H3 Driving Light = eBike Headlight?

TonyReynolds

TonyReynolds

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Jun 13, 2011
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315
Location
Seattle, Washington, USA
I've been looking for a good headlight for my new eBike and have tossed around using flashlights, but wanted a headlight with a cutoff so as to not blind oncoming drivers. I know that opens up a can of worms for some people, so let's not discuss that in this thread. The light I decided on is this one:

image_17203.jpg


Lightweight moulded plastic with a glass lens... just one, of course. I've already looked at it in front of the handlebars and think it will be a great fit with my new bike. The light has a good vertical cutoff, and lights the periphery enough that I wouldn't feel like I was riding through a tunnel.

Most H3's are either 55W or 35W. The smallest H3 halogen I can get is 25W, from a guy on eBay. The problem is that at 12V, that still is 2 amps, and for a ride into work, I would drain too much of my main battery, about 2.25Ah.

I have an H3 LED replacement on order from superbrights. I use their 1157 LEDs on my motorcycle, though I am not naive enough to believe that the LED output will equal the H3 halogen. Still, I want to try one and see what it does:

h3-whp1.jpg


It *might* be enough for a bike at 20-25 MPH.

I will also be using two of these:

qh8cc.jpg


I have 3 x 1W MR16 yellow LEDs for these and will mount them low on the front rack so I have a triangle of light for conspicuity, daytime and nightime.

If I wanted to build a battery pack for the 25W halogen bulb using A123's at 3.6V, would I be correct in assuming that this is would be a 4s2p pack and would work, 2 x 4 batteries in series for 14.4V, doubling my capacity? The cost is not cheap, but if this is the correct configuration it might give me the separate Ah's I need to drive the headlight... I've found A123 cells for $11.50 to $18 per cell. Any better deals out there?

A tail light *might* run off this same pack, a 9-LED round, red marker light from HF that's already set for 12V. It wouldn't draw that much...

Any thoughts?
 
I don't know what your budget is for lights but I suggest you check out these lights. They are LED and work great. I have 6 different lights from this company.

http://www.advmonster.com

I use them on my adventure touring bike. The 22w lights are like a HID light with the way the light up the road. They also have options with PWM dimmers so you can dial them down a bit. I've used 2 of the 22w lights in excess 140 mph on some desert roads and had no issue over driving my lights. On an ebike the 22's might be overkill but dang they work great. I started out with their 10w wide angle lights and was hooked.

They aren't dirt cheap but the quality is very good. I am going to mount up 1 or 2 on my ebike once I get a DC to DC converter. As I've mentioned I've had 6 of these on a big V-twin adventure touring bike and I've been out in the desert and mountains haulin' butt on fire roads, picked my way through some pretty rough trails and spent over 30,000 miles with them and absolutely no issues. Think "cell man" quality but for LED lights.
 
Taz said:
http://www.advmonster.com
Click to expand...

Nice lights; I ride an R1100GS. They're a little beyond my budget and none of them are DOT approved, i.e. they'd need to be aimed down for approaching traffic, but look superb for offroad at night!
 
I've never had an issue using then on the road with respect to DOT approval. The 22w ones you have to be more careful with but the 10w I use as visibility lights all the time. The 22w in the daytime will even get people attention. Check on ADV Rider and sometimes you can pick up the earlier versions of these lights pretty reasonably.

The great thing about them is I don't over tax the electrical system on my Multistrada and can have a little power left over for heated gear. Thinking of which I should set that up for my ebike as well. It was well below freezing here today. No ice or snow on the roads but outside temps were on 11F.
 
auraslip said:
http://www.shelbyelectro.com/general-ebikes/design---building/ebike-lighting

see here. looks like you're on the right path!
Click to expand...

I've seen this, very nice site. Did you do it?

Something you're not! It's better to let drivers assume you are a motorcycle, so they won't pull out in front of you when they underestimate your speed.
Click to expand...

Exactly!

What I don't understand is the math. I have a 52V LiFePo pack. Is my amps calculation based on the 52V of the pack or the 12V value after step-down with a dc-dc convertor? 25W/52V would then be 0.48A, versus 2.083A.

Other than that, we agree, except I'm also interested in cutting off the top of the beam, as I will be riding in traffic and won't be concerned about seeing branches in teh woods at night, which is the main advantage of the Magicshine and other lights like it: a complete cone of light in the woods.
 
A little research on effective lumens may kill the LED H3 before it arrives. 12V halogens produce 30 lumens per watt. No wonder my overvolted 14.4V test last night did so well: 55x30 yields 1650 lumens. even a 25W lamp would yield a very respectable 750 lumens. The H3 LED is rated at a measly 70 lumens. That said, what's important is how the light is directed on teh subject, in this case the road and what I need to see, versus raw power.

The savings of going wwith the less expensive halogen system yields more dollars for a battery. The one advantage halogens have over LED's is more realistic color rendition. Colors are more natural and objects in the periphery are more recognizable. As always, this last is personal opinion: YMMV...
 
These work great for me. Most of the time I only use the 10 led mode and they run about 10-15 hours on 3 AA batteries which i recharge.
http://www.ebay.com/itm/56-LED-Torch-Bike-Bicycle-Head-Light-5-LED-Rear-Light-/110427608704
 
I have a 52V LiFePo pack. Is my amps calculation based on the 52V of the pack or the 12V value after step-down with a dc-dc convertor? 25W/52V would then be 0.48A, versus 2.083A.
Click to expand...

I'd love to have an answer to this question if someone knows...

I was thinking that 2 of these in parallel might be the ticket for my halogen lights:

T50004S-20HC.jpg


http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=15521

That'd be about $45 for 10Ah of 14.8V. Perfect for the 12V 25W H3's, as my understanding is that slight overvaulting produces output closer to HID, without the cost of HID...

Might be a good, relatively inexpensive introduction to Lipo
 
TonyReynolds said:
A little research on effective lumens may kill the LED H3 before it arrive. 12V halogens produce 30 lumens per watt. No wonder my overvolted 14.4V test last night did so well: 55x30 yields 1650 lumens. even a 25W lamp would yield a very respectable 750 lumens. The H3 LED is rated at a measly 70 lumens. That said, what's important is how the light is directed on teh subject, in this case the road and what I need to see, versus raw power.

The savings of going wwith the less expensive halogen system yields more dollars for a battery. The one advantage halogens have over LED's is more realistic color rendition. Colors are more natural and objects in the periphery are more recognizable. As always, this last is personal opinion: YMMV...
Click to expand...

I was thinking about going with an "H3" LED...
I'm SUPER curious as to how it performs against the Halogen..

Please let me/us know how it turns out!
 
I received the H3 LED today from superbright LEDs. I put it in the light housing and fired it up with 14.4V. The light definitely is bright, but throws hardly any light any appreciable distance. That and the fact that having 9 surface mount LEDs, there a LOT of shadows and artifacts in the beam. I then tried a 19.2V power source, and while better, there's just no way a 1W LED, even driven well past 12V can compete with a halogen bulb.

I then tried one of my 25W H3 halogens versus the LED: there's simply no comparison. I really think the 25W halogen is going to be fine. Unlike the LED, the filament is perfectly positioned in the reflector and throws light a very long way. There are no shadows or artifacts and I get good spill to the side of the road. I don't think I'll have have any problem over-riding that bulb, even at 25MPH. If I need more throw, I can go to a 35W or back to a 55W. There is a decrease in perceived brightness between the 25W and 55W halogen, but it's not that bad.

One other thing was that I happened to have an old mirror in my garage as I was trying these different bulbs, an that allowed me to see what each lamp looked like off-axis, not just the amount of light thrown forward. Off-axis visibility is important, because that's what cars will see at intersections. A large, bright, rectangle of light makes me look more like a motorcycle and less like a bike, which is my goal.

Now I have to put together a battery source for the headlight. I still haven't gotten an answer as to whether there's a difference in amp hours used when drawing through a DC-DC convertor off my main battery versus driving with a separate , lower-voltage battery, i.e. stepping down from 52V to 14V to drive the motor and the light versus going with a straight 14.4V battery to just drive the light.

Tony
 
And that I can answer to...
At 14.4v the 55w halogen will pull about 4.83a
At 12.8v it will pull about 4.3a
So if you're using a higher voltage it will pull more amps..
But you also have to figure in the efficiency of the converter...
A 6v battery will draw about 2.1a from the same bulb, but it will produce less light..

You have to weigh all the options...

I hope that helps.. If not, ask away...
 
Have you compared it to a 55w Halogen lamp though?

Everyone keeps talking about how great LEDs are compared to halogen (in regards to power consumption), but I still haven't seen a comparison in terms of actual brightness and fullness of light in a side to side test.

When I tell you that my 55w halogen front headlight NEVER goes un-noticed during night OR day, you can believe it.
I've tried a few LEDs in my day (albeit not $70+ ones) and they all seem to suck compared to my Hal.
 
Riche said:
I have the bike version of this light (bought from BMSBattery) and its an excellent light, 1000 lumens, I have had to re-wire the battery once or twice as the clacky wire broke but now it seems reliable.
http://www.ebay.co.uk/itm/CREE-XM-L...ing_LightsLanternsTorches&hash=item2a15fcfd65

actually here it is and its now listed as 900 lumens http://www.bmsbattery.com/led-bike-...de-900-lumen-led-bike-light-headlamp-set.html
Still very bright.

Rich
Click to expand...

Thank you. I know that there are a plethora of very bright FLASHLIGHTS that consume little power compared to halogens, but almost all of them have a conical beam that is blinding to oncoming traffic. I want a DOT approved beam that has an upper, horizontal cutoff, in order to be legal in traffic, which is where I intend to ride, and to be less blinding to oncoming bikes on trails. Those bike lights that DO have a reflector that creates cutoff are, in large, very expensive. This quartz driving light cost me $8. I already have the 25W H3 lamps from a prior motorcycle. A suitable lifepo4 battery should be about $75 - $125 . That's fairly reasonable for a light with cutoff.
 
Hooking up that 25w h3 will use about 2.2a (at 14.4v)
So figure what you need in Ah given your time that you can run your bike...
 
sangesf said:
Hooking up that 25w h3 will use about 2.2a (at 14.4v)
So figure what you need in Ah given your time that you can run your bike...
Click to expand...

Yes, it's looking like 4 A123 batteries in series, paralleled with another set of 4 in series, would yield the runtime I need.

Is that 4s2p?

Tony
 
TonyReynolds said:
sangesf said:
Hooking up that 25w h3 will use about 2.2a (at 14.4v)
So figure what you need in Ah given your time that you can run your bike...
Click to expand...

Yes, it's looking like 4 A123 batteries in series, paralleled with another set of 4 in series, would yield the runtime I need.

Is that 4s2p?

Tony
Click to expand...
Yep.

OR
At 6.4v (SLA/LiFePo4(2s)/etc) with diminished light it will pull .97a

OR
At 7.2v (various (2s) LiPo) with less diminished light it will pull 1.1a

Always remember these equations...

I(amps)=V(oltage)/R(esistance)
W(atts)=V(oltage)*A(mps)

If you use those equations, you can figure out just about any electrical measurement you want.
(Within reason)
;)

P.S. ALWAYS parallel, THEN series.
 
sangesf said:
P.S. ALWAYS parallel, THEN series.
Click to expand...

Hmmm, that's not the way I was to understand it. You build your series packs to get the voltage you want and then place those in parallel to get the capacity.

In my case, 4 - A123 batteries gives 14.4V at about 2.2 Ah, so two of those packs in parallel yields 14.4V at 4.4 Ah...
 
TonyReynolds said:
sangesf said:
P.S. ALWAYS parallel, THEN series.
Click to expand...

Hmmm, that's not the way I was to understand it. You build your series packs to get the voltage you want and then place those in parallel to get the capacity.

In my case, 4 - A123 batteries gives 14.4V at about 2.2 Ah, so two of those packs in parallel yields 14.4V at 4.4 Ah...
Click to expand...

Maybe you misunderstood what I meant..
(Yes you are correct in your statement as to what the pack will ultimately yield)..

I meant parallel each A123 (in a 2p configuration - in other words, pair two cells) and THEN series the 4 Pairs of cells.
 
The very best thing I could do is to order another 11.5 Ah A123 pack from cell_man to mount on the front rack, run the lights off that and use it as a range extender for my main triangle mounted pack. I was planning on a second Lifepo4 pack eventually anyway, but it's $550 plus freight.

OUCH!
 
For lower wattage halogens it comes down to reflector and prism design. My older NightSun 25W bicycle headlamps threw a much better beam wider and farther than my 50W H3's that had only a simple reflector and a clear prism, mostly it dumped heat and didn't produce enough light while riding at speed. They're a discontinued product but they sold for like $250 back in 1995 and I picked mine up on ebay for $30 in 2007, still work well.


img_0281.jpg

That was always the problem when I used to ride mopeds, most of those older systems were 6V and didn't project light in any useful capacity at all mostly just so other drivers could see that you were there instead of you being able to see the road ahead. To top it off they were RPM depended so you had to keep moving to get an decent light. At the time we just invested in bezels from other models or a newer magneto and changed to 12V system for slightly better lighting.

What I've considered using the H3's for since they're so much better at dumping heat than providing light is as an inductive load to test my Konions and A123's. I wanted to hook about 6 to 12 - 55W H3's in parallel to my Wattmeter then to the cell to be tested, yeah it's pretty ghetto because I'll have to keep an eye on them to prevent damaging voltage drops but it sure beats relying on the 30W resistors of the iCharger 1010B. Just an idea.... :wink:
 
Maybe have a look at ATV / Enduro motorbike lights I believe they have high / low beam.

By the way I was under the impression that LED is much lower power per lumen than the rest. Is that not true?
 
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