Hub motors: How much will they handle?

[DieselTech]

Guys & gals I'm new to this ebike game. What kinda voltage & amperage will these hub motors handle? Say on a bafang G062 hub motor, at what voltage & amperage do they self destruct?

Can a hub motor that's powered at 48 volts & 30amps, be juiced to 52 or 72 volts at 45amps.

When do they start destroying sun gears & pinion gears? Thanks.

 

[biknut]

I've gone through several Bafang 750w motors. I run mine at 48v 30 amp. The most common problem I've had with just about every one of these motors is magnets coming loose. Easy and inexpensive to repair if you have the inclination, and tools.

 

[DieselTech]

I've gone through several Bafang 750w motors. I run mine at 48v 30 amp. The most common problem I've had with just about every one of these motors is magnets coming loose. Easy and inexpensive to repair if you have the inclination, and tools.

Do these numbers mean anything, other than its showing 48 volts. Thanks.

 

[biknut]

Do these numbers mean anything, other than its showing 48 volts. Thanks. View attachment 11041

Looks like 48v 750w front wheel motor to me. That doesn't mean much though because manufacturers can order 750w motors with 500w magnet rings (RAD). The only way to know for sure is to open the motor, and look at the size of the magnet ring.

 

[DieselTech]

Looks like 48v 750w front wheel motor to me. That doesn't mean much though because manufacturers can order 750w motors with 500w magnet rings (RAD). The only way to know for sure is to open the motor, and look at the size of the magnet ring.

Can you or is there a video, showing the difference between the 2, once a motor is opened up. Does the 500watt magnet ring use a thinner ring of magnets? Thanks. I'm just trying to learn what I can.

 

[biknut]

Can you or is there a video, showing the difference between the 2, once a motor is opened up. Does the 500watt magnet ring use a thinner ring of magnets? Thanks. I'm just trying to learn what I can.

The 750w is on the right. The 500w and the 350w use the same smaller magnet shell, but the 350 is 36v, and the 500 is 48v. All three motors fit inside the same hub.

 

[DieselTech]

The 750w is on the right. The 500w and the 350w use the same smaller magnet shell, but the 350 is 36v, and the 500 is 48v. All three motors fit inside the same hub.
View attachment 11062

Thanks biknut! Will I need to do maintenance on them sun gears & pinion gear? Clean & re-grease them? Thanks again. Will these hub motors handle 52 volts & say 45amps?

 

[fabbrisd]

Going back to your original post - the Bafang G062 is a 1000w - with 1500w peak - and about 90nm torque - Ariel Kepler uses G062 30a controller 52V 21700 20ah battery - the Wired Freedom V2 uses Hengtai 1500w - 2200 peak - 30 a controller 60V 21700 20ah battery . For me the Kepler is strong power - and Bafang G062 is a much/much quieter hub motor than the Hengtai.

 

[ElHegpah]

If you really want to run high power, you need to get away from geared hubs to direct drive units. 3,000 watts and higher. Just prepare to do some cooling.

They are heavy, and drag when coasting, but you also get regen braking, and no moving parts.

There is no such thing as a "36V motor". Controllers are voltage specific, motors are not. Feed them more voltage and they will spin faster, within reasonable limits.

 

[m@Robertson]

the Wired Freedom V2 uses Hengtai 1500w - 2200 peak

The Hengtai is rated for less torque even though higher watts are printed on the outside casing. I've heard them described as gutless from people who are used to Bafang G060's. IIRC the Hengtai is rated for 60 Nm.

The 750w is on the right.

If you take apart the current Bafang 750w motors, they now use a smaller motor core same size as the low power motors. I've seen complaints from people who took them apart to verify they aren't getting cheated (Rad) and the vendor went all the way back to Bafang who confirmed they are no longer using the bigfoot cores. Not surprising really. Bafang has always tried to standardize parts on the inside and just change the engraving on the casing. The good news used to be the lower-power motors were really capable of much more than what was listed on the outside. No idea how this breaks down currently.

The new Bafang 2-speed fat motors are rated for 95 Nm at 52v nominal.

 

[m@Robertson]

There is no such thing as a "36V motor". Controllers are voltage specific, motors are not. Feed them more voltage and they will spin faster, within reasonable limits.

My 36v Bafang 350w motor (rated as such on the casing) worked just fine when I plugged in a 52v battery. I also changed the 12a controller to a 25a, which for me in January 2017 was a big upgrade.

 

[DieselTech]

How hard is it on these ebikes to: Ride 12-15miles at full throttle & never let up on the throttle, till you arrive at your destination? Thanks.

 

[m@Robertson]

How hard is it on these ebikes to: Ride 12-15miles at full throttle & never let up on the throttle, till you arrive at your destination? Thanks.

On a dual-motor bike its not hard on them at all. Its hard on the frame when you hit potholes at speed. And on wheels. Don't underestimate the pounding the whole bike takes if its running full blast all the time.

Its hard on the battery because you are flogging it... but thats why you build a very big single battery with a badass BMS whose continuous output rating well exceeds your controllers' peak rating. If you use two packs, then those smaller packs will be stressed harder than one big pack regardless of whether the two packs are equal in amp-hour size to the single big one. Your controller will be running at its continuous level, not its peak level which is good, but if you have a commercial setup running a single controller, you may cook that little sucker. You'll have to put a temp sensor on it and see how hot it gets. For a single motor bike I measured a 35a controller getting up to about 150 degrees with a 52v pack, so I did some mods to give the thing flow thru ventilation. Dual motor bikes... controller just gets warm. Maybe 100 degrees. I keep my front controllers enclosed and don't worry about them.

On this article below I linked a very long presentation on dual-motor systems from the Grin Tech guy, and I tee'd up the link to go directly to the part where he gives the technical explanation as to why the heat on a 2wd motor system is barely warm vs. too hot to touch. Total motor heat for a single motor is 504 watts. But if you use two motors, only 150 watts of heat is generated. Scroll about halfway down the page to get to the link. Its the only Youtube vid on the page. The point of this is to illustrate how the motors are getting it easy and aren't the likely thing that will fail here (assuming you re-grease them inside about every 3000 miles and don't get water inside of them).

Dual Motor AWD Electric Bikes (the good and bad)

I like to build top-quality-component ebikes from the frame up. Quite a few of them are dual motor or AWD or 2WD or whatever you want to call them. Why would you build an AWD ebike?

talesontwowheels.com

 

[James340]

I bought a "48 volt 1000 watt"DD hub motor from Alibaba.I have a UPP 48 volt 14.4 ah battery with 21700 cell.It goes 35 mph on just motor and 40+ pedaling.A mention about Alibaba.The sw900 display was missing options #9-12.These are to find tune PAS.Seller just made excuses so I opened a dispute with Alibaba.I paid $16 for the controller and the seller offed $15.Alibaba offered the $ 15 plus $65.I paid $128 for the entire kit.I was very skeptical of Alibaba.