Would a 1500w Direct Drive Hub Get Me Up Short but Steep Hills on Full Suspension Bike without frying?

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itsallwhite   100 mW

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Would a 1500w Direct Drive Hub Get Me Up Short but Steep Hills on Full Suspension Bike without frying?

Post by itsallwhite » Feb 27 2019 8:18pm

I've got a GT Sensor full suspension bike I'd like to 'electrify'. I've already got a hybrid bike running a TSDZ2 mid-drive which works pretty well, but I'd like to have a mountain bike too.

I can't do a mid-drive as the way the bottom bracket is mounted isn't standard so its either a geared rear hub or a direct drive.

The mountain bike will be used mostly for short rides towing 2 kids in bike trailer around property where we live (300 acre multiple occupancy community). There are 3 short (20 - 100 metres long) but very steep hills. I can just ride up them on my own without electric without trailer, and can sometimes get up them with trailer on a good day! Roads are gravel / dirt.

Also used for some longer rides on mostly gravel roads, with some hills and some flatter sections.

I have a spare 48v dolphin battery which I think I could mount on the bottom of the frame where there are a couple of water bottle mounts (no room in triangle due to suspension) with some extra zip ties or brackets for safety.

But the bit I'm stuck on is the motor. I'm on a budget with this one and I'd like to do it as cheaply as possible.

I've seen some cheap 1500w 26" direct drive hub motors on ebay. Do you think they would get the bike + trailer up the steep sections? Will I overheat the motor at low speeds but short distances? I am happy to pedal to assist.

Or will I need a more expensive geared motor (like the Mac with 12t winding)?

I'd prefer to go with the cheaper direct drive option if it'll work. What do you think?
Bike 1: Giant Hybrid Steel Frame (old) with TSDZ2 48v 500w.
Bike 2: GT Sensor 2 full suspension mountain bike. Work in Progress - ready to 'electrify'!
House: 100% off grid - 5.6kw solar array with selectronics inverter and 24 Volt 1450 Ah BAE Gel battery Bank

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Re: Would a 1500w Direct Drive Hub Get Me Up Short but Steep Hills on Full Suspension Bike without frying?

Post by Sunder » Feb 27 2019 8:29pm

Most of them should, but it's hard to say for sure without seeing one. It's really just a function of mass and ability to absorb, then shed heat.

Automatic Transmission Fluid, or statorade both help with those functions, so if you're concerned, you can remove the cover, and add a small amount of that into the case, and seal it . (May need some fiddling to get it to not leak, especially when the motor heats).
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Re: Would a 1500w Direct Drive Hub Get Me Up Short but Steep Hills on Full Suspension Bike without frying?

Post by Grantmac » Feb 27 2019 8:31pm

What year Sensor? There is a new mid-drive on the market which might fit, it works better on modern frames than the BBxxx

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Re: Would a 1500w Direct Drive Hub Get Me Up Steep Hills on Full Suspension Bike?

Post by Chalo » Feb 27 2019 8:51pm

The wattage you specify will climb a steep grade with a lot of weight, if it's delivered at a modest enough RPM. I use a nominal 48V/35A direct drive hub motor with a nice slow wind (tops out at 22mph with a fresh battery). My bike plus me and some cargo can easily total 500 pounds. It climbs nicely up the steepest grades I have in my usual circuits (>10%) with only modest help at the pedals. If your bike's gross weight is a lot less, you can either get better performance with the same power or equal performance with less power.

My advice is to make a careful evaluation of how fast you really must go to be happy with your bike. Then get a motor winding that will cruise at that speed, but not faster. That leaves you the largest surplus of torque available at lower speeds.

The very cheapest hub motors don't usually offer a choice of windings to optimize for particular speeds and gradability. Leaf Bike does, and Crystalyte.
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Re: Would a 1500w Direct Drive Hub Get Me Up Short but Steep Hills on Full Suspension Bike without frying?

Post by itsallwhite » Feb 27 2019 9:38pm

Grantmac wrote:
Feb 27 2019 8:31pm
What year Sensor? There is a new mid-drive on the market which might fit, it works better on modern frames than the BBxxx
Thanks, but don't think my budget would stretch to a mid-drive for this one. Think its around 2011. Out of interest though what is the mid-drive might be interested for another project.
Bike 1: Giant Hybrid Steel Frame (old) with TSDZ2 48v 500w.
Bike 2: GT Sensor 2 full suspension mountain bike. Work in Progress - ready to 'electrify'!
House: 100% off grid - 5.6kw solar array with selectronics inverter and 24 Volt 1450 Ah BAE Gel battery Bank

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Re: Would a 1500w Direct Drive Hub Get Me Up Steep Hills on Full Suspension Bike?

Post by itsallwhite » Feb 27 2019 9:46pm

Chalo wrote:
Feb 27 2019 8:51pm
The wattage you specify will climb a steep grade with a lot of weight, if it's delivered at a modest enough RPM. I use a nominal 48V/35A direct drive hub motor with a nice slow wind (tops out at 22mph with a fresh battery). My bike plus me and some cargo can easily total 500 pounds. It climbs nicely up the steepest grades I have in my usual circuits (>10%) with only modest help at the pedals. If your bike's gross weight is a lot less, you can either get better performance with the same power or equal performance with less power.

My advice is to make a careful evaluation of how fast you really must go to be happy with your bike. Then get a motor winding that will cruise at that speed, but not faster. That leaves you the largest surplus of torque available at lower speeds.

The very cheapest hub motors don't usually offer a choice of windings to optimize for particular speeds and gradability. Leaf Bike does, and Crystalyte.
Helpful advice, thank you.

I can see benefits of getting a slow wind and will if budget will stretch to Crystalyte etc. I'm in Australia and if I purchase internationally costs go up quite a bit with weak Aussie dollar and int shipping costs.

I found a 1500w direct drive kit on ebay in Australia. Its $260 AUD (about $180 USD) with free shipping.

Brand: Voilamart. Someone told me hey are re-brands of 9 continent (9C) motors? Reviews seem okay on ebay and Amazon, but understand its 'cheap' in terms of components and quality.

https://www.ebay.com.au/itm/26-1500W-Re ... ctupt=true

Would it do the job for a while at least do you think?
Bike 1: Giant Hybrid Steel Frame (old) with TSDZ2 48v 500w.
Bike 2: GT Sensor 2 full suspension mountain bike. Work in Progress - ready to 'electrify'!
House: 100% off grid - 5.6kw solar array with selectronics inverter and 24 Volt 1450 Ah BAE Gel battery Bank

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Re: Would a 1500w Direct Drive Hub Get Me Up Short but Steep Hills on Full Suspension Bike without frying?

Post by Grantmac » Feb 27 2019 10:13pm

itsallwhite wrote:
Feb 27 2019 9:38pm
Grantmac wrote:
Feb 27 2019 8:31pm
What year Sensor? There is a new mid-drive on the market which might fit, it works better on modern frames than the BBxxx
Thanks, but don't think my budget would stretch to a mid-drive for this one. Think its around 2011. Out of interest though what is the mid-drive might be interested for another project.
CYC Pro1. Significantly smaller diameter, half way to a Tangent in size.

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Re: Would a 1500w Direct Drive Hub Get Me Up Short but Steep Hills on Full Suspension Bike without frying?

Post by Bigwheel » Feb 27 2019 10:26pm

Looks like the price is right and my experience with a similar DD motor would say it is entirely possible to do as you suggest, especially if you are willing to assist pedaling and use low enough gearing so that you are in sync with the motor. At worst you may find the controller to be insufficient but you could save up and get a better one and a Cycle Analyst even at a later date.

I would suggest you invest in some Statorade though. You can drill a through hole using the disc mount to inject it without having to take apart the motor and to apply more in the future. Just keep a bolt in it if you aren't using a disc. I find that Statorade works really well to help with the heat issue as well as it seems to cut down on parasitic drag although that is just a personal theory not based on scientific evidence only my own experience.

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Re: Would a 1500w Direct Drive Hub Get Me Up Short but Steep Hills on Full Suspension Bike without frying?

Post by itsallwhite » Feb 27 2019 10:36pm

Bigwheel wrote:
Feb 27 2019 10:26pm
Looks like the price is right and my experience with a similar DD motor would say it is entirely possible to do as you suggest, especially if you are willing to assist pedaling and use low enough gearing so that you are in sync with the motor. At worst you may find the controller to be insufficient but you could save up and get a better one and a Cycle Analyst even at a later date.

I would suggest you invest in some Statorade though. You can drill a through hole using the disc mount to inject it without having to take apart the motor and to apply more in the future. Just keep a bolt in it if you aren't using a disc. I find that Statorade works really well to help with the heat issue as well as it seems to cut down on parasitic drag although that is just a personal theory not based on scientific evidence only my own experience.
Awesome, thank you. Statorade looks ideal, can't see it in Australia but think I can get if from https://www.ebikes.ca and get it shipped here, will do a bit more digging! Cheers
Bike 1: Giant Hybrid Steel Frame (old) with TSDZ2 48v 500w.
Bike 2: GT Sensor 2 full suspension mountain bike. Work in Progress - ready to 'electrify'!
House: 100% off grid - 5.6kw solar array with selectronics inverter and 24 Volt 1450 Ah BAE Gel battery Bank

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Re: Would a 1500w Direct Drive Hub Get Me Up Steep Hills on Full Suspension Bike?

Post by Chalo » Feb 27 2019 10:40pm

itsallwhite wrote:
Feb 27 2019 9:46pm
I found a 1500w direct drive kit on ebay in Australia. Its $260 AUD (about $180 USD) with free shipping.

Brand: Voilamart. Someone told me hey are re-brands of 9 continent (9C) motors? Reviews seem okay on ebay and Amazon, but understand its 'cheap' in terms of components and quality.

https://www.ebay.com.au/itm/26-1500W-Re ... ctupt=true

Would it do the job for a while at least do you think?
"You’ll be out cruising along at34 mph without a sweat!"
This implies a free speed so high that climbing torque and efficiency are both impaired. Running the same motor with lower voltage and higher current (different controller and battery) would somewhat compensate for that.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

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Re: Would a 1500w Direct Drive Hub Get Me Up Short but Steep Hills on Full Suspension Bike without frying?

Post by markz » Feb 27 2019 11:13pm

Question is how often are you riding on them short but steep hills?
And how long are them hills?

Why not just go ahead and buy the Leafbike kit, yes its a bit more money at $350usd so in AUS/CDN its like $460, but its a great motor if you require more power in the future! And yes you know you will want more power, EVERYONE ALWAYS! WANTS MORE POWER! Leafbike has got great efficiency rate unlike the ebay wonders and generics, it can easily take more power :bigthumb: You want to buy quality that will last and that you know you can upgrade later.

Like Chalo I too have a heavily loaded bicycle of close to 400lbs, mxus 3000W v2 with a 4 turn on a 26" and a 30A can do short steep hills at a decent speed with some help pedaling. If you get a 6T


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Re: Would a 1500w Direct Drive Hub Get Me Up Steep Hills on Full Suspension Bike?

Post by E-HP » Feb 27 2019 11:47pm

itsallwhite wrote:
Feb 27 2019 9:46pm
Helpful advice, thank you.

I can see benefits of getting a slow wind and will if budget will stretch to Crystalyte etc. I'm in Australia and if I purchase internationally costs go up quite a bit with weak Aussie dollar and int shipping costs.

I found a 1500w direct drive kit on ebay in Australia. Its $260 AUD (about $180 USD) with free shipping.

Brand: Voilamart. Someone told me hey are re-brands of 9 continent (9C) motors? Reviews seem okay on ebay and Amazon, but understand its 'cheap' in terms of components and quality.

https://www.ebay.com.au/itm/26-1500W-Re ... ctupt=true

Would it do the job for a while at least do you think?
I got lucky when I picked up the cheapest 48V 1000W kit I could find on ebay:
https://www.ebay.com/itm/322440778491

It's a slow wind MXUS, and with a 52 V pack tops out at 23 mph (24 mph fresh off the charger). I only used the wheel, brake levers and PAS sensor from the kit, and added a half throttle, sine wave controller and display. Climbs great (I live on a hill). I did a 1000 ft elevation offroad climb with mixed grade hills and the motor was barely warm. >20% grade for <100 yards or riding around my neighborhood (6%-10%) are no problem, but I'll feel more confident after I get around to adding some Statorade to it and before really torturing testing it.

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Re: Would a 1500w Direct Drive Hub Get Me Up Short but Steep Hills on Full Suspension Bike without frying?

Post by donn » Feb 28 2019 1:01am

itsallwhite wrote:
Feb 27 2019 8:18pm
The mountain bike will be used mostly for short rides towing 2 kids in bike trailer around property where we live (300 acre multiple occupancy community). There are 3 short (20 - 100 metres long) but very steep hills. I can just ride up them on my own without electric without trailer, and can sometimes get up them with trailer on a good day!
You have a start here, but you haven't got to the point where your questions have answers. Express the kids/trailer/etc. in units of weight (or perhaps mass if you prefer the metric system.) Express the steepness of the hills in percent grade (= 100 x rise/run.) It's OK if you don't know exactly, but these are values that can be used to determine what you can and can't do. Without numbers, we can just say maybe, probably, I ride one and it's OK, etc.

If you can get detailed information about the battery, check the maximum current draw. That 1500W figure means "48V" system with a 30A controller, but the battery you plan to use may for example specify a 20A max current draw.

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Re: Would a 1500w Direct Drive Hub Get Me Up Short but Steep Hills on Full Suspension Bike without frying?

Post by E-HP » Feb 28 2019 2:06am

itsallwhite wrote:
Feb 27 2019 8:18pm

Or will I need a more expensive geared motor (like the Mac with 12t winding)?
Don't forget to use the ebike motor simulator. Not sure the Mac will cut it, based on the simulator, on a 12% grade, with 352 lb payload, the motor overheats in 5 minutes. https://www.ebikes.ca/tools/simulator.h ... 2&axis=mph

There are a few motors that will go for an hour under the same conditions.

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Re: Would a 1500w Direct Drive Hub Get Me Up Short but Steep Hills on Full Suspension Bike without frying?

Post by itsallwhite » Feb 28 2019 4:37am

Thanks for your input and comments so far - I am still looking at options.

I think combined weight (me, bike and trailer with 2 little ones) is about 350 - 400lbs.

Total time on bike: 5 - 10 minutes (except for occasions when I do longer rides on my own).

Roads: Gravel - mostly firm but loose in patches on smallest and steepest hill

Hill length & grade: Basically go up and down 3 hills in a row...

Hill 1 - 20 metres - shortest and sharpest hills. Can ride up unassisted without trailer but need to pedal hard
Hill 2 & 3 - 50 metres each - steep but can pedal up with trailer and kids but its hard work

(sorry I'm not sure how to measure hill grade?)

Its mostly to get kids to school bus stop at end of our property, to ride around our community, and to run them around to friends houses etc nearby. As well as a few extra fun rides for me - but nothing crazy.
Bike 1: Giant Hybrid Steel Frame (old) with TSDZ2 48v 500w.
Bike 2: GT Sensor 2 full suspension mountain bike. Work in Progress - ready to 'electrify'!
House: 100% off grid - 5.6kw solar array with selectronics inverter and 24 Volt 1450 Ah BAE Gel battery Bank

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Re: Would a 1500w Direct Drive Hub Get Me Up Short but Steep Hills on Full Suspension Bike without frying?

Post by TheBMallory » Feb 28 2019 5:10am

if you're still looking for inputs, I've been running a 1500w motor for years on a qulbix raptor (not the lightest ebike)
Image

It can definately climb some steep hills no problem without pedaling (maybe not for more than 20mins though). One thing you can do if your bike allows it and if it doesn't screw up the geometry too much is to get a smaller wheel size. I had before a 26inch rear wheel and switched 2 years ago to a 20inch and the gain in torque was very noticeable

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Re: Would a 1500w Direct Drive Hub Get Me Up Short but Steep Hills on Full Suspension Bike without frying?

Post by Tolkano » Feb 28 2019 7:03am

TheBMallory wrote:
Feb 28 2019 5:10am
if you're still looking for inputs, I've been running a 1500w motor for years on a qulbix raptor (not the lightest ebike)
Image

It can definately climb some steep hills no problem without pedaling (maybe not for more than 20mins though). One thing you can do if your bike allows it and if it doesn't screw up the geometry too much is to get a smaller wheel size. I had before a 26inch rear wheel and switched 2 years ago to a 20inch and the gain in torque was very noticeable
What stem is that? I like that style

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Re: Would a 1500w Direct Drive Hub Get Me Up Short but Steep Hills on Full Suspension Bike without frying?

Post by TheBMallory » Feb 28 2019 7:36am

it's an SB3 terror stem I had laying around. It's not produced anymore

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Re: Would a 1500w Direct Drive Hub Get Me Up Short but Steep Hills on Full Suspension Bike without frying?

Post by AHicks » Feb 28 2019 9:25am

Well, I'm 315lbs, and the bike is a modified Rad City that I've repowered with a 1500w DD "kit" very similar to the one sold by Leafbike. It has a 35 amp controller and a battery able to deliver 25 amps, or maybe a little more for short bursts like a hill might represent.

I would not recommend it for steep hills even with just me on it. I use it in a rolling coastal area, so nothing real tall as far as hills, but some are long pulls and pretty steep. The bigger hills forces me down into 2nd or 3rd gear, peddling hard, and maxes out the available 12-1300 watts in the controller setup. While I doubt I would overheat anything (but me), there is no excess power available. While I enjoy the bike most of the time, it's a very rare occasion where it see 20 mph (unless going down hill).

My point is though I enjoy the simplicity and silent power from the 1500w DD, I think I might like the extra "grunt"/power available with a gear driven rear hub. The fact I'm not interested in speeds over 20 mph means the gear drive could operate easily at the speeds I'm after.

Currently researching my options regarding a switch from DD to gear drive. As the bike is equipped with a KT systems controller and LCD3 display, not sure if it's going to amount to a simple motor swap, or much more.

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Re: Would a 1500w Direct Drive Hub Get Me Up Short but Steep Hills on Full Suspension Bike without frying?

Post by donn » Feb 28 2019 9:58am

Let us know how it works out, when you've made that switch to a geared hub. From haunting the online calculator, it has been my impression that while geared hubs can manage a little better on climbing, you'd still need to get the right hub for it and it would be a close thing anyway. Especially assuming your direct drive hub is the slower configuration that everyone has been recommending here.

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Re: Would a 1500w Direct Drive Hub Get Me Up Short but Steep Hills on Full Suspension Bike without frying?

Post by itsallwhite » Feb 28 2019 5:27pm

Interested in the idea of a smaller wheel, but wouldn't a 24" or 20" rear wheel affect the bike significantly?

Will have a look at geared rear hubs again. Think I need to decide between a cheap kit that will get me started, but might not last for ever, and saving up and waiting a bit for something higher quality.
Bike 1: Giant Hybrid Steel Frame (old) with TSDZ2 48v 500w.
Bike 2: GT Sensor 2 full suspension mountain bike. Work in Progress - ready to 'electrify'!
House: 100% off grid - 5.6kw solar array with selectronics inverter and 24 Volt 1450 Ah BAE Gel battery Bank

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Re: Would a 1500w Direct Drive Hub Get Me Up Short but Steep Hills on Full Suspension Bike without frying?

Post by itsallwhite » Feb 28 2019 6:28pm

E-HP wrote:
Feb 28 2019 2:06am
itsallwhite wrote:
Feb 27 2019 8:18pm

Or will I need a more expensive geared motor (like the Mac with 12t winding)?
Don't forget to use the ebike motor simulator. Not sure the Mac will cut it, based on the simulator, on a 12% grade, with 352 lb payload, the motor overheats in 5 minutes. https://www.ebikes.ca/tools/simulator.h ... 2&axis=mph

There are a few motors that will go for an hour under the same conditions.

looking at the simulator, what motor would I select for a 1000w DD with 470rpm?
Bike 1: Giant Hybrid Steel Frame (old) with TSDZ2 48v 500w.
Bike 2: GT Sensor 2 full suspension mountain bike. Work in Progress - ready to 'electrify'!
House: 100% off grid - 5.6kw solar array with selectronics inverter and 24 Volt 1450 Ah BAE Gel battery Bank

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Re: Would a 1500w Direct Drive Hub Get Me Up Short but Steep Hills on Full Suspension Bike without frying?

Post by donn » Feb 28 2019 8:44pm

itsallwhite wrote:
Feb 28 2019 6:28pm
looking at the simulator, what motor would I select for a 1000w DD with 470rpm?
I guess that's close to 9C 2707, which I understand to be 9 rpm/v. Depending on what voltage that 470 rpm goes with. I hope you can find something slower, though I don't have any suggestions. Watch the "efficiency" figure plummet on steep grades and big loads - means it's cooking instead of rolling. That can be OK if it's brief, but not the ideal thing for regular use under those conditions. I'm assuming that "very steep" is well over 10%.

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Re: Would a 1500w Direct Drive Hub Get Me Up Short but Steep Hills on Full Suspension Bike without frying?

Post by itsallwhite » Feb 28 2019 9:45pm

donn wrote:
Feb 28 2019 8:44pm
itsallwhite wrote:
Feb 28 2019 6:28pm
looking at the simulator, what motor would I select for a 1000w DD with 470rpm?
I guess that's close to 9C 2707, which I understand to be 9 rpm/v. Depending on what voltage that 470 rpm goes with. I hope you can find something slower, though I don't have any suggestions. Watch the "efficiency" figure plummet on steep grades and big loads - means it's cooking instead of rolling. That can be OK if it's brief, but not the ideal thing for regular use under those conditions. I'm assuming that "very steep" is well over 10%.
Thank you for your help. Looking at the simulator with a 9C 2707 with a 20amp controller and 48v battery (which would give 960w). Total load of 352lb, with a 100w human power and 20% grade. Overload time 6 minutes.

If I could maintain a speed of 10km+ the motor would overheat in 9.7 minutes with a 930w load and 41% efficiency. If speed dropped to 5km p/h efficency drops to 24% and overload time <5 minutes.

My hills are steep but very short and total journey is 5 minutes usually.
Bike 1: Giant Hybrid Steel Frame (old) with TSDZ2 48v 500w.
Bike 2: GT Sensor 2 full suspension mountain bike. Work in Progress - ready to 'electrify'!
House: 100% off grid - 5.6kw solar array with selectronics inverter and 24 Volt 1450 Ah BAE Gel battery Bank

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