ICE Trike with Falco e-motor (no, not mine!)

Cycling friend Kim, who rides a recumbent bicycle regularly, has written a report about a modification she did to her partner N’s ICE Sprint trike recently.

I thought it was a very good read and would be worth reproducing here, with Kim and N’s permission (which they gave). N’s bike was already previously adjusted for some physical disabilities (gear selection, etc) but is otherwise a reasonably standard model. As you can see from Kim’s report below, she has rather more electronic knowledge and skill than most of the population and has managed to produce a rather excellent result!

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So, for various reasons N hasn’t been getting the miles in. This means less cycling fitness, which has been limiting how far she can ride. Unfortunately, we live a 10km and at least one Bastard Hill round-trip from any pleasant cycling roads, which means we’ve been mostly pootling on the Rea Valley cycle route. Which is nice enough as Sustrans paths go, but gets a bit dull and doesn’t go anywhere – which doesn’t give you an incentive to get the miles in.

This seemed like an excellent job for electric assist – to give a little more speed and make the local hills less of a barrier.

We wanted something that was relatively straightforward to remove, for times when her cycling fitness is better. As the Sprint is a tadpole trike, this pretty much limits the motor options to those that fit in a rear hub. Since the aim of the game is asisted cycling, rather than an electric motorcycle, the BionX system seemed like the obvious choice. Unlike most systems, which simply apply power whenever the pedals are turning, this uses a torque sensor to provide power in proportion to the force exerted through the pedals. As a bonus, this means relatively little button-pushing in normal operation – N already having her hand full with the usual bike controls.

Unfortunately, BionX is currently unobtainum in Europe, and US dealers are reluctant to ship internationally. At this point, a fellow cyclist drew my attention to Falco, a relative new kid on the block. Slightly dodgy website, but the technology is getting good reviews. Their motor supports torque-sensor operation like the BionX, with a higher efficiency, lower rolling resistance when ‘off’ and – even more pleasingly – doesn’t require an expensive proprietary battery pack.

After an email exchange with the lovely Mark at Team Hybrid (the UK importer), I ordered the road legal version of the Hx motor, built into a 406 rear wheel with 11-34 9-speed freewheel (hub motors use freewheels rather than cassettes, presumably due to the larger axles). I’ve fitted larger middle and big chainrings to compensate for the loss of the 10t and 9t sprockets.

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The battery was more difficult. We wanted something with lots of capacity, with a view to being able to do the standard 100km/1000m social ride at the lowest level of assistance. There’s nothing off the shelf that fits the rear rack on a Sprint RS (which has a suspension-specific luggage rack), so I decided to molish something. Reading around on e-bike fora suggested that the slightly dubious looking Ping Battery is a good source of LiFePO4 batteries (I decided that LiPo was too scary, and a false economy in the longer term. With EU Pedelec speed/power limiting, the battery won’t be under much stress anyway). I ordered a 48V, 20Ah battery from Ping, along with a 5A charger (this is a simple 60V SMPSU with a really noisy fan – the BMS controls the charge cycle).

So, after a *lot* of tedious research, I decided the simplest approach was to mount this in a durable box on the rear rack. I discovered that Rixen & Kaul make a luggage box that was just about big enough for the battery and some electronics, with a cunning quick-release adaptor plate that fixes to the rear rack (a bit like the Topeak rack bags).

Then it was just a small matter of electronics. Ping batteries include a Battery Management System (which prevents overdischarge and balances the cells properly when charging. I mounted this in a proper enclosure – rather than the mechanically dubious heatshrink wrapping it comes in – taking the opportunity to add a header for a remote shutdown switch. In a second enclosure, I mounted the guts of a Turnigy power meter (a CycleAnalyst seemed like overkill), and a board with DC:DC converters to power the existing dynamo lighting (experimentation showed that a Cyo wants 7.5V +-0.1V to run on DC at decent brightness) and relay logic to enable the BMS when the charger is connected:

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The glowing green ring on the outside of the enclosure is the BMS shutdown switch. This avoids the need for a high-current isolator. I’ve used a 4-pole Speakon connector for the motor and lighting power – They’re rated for 40A RMS, the IP54 rating should be adequate protection against rain, and more critically, they’re a latching connector that N can actually undo easily. The charging port is standard 3-pin XLR. I’ve also added plenty of fuses – using 58V automotive fuses on both positive lines to the battery (5A and 30A respectively – the big one is visible front right).

The USB port is there primarily because the Falco console (slightly pointlessly, in this case) uses Ant+ wireless to communicate with the motor (there’s a dongle under the seat), and recharges its internal battery via USB. It also gives the option of using the pack as a 1550000mAh backup battery for your iThing!

I extended the cable between the console and the assistance level control buttons to put them somewhere sensible for under-seat steering:

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The console is the weak point in the system, IMHO. While the motor is reassuringly solid, it feels cheap and plasticy, and the display has poor contrast. Advanced functions are accessed via cryptic combinations of presses on *spit* membrane switches. On the other hand, the wireless link to the motor seems surprisingly robust, and it can display the heartrate from an ANT+ strap. There’s a possibility that future firmware might allow a device like a Garmin Edge to communicate with the console to record torque sensor data.

The remaining piece of the puzzle is a crank rotation sensor:

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Theoretically this shouldn’t be needed, but it provides a backup interlock to the torque sensing to ensure that the motor stops properly when it should. This consists of a unit containing a pair of Hall-effect sensors and a ring of magnets – unlike a standard cadence sensor, this can tell which direction the cranks are turning, and responds more quickly. It’s designed to fit inboard of the chainrings, with the sensor on a collar that’s secured by the bottom bracket. Unfortunately, ICE use a fairly narrow bottom bracket to keep the Q factor down and there simply wasn’t room. Mark suggested that I could fit it to the drive-side idler pulley instead, which seemed feasible with a bit of bracket fettling, but I opted for inboard of the the non-drive side crank instead, on the basis that it would be clear of skog, twigs and so on. As the sensor is directional, this meant mounting it upside-down. Hose clips and self-amalgamating tape to the rescue!

Beyond that, it’s cable ties all the way down. Lots of wiring for power, lighting (I removed the existing bottle dynamo, and provided a connector for re-fitting it in future), and the various data lines. All bundled up with the existing lighting and computer wiring, and the usual proliferation of brake and gear cables.

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I took it for a proper road test today, and the motor performed as expected. It takes a bit of getting used to – the feeling is something like a strong tailwind that kicks in as you reach about 3mph and stops when you exceed 15mph. It took a bit of time to learn how to use the gears effectively to find the optimum balance between human and motor effort. Yes, there’s a lot of mass on the rear rack (though well within its load rating), and you do feel it’s there in corners. It’ll do, but if I were building this with a motor programmed for *cough* ‘off-road’ use, I’d want the centre of mass lower down. On the other hand, having lots of weight on the back greatly improves the rear wheel traction on mud. There’s also some rattling going on somewhere that needs attention – probably the box’s QR bracket moving in its clip.

Bastard Hills are where it really makes a difference. With the legal power limit of 250W, it’s not going to conquer a chevron without a bit of work from the rider, but you can maintain a much more respectable pace without stressing your lungs too badly. You certainly don’t notice that you’re lugging an additional ~15kg of battery and motor!

In the interests of SCIENCE, I just took it for a 30km ride, including the silly slalom hill in Cannon Hill Park, Primrose Hill and Weatheroak Hill, with the lights on (not that they use much power in the scheme of things – I estimate they would discharge the battery in a little over two weeks) and being less than sparing with the assistance level. When I got home, N took it out for a quick lap of Canon Hill Park. 35km in total, and some 300m of climbing. Ambient temperature was mostly around 9C, though the battery and electronics felt slightly warmer in use. The power meter claimed it had used 4.5Ah (234Wh) in that time. If those readings and the battery rating are accurate, that bodes well for a range in excess of 100km…

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and then an update:

And we’ve just ridden our 36km loop (which N hasn’t managed since last summer) out to the reservoir and back. Average speed of 17.8kph, which would probably have been higher if it hadn’t been for N and her motor having to wait for me to catch up on hills.

Rattling greatly reduced by the addition of a ratchet strap around the box, to stop it bouncing upwards.

I’ll check the exact figures later, but electron use was in the region of 240Wh again.

7 Comments

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7 Responses to ICE Trike with Falco e-motor (no, not mine!)

  1. John Jackson

    Excellent bit of shed-ery there Kim. Thanks for exposing all the details for us all

  2. Neil Earley

    Hi kim could you pass on my e mail to falco assist owners if possible as I am considering buying a falco e motor ,would be nice to get a long time review, regards Neil

  3. Kim

    A long-term update seems like a good idea, so I’ll post one here…

    It’s been a few years now, and while poor health hasn’t allowed N to do much cycling in the last year and a half, that’s not the trike’s fault. Overall, we’ve been pretty pleased with it. There have been a couple of issues though, and decisions that we would make differently with the benefit of hindsight.

    The DIY battery pack has performed flawlessly. I genuinely thought this was going to be the weak point, but it’s been fine, in spite of the occasional ride on really rough surfaces.

    The motor itself has been extremely robust, though an experimental attempt at removing the freewheel was a failure. (I’ve never had much luck removing freewheels, and dread what happens when the sprockets wear out.)

    No problems with the crank sensor either, it was fit and forget.

    We had a problem with the console randomly losing its wireless connection to the motor (requiring a wait for the console to go to sleep and a power-cycle of the system to re-establish communications). This was less annoying than it might have been, as the system is capable of operating without a console, but you need it to change assistance level. This was eventually resolved by obtaining a newer version of the motor’s Ant+ dongle from Falco.

    The Falco console itself is rubbish though. It’s a silly shape that takes up too much space, the screen has poor contrast, the assistance level display is too small, and the membrane switches are horrible to use (there’s no tactile feedback). More critically, the waterproofing is pretty much non-existent. It didn’t occur to me to open it up and disconnect the internal battery after a ride that ended in monsoon conditions, and when I tried it the next day I discovered that the internals were corroded to the point of permanent damage. (We removed power from the motor immediately at the end of the ride, and once dried out it was fine.)

    To their credit, you can use an Ant+ equipped smartphone app as an alternative to the console. But that’s a poor solution for all the usual phones-on-bikes reasons.

    There’s Windows software for fine-tuning of the motor parameters, which is a good thing. It’s buggy and completely lacking in documentation, which isn’t.

    More practical considerations:

    Torque sensing is great, but it’s not really compatible with gearing down and climbing slowly. N’s preferred technique is to engage ‘Turbo’ mode (which puts the motor to full power irrespective of torque) for serious climbs, and wait for me at the top. As such, we’d quite like easier access to ‘Turbo’ (you have to hold down one of the console buttons for just the right amount of time, which is awkward on the fiddly membrane switches) – eg. as another level of assistance beyond ‘+5’.

    Having a massive battery pack on the rear rack is good for rear-wheel traction (often a problem of tadpole trikes), but the handling of the trike really suffers. This isn’t a deal-breaker for us, as N isn’t really a speed-demon, but I’d advise against it. With hindsight I overspecced the capacity of the battery, but that’s more down to N’s health not being up to the longer rides that we initially anticipated.

    Our main reason for choosing a hub motor was that it was the easiest way to fit a motor to the trike in a way that was removable in future. In practice, this hasn’t been as useful as we anticipated. The only times I’ve really wanted to use the trike myself have been *because* it’s got a motor on it (for hauling a heavy trailer, and when recovering from injury), and N prefers to have the option of assistance for hills, even if she’s mostly pootling on the flat under her own power.

    The console being wirelessly connected to the motor remains a pointless complication. I can see it might be beneficial on a mountain bike, but it’s really not worth the faff of an extra battery to worry about otherwise.

    If I were doing it again, I’d go for a lightweight motor at the bottom bracket and a much smaller battery mounted under the seat. I’ve recently helped a friend choose an upright bicycle with electric assist (they settled on a high-end Kalkhoff with a STEPS system, and it’s revolutionised their mobility), and have been very impressed with the current offerings from Shimano and Bosch.

    Falco are still going, but seem to have lost the plot slightly, concentrating on using regeneration as a fitness aid, rather than improving their console.

    Team Hybrid are no longer a Falco importer. I believe they had too many quality control issues. Make of that what you will.

  4. Neil Earley

    Thanks for your comprehensive review was undecided which e assist to go for,may decide on a banfang mid motor [CRANK DRIVE} like the shimano steps but just over £2000 is out of my budget, hope N,s health improves and you will be riding more together

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