Build spec by committee, might that include you?
- Thread starter FastFreddy2
- Start date
I have a very similar kit of the same company. Just a front wheel hub. While it is perfectly fine for roads and very gentle offroad tracks I would never use it on any mtb track. For that only mid drive.
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Let me repeat this once again ....
Let me repeat a recent remark: In 25 years of off-road cycling I have never seen a uniformed person while out. So even if there was a need for 'plausible deniability' fitting a 48v battery in lieu of a 36v one, I don't expect to be challenged. Not the case case perhaps along disused rail tracks (although no uniforms seen there either), although I have seen uniformed people on boats racing up and down the Thames. Doubtless helping folk in trouble on the water, not on bicycles.
Sadly, it appears I'm not going to get answers to the technical queries. I've said I'm not going to use a throttle, and a third of the replies tell me of the benefits in using one. I've said I'm going to have a hub motor, and now I'm being told of the benefits of a mid-drive.
This thread was a request for technical help. I seem to have made a mistake in asking.
After some 12+ miles of what seemed like nothing but hill climbs, with my chunky mud grade tyres literally full of mud, I had to get off my bike and push it up what might have been the 15th steep hill we had gone up that day. There is no way I need a mid-drive for the off-roading I do. Maybe in 5 years I might need it, but right now, 10% extra help up that hill would've kept me riding not walking. I still climbed a couple more hills before getting home. I live in Hertfordshire, not Yorkshire or Wales. I'm looking for something that will nudge me along when I need it, not something that provides help across all gears.
If I were that keen, I'd buy something with an integrated system, but many I have read about, are just too unreliable. I'm not spending £5k on a bike that I have to throw away when the warranty runs out. Or have to spend another £1k replacing motors every two years or similar sort of money having battery packs replaced by specialist companies.
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double the voltage half the amps half the voltage double the amps so more voltage is what you want as less amps less heat.
I've already mentioned 10mph is fine for me. I manage 8-9mph average speeds off-road. I go out for exercise, I don't race, but I'd like to be be out for longer periods. I've mentioned a canal (path) trip that might be 17 miles + 17 miles in and out of North London. I'd like to start further out, so possibly 25 miles + 25 miles, at likely 6-8mph so I'm no danger to pedestrians.
Unlike your good self, I'm a plodder.
What I want to avoid really, is buying a "kit" as I linked earlier, 36v battery + 250w hub motor, to find it doesn't help enough getting up 20 hills while I'm out on a ride. I'm pretty sure it will, I've no reason to think it won't, but I don't want to be replacing everything if I've made a mistake. Basically, I'm looking for an escape route if I make a mistake.
A hub motor marked "250w" if used with a 36v battery, but fitted with a compatible duel voltage controller and a 48v battery, seems like a viable escape route that another member here had managed with some success. But I don't have the technical knowledge to make sure I acquire the right hub, the right controller (integrated or otherwise), and the right battery adapter I might use for both 36v and 48v batteries. I have access to a 36v x 20ah Hailong 1 battery with blade connectors. Before I commit to buying a similar battery, I could trial the 36v system. If it proved more grunt was necessary, I would buy a 48v with the same battery housing and connector system. If such a choice exists....
A question I had asked I think I may have worked out the answer to, was providing lower voltages to a motor. I had suggested a motor might work at 36v and 48v. I know there will be internal wiring differences, or at least there is some acceptance this is the case. I know there are windings for speed, windings for torque. What I found out (by accident) was that not only are amps throttled, but voltage is too? Meaning, a 36v hub will not overheat with less volts, but will just produce less torque? I had thought a 36v system always worked at 36v, and it was the amperage that was reduced. Hence my earlier suggestion that a 48v system (350w motor +48v battery/controller) might not work with a 36v battery. (Because it would overheat.)
I think I worked out some weeks ago, 350w hub motors using a 48v system, were being rebadged as 250w motors when sold with 36v batteries and controllers. My 'escape route' would be to fit a 48v battery which does in itself not form part of the restrictive spec. I would have a hub clearly bought, installed, receipted as a 250w hub. Any cursory (and very very very unlikely) inspection would not reveal anything amiss, and I have plausible deniability of any wrong-doing.
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a bafang mid drive will be the best option and there not really that hard to fit to a donor bike and if you buy it from cogs you will have warranty in the uk.
the bbshd is 1000w at 30a with a 52v batt and it can drop me from a standing start buy 50-60m with the throttle alone and has used it for 2 years now in all weathers to get to work on tho going 40mph with a 20ah batt means less than 20 mile range, but he has 4 batts and pay for them self.
so a 36v batt is all you need 20ah batt should get you around 100 miles if you paddle.
id get that also ask neil if there is a option to buld and test the bike for you and ship it white van man might cost 100 quid tho
the bbshd is 1000w at 30a with a 52v batt and it can drop me from a standing start buy 50-60m with the throttle alone and has used it for 2 years now in all weathers to get to work on tho going 40mph with a 20ah batt means less than 20 mile range, but he has 4 batts and pay for them self.
so a 36v batt is all you need 20ah batt should get you around 100 miles if you paddle.
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id get that also ask neil if there is a option to buld and test the bike for you and ship it white van man might cost 100 quid tho
Voltage used for weapons and motions systems cannot exceed a nominal 60 volts, with the maximum voltage allowed for any low-power auxiliary systems elsewhere in the bot is 240 volts. For more information about the electrical system of BattleBots, check out the Design Rules.
ok 60v 600a
ok 60v 600a
motors have constants, Kv, Kt, Km are the most used for selecting the best motor for a job.
Nobody lists them in a table for you to use but wiki motor constants, the article explains better than me.
Hiya. You've appeared to have ended up in the weeds here. Let's start again...
700cc Triban: What gears? 8-speed, 9-speed? What range? 11-32t? Carbon frame, aluminium? Steel?
How heavy are you? Do you need chunky off-road tyres? Do you use panniers and a rack or a rucksack?
Really any 250w-rated rear hub will do. If you can borrow a battery then try that first - you can finesse 36v/48v later.
PS. Welcome to the circus!
700cc Triban: What gears? 8-speed, 9-speed? What range? 11-32t? Carbon frame, aluminium? Steel?
How heavy are you? Do you need chunky off-road tyres? Do you use panniers and a rack or a rucksack?
Really any 250w-rated rear hub will do. If you can borrow a battery then try that first - you can finesse 36v/48v later.
PS. Welcome to the circus!
This is tricky, you're still not getting it.
A motor marked as 250w does not consume or output 250w. It consumes what the controller gives it.
As Saneagle explained, the 250w rating is merely a statement by the manufacturer that the motor will not overheat if fed that power continuously.
So a motor run at 36v and fed 10A will be 'using' 360w. If fed 15A it will 'use' 540w. Now run that motor at 48v with the same current applied and the figures would be 480w and 720w.
The motor will happily run at these wattages for some time as there is always 'headroom' built into the figures.
To re-state. Any motor labelled by the manufacture as 250w will be legal. What you feed into it is up to you and your requirements.
Speed limitation is achieved by the controller, normally via a wheel size setting. It gets rpm feedback from the motor so knows what to allow at the stated wheel size. So long as this is limited to 15.5mph, the bike will be legal.
Kt controllers are dual voltage (36,48), it is possible to run a system on either voltage with one of these. Motors are not voltage sensitive (within reason) and a motor specced as 36v but run at 48v will give approx 30% more power and torque. Speed will still be limited to 15'5mph as this is rpm derived. So the bike will still be legal.
So this controller:
is a dual voltage 22A sine wave controller. 22A is the maximum current only achieved in the top assist setting. At 36v this will give 792w, at 48v 1056w. It would need to be backed by a battery with a maximum output amperage of around 30A in order to avoid voltage sag and potential battery damage/life shortening.
Sine wave controllers make the motor quieter as opposed to square wave where the motors tend to growl more at low revs.
A motor marked as 250w does not consume or output 250w. It consumes what the controller gives it.
As Saneagle explained, the 250w rating is merely a statement by the manufacturer that the motor will not overheat if fed that power continuously.
So a motor run at 36v and fed 10A will be 'using' 360w. If fed 15A it will 'use' 540w. Now run that motor at 48v with the same current applied and the figures would be 480w and 720w.
The motor will happily run at these wattages for some time as there is always 'headroom' built into the figures.
To re-state. Any motor labelled by the manufacture as 250w will be legal. What you feed into it is up to you and your requirements.
Speed limitation is achieved by the controller, normally via a wheel size setting. It gets rpm feedback from the motor so knows what to allow at the stated wheel size. So long as this is limited to 15.5mph, the bike will be legal.
Kt controllers are dual voltage (36,48), it is possible to run a system on either voltage with one of these. Motors are not voltage sensitive (within reason) and a motor specced as 36v but run at 48v will give approx 30% more power and torque. Speed will still be limited to 15'5mph as this is rpm derived. So the bike will still be legal.
So this controller:
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Sine wave controllers make the motor quieter as opposed to square wave where the motors tend to growl more at low revs.
All, good stuff, but would you say a 22A controller is really needed? If going that high you need to make sure your battery pack is able to deliver 22 A+ continuously.
Aluminium dropouts stopped me considering installing a powerful (22A) but legal 48V 250W rated rear hub motor to my Dahon Espresso.
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I had a look at the Wiki page as suggested.
I'm embarrassed to say I understood very little, but it looked like a series of formula to determine performance. There are people here that could work out the potential for any given motor, (though I'm not one of them), but at this time, I'm still working out what is or isn't an opportunity. Meaning what might work.
Gears, currently 7 but moving to 8 via a cassette.
Rear sprocket hasn't been bought yet but 11-32 is likely.
Frame aluminium.
13st.
I have chunky tyres for offroad, less chunky ones for tarmac. 52mm/2" width for both.
Thank you for the welcome.
Bushes are full of badgers. Trust me.
that's forest of dean with a bosch performance motor 63nm 42v batt 20a controller.
robins wood hill Gloucester.
there all my vids