a guy called Berni from a company called Bikes and Batterys 01780 471 010 or 07913 740 055 who should be able to swap the batteries into your case. He will also be able to tell you if the batteries would be compatible with your bike. I don't think it will be a problem though. We have 2 different types of lithium batteries, LITHIUM LITE 6ah or LITHIUM PLUS 10ah. Range is circa 10 miles in pure power for the LITE and 20 miles+ for the PLUS.

Regards

FrankC
Powabyke Ltd
fcurran@powabyke.com
01225 443737

 

[Footie]

Thankyou FrankC for your reply. I emailed Bikes and Batteries (because I was working odd shifts this week and not able to call them) unfortunately, not had a reply from them.

I have searched and emailed a number of other companies and it appears that the battery I want (dimension wise 110x85x100 high) is no longer available. The forum posts back this up, as other members appear to have had the same problem.
So I am now faced with the problem that when my batteries do eventually die I won't be able to get batteries to fit my bike at all

However I have a question that the forum members may be able to help with. I can get a 12v 7ah battery but its dimensions are (151 L x 65 W x 98 H).
My question is, can SLA batteries be used when turned on their sides?
If they can, I could use three of these (on their side) modify the case (lengthwise) and everything would be ok. I have 465mm from the power pins to the under side of the rack and 525mm to the under side of the seat - it may mean the rack has to go.
Any one know if this will work?
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[flecc]

Yes, they can and that would work fine. The normal orientation of SLA batteries with their gel electrolyte isn't vital.

While your size of battery isn't available here, they are still available in China in around 6 Ah capacity, and I don't understand why no-one is bringing them in.
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[Footie]

Thanks flecc, for replying so fast.
I thought they would work on their side but wanted confirmation before I committed my self.
I can know confidently go search for a good battery for my bike and hopefully get a bit more distance
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For anyone else looking for battery suppliers my searching has come up with the following companies - may save you some time searching

YUASA BATTERIES

Rechargeable kids powered bikes, battery ride on toy cars,sit-ons,bikes,battery scooters and more. Over 100 to choose from .

http://www.pentupenergy.co.uk

Maplin > Sealed Lead-Acid Batteries

bikesandbatterys.co.uk

http://www.mdsbattery.co.uk

Electric Bicycle Battery

Batterymasters.co.uk - Sealed Lead Acid Search - Yuasa, Powersonic, Ultra Max

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[flecc]

And to add to Footie's list, here's another one recommended by Jeremy:

Component-shop
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