Hello folks, need some unbiased advice. My wife is looking for a replacement for her Smartmotion E-metro. She has been very pleased with it, but on a recent trip, she struggled to climb a short, but very steep hill. Bike has 3spd hub gear and battery (10 Ah), was fully charged. Looking at different bikes today, a dealer suggested she needs at least a 16Ah battery (discounting crank drive bikes due to cost) because they give you more power. Now I'm a Mech Eng., not an Elec Eng., but I always thought that battery capacity only affected how long the battery would provide power, i.e. range, and had nothing to do with performance. Is the dealer correct, or do I smell B.S. ? Thanks, Mike.
Battery capacity / bike performance
- Thread starter Mikeyb
- Start date
A larger capacity when under load gives a very slight power gain due to lower resistance in issuing the current, but not crucial enough in this case to solve the problem.
The real problem here is twofold, firstly an average power hub motor, not ideal for very steep hills and the limitation of the 3 speed hub gear. Some lower gears would enable your wife to give more effective help to the motor when the speed drops.
An e-bike with a more capable motor and a larger number of gears would be ideal, even if it had a 10 Ah battery, so long as the battery delivered current ok.
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The real problem here is twofold, firstly an average power hub motor, not ideal for very steep hills and the limitation of the 3 speed hub gear. Some lower gears would enable your wife to give more effective help to the motor when the speed drops.
An e-bike with a more capable motor and a larger number of gears would be ideal, even if it had a 10 Ah battery, so long as the battery delivered current ok.
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If you look at the battery level on the LED display panel when riding up that steep hill, you will see one or two or three LEDs go off.
If only one LED goes off, then replacing the battery won't change much, you'll need a stronger motor and controller with higher amps.
If two or three LEDs go off, then replacing the battery will fix that.
D
Deleted member 4366
Guest
A lot of dealers get confused between amp-hours and amps, so maybe that's what was on his mind.
If you want good hill-climbing, you have to find a bike with a high-torque motor. Battery size has virtually no direct bearing on torque. Though if you use a lot of power for climbing, a bigger battery will last longer.
If you want to increase the the climbing power of her present bike you can add a bit of solder to the shunt in the controller, which will increase the torque by about 30%.
If you want to get a new high torque bike, the Woosh Big Bear LS will do the job.
Thanks for the replies and advice everyone. You have confirmed what I thought. Yesterday we tried a Smarta at our local Electric Transport Shop in Bristol ( not New Zealand trex, but that is indeed where the Smartmotions originate from, and I'm impressed with their quality). This bike certainly had more 'oomph' than the Smartmotion,and although very keen,we decided to continue looking for a little longer. However, checking E-bay this morning I found that the ETS are selling some Smarta LX7's for £500 !!. .They have been used in a trial for 3 months, but will be checked and given same warranties as a brand new bike. Snapped one up and saved bags of dosh. My wife will use this, and I will use her old bike. As I don't have her medical problems it will suit me fine. Might even try d8veh's mod. Thanks again, Mike.