Front lighting suggestions for 36v bike

halfer

Esteemed Pedelecer
Hi all

Just purchased a new Juicy Sport Original from Eco Republic and I'm generally very pleased with it. I plan to take some pictures and write up a review at some point. In the meantime, I am buying some bits and pieces to help complete my necessary kit. Just purchased a new Bontrager cycle computer for GBP25 at a high-street store, and this seems to do the job fine. Next job: lights!

My version of the Sport has a built-in rear LED light that runs directly off the battery. It's not particularly bright, but it will do for the time being. Since there is no front light, that's my priority. My purpose is late-night road commuting. It seems sensible to run the front light off the existing battery pack, but my internet research shows that this is quite involved. This requires the purchase of a lighting unit, which might be any of:

  • a standard cycle headlight bought separately from the battery pack (this one is 60GBP)
  • a general purpose LED torch (such as this one)
  • a cheap cycle headlight case with high-intensity LED modules custom-mounted inside (lots of DIY required)
Once this is purchased and mounted, it looks like people are purchasing DC-to-DC converters and stepping down their e-bike battery (from 36 or 26v) to 12v. At 2-5W rating, these seem to cost around 10-15GBP. This then needs to be housed, connected to the battery by breaking into the battery leads, and then routing wires from the break-point to the handle-bars.

How are people doing this? - I have searched here and lights don't seem to come up often as a topic. Is the above so much hassle that it would be better to run LED lights on AA batteries, even though this is another thing to recharge? I have rechargeable AAs and a charger already, so this might be easier...

I should be looking to spend around 40GBP or so on my front light solution - there are some nice lights out there for professional use, but I am sure I can't justify 300GBP! Thanks all.
 

halfer

Esteemed Pedelecer
Addendum: there is a thread about this over at Endless Sphere. However since it is all US-centric, I am not sure it is of much use to UK/EU readers - and I tend to be averse to ordering components from abroad.
 

Scimitar

Esteemed Pedelecer
Jul 31, 2010
1,772
40
Ireland
I can tell you what I've done and plans to improve it.
I bought a couple of cheapy 5W( 300Lumens) (claimed) single LED torch/handlebar lamps and mounted them in tandem. They work rather well on Eneloop AAAs. Two of these, in fact...
5w LED Bicycle Front Rear Head Light Flashlight Torch R on eBay (end time 06-Sep-10 00:29:54 BST) from this seller... CyberPort888 items - Get great deals on LED Light, RC Battery items on eBay.co.uk Shops! he's got lots of other goodies in the LED lamp line of things. I might buy more from him.
I don't know about battery life yet, as I haven't used them in earnest, but for the longer term I shall run them from the main bike traction battery with a DC/DC converter.
For the longer term I'm looking at a 25W LED array, which are now dirt cheap and mounting that in a suitable shell. This can be supplied via a laptop charger bent to suit.
 

NRG

Esteemed Pedelecer
Oct 6, 2009
2,592
10

daniel.weck

Esteemed Pedelecer
Aug 8, 2009
1,229
2
Assuming good reflector/optics design (whether it's a torch or dedicated bike light), a SSC P7 900-Lumen LED unit floods lots of useful light on the road. The 18650 Lithium-Ion rechargeable cylindrical batteries deliver plenty of juice, but be sure to get good quality 2200mAh (or 2400mAh max) examples, don't be fooled by larger capacity ones which can be physically larger, and which actually don't deliver their promises (plenty of online info on this subject). Search for "SSC P7" on eBay and you will find the best deals.

The makers of Cycle Analyst sell good-quality DC-DC converters (waterproof, etc.), but this would be delivered from Canada or it would have to be ordered through a local UK dealer...not sure which is the most cost-efficient. Warranty issues are worth considering, so a local purchase may be a better choice.

Renaissance Bicycle Company



Cheers, Dan
 

Straylight

Esteemed Pedelecer
Jan 31, 2009
650
2
Of course there's always the option of running a front hub dynamo, that effectively draws power from the battery via kinetic energy transfer, and has the benefit of also drawing energy from you - particularly useful if you get caught short of battery power in the dark. My wisper came with a Shimano Nexus unit that's never missed a beat, I coupled this with one of these, which gives a fantasic ammount of light, and includes a connection for pairing a backlight.

Just a thought...

Sadly it seems Wisper have stopped including the dynamo with their 905s, probably a cost thing, as it really adds a minimal amount of drag.
 

JuicyBike

Trade Member
Jan 26, 2009
1,671
527
Derbyshire
We have these wind-up LEDs in the shop at £11.99.

You could also tap into the rear light cables, to power LEDs to the front.
 

Neil

Pedelecer
Mar 28, 2008
63
0
Im with the NRG

I Have both the first two light from Deal Extream. They are very bright and well worth the money. If you travel along unlit country roads then they are for you. Neil
 

halfer

Esteemed Pedelecer
Thanks all for your thoughts - the DealExtreme ones seem to offer a good cost/brightness ratio. However Straylight's point about running out of power is well made: I did a 18-20 mile round trip on Sunday, and since I'd used the throttle assistance quite a bit, the battery died completely. I presume the battery protection kicked in, which meant that it would not even run the rear lights for the last few miles home :eek: (and yes, I had to ride a 22kg bike up some inclines without power - not my idea of fun!).

I am tempted therefore to go for the 900 lumen ones, and run them from the supplied pack to start with, and then either to get a second battery pack, or to run them from a converter and to keep a charged pack available as spare.
 

TylerD

Pedelecer
Jul 8, 2010
175
0
Halfer, I've just bought the 900 lumens and it is a good bright light. I cycle along a very dark , completely unlit cycle path though and I'm still thinking of getting another light to use at the same time, although its not an absolute necessity. You'll also need an adaptor to use the charger as it doesn't come with a uk plug. I was also a bit worried by the comments left by other buyers on the Deal Extreme website, but as i didn't read them until I had bought the light I'm just going to use it and see how it goes.


I've also just bought 2 Smart 1/2 watt rear lights, which are every bit as bright as all the 5 star review say, I would definitely recommend them