News

There are a number of information pages that we were working on this year but only now with the relative calm of the winter season have we had the time to wrap them up. So for your fireside reading pleasure, we offer you

1. Grin's Ebike Connector Guide:  A summary of the various standard connector types encountered in ebike conversions and our take on them from the DIY user perspective. For those dizzied by the wide assortment of connectors out there hopefully this page can help you make sense of some of it.
 
2. Our take on the Merits of Hub Motors: In our travels this summer to meet with other ebike businesses, one recurring theme was that most of them felt hub motors have been subject to a lot of misleading marketing in recent years by mid-drive companies. We've played with many mid-drives as well since our founding days, and while they have a few advantages in some situations our feeling has always been that hub motors are a better overall solution for the needs of 80-90% of ebike users. Even with the popular proliferation of BBSXX type drives, that viewpoint hasn't changed at all. To see why, read here.
 
3. How many watts is that motor?: This is a question that makes Justin's blood boil a little. If there is one thing that is most often misunderstood about ebike technology it's the topic of motor power ratings. Did you know that the european Bosch ebikes will draw 700-800 watts of power form the battery even though they are, you know, supposedly 250 watt systems? It's true. We've always avoided giving specific power ratings on our motors because the number you choose is rather arbitrary, and this more technical article explains why. 
 
4. From the past: We also found the draft documents from an old article we wrote in 2010 on the role of the DIY ebike scene at that point, and we thought would be nice to dust off and make available online again.

We've got two new Grin items hot off our milling machine that should help overcome difficulties in electric conversions.

The Handle Bob

The first idea actually comes courtesy of our customer Bob. Bob you see has a Grin All-Axle bike conversion and ran into the familiar situation of having handlebars that didn't lend themselves to sliding on a throttle. This happens all the time with curved drop bars, oversized handlebar tubing and whatnot. His solution with a piece of 22mm OD tube cut and drilled to secure at right angles with a pair of cable ties was so elegant and simple that we had to make this into a product.

So in his honor we introduce the Handle Bob, allowing you to easily attach a small bobbin to handebars on which you can affix a thumb throttle, CA aux input, headlight button or other small device without needing to remove your grips or anything else. It's the simplest and lowest tech product that we've ever manufactured in our little machine shop, but one that just might have a big impact for many builds.

The Bottle Bob

The 2nd item helps when installing downtube and waterbottle batteries on bike frames that don't have properly located waterbottle braze-ons. We're calling these our Bottle Bobs, and they let you add a solid M5 threaded attachment point anywhere on your bike tubing with the security of a stainless steel hoseclamp.

In fact, these attachments are stronger and more secure than many of the riv-nut frame eyelets which can occasionally tear out of the frame tubing with heavy batteries, and allow you the security of having 3 or 4 attachment points to the battery base plate rather than just the 2 when you use the frame's bottle mounts.

And of course, you can also use them to attach more waterbottle cages to your bike!

Both the Handle Bobs and Bottle Bobs are already available from our store, manufactured at Grin from machined aluminum and black anodized for a lasting sharp look.

At the VEVA electric vehicle show this summer we showed up with two electrified penny farthing bicycles, thinking that we could stage electric high-wheeler races around the mini test track. The racing didn't happen but the fun of riding these around Vancouver hasn't abated. There haven't been too many accidents and the reaction on the streets is pretty amazing if you like making people crack a smile. Aaron and some of the new staff at Grin made a nice video from an afternoon spin:

More specific details on how these were built are shown on the endless-sphere build thread: https://endless-sphere.com/forums/viewtopic.php?p=1309060#p1309060

Anyways it turns out that there are a couple dozen more replica high wheel bikes from this source in a storage locker looking for a home, and we wonder if there is a case to sell them electrified with small hubs in the rear wheel. The bikes are available in wheel sizes ranging from 36" to 54", and they have a custom machined freewheeling front hub so you can coast without pedaling. If owning a piece of 19th century bike technology merged with 21st century electronics like this tickles your fancy, then send us an email and we'll see if there's enough interest to convert a batch! Price would depend on the specific conversion options but can expected between $1500-$2000.

It's high time to formally introduce our Battery Grinspector, a device that converts a Version 2 Cycle Analyst into a full computer controlled battery test station. Here is a nice video that Bruno made while we had a prototype to show at the Taipei Cycle Show earlier this year:

This is our first foray into products aimed at shops and businesses that have to maintain and service electric bicycles rather than to ebike end users. As more and more ebike shops open up, there's an increasing need for ebike specific diagnostic and repair tools. We hope it finds a small but growing audience!

A little background

Over the years we've built all kinds of custom battery discharge testing rigs for the troubleshooting, QC, and R&D needs of our operation. But each has been very much a one-off project, rather than something designed with the idea that we could manufacture it as a product. The one on the left is Justin's very first battery charge/discharge machine built for conditioning and testing salvaged NiMH batteries for his first ebike project at university, while on the right was a comprehensive labview controlled solution that would cycle test 8 packs at a time.

Commercial equipment available on the market for testing batteries tends to be bulky and expensive, made for laboratory or industrial use and wholly out of place in a bike shop. As a result, we noticed many of our dealers have setup simple improvised rigs using a Cycle Analyst and load resistor to do a simple battery capacity test.

The Grinspector station builds on this concept, allowing allowing shops to use their familiar Cycle Analyst while a computer is able to control the charging and discharging of the battery, with real time discharge graphs as well as a final printable QC report. Everytime someone purchases a battery from us, they get a printout of the battery discharge curve showing actual capacity and other test data. That's our own bank of Grinspectors at work, and we hope to empower other shops to do the same.

Over the last few months we've quietly slipped a number of other small improvements to our website. For instance, from the spoke calculator page you can now directly add spokes to your cart from the calculator, no need to write down lengths and navigate back to the online store.

Similarly, when you are shopping for the conversion kits, the simulator link on the bottom will launch the motor simulator page with the correct motor, controller, wheel size etc. already pre-selected.

And if you have individual motors, controllers, batteries etc. in your shopping cart, then you can launch a local instance of the simulator tool from inside the cart to see exactly the performance of these items and how they work together.

Additional Simulator Updates

The simulator improvements have only kept continuing since the September update. There's now the ability to model custom motors, to set a controller for a torque or amps throttle, and to have the throttle automatically adjust itself based on where you click the graph. Read the updated FAQ section and have fun.

Much of this work and the associated tools for motor thermal analysis was possible with the help of our summer software coop students from SFU and UBC; Stefan, Gary, and Adam. It's long overdue we gave them a big public thanks for their fine contributions.

Hope that everyone is having a great labour day long weekend. This past month we've wrapped up signficicant batch of upgrades and new features to our online hub motor simulator. This list includes

• Addition of human power to set default cursor calculation
• Ability to vary motor core temperature and see the effects on performance
• A KV adjustment slider to simulate faster or slower windings of same motor type
• The inclusion of wind speed (tailwind or headwind) to the vehicle load simulation
• The addition of motor phase current limiting to controller parameters.
• 2 independant cursors for comparing results of System A and System B
• Ability to add output of two motors systems in a single vehicle for dual drive simulation
• A much more comprehensive thermal model of motor heating, with predicted steady state temp
• A unique URL for each simulation result that you can copy and paste

One of the common sources of fitting issues with conversion kits is interference between the throttle and existing lever shifters on the bike. We have two new throttle options that help things on this front. The T-Lever throttle fits equally well on both the left and right side of the handlebar for maximum install flexibility and is ~2mm smaller in diameter than our previous thumb throttles. And the T-HTwist_Slim throttle is a split grip throttle with an impressive 36 mm max diameter (vs 45-50mm with other common models), allowing it to replace almost any right side grip without concern for shift lever interference. It has a standard handlebar grip diameter right to the end. 

We've similarly upgraded our basic mechanical ebrake option to a sturdier model with a longer black lever arm and rubber grip in the front. Both this and our previous silver model are all metal construction, but the new black one is better suited to the quality standards that we'd like associated with our offerings. Our remaining stock of the previous model of ebrakes and throttles are available for sale on our new sale/clearance page.

We've spent 10 years of determined effort keeping all of our kits, controllers, and motors interchangeable and standardized around the same 3-pin Anderson and 5-pin JST hall connectors, but we're moving on! At this point, most manfufacturers of small ebike motors have adopted the overmolded 9-pin Higo Z910A plug as a default connector type, and rather than always cutting this off and replacing with andersons we've decided to roll with it and make our smaller 20A Grinfineon Controllers directly compatible.

The extra 6th signal wire is used in geared motor setups for an internal wheel speed sensor that is present in many geared hubs, allowing you to get vehicle speed info from a simple CA-DP device rather than needing a separate speedometer sensor and spoke magnet with the CA-DPS. In our small direct drive motors, we've used this 6th wire for the internal motor temperature sensor that is brought out of the controller assembly, so that you can still take advantage of the CA3's temperature sensing and thermal rollback, all with just a single connector and wire to the motor.

There are downsides to an overmolded plug. You can't measure hall sensor voltages for troubleshooting when it is plugged in, swap phase wires around, or separate the halls from the phase wires to run it sensorless. And replacing damaged connectors is not easy. But for low to medium power ebikes the benefits of this clean single plug are worth it. We have all of our Bafang G01 and Brompton SAW20 motor kits in stock now using this Z910A plug style. And in unusual form, we even finished the user manuals in time for this announcement too. 

Well we managed to have the most crashes in one ride during the cargo bike championships last friday; tip for future events, 2 wheels is better than 3 for fast cornering! Anyways this coming weekend is also packed with with activity, and that includes Grin having a booth both at the inaugural Main Street Bike Expo on Saturday June 10th, and also both Saturday and Sunday at the Vancouver Mini Maker Faire.

After missing the beat last year we're back to being involved with now the 3rd annual Vancouver Cargo Bike championship this Friday. It's happening once again at the end of Bike to Work Week at Creekside park, only this year there's a dedicated track so less dodging of pedestrians around the seawall bike path.

It's not too late to register and we'll be sponsoring a prize of a $150 (or 15% off an order) gift certificate for anything at Grin to a winner in the e-cargo category. We hope to see many of our customers there and if you've been considering a cargo ebike yourself this would be a great event to check out. We'll be racing our legendary Frankentrike and as always we have a fondness for the homemade and wacky.