Help! Upgrading my bike for hills

Alex-thebiker

Just Joined
May 4, 2023
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I have some ideas to upgrade my ebike from a kit
Currently I have a Yose 250 watt ebike kit

1. Can you put 2x 250 watt motors on a bike without getting a license and how good is it going up hills / fast ?

2.is it possible to use a higher 1000 watt motor to some how recharge the battery(I think it would be connected to a small batter to sore the power
but would it classed as a moped even though it's used for charging the battery if it does work

3.if I keeped just the 1 motor but upgrade the controller a little higher say 350 or 500 would it improve the speed - I've read it can heat up the motor too much ?

I have very steep hills with my location?
 

flecc

Member
Oct 25, 2006
52,819
30,381
I have some ideas to upgrade my ebike from a kit
Currently I have a Yose 250 watt ebike kit

1. Can you put 2x 250 watt motors on a bike without getting a license and how good is it going up hills / fast ?

2.is it possible to use a higher 1000 watt motor to some how recharge the battery(I think it would be connected to a small batter to sore the power
but would it classed as a moped even though it's used for charging the battery if it does work

3.if I keeped just the 1 motor but upgrade the controller a little higher say 350 or 500 would it improve the speed - I've read it can heat up the motor too much ?

I have very steep hills with my location?
All three are illegal, only one 250 watt rated motor is legal.

However, with option 3, if your motor is marked and rated at 250 watts, using a higher current controller will give you the increased hill climb ability and wont be detected or looked for by the authorities.

You'll need to tell us what motor or controller you have at present, post detailed photos of them if not sure.
.
 
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saneagle

Esteemed Pedelecer
Oct 10, 2010
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You have three options:
1. If you have 36v, increase the voltage to 48v with a new battery. Depending on what controller and LCD you have, you might need to replace them too.
2. Replace the controller with one that allows more current. Look on the label to see what the max current is. 30% more current will give you 30% more hill-climbing power. This depends on your battery being able to provide the power. You need to look at the original listing to see what they say is its max current. You need a bit of headroom otherwise the battery will cut out - say 25A battery for 20A controller.
3. Add some solder to the shunt in the controller. That will increase its maximum current in proportion to how much of it, you solder. A blob that covers 20% of its length will increase the current by 20%. Don't go more than 25%. The same applies about the battery.

All three options are completely legal as long as you keep the speed limit at 25km/hr.
 
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Cadence

Pedelecer
Feb 23, 2023
178
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I recently bought a Yose 250w. rear wheel kit. It came with a 15 amp max current controller. I have substituted this with an 18 amp controller that Yose sell as a "350w. rear controller". This has improved the hill climbing ability quite significantly. It has also "unlocked" the throttle, which was fixed at 4-5mph "walk assist" with the 15 amp, but now full throttle is available with the 18 amp.
What it hasn't done is allow an increase in top speed. There is no speed setting function on Lishui C500 display that came with the 250w. kit. It's possible that a C500 display bought separately would have a speed setting function (it has on another, 350w rear wheel kit that I bought), but I'm not bothered about increasing top speed with the 250w. motor. I did try swapping the displays over just to see what happened, and the 250w. did then have top speed adjustment.
I see yours is a front wheel kit with a front light. Your controller will have 5 leads and a 5-in-1 main cable. If you want to fit the 18amp controller you will need to ditch the light and probably also buy a new 4-in-1 cable, which is also available from Yose separately.
It is all "plug and play".
 
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Alex-thebiker

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May 4, 2023
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Ok thanks for the advice I'll look into it more later , is it possible to get it cheaper from another company or could there be a risk of being not good ?

I hardly use the light anyway because I've got a much more powerful one that has another rechargeable battery
 

Cadence

Pedelecer
Feb 23, 2023
178
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I've ordered all my Yose stuff from Yosepower UK. Both of my kits arrived within 3 days. The controller took 3 weeks to come from China. They seem to be cheaper than ebay or Amazon, but the prices do fluctuate. If you are going to order a C500 display I would suggest you use the "from China" option as you can be more sure of getting one with a speed setting function. It's possible that their UK stock is "UK or EU legal" - no speed setting. (just checked- they are showing no UK stock anyway at the moment.)
I have found the customer service via email very good.
 

AndyBike

Esteemed Pedelecer
Nov 8, 2020
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All three are illegal, only one 250 watt rated motor is legal.
In a road setting. But hills imply offroad which makes it effectively private land. But even if it is publicly owned land, the cops arent really patrolling the area.

Whatever you come up with to help the going up bit, the real danger is the
going down bit.

Brakes arent just a cosmetic addition, you need to spend real money on them, and be of the type that have been reviewed by people who ride down these hills.

A 4 pot, probably £100 per end
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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It is nonsense deciding whether to buy a 350w or 500w controller because the power rating means nothing , one needs to think in terms of current/amps and not a label watt rating. Before upgrading one has to know the spec of the battery and it's continuous current/amps out put and not the higher temporary output it might handle.
With that said one idealy needs the battery to have margin of current rating greater then the controllers max rating so it isn't just a case of buying a new controller, one has to think about the battery rating as well.
 
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Cadence

Pedelecer
Feb 23, 2023
178
143
It is nonsense deciding whether to buy a 350w or 500w controller because the power rating means nothing , one needs to think in terms of current/amps and not a label watt rating. Before upgrading one has to know the spec of the battery and it's continuous current/amps out put and not the higher temporary output it might handle.
With that said one idelally needs the battery to have margin of current rating greater then the controllers max rating so it isn't just a case of buying a new controller, one ahs to think about the battery rating as well.
Indeed, you are quite right. I bought my Yose 250w. kit complete with a 36v/13ah battery (max continuous current 20amps). They supply the same battery with their 350w. kits, so i didn't forsee any problems with using their 18 amp controller that they supply with the 350w. kits for the 250w. motor - which there aren't. I have the max current set at 15 amps via the display.
I've just realised that the OP has bought a kit without battery. He hasn't said what battery he is/intends using.
 
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Bogmonster666

Esteemed Pedelecer
Jun 6, 2022
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I have very steep hills with my location
How steep are the hills. Or perhaps what gradient of hills can you currently get up adequately with you current configuration Vs what gradient hills do you want to get up?

E.g. if you can comfortably get up only a 10 % hill today, then increasing the current by 30% is unlikely to get you up 25% hill.

And then there is gearing, can you reduce your bike gearing to allow you to add more effective rider input whilst not slowing your progress down so much that the motor becomes bogged down?

You can use the ebike motor simulator to calculate the likely torque and power loaf for a given gradient and base some calculations off that.
 

Alex-thebiker

Just Joined
May 4, 2023
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36V 10A , that's my current battery
My old bike is a Appollo bike from halffords
I live 9 miles from the nearest town
The hills are pretty steep but like the ones at Rutland water
The use age is mainly on on the Uk road
I have a transport box at the back for storage

So the options I have is

350 controller mod or 500 controller
Increases the battery 48v for more powers

If I upgraded the rear gears what would you recommend for value for money?
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
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36V 10A , that's my current battery
My old bike is a Appollo bike from halffords
I live 9 miles from the nearest town
The hills are pretty steep but like the ones at Rutland water
The use age is mainly on on the Uk road
I have a transport box at the back for storage

So the options I have is

350 controller mod or 500 controller
Increases the battery 48v for more powers

If I upgraded the rear gears what would you recommend for value for money?
We already told you. You choose a controller on the basis of current (max amps), not watts. In some cases a 250w controller will give you less hill-climbing power than a 500w one.
 
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Nealh

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Aug 7, 2014
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36v 10a is incorrect , it is 36v 10ah there is a big difference . The ah decides the battery capacity x the voltage gives one the theoretical wh usage .
What you need to know before buying a controller is the battery continuous current (CC) out put , is it 15a , 20a, 25a or something else.
For instance if the battery has only a 20a CC then one is restricted to a 15a or 17a controller.

One needs to be guided by the battery specs then from there can decide if it is feasible to upgrade to another controller or shunt mod the controller. If the battery is lacking the required CC one has to si mply get on and use what they have or buy another better battery that can handle more current.
 
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