Cool MTB Light Comparison

Quoted post said:

Originally posted by hippy
http://www.mtbr.com/spotlight/lightshootout/

hippy

noice!

how many of those are available here tho?
(and how many times do i find myself rueing that???)

[QUOTE]Originally posted by hippy
http://www.mtbr.com/spotlight/lightshootout/

hippy [/QUOTE

ooh. ta. good research for the november 24hr...

now if only i could afford these rather than the 'halogen & a hose clamp' approach that i'll end up taking!]

"hippy" <[email hidden]> wrote in message
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Quoted message said:

mtbr.comlightshootoutOpen ↗

hippy

elektrolumens.comUltra 8.htmlOpen ↗ Check this
out.....eight x 3W LuxeonStars......Now thats bright!!!!

niteflux.comcustompage.aspxOpen ↗
Saw these the other day in Ivanhoe Cycles....I am a big
exponent of homemade lights but I am sorely tempted to fork
out for a set of these. They looked to be an excellent
product and as far as I know they are basically an Aust
version of the Vistalight (but better IMHO). I reckon that
the Visionstick 20s are a goer (I am pretty sure that
DeanWoods had them for $289 but I can't remember what they
were worth at Ivanhoe Cycles) which is pretty comparable
with Vistalight Nightstick 20 I think.

Gags

Quoted message said:

Originally posted by Gags
http://elektrolumens.com/Ultalux-8/Ultra-8.html
Check this out.....eight x 3W LuxeonStars

I had a little look - looks pretty bright.. bit big though.
Those LEDs must be expensive.. I've seen the 5w ones
for $55 ea. and this guy used 3 of the 8w ones!!

Quoted message said:

http://www.niteflux.com/custompage.aspx?custompage=Features

Quoted message said:

DeanWoods had them for $289 but I can't remember
what they were worth at Ivanhoe Cycles) which is pretty >comparable with Vistalight Nightstick 20 I think.

I've got 2 of the 15w VistaLites. Other than the reflection
off road signs it's hard to tell if they are on when riding
with street lights on. In the bush is a different matter
though - the 10w and 5w were pretty good in Kona24hr.
I'm really keen to try a HID setup though.. helmet mounted
for some serious driver blinding 😉 (pay attention to the
winking smiley netcops! :P)

hippy

must be some special battiers he has there as well 4D cells=
4*1.2V=4.8V 8 x 3W LEDs=24W 24W/4.8V=5amps 5amps x 4 hour
run time = 20Ah where can you get 20000mAh batteirs?? the
best I have seen are 9500mha or is my maths wrong? stuart

"stu" <[email hidden]> wrote

Quoted message said:

must be some special battiers he has there as well 4D
cells= 4*1.2V=4.8V 8 x 3W LEDs=24W 24W/4.8V=5amps 5amps x
4 hour run time = 20Ah where can you get 20000mAh
batteirs?? the best I have seen are 9500mha or is my
maths wrong?

5 amps out of a D cell? No way.

Theo

Quoted post said:

Originally posted by Stu
must be some special battiers he has there as well 4D cells=
4*1.2V=4.8V 8 x 3W LEDs=24W 24W/4.8V=5amps 5amps x 4 hour
run time = 20Ah where can you get 20000mAh batteirs?? the
best I have seen are 9500mha or is my maths wrong? stuart

Let me have a go at this.
The 3W LEDs each take 1000mA to produce 72 Lumens = 8000mA, Ni-Mh D cell = 8/9000mAh, 4 x D cells = 4 hours?

Quoted message said:

Quoted message said:

must be some special battiers he has there as well 4D
cells= 4*1.2V=4.8V 8 x 3W LEDs=24W 24W/4.8V=5amps 5amps
x 4 hour run time = 20Ah where can you get 20000mAh
batteirs?? the best I have seen are 9500mha or is my
maths wrong?

5 amps out of a D cell? No way.

They are NiMH - "Yes way". That is only about 0.5C discharge
rate. RC people regularly discharge NiMH and NiCad batteries
at ~5-10C (that would be maybe 50A!), some even up to 20C
[PLEASE DON'T TRY THIS AT HOME...]

11,000mAh NiMH D's are readily available. He's probably just
exaggerating the run time a bit; who doesn't do that?

Quoted message said:

Originally posted by hippy
I had a little look - looks pretty bright.. bit big though.
Those LEDs must be expensive.. I've seen the 5w ones
for $55 ea. and this guy used 3 of the 8w ones!!

No wonder it didn't make sense when I looked at the pic
and then the text! The guy's first sentence is "This remarkable homemade bike light uses three 8 watt Luxeon Star LEDs."

It is actually 8 * 3watt LEDs, not the other way around.

Sorry peeps...

hippy

Bikesoiler <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

Let me have a go at this. The 3W LEDs each take 1000mA to
produce 72 Lumens = 8000mA, Ni-Mh D cell = 8/9000mAh, 4 x
D cells = 4 hours?

Nope. The 4 D cells are all being drained at the same time.
However, it's not entirely unbelievable for LEDs - I'm
guessing he's actually undersupplying them a tad, say 10%. I
reckon he's only getting an hour or so of truly bright
light, but still getting around 8-10W worth of light for a
few more hours.

The 3W LEDs are probably pulling around 900mA at 4.8V. In
fact they should work OK off around 3.6, but it helps to
chuck a current regulator on and that sucks a bit of power.
In theory that means the 8 LEDs should only run for around
(9A/(900mA*8 LEDs) = roughly 1.2 hours. But LEDs have a nice
feature; they run nicely as V goes down, and the load is low
enough the cells should fail fairly gracefully. I can get 12
hours+ out of 1.2Ah AAs with a 300mA load. Of course, after
about 4 hours it's getting too dull to ride by, but it's
still good for letting drivers see me [1].

Dave - who must put the 5W LED driver circuit together.

[1] Whether that's a good thing is an exercise left for
the reader.

--
Dave Hughes [email hidden] A man might spend his
life peering at the private life of elementary particles and
then find he either knew who he was or where he was, but not
both. -- Terry Pratchett, Hogfather

"Glen F" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Quoted message said:

Quoted message said:

must be some special battiers he has there as well 4D
cells= 4*1.2V=4.8V 8 x 3W LEDs=24W 24W/4.8V=5amps
5amps x 4 hour run time = 20Ah where can you get
20000mAh batteirs?? the best I have seen are 9500mha
or is my maths wrong?

5 amps out of a D cell? No way.

They are NiMH - "Yes way". That is only about 0.5C
discharge rate. RC people regularly discharge NiMH and
NiCad batteries at ~5-10C (that would be maybe 50A!), some
even up to 20C [PLEASE DON'T TRY THIS AT HOME...]

I didnt think NiMH liked high C rates. Isnt that why NiCads
are still use in reghargable drills etc? or have NiMH
improved there to?

Quoted message said:

11,000mAh NiMH D's are readily available. He's probably
just exaggerating the run time a bit; who doesn't do that?

Me. I get 3 hours+ out of my lights. problem is I have no
idea how long a SLA will put up with this DOD. (and I
cant remember the end V at the minute) oh and it does
weigh 2.5kg lol stu

Quoted message said:

Quoted message said:

RC people regularly discharge NiMH and NiCad batteries
at ~5-10C (that would be maybe 50A!), some even up to
20C [PLEASE DON'T TRY THIS AT HOME...]

I didnt think NiMH liked high C rates. Isnt that why
NiCads are still use in reghargable drills etc? or have
NiMH improved there to?

That's correct - why the RC car people still seem to prefer
NiCad. Aircraft people, OTOH, prefer NiMH or even LiPoly for
the much greater energy density, and just flog the cells at
well above recommended discharge rates. They get hot, but
none of mine have exploded (yet).

There are cells and cells. Some NiMH are optimised for
higher discharge rates, but there seems to be a
capacity tradeoff.

Quoted message said:

Quoted message said:

11,000mAh NiMH D's are readily available. He's
probably just exaggerating the run time a bit; who
doesn't do that?

Me. I get 3 hours+ out of my lights. problem is I have no
idea how long a SLA will put up with this DOD. (and I
cant remember the end V at the minute) oh and it does
weigh 2.5kg lol

I've given up on my SLA system. The energy density is
just too low.

"Glen F" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Quoted message said:

Quoted message said:

RC people regularly discharge NiMH and NiCad batteries
at ~5-10C (that would be maybe 50A!), some even up to
20C [PLEASE DON'T TRY THIS AT HOME...]

I didnt think NiMH liked high C rates. Isnt that why
NiCads are still use in reghargable drills etc? or have
NiMH improved there to?

That's correct - why the RC car people still seem to
prefer NiCad. Aircraft people, OTOH, prefer NiMH or even
LiPoly for the much greater energy density, and just flog
the cells at well above recommended discharge rates. They
get hot, but none of mine have exploded (yet).

There are cells and cells. Some NiMH are optimised for
higher discharge rates, but there seems to be a capacity
tradeoff.

they just keep getting better and cheaper, don't they

Quoted message said:

I've given up on my SLA system. The energy density is just
too low.

unfortunately so is mine lol stu