old bikes, new batteries ?

[mitty]

Hi guys, I was wondering if older bikes such as the original lafrees with crank motors and big heavy batterries (9kg +) can be replaced or recelled to make the battery lighter and more poweful ? recycling good bikes should be an option, if so which are the bikes to lok out for ?

cheers M

 

[flecc]

It's perfectly possible to build an NiMh cellpack into the SLA casings on these bikes, but it might not be worth it. We're are at the stage where there's an increasing number of failures of the original SLA Lafree models now, there's been about three reported in here, and both A to B magazine and I have also been contacted by other owners both in the UK and the USA with problems.

It's not just the old Lafree, E-bikes won't last for ever, and that's likely to be especially true of earlier models from 2000 or before. They only appeared first barely ten years before that, and it's only now we're halfway through the second decade that the market and model design is really maturing.

If you did go ahead with recelling a battery with NiMh cells, you'd need to build in a thermistor, and those are specified by the charger being used, not the battery itself. Some suppliers include a thermistor with the charger when purchased, but that's rare. However, good chargers have their specification available which makes it possible to buy the thermistor separately from RS Components etc.

Recelling using Li-ion types isn't practical and could be dangerous, but a complete Li-ion battery of suitable voltage and capacity could be substituted.

Given my comments at the beginning, I've got no model recommendations for this action, todays bikes are so much better in my opinion.
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[mitty]

Thanks Flecc, I was just curious as there was a lafree on ebay which looked in good nick for a couple of hundred
http://cgi.ebay.co.uk/giant-electric-bicycle_W0QQitemZ300102334224QQihZ020QQcategoryZ33503QQrdZ1QQcmdZViewItem
I was wondering if it was just the battery technolgy and weight which let these bikes down ? Also would you reccomend the quando 2 over the sprint for pulling a couple of kids (30kg in total) in a trailer in a hilly area, top speed is not a big concern as there are kids in tow. Have you ever tried out any of the more powerful hub kits which are availible for "off road use" such as the heinzmans' or the puma ? would these give the same performance as the quando on hills but on a larger wheeled bike which could be ridden unassisted without the trailer ?

thanks M

 

[flecc]

It's just the reliability factor that cause me to rule out the older designs, the weight isn't much of an an issue once the SLA is removed.

Both the Quando and Sprint will do the towing job well, but the Sprint's gears could prove useful. The Quando II is best for fairly fast climbing as the 70" gear isn't so suitable at slower speeds. The kids might prefer the view from the trailer with the Quando though, as they won't have so much wheel in the way.

I'd decide this on the basis of how steep the hills are. If they are up to 10 (1 in 10) at most, I'd choose the Quando, but with 30 kilos plus trailer, hills steeper than that might be easier at lower speeds with the seven speed hub gear as it would mean sometimes standing on the pedals for the fast climb on the Quando.

I've never tried the modern (illegal) performance motors, but most are meant for speed rather than pulling power. Many use the higher voltage route for that. They will tow more powerfully to some extent, but it's in speed that there's most of the gain. One problem is that the range is almost invariably short, 10 miles at most being common, so a second battery may need to be carried.

As speed is not a problem, you might consider the legal geared down hub motors which pull much better than those standard geared. There's the Heinzmann low geared version with 11.5 mph maximum assist speed but very good hill climbing, and there's also the eZee Chopper which could be good for the job. Basically it's the Sprint with 20" wheels instead of 26", so for hill climbing and towing it's very powerful, it still has the Sprint 7 speed hub, and the view for the kids would be better too. The only possible problem is if you are fairly tall, only for a rider up to 5' 6" according to 50cycles.

 

[mitty]

Good info as always, the hills where we are in falmouth cornwall are steep 1 in 10 to 1 in 6 at worst i guess, but in town none are more than half a mile in length, I am trying to source bikes for both myself 6' and my wife who is 5'6" aprox.
I tried a sparta and a old twist in london and realised I would need more power or better gearing/smaller wheels for cornwall if I hope to replace the car for most local journeys.

thanks again M

 

[flecc]

The Sparta wouldn't be a good choice for hill climbing. For me those hills and towing indicates a Sprint for you and a Chopper for your wife. Either could do the towing. If you are a reasonably strong rider the Sprint will handle the steep hills but it would mean some strong input from you when towing that 30 kilos plus on the steepest of them. I think the Chopper's 23% better hill climbing due to the smaller wheels will be appreciated by your wife. If you rode together you'd need to throttle back to stay with the Chopper at around 12 to 13 mph on the flat. If you are doing the towing that wouldn't be a problem though.

 

[Baboonking]

Mitty,

Nothing to stop you either modifying an exisiting second hand electric bike for more torque or building yourself new bike using higher power/torque motors like the puma (especially) or crystalyte motors. In answer to your question about batteries, there is no technical obstacles to higher power electric bikes only the UK law. Building/modifying your way to a more powerful ebike is a road less travelled and requires a bit more input, both in learning about electrics and fixing the bike together Not as easy simply buying a normal UK electric bike.

As Flecc says you can rule out standard battery packs as they will only give something under 10 miles range. There are larger nimh and lithium packs available that will give long range and a lot of pulling power but they do cost more money.

I have one home made bike that I plan to use for towing all my building materials to and from work, which has stacks of torque and I'm modifying an old powabyke as a backup bike, if all goes to plan this will also be able to tow a heavy trailer up hills.