Should I go electric ?.

[orienteer]

For transport maybe we could arrange to relay you and/or trike to wherever, I'm not far from you. Is it the same trike I took you to near Ely with a few years ago?

[Kim]

Do any of these e-bikes allow for charging from the bicycle’s motion? I’m thinking mainly of regen on descents (while holding a button down that would act like a brake?), but in emergency situations it may be useful to trickle charge on the flat to enable climbing of the next hill.

The gearless hub motor ones generally do, because it's literally just a software feature to add.  The range benefit is marginal, because a pedal cycle has so little mass (compared to eg. a car) that after aerodynamic drag, rolling resistance and charging inefficiency there isn't all that much energy to recover.  There's some merit for off-road riding, because a regenerative braking hub can act as a kind of ABS (though the MTB consensus seems to favour the higher torque available from mid-drive motors).

Geared hub motors and anything upstream of the chain's freewheeling mechanism can't regenerate, for obvious reasons.  This is perhaps offset by reduced losses when under human/gravity power.

[Kim]

I must admit the charging whilst touring does worry me a bit. I think that I fear getting stranded with no power and damaging the battery by not being able to recharge it as soon as it needs it.

They're not going to die if you go a day or two without recharging, though obviously they do prefer to be kept partly charged.  The way it works is the protection circuitry cuts the power when the battery reaches the minimum safe level.  There's still some charge in the battery at that point, and damage happens as that self-discharges over a period of weeks and brings the cell voltage into the region where lasting damage occurs.  Just like a mobile phone battery, in that respect.

I do like the potential 100 miles range . If I rode to wing with electric assistance I would probably have to recharge around Northampton . Now I expect that to prove a interesting challenge

There's a song about that:
<a href="http://www.youtube.com/v/4xKjGqefH7U&rel=1" target="_blank">http://www.youtube.com/v/4xKjGqefH7U&rel=1</a>
https://youtu.be/4xKjGqefH7U

Your problem I guess will be as much about charge time as availability.  I have no idea how long your charge time will be and, I guess that if you have two batteries you'd need to potentially carry two chargers unless your charge time was about 30 minutes.  I think though that your charge time per battery will be in hours.

Yes, probably 2-3 hours.  With two chargers you could of course charge two batteries in parallel.  (And you've covered yourself against being stranded by charger failure.)

Power tool batteries charge faster, but they're much smaller, so you'd need a lot of batteries and chargers (which means bulk, if not weight) to get a benefit.  It would be expensive and complicated for not much gain.

I wonder if we could set up an electric bike socket sharing group.   There is such a thing in the ev community so perhaps we can...

The thought occurs that some of the older public EV charging infrastructure (using BS1363 or Ceeform sockets, which don't communicate with the car) would be suitable for charging an e-bike.  Not that spending a several of hours in some council/hotel car park making sure your trike doesn't get nicked is much fun, or - given the way the payment works on some of the networks - that it would be economically sensible compared to buying lunch at a pub/cafe and using their socket.


_{(No, I didn't - those chargers were all Mennekes.  The trike just posed for the photo while the electric car sucked up electrons from the rapid charger out of shot.)}

The further thought occurs that - on the principle that everyone loves a cycle tourist on a mission (especially if you can be a bit cripspirational about it) - you'd probably be able to blag a charge from most bike shops if you asked nicely.

[grams]

Do any of these e-bikes allow for charging from the bicycle’s motion? I’m thinking mainly of regen on descents (while holding a button down that would act like a brake?),

This makes a good argument for why this doesn't make sense for bikes:
https://www.pandaebikes.com/regen-braking-ebikes-worth/

(tl; dr: Most of your energy is spent fighting air resistance, only a tiny fraction is dissipated in the brakes, therefore regenerative braking wouldn't make a significant difference to range)

but in emergency situations it may be useful to trickle charge on the flat to enable climbing of the next hill.

I'd expect the ratio of flat:hills and the amount of energy you're willing to spend on "trickle charging" may both need to be very high for this to make a significant difference on climbs.

[Samuel D]

(tl; dr: Most of your energy is spent fighting air resistance, only a tiny fraction is dissipated in the brakes, therefore regenerative braking wouldn't make a significant difference to range)

It wasn’t tl or even l and I read it, but I see a couple of problems with this line of argument.

First, the purpose of regen on descents would not be to recoup the trivial energy lost to braking but to use your potential energy at the top of a hill to get up the next hill. There are people who have trouble with this. Maybe cycleman on a bad day is one of them? (I don’t know him as others in this thread seem to.)

When descending, you would press the button to slow yourself down to 10 km/h or some other low speed that avoids frittering away most of your potential energy on aerodynamic drag and instead charges the battery enough to climb a substantial portion of the next hill. Even if you have low enough gears to climb any hill comfortably, any reasonably efficient charging system would give you a net gain in speed because it would avoid precisely the aerodynamic waste that the page uses as a reason against regen.

Second, the page assumes regen would only be “worth it” (“it” not being clear) for a 20% range increase. I think a much smaller increase in range would be worth a few lines of code, even if any range increase couldn’t be converted to more useful metres climbed – which it could.

Maybe there are technical hurdles or these benefits are too hard to explain to the typical buyer. Already I hadn’t considered kim’s point about regen being impossible with certain common gearing arrangements. I haven’t had the chance to study one of these bicycles yet.

[Auntie Helen]

Cycleman, I have the Bafang option that Torslanda mentioned above and it has been very good.

You can read about it here: http://www.auntiehelen.co.uk/alfie-gets-an-electric-motor/

[Kim]

(tl; dr: Most of your energy is spent fighting air resistance, only a tiny fraction is dissipated in the brakes, therefore regenerative braking wouldn't make a significant difference to range)

It wasn’t tl or even l and I read it, but I see a couple of problems with this line of argument.

First, the purpose of regen on descents would not be to recoup the trivial energy lost to braking but to use your potential energy at the top of a hill to get up the next hill.

Sure, but that doesn't change the fact that on a pedal cycle you use most of the potential energy at the top of the hill to get down the hill.  It's only the fraction used in the brakes (or to being deliberately unaerodynamic) that's available to be recovered.

There is some scope for descending more slowly in order to reduce the amount lost to aerodynamic drag and make it available for regenerative braking (a strategy I've used to good effect while driving an electric car), but it's still not going to get close to breaking even.

Indeed, in rolling terrain, I wouldn't be surprised if improving your aerodynamics with a view to moving as fast as possible at the bottom of the hill, so you can use that momentum to climb the next one, is going to make more effective use of the potential energy than charging and discharging a battery.  (Of course the advantage of regenerative braking is that you don't lose it all when you have to stop for a junction at the bottom of the hill.)  And cycleman's already riding a recumbent.

[Kim]

Maybe there are technical hurdles or these benefits are too hard to explain to the typical buyer. Already I hadn’t considered kim’s point about regen being impossible with certain common gearing arrangements. I haven’t had the chance to study one of these bicycles yet.

As I say, systems that are mechanically able to do regenerative braking generally already do.  It's free to add and looks good on the marketing materials, even if it doesn't gain you much in the real world. 

Those that can't have other advantages (typically lighter weight and more torque) that are more useful.  You can always use some of the weight saved by a geared motor to carry a larger battery.

[Samuel D]

Sure, there is some scope for descending more slowly in order to reduce the amount lost to aerodynamic drag and make it available for regenerative braking (a strategy I've used to good effect while driving an electric car), but it's still not going to get close to breaking even.

You won’t climb a 100 metre hill on the energy regenerated down a 100 m hill, because the perpetual-motion machine remains some way off. In that sense you won’t break even.

However, compared to a cyclist on a non-electric bicycle, you would do even better than “breaking even”. The aerodynamic losses of descending speeds (even 30 or 40 km/h) are so terrible that descending at very low speed while charging a battery with the excess power, and then using the stored energy to power up the next hill, does even better than breaking even: it gives you a net gain in speed over the course. This is true for any moderately efficient regen system. What you lose to charging efficiency you more than gain in avoiding losses to aerodynamic drag on the descent. If the system can cope with your pedalling down the hill at 10 km/h, even better.

Scribble on the back of an envelop if this is not intuitive.

[JennyB]

I must admit the charging whilst touring does worry me a bit. I think that I fear getting stranded with no power and damaging the battery by not being able to recharge it as soon as it needs it.

They're not going to die if you go a day or two without recharging, though obviously they do prefer to be kept partly charged.  The way it works is the protection circuitry cuts the power when the battery reaches the minimum safe level.  There's still some charge in the battery at that point, and damage happens as that self-discharges over a period of weeks and brings the cell voltage into the region where lasting damage occurs.  Just like a mobile phone battery, in that respect.

You'll probably notice a lack of power before the battery gets low, and then the BMS will start to cut out when the voltage goes too low under load, such as on a steep hill. At that stage you may get a few more miles of assistance on the flat, but with a decent meter you will soon learn pretty accurately how far you can go.

 

I do like the potential 100 miles range . If I rode to wing with electric assistance I would probably have to recharge around Northampton . Now I expect that to prove a interesting challenge

My preferred technique for recharging during the day is to have the battery and charger pack small enough to be unloaded from the bike and brought inside. I normally recharge whenever I stop to eat at a café. I haven't had a refusal yet.

Your problem I guess will be as much about charge time as availability.  I have no idea how long your charge time will be and, I guess that if you have two batteries you'd need to potentially carry two chargers unless your charge time was about 30 minutes.  I think though that your charge time per battery will be in hours.

Yes, probably 2-3 hours.  With two chargers you could of course charge two batteries in parallel.  (And you've covered yourself against being stranded by charger failure.)

Power tool batteries charge faster, but they're much smaller, so you'd need a lot of batteries and chargers (which means bulk, if not weight) to get a benefit.  It would be expensive and complicated for not much gain.

Mostly you want to charge as slowly as possible, so with two chargers you should only use one for overnight charging. During the day you can set the second charger to bulk charge directly through the output,  bypassing the BMS. You need to keep an eye on it, and unplug before the battery gets too full, as  soon as the BMS lights start flashing. The final balancing phase of the charging cyclé takes the most time, but you can avoid that if you stop early.  If a single charger can charge your battery fully in six hours, then two used together like this can restore charge from 40% to 80% within an hour.

Here's an account of the mad attempt I made on the Mille Failte four years ago, to show you what is possible. 

[cycleman]

Orienteer  , yes it is the same trike  . I am happy to accept a lift to events if they are made and am happy to share fuel costs    .
So if for instance l I did run out of charge and was unable to recharge for a couple of days I would not damage the battery? .
Aunty Helen  thanks for your link. A very interesting read. I like the fact that the unit can be fitted to the existing boom . I have spram dual drive system fitted to my trice which I hope would allow me keep some nice low gears in the case of running out of charge somewhere. I realize that with the assistance working I would be using the higher end of the range  . I am leaning towards the bafang system at the moment. Torslanda may be getting another trike to fettle

[Auntie Helen]

I am actually selling my trike as is for 2500€ so that could even be an option!

[CAMRAMan]

Batteries are fairly robust and will withstand a few weeks of being left alone. Longer term and you'd need to top up monthly or so. My Oxygen's 2.5-year-old battery was activated on Tuesday this week after being left standing over a month and had lost 0.1V and read 41.8V.

If you go ahead with the conversion, consider a call to Jimmy at BGA Reworking*. He specialises in one-off battery builds and can probably recommend a high-capacity one for you. His price will be lower than an off-the-shelf option and will be made to suit your application. A 21.5Ah one might do the trick.

* No connection other than being a satisfied customer.

[cycleman]

Any idea what 2500 euro is in real British money? . I might be able to convince the trust fund  .

[Kim]

Any idea what 2500 euro is in real British money? . I might be able to convince the trust fund  .

Top tip: You can just ask google "2500 EUR in GBP"

Currently £2206.08

[jsabine]

Any idea what 2500 euro is in real British money? . I might be able to convince the trust fund  .

Top tip: You can just ask google "2500 EUR in GBP"

Currently £2206.08

I was going to say that www.xe.com was your friend for all currency conversion queries - it currently reckons £2205.68.

[cycleman]

Thanks both of you 

[CAMRAMan]

I am not sure how the SRAM Dual Drive will cope with the Bafang BB solution. It might be fine, but it depends on how well you time the hub gear changes. Aunty Helen's blog gives a good way to make smoother gear changes. It's a fair way through the passage though. BB drives are harsher on the drivetrain, IME, so bear this in mind if yours is in any way creaky. There are gear sensors fitted to some off-the-shelf ebikes that cut out the power very briefly during gear changes, whether these are available to kits like the Bafang is something worth finding out.

[Kim]

I am not sure how the SRAM Dual Drive will cope with the Bafang BB solution. It might be fine, but it depends on how well you time the hub gear changes.

I'd imagine the hub gear would stay in high range most of the time the motor was being used, tbh.

There are gear sensors fitted to some off-the-shelf ebikes that cut out the power very briefly during gear changes, whether these are available to kits like the Bafang is something worth finding out.

The STEPS system when integrated with a DI2 hub (which can give you the option of fully automatic gear changes) seems to manage this fairly well, as long as you're actually using the motor assistance.  It's possible to catch it out if you give it a load of welly, but if you're giving it a load of welly, why are you riding an ebike in the first place?  With the assistance at zero graunchy gear changes are entirely possible if you don't ease off - auto mode is a bit like being the stoker of a tandem in that respect, the changes can take you by surprise until you get to know your pilot's habits.  The STEPS system can be set to beep when it changes gear, so you get a bit of a warning.

I haven't properly ridden a non-DI2 hub-geared cycle with a mid-drive motor to compare, I expect that without some sort of sensor there's potential for quite a lot of wear on the hub unless gear changes are treated with tranquillity (as per Auntie Helen's description of the problem).  Derailleurs seem to cope, as they're better at shifting under load.

[cycleman]

At the moment I tend to use the derailler for the majority of gear changes  . In London and the Thames valley the hub is normally in top in the hills however ...............'

[Butterfly]

I must admit the charging whilst touring does worry me a bit. I think that I fear getting stranded with no power and damaging the battery by not being able to recharge it as soon as it needs it . I do like the potential 100 miles range . If I rode to wing with electric assistance I would probably have to recharge around Northampton . Now I expect that to prove a interesting challenge

I think most trips, if you use the e-assist only for the harder bits, rather than like a motor bike, wouldn't be a problem unless you are riding up mountains. For a normal trip across middle earth with flat bits and downs as well as ups, you would mostly get more. Charging at campsites will often be quite easy, as they are all now used to being asked to charge mobile phones etc. You could possibly get away with asking wherever you stop for lunch if they would charge it for a bit.

I think it's a great plan and it's the route that I'm hoping to go down myself. 

[cycleman]

Due to my normal lack of fund's I have tried to wild camp as much as possible but having use campsite s will be more expense and less trips . On the plus side I will no longer hold forum rides up and therefore have more choice of riding 

[CAMRAMan]

Charging at lunch breaks might buy you some time, but the rule of thumb is ten minutes per mile to charge a battery.

[rogerzilla]

It's a shame that front-wheel drive isn't practical with a tadpole trike; I suppose you'd need two motors.  Received wisdom is that front-wheel drive is awesome on a bike.

[CAMRAMan]

I've had all three: FWD, RWD and BB drive. All very different bikes, but the rear wheel drive Oxygen I have is by far the best. It makes for a heavy rear end, but the torque from the motor far exceeds that from the converted FWD kit. The BB drive was on an awful BSO, so probably not a fair comparison.