Best for hill climbing. 350watt vs 250watt

Pennybeth

Finding my (electric) wheels
Sep 1, 2015
5
0
78
Hi
Seeking some advice on the best ebike for hills. Age and size dictates that I need to get up steep hills relative easy....to help me decide I had a ride on a 350 watt speed pedalec recently and found it excellent on the hills (although how someone is able to pedal one up to 30mph beats me!)
I do not want to purchase an illegal pedalec so would rather stick to a 250watt 15mph limit....but will this make it less powerful on hills and what bike should I be looking for please?
Many thanks.
Brian
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,913
8,529
61
West Sx RH
Staying legal, opt for more voltage as more voltage means more torque, it also means more speed (but only if used unrestricted) esp on level terrain but for hills torque is where it counts. Look for a 250w 48v bike or kit though there aren't many about.
Woosh sell kits 48v 250w not sure about their built bike line up, though they will convert a bike for you with a kit.

Wisper sell their new Wayfarer range with a 40v system so it has 10/11% more torque and power over conventional 36v bikes.
36v is adequate but for hills 48v just gives that bit more power, I say bit more power we are talking 33% more. The power doesn't make the bike illegal as the power is only temporary power, what counts is the bike/motor is rated and marked as 250w.
 
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Nealh

Esteemed Pedelecer
Aug 7, 2014
20,913
8,529
61
West Sx RH
The other main issue to consider besides bike style is the drive system, some riders like the torque sensing crank PAS systems that give more power up to 300% the more effort you can in put. Ideal for those who don't have serious health issues, the other system is cadence PAS system mostly found on hub drive bikes, the sensing is a simple magnet & sensor set up that simply needs the pedals to rotate. No real exertion is needed to get going and if one tires or has health issues are ideal, also one can have a throttle that is configured to pedal first then one can activate a thumb throttle to take over.

Ideally you need to try out both types to see which you prefer.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,993
Basildon
250w or 350w means nothing. It's just a label on the motor for legal compliance. In some cases, motors stamped 350w are identical in all respects to one stamped 250w.

The power doesn't come from the motor. The controller decides how much power you get and the battery provides it. Some 250w bikes give a lot of power and some 350w or 500w ones are useless.

Generally, the higher the voltage, the higher the power, so if you need high power, look for a 48v 250w bike. Wisper are 44v, so 20% better than 36v ones, but 10% less than 48v. Some NCM bikes from Leon Bikes are 48v.

The motor controller regulates the power. Typical for 36v is 15A. I saw a Wisper controller recently with 17.5A written on it, which would be 17% more powerful. Woosh do at least one bike with 20 amps, which would be 33% more powerful.

15A at 48v is the same power as 20A at 36v.
 

Atlav4

Pedelecer
Feb 16, 2020
179
75
Sorry to crash the thread but do some manufacturers make 48v downtube batteries with 20A controller built into the holding cradle housing, and would this be to much voltage/amperage for the 250W aikema s85x motor. Just trying to live and learn.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,993
Basildon
Sorry to crash the thread but do some manufacturers make 48v downtube batteries with 20A controller built into the holding cradle housing, and would this be to much voltage/amperage for the 250W aikema s85x motor. Just trying to live and learn.
Yes they do.
No, it won't work. I think even 15A is stretching it for that motor unless you're quite light and always go fast, otherwise 12A.

20A is about the maximum for an AKM128, which is twice the size.