What LED lights for AXA HR Traction bottle dynamo?

[Boyonabike]

Can anyone please advise what is the most powerful front (and rear) light combination that can be run from a decent bottle dynamo such as the AXA HR?

I'm planning to fit an electric front hub motor to my trusty old hub-geared bike to help with a 25 mile commute along canal towpaths. As this rules out a hub dynamo and the ebike conversion battery won't connect to lights, my only option is a bottle dynamo. I'm already using a bottle dynamo but would like to upgrade to the AXA HR on the grounds that it's rated as one of the best in class. I certainly need to improve the output I get from my present bulb lights.

I see good things said about the B&M Lumotech Cyo IQ range and was thinking of the Premium 80 lux version, run together with a rear LED Linetec light. However, I'm getting conflicting advice from different bike shops about whether that combination is compatible with a bottle dynamo or whether I need a much duller front bulb (30 t0 50 lux). Can anyone with experience of a decent bottle dynamo and LED front bulb please suggest what is the maximum brightness I should be looking for? Unfortunately I can't find any wattage listed in the B&M specification so have no way of knowing on paper whether a bottle dynamo could generate enough power to fully light it up as well as a rear light.

[mercalia]

I think most bottle dynos come from the halogen bulb era which were very inefficient, so I doubt any normal commercial led cycle lamp would tax it? Dont really know. My experience moving from such to a modest Axa pico 30 was that it was twice as bright. SInce you are doing canal paths I suppose you need to consider beam spread, you need quite a wide spread so you dont cycle into the canal? Dont know about your bottle but a more reliable one might be the B&M bottle ( now discontinued but there are still supplies) with a wire roller that will work under any conditions, since you intend commuting and need 100% reliability? Does mean the tyre has to have a dyno track, like the Marathons. For a bottle dyno you dont need any of the fancy stuff that hub dyno lights have, would be a waste of money. But finding such a light might not be easy?

[wjhall]

I assume that LED dynamo lights generally have been designed to draw the currents at 6 V that can be supplied by dynamos from the filament bulb era, but the obvious answer to your question is to ask the manufacturer, or strictly, the supplier.

I have an AXA-HR driving a 30 Lux B&M Upp-N. Paired with an AxaBasta Ray Steady LED this reached a maximum voltage reading of 6.7 V rms on a digital multimeter, which suggests that everything is in order. Both the lamp and the AXA-HR have regulators, presumably Zener clippers for the dynamo. Unfortunately my notes on DC measurements are no longer clear to me, they seem to say that 5.65 DC would drive 0.20 A, which is lower than the traditional 0.4 A. I would be interested to hear from anyone with more consistent measurements. The range includes what appear to be higher power variants, presumably with electronics set to provide higher voltages, which the 0.2 A appears to allow for. I would guess at DC-DC switched regulators, but again, a question for the manufacturer, or does anyone else know?

The AXA-HR is electrically good, with a low electrical resistance, probably below 2 Ohms, but I find that the rubber tyres have a fairly short life. The life is extremely short, about 10 km if I do not glue them on with Evo-Stik. I get the impression from suppliers websites that only some people have this problem, but can see nothing wrong with my installation. As I do not commute but use the lights increasingly as daytime running lights on busier rural roads, I decided that buying a lifetime's supply (10 for 20 years) of rubber tyres was a suitable solution. Again, I would be interested to hear of other people's experience.

Given that you are planning to fit a large battery to the bicycle I suggest it would be best to look for a point to which appropriate converter electronics could be connected, thus eliminating the bottle dynamo.

[Brucey]

if you want a brighter light, get the 80 lux version. Worst case is that it will

a) have a switch in that it doesn't really need and/or
b) it may not reach full brightness depending on how close to 3W the generator makes

It will make as much or more light per watt that the generator produces.

FWIW I'd rather pedal a bike with a hub dynamo than put up with a bottle dynamo on an e-bike.

There are such things as rear wheel motors; depending on your bike one of those might make a better choice.

cheers

[cycle tramp]

This is my current set up - an AXA dynamo and an IQ front LED - no back light. Seems to work well enough for the dark lanes around here

[Boyonabike]

Thanks - as explained earlier a front hub dynamo is out as I have rear hub gears so if electrifying the bike I'd need to fit a front motor. Yes I know there are aftermarket crank motors but for various reasons including extra cost, complexity and chain wear I'm not really considering such an option. Unfortunately the motor kit battery I'm considering isn't designed to have lights run from it, which limits my options to a bottle dynamo or AA powered lights. My bike currently has an elderly Union bottle dynamo and bulb which whilst legal are night and day compared to my wife's hub dynamo and B&M LED lights so I am aware of the limitations of bottles but willing to upgrade mine to the best currently available as the AXA sounds a significant improvement on what I've got.

Cycle Tramp what model IQ is your dynamo/what's its light output?

[the snail]

I think you'd be better off running lights off the battery. If there isn't provision for running the lights off the controller, then you should be able to run lights directly from the battery (B&M and others make DC versions of their lights), or possibly from a USB connection on the battery.

https://www.peterwhitecycles.com/b&m_e-bike.php

[Boyonabike]

On what grounds? I've been advised by the supplier of the ebike conversion kit that I'm considering that it isn't possible to connect their batteries to any lighting. Hence my only lighting option (other than powering with AA or similar batteries) is a bottle dynamo as front and rear hubs are obviously accounted for already. What I am trying to establish is whether the lighting/power output of a good bottle dynamo is as good as that of a hub dynamo.

[the snail]

Surely you would have the option of tapping into the output from the battery, and connecting lights directly? As far as I can tell, the Axa HR is rated 6V 3W, same as a hub dyno, so you should be able to run any standard dyno set-up, e.g. B&M IQX, CYO premium etc

[rjb]

Everything well almost everything you need to know is here. http://pilom.com/BicycleElectronics/DynamoCircuits.htm

[andrew_s]

What I am trying to establish is whether the lighting/power output of a good bottle dynamo is as good as that of a hub dynamo.

It will be very similar.
When using halogen lights, it was the same, but the better LED lights do various electrical tricks to tease out a bit of extra power. These will be tuned for dynohubs, which are all very similar, and may not work as well with a bottle dynamo.

Whatever, you are best off with a Cyo Premium or similar. You'll get more light than with a nominally less powerful light, particularly when going downhill fast, when you need it most. Don't pay for senso, brake light functions, and daylight running lights unless you can't get a version without.
Don't get too hung up on lux numbers. The eye isn't very good at spotting small differences (compared to day and night) in lighting levels, and you'd be hard put to tell the difference between 60 and 80 lux without flip back and forth comparisons.

Bottle dynamos are best on the rear wheel unless there's a solid brazed on mount on the front (like the twin bolt plate on cycle tramp's Thorn, or off a V-brake boss). Clamps aren't reliable on tapered fork blades, and a dynamo in the front wheel spokes could see you landing on your face.

The roller should run on actual rubber (rather then fabric sidewalls), preferably on a ribbed dynamo track, and take care with alignment. The dynamo spindle should be exactly perpendicular to the wheel rim and tyre (so its axis and the wheel axis intersect).
If the alignment isn't good, you'll get more drag, and both roller slip and tyre damage are more likely.

[Brucey]

the main reason a motor supplier recommends that you don't connect lights (designed for the purpose, no less) to your battery is that this means there is one less way you can make the whole system not work, and fewer 'warranty' problems for them.

Front wheel motors may look appealing (cheap and simple on first sight) and they can work well, provided they are well-attached to a suitably robust fork. But plenty of forks are not robust enough, and the mountings for the motor are simply not good enough either. The result is often a broken bike. I've simply refused to have anything to do with most front motor conversions because there is something obviously flawed with the whole idea.

In the above vein are you sure that your fork is really suitable for attaching a motor to? [As a rule of thumb if the fork is steel, built heavy (2kg or more), 1-1/8" steerer, suitable for disc brakes, and has robust "lawyer's lips" it will probably take a motor if you go about it in the right way. You can often attach a reaction arm to the disc mount. If the answer is 'none of the above' it is usually a big 'no' to a front motor, and if it is 'some of the above', approach with caution. Fork breakage on converted bikes is depressingly commonplace and it can cause a really nasty accident]

There are loads of other ways of motorising you bike (which lack the appeal of a front hub motor but can result in a better bike) for example

a) A rear wheel hub motor that converts your bike to derailleurs is not a bad idea at all; the stresses on the bike are far less adverse and you may need different gear ratios anyway. You may be thinking that you would like to keep the hub gear (nice reliable thing) but even the worst derailleur system won't be the least reliable thing on the bike once it is converted.

b) I expect you will shortly be able to buy this combined motor and IGH (if you can't already) https://cyclingindustry.news/sunrace-sturmey-archer-create-5-speed-motor-gear-hub-for-accell/ which ought to be a good arrangement

c) you can get motors that drive an extant rear wheel by using a drive sprocket that attaches to the left side of the rear wheel.

FWIW I don't think mid-drives that drive through the extant bicycle transmission are a terribly good idea; the usual result is that the extant transmission wears out prematurely.

cheers

[mercalia]

Thanks - as explained earlier a front hub dynamo is out as I have rear hub gears so if electrifying the bike I'd need to fit a front motor. Yes I know there are aftermarket crank motors but for various reasons including extra cost, complexity and chain wear I'm not really considering such an option. Unfortunately the motor kit battery I'm considering isn't designed to have lights run from it, which limits my options to a bottle dynamo or AA powered lights. My bike currently has an elderly Union bottle dynamo and bulb which whilst legal are night and day compared to my wife's hub dynamo and B&M LED lights so I am aware of the limitations of bottles but willing to upgrade mine to the best currently available as the AXA sounds a significant improvement on what I've got.

Cycle Tramp what model IQ is your dynamo/what's its light output?

the night and day isnt between bottles and hub dynos but between your wifes led and your bulb lights.One advantage of bottles is the light output is more constant at low speeds eg walking than a hub which can become a rapid flashing.

I did a search on ebay and i see there are some B&M ones still available at a very good price

https://www.ebay.co.uk/itm/BUSCH-MULLER-DYMOTEC-6-SIDEWALL-BOTTLE-DYNAMO-GENERATOR-6volt-3w/183532572655?hash=item2abb64cfef:g:WlYAAOSw41Jb6aqe

for use on the left side ( front fork). This is the one I have & had proved very reliable

This is the all weather roller

https://www.ebay.co.uk/itm/Busch-and-Muller-All-Weather-Wire-Roller-for-Bottle-Dynamo/202153577125?hash=item2f114acaa5:g:HGwAAOSwQgpXApy6

[asinus]

For years I've run a Lumotec IQ Fly at the front and a B&M Toplight D at teh back off AXA roller dynamos with little trouble, except slipping in wet (or particularly foggy) conditions. I suspect that, because the current being drawn will be much less with LEDs than incandescents, the drag of the dynamo is a lot less. Go for it!
Asinus

[cycle tramp]

Cycle Tramp what model IQ is your dynamo/what's its light output?

That's a very good question - both items were purchased 2nd hand from this forum, although about six years apart. In fact most of the bike is second hand
The AXA dynamo is a much older style model with a metal roller, not sure about the headlight, but has the words Cyc plus written on the side.
I'm impressed with the beam of light it produces, longer and brighter than a filament bulb and comes on at a much lower speed too. I'm really impressed with it. Its certainly capable of lighting the dark lanes & cycle paths where I live.