Before I rush of to buy a Kalkhoff....

[Jeff Mowatt]

I bought an Izip CB26 for a lot less money which I'm not entirely sure is working properly.

There are 3 green and 1 red led, the latter indicating a low charge state. I had the supplier replace the original battery under guarantee, but there's no difference.

After charging it never fully illuminates more than one of the green leds. It seems to be pretty good at helping up hills, for a short distance with me giving it some grunt, but runs out of steam after only about 3 miles uphill. It can't be that steep because it's a former rail track I'm using and I can do it on a conventional bike with a little more grunt. I would guess perhaps 8%?

To be fair, I have put on weight and with my 110kg and the bike at about 40kg thats over 300lbs to be heaving around. I could be expecting too much though it still seems as if the battery may not have charged fully. It's lead acid BTW, for those not familiar with the model.

What I don't want to do is go off and buy a better bike when I could be expecting too much from them.

Jeff

 

[jimmyengland1000]

I don't think you're expecting too much from an electric bike....just too much from that particular one. Your bike weighing in at 40kg won't help things and lead acid batteries are very heavy. A Wisper 905 weighs about 22.5kg including the battery (li-ion)... getting on for half the weight of yours and mine copes with me (12.5 stone) and little boy on the crossbar (3.5 stone)... we go everywhere on it, including hills etc. We also pull a trailer! We regularly got 26 miles from my first Wisper 905e and I would guess even more out of my new 905SE

If you are thinking of a Kalkhoff gents frame version (diamond frame), I would bear in mind that you might have a long wait for it to arrive (check this forum).

Have a look at Item number: 330213927939 on eBay. The bloke selling them is trustworthy and my own 905SE came from him originally. If you buy it, you will possibly need to modify the wiring... easily done and the instructions are on this forum. Dominic (the seller in Germany) may have started modifying them himself though as I told him about it (you could ask when buying). They had a small wiring fault originally but it takes 15 mins to fix and is very easy to do...

 

[fishingpaul]

Hi jeff are you talking about a 3 mile hill or a mixture of flats and hills,if you look up extra energy.com, they have tested many electric bikes,even the best electric bikes, often only managed 3 to 5 miles of constant hill climbing,or 20 to 30 miles on a mixture of mainly flat surfaces with a few inclines,hills can really flatten batteries very quickly.extra energy probably only tested with lighter riders,extra weight would see these figures tumbling further.

 

[Jeff Mowatt]

Fat man on a bicycle

Hi Jimmy & Paul,

Yes, these were constant climbs. I live in a valley so everywhere is uphill.

Talking to an electronics engineer neighbour yesterday, he suggested that although the battery charger may be indicating a full battery it might be worth leaving on overnight. He said the potential difference being smaller toward the end of charging might mean that leaving it longer could have the desired result. I did that, and checking it on the bike this morning there's a difference with the top two leds lit, albeit faintly. I'll test the hill again later.

That Whisper bike certainly looks the business, disk brakes would be an asset around these parts for the other problem - 150kg total weight going downhill is quite something to stop.

Riding a 40kg bike with a flat battery is rather akin to letting one's tyres down. I had to keep looking.

BTW As an aside, yesterday I found a blog site for that Frisbee bike from Italy. Right at the end there are specs for a sport model weighing in at 16.9 kg and limited to 85 km/h if I'm reading it correctly as 'maximum velocity'

Weblog FRISBEE®

Jeff
Jeff

 

[flecc]

It can't be that steep because it's a former rail track I'm using and I can do it on a conventional bike with a little more grunt. I would guess perhaps 8%?

What I don't want to do is go off and buy a better bike when I could be expecting too much from them.

Jeff

The steepest railway gradient in the UK is 7% Jeff, and that is quite exceptional, so your old track route is unlikely to be more than 6% at most.

The advice to leave on charge overnight with lead acid batteries is good, since they do continue to gain at a trickle rate. However, I think weight and the fact that the Currie motored bikes have short range anyway are the keys to the problem.

A typical 70 kilos rider on a normal bike with Currie motor added, weighing about 32 kilos, and in moderate territory can have as little as 10 miles range. Fifty percent more weight needs 50% more power, corresponding to a big reduction in range at low speeds.

You would get much better performance and range from a good powerful bike with a more modern battery, like the newer hub motor models from Wisper and eZee.

There's also the Panasonic motored bikes like the Kalkhoff which can handle anything with a long range as well. With that you could expect to climb the slope with ease and still have a 30 miles range. The downside is that they are not cheap, but they are well made and will last for years.
.

 

[Jeff Mowatt]

Calculating the gradient

Thanks Flecc,

I figured out a way to calculate the overall gradient, which for the most part is a former coal hauling track. It's part of the Forest of Dean cycle route BTW.

Thinking about the old OS benchmark on my house , I couldn't find any records of the elevation but I got onto Google Earth which told me I was climbing about 550 feet in the first 2.5 miles.

The bike is perfectly willing in this climb, needing only to drop to the second highest gear on the steepest point, otherwise I could do it in top. So a reasonable bike for a lighter man in flatter terrain I guess.

I'm keen on the pedelec concept, ie Kalkhoff. On the Currie, the 'throttle' isn't much more than an on-off switch and on this makes it more 'electric bike climbs hill with man assisting slightly', which makes it all too easy until the power runs out.

Jeff