Blog

We’ve had the BMS on both the 36V 14Ah and 48V 10Ah eZee lithium packs upgradedto handle up to 40A of current, meaning that it’s no longer necessary to run two batteriesin parallel for high power setups. These packs are all now made with the more premiumPP2250 Samsung Cells that are 5C discharge rated, as opposed to the 3C rated cells thatwere formerly in use.

If history is any guide, it takes us 12-18 months from releasing a product before wefinally get all the documentation and user guides finished. So on that note, we’re pleased to release the first proper revision of the Cycle Analogger owner’s manual. This explains many features that we had built into the device but had not yet advertized, from dualchannel temperature sensing to customizing the file names, and other tweaks. Feedback is always welcome.

While we were at it, we also had a set of spacers made up to help deal with caliperclearance problems that often accompanies disk brake compatibility with Chinese hub motors. This is especiallya problem with the Nine Continent hubs that only give ~15mm of space for the caliper. The spacers are 1.6mm thick and either one or two of them can be placed under the disk as required.

After a lot of design prototypes and field testing we have finished a new torque armspecifically for rear hub motors. This unit is made from thick ¼” stainless steel plate,meaning it can resist axle spinout in even highly overclocked motor axles. And theunique 2-piece design allows it to work with vertical dropouts, horizontal dropouts,machined cavity dropouts, and anything in between. The support arm clears up and abovemost fender eyelets and includes slots for up to 3 hose clamps for extra security.

We’re now providing the option of a drilled out side cover for the Nine Continent andCrystalyte motors based on results from our water ingress tests. For people who rideregularly throughout the winter but bring their bikes indoors overnight, this provides thebest way to prevent water from getting trapped inside the hub and rusting out both thestator and the hall sensors. We also coat all the exposed iron with Boeshield T9, sothat the temporary water that does make it in will evaporate without leaving a trace.

A few shipments came in over the winter adding more motor direct drive motor choices to our collection. The powerful HS35 series from Crystalyte which was previously only in the rear is now available as a front motor as well. They did this while still maintaining 17mm of disk caliper clearance, and a motor exit cable on the axle side rather than the end. We’ve also got our front and rear 20” Crystalyte motors made with an even faster winding choice,the HS3548, to make up for the smaller diameter.

From the Nine Continent shipment, we now brought in the somewhat slower 2808 hub as well. This motor wind has the highest copper fill factor of all the NC hubs (64 strands, vs. 60-63 strands in the other winds) and the slower wind is better suited for those running at high voltages.

Both this hub and the new HS3548 from Crystalyte have been fully modeled and put on our simulator too.

This is also the time of year when we start dealing with a lot of troubleshooting issues related to the cold and wet weather, so here are a few tips:

• Lithium battery performance degrades a lot near freezing temperatures, resulting in 20-25% less capacity, and the battery BMS circuit can trip prematurely from additional voltage sag at these lower temperatures. If you can keep batteries indoor and warm until just prior to the ride, they'll deliver closer to full capacity.
• If you are parking the ebike for winter, be sure that the lithium battery is stored in an initially charged state and is unplugged from the controller. A lithium battery that is flat and then stored for several months is liable to self-discharge to the point that the cells are irrecoverably damaged.
• Water has a way of getting into even totally sealed hub motors and causing them to rust out on the inside. Usually the hub will run for weeks or even months with water in it before the corrosion builds up enough to have an effect, so we recommend opening up the motor on occasion to have a peak and let it dry out if necessary. We suspect that the primary avenue for water entry is through the inside of the wires, and so it's advisable to cover up the connector area.

The store will be closed for the Christmas break from Saturday 24th December until Monday 1st January 2012. We will however be open on Wednesday 28th December from 11am to 6pm for anyone that wants to stop by the shop to see us! We will still be responding to emails and processing online orders during this time so if you want to get in touch email is the best way to do it. We wish everyone a Merry Christmas and a Happy New Year and we'll see you all in 2012 for what should be an exciting year for Grin Tech and ebikes in general!

Justin will be a guest speaker for the December meeting of the Vancouver Electric Vehicle Association (VEVA). The topic this year is going to be a tell-all tale about everything related to hub motors. Issues will range from the many lessons learned from 7 years of dealing with imported hubs, to technical optimization and modeling details, to glimpses of what may be on the horizon. This should be an exciting talk for those interested to know more about the little engine that makes ebikes move. Location details are here.

We've extended our store open hours to include Saturdays as well for the past couple weeks and during the rest of December as well. If you're into Christmas shopping for ebike conversion parts or unicycles, we'll be around to make scheduling a trip a little easier.