9C 2812 hub motor review

Ian

100 W
Joined
Feb 8, 2008
Messages
103
Location
Lake County, CA
Greetings

Sunny of 9C China was good enough to ship me a single 9C 2812 earlier this year so I wanted to post a few comments, there are threads already on this motor but not for a while. Sunny mentioned he'd accept orders minimum 10. Not so easy to buy this very slow winding I couldn't find anyone in the states so I appreciate him going to the trouble. I've been using a 2810 with no issues for 5 years on my evg ebike (rear 26" wheel) running 2000 watts max, and wanted the 12 winding to see how it would stack up for a long distance tour scenario so that I could climb pretty much any mountain while using a xtrawheel trailer. Bottom line answer: very well and like dogman's review from a year or two ago, the efficiency compared to 2810 is quite significant, I'm no techie but after using the hub for a couple months I would say the 2812 is at least 10% more efficient real world than the 2810.

Of course you got to run high voltage so not for everyone. I might try as low as 66v and see how that works. Anyways, I was mostly running 74v on the 2810 and now run 81v or 88v on the 2812 so a little extra battery is needed. My needs is not so much top speed as 18 to 22mph cruising is my kind of fun, but I like to maintain a steady clip up hills and not have to worry about overheating. This motor does the job. Even steep hills are taken in stride. I use one of icecube's connector dongle to avoid any sparking. I'd like to get the CA V3 next I think as it has that cool feature of throttle adjustment so you can smooth out the response, right now its a bit twitchy but totally usable once you get used to it.

So my morning "coffee run" stats:
2812 74v20ah 10 miles total AH average consumed 5.3 Max Amps 26
2810 82v20ah 10 miles total AH avg consumed 4.0 max amps 23

For my round trip leisure run of around 25 miles, which is a hilly route (ending with a .7 mile elevation climb of 600ft on gravel path) it gets even better, at 72v I'd have consumed up to 14ah, at 88v I am always at 10ah. Thought I had my CA shunt settings wrong at first but no....the longer you go and the hillier it gets, the more the efficiencies start to emerge. I have yet to do a long distance run on more flat terrain with 30ah pack, but am expecting to get quite a bit more range.

The motor stays significantly cooler than the 2812. So sticking to 1800 to 2000 watts peak, you'd really have to work at it to cook this motor. In normal use you never would. At similar wattage compared to the 2810 it maintains a higher speed up hills. I can set the cruise on 18 to 19mph and it will maintain it pretty much all the time and its very hilly round here in Lake County - as the lack of normal cyclists in my area will attest. I can literally feel that the motor is just spinning at a higher rpm and in its efficiency zone most of the time.

So...the 9C 2812 remains an excellent choice for a mid-weight DD hub motor with the only drawback (for some) being that you have to run a high voltage setup minimum 60v for a 20mph top speed and 80v or over really if you want the fun factor and efficiencies to come into play. Glad I got it, it will do me just fine for the next few years!

Ian
Kelseyville CA
 
2810 is as slow as most will ever need. But I did like the 2812 a lot for riding dirt, where you are constantly going up to 15 mph, then slowing to 5 mph for a tight corner. Even on the flat, if those corners come every 50 feet, it will smoke a motor even faster than hills.

The only slow motor being sold in the USA I know of, is the one I sell at E-Bike kit. The heavy duty kit is a 2809. 48v, so not as perky as a 72v setup by far. But a good solid kit for a longtail, or riding dirt with pedaling.

Most just prefer to power up, and run a faster motor with 5000w if they crave high performance. The slow motors are for those that want a cooler motor when running at 1000w. They do get the most out of moderate power, when it gets steeper. The 28mm motors can definitely go to 2000w though. 8)
 
Back
Top