Hardcore offroad machine *g*

50W.....is that all?????

At the MONT 24hr last year I saw a dude with a rectangular 120W driving
light from a car mounted on the bracer bar on his downhill handlebars. He
had a 7Ah battery and was about to set off on a lap. I think the quickest
lap time was about 45min or something, with most people doing more like an
hour. A few quick calculations....120W at 12V = 10A. There was no way that
his battery was going to last a lap and I told him so....he was pretty
confident that it would so off he went. I must admit, it did look pretty
spectacular as he took off, but I later saw him come in at the end of his
lap.....he was sitting right behind another guy as he had no juice left in
his battery.

Hated to say it, but as he rode up the last stretch of road I yelled out
"bloody toldya mate".....he thought that was pretty funny (at least I think
he did)

Gags
"Arpit" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Im becoming more and more serious about off road riding on my kmart
bike. At the moment, I have a 50 watt halogen light with a 60 degree
spread. Im planning to add onto this 4 20 degree 20 watt halogen spots
pointed much further away. Ive worked out that a car battery would be
an easy way to power these. Yes, it'll be heavy, but 15 kilos or so
isnt much compared to a human's weight. Plus it'll make me go faster
downhill 🙂 Im thinking about mounting it on a rear rack, panniers i
think they are called. WIll a cheap one be strong enough to hold it as
im bouncing over rocks?

Arpit said:

Im becoming more and more serious about off road riding on my kmart
bike. At the moment, I have a 50 watt halogen light with a 60 degree
spread. Im planning to add onto this 4 20 degree 20 watt halogen spots
pointed much further away. Ive worked out that a car battery would be
an easy way to power these. Yes, it'll be heavy, but 15 kilos or so
isnt much compared to a human's weight. Plus it'll make me go faster
downhill 🙂 Im thinking about mounting it on a rear rack, panniers i
think they are called. WIll a cheap one be strong enough to hold it as
im bouncing over rocks?

Can I suggest a SLA 12V 18AmpHr battery instead. Weighs 6kg. Modify a
battery holder to camp it to a back rack (I brazed a support plat onto
mine). My racks are proper touring racks (test for side sway).

I have found that 2 x 20Watt set off at angles are sufficent for bush
track of a night time, althought the 50W in a closer beam would be handy
on the good runs.

I like Moz's bent bicycle spoke attachment methods for the MR?? halogen,
or you can pick up a pair of halogen driving lights from cheap auto
stores.

--
Terry Collins {:-)}}} email: terryc at woa.com.au www:
http://www.woa.com.au
Wombat Outdoor Adventures <Bicycles, Computers, GIS, Printing,
Publishing>

"People without trees are like fish without clean water"

haha - I saw that thing too

"Gags" <drgagnon@nospam_ozemail.com.au> wrote in message
news:[email hidden]...
50W.....is that all?????

At the MONT 24hr last year I saw a dude with a rectangular 120W driving
light from a car mounted on the bracer bar on his downhill handlebars. He
had a 7Ah battery and was about to set off on a lap. I think the quickest
lap time was about 45min or something, with most people doing more like an
hour. A few quick calculations....120W at 12V = 10A. There was no way that
his battery was going to last a lap and I told him so....he was pretty
confident that it would so off he went. I must admit, it did look pretty
spectacular as he took off, but I later saw him come in at the end of his
lap.....he was sitting right behind another guy as he had no juice left in
his battery.

Hated to say it, but as he rode up the last stretch of road I yelled out
"bloody toldya mate".....he thought that was pretty funny (at least I think
he did)

Gags
"Arpit" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Im becoming more and more serious about off road riding on my kmart
bike. At the moment, I have a 50 watt halogen light with a 60 degree
spread. Im planning to add onto this 4 20 degree 20 watt halogen spots
pointed much further away. Ive worked out that a car battery would be
an easy way to power these. Yes, it'll be heavy, but 15 kilos or so
isnt much compared to a human's weight. Plus it'll make me go faster
downhill 🙂 Im thinking about mounting it on a rear rack, panniers i
think they are called. WIll a cheap one be strong enough to hold it as
im bouncing over rocks?

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

Quoted message said:

Can I suggest a SLA 12V 18AmpHr battery instead. Weighs 6kg. Modify a
battery holder to camp it to a back rack (I brazed a support plat onto
mine). My racks are proper touring racks (test for side sway).

Even 18Ah is big. 7A gel cells are easily available and should run a
single 20W for around 2-3 hours, which is enough for most night rides.
A decent 20W with a narrow beam is fine for the bars - something using
Jaycar cat SL2729 for example. I find that's good for around 50kmh on
the road, so should be similar off road (given that tar is
considerably less reflective than most dirt tracks)

The guy who was using the driving light knew it was going to run out,
and didn't care. Anyone riding a DH bike probably wasn't taking it too
seriously anyway, and given the amount of silliness in the Southside
Mafia's compound there's even more evidence that he was there for fun.
Yes, I was laughing at/with him beforehand.

I'm a big fan of having a helmet light as well, since it lets you look
around corners off road. Still playing with helmet lights, since my
current one is far too expensive to ride into low branches...

If anyone hasn't seen it, I've got some stuff up on
http://www.hired-goons.net/lights regarding home made lights. Needs
some updates, but I've been playing around with building rather than
documenting lately...

Dave - who has nearly got the nice 6.5V regulator working

--
Dave Hughes
[email hidden]
Like most computer techie people, I'll happily spend 6 hours trying to
figure out how to do a 3 hour job in 10 minutes. --Rev. James Cort

"Random Data" <[email hidden]> wrote in message
news:[email hidden]...

<...>

Quoted message said:

Even 18Ah is big. 7A gel cells are easily available and should run a
single 20W for around 2-3 hours, which is enough for most night rides.
A decent 20W with a narrow beam is fine for the bars - something using
Jaycar cat SL2729 for example. I find that's good for around 50kmh on
the road, so should be similar off road (given that tar is
considerably less reflective than most dirt tracks)

The guy who was using the driving light knew it was going to run out,
and didn't care. Anyone riding a DH bike probably wasn't taking it too
seriously anyway, and given the amount of silliness in the Southside
Mafia's compound there's even more evidence that he was there for fun.
Yes, I was laughing at/with him beforehand.

I'm a big fan of having a helmet light as well, since it lets you look
around corners off road. Still playing with helmet lights, since my
current one is far too expensive to ride into low branches...

If anyone hasn't seen it, I've got some stuff up on
http://www.hired-goons.net/lights regarding home made lights. Needs
some updates, but I've been playing around with building rather than
documenting lately...

Dave - who has nearly got the nice 6.5V regulator working

That's a great site ;-)

It's made me interested in creating my own light set for commuting.

I'm thinking of creating one with a 12V halogen and 8 rechargable
batteries - if I went for 8 2100mA hour 1.5V batteries, this should give me
about 2 hours use right? My thought is that I could create the light and a
flexible mount for the batteries that I could wrap around the top stem near
the light with velcro.

Any thoughts?

The batteries would be very expensive however.

What sort of batteries do you use? I saw at [censored] smith they have a RC car
battery (9.6V 650mAH) for $20 that would be probably suitable for a night or
two of commuting, and at that price can afford two or so. Are there halogen
lights that would suit this sort of battery?

The reason I'm interested in a decent light is for riding on bike tracks at
night.

Cheers,

Tim

On Thu, 11 Sep 2003 21:24:56 +1000, Terry Collins <[email hidden]>

Quoted message said:

Arpit said:

Im becoming more and more serious about off road riding on my kmart
bike. At the moment, I have a 50 watt halogen light with a 60 degree
spread. Im planning to add onto this 4 20 degree 20 watt halogen spots
pointed much further away. Ive worked out that a car battery would be
an easy way to power these. Yes, it'll be heavy, but 15 kilos or so
isnt much compared to a human's weight. Plus it'll make me go faster
downhill 🙂 Im thinking about mounting it on a rear rack, panniers i
think they are called. WIll a cheap one be strong enough to hold it as
im bouncing over rocks?

Can I suggest a SLA 12V 18AmpHr battery instead. Weighs 6kg. Modify a
battery holder to camp it to a back rack (I brazed a support plat onto
mine). My racks are proper touring racks (test for side sway).

Thing is those are twice the price of a sealed car battery, and haldf
the capacity.

Quoted message said:

I have found that 2 x 20Watt set off at angles are sufficent for bush
track of a night time, althought the 50W in a closer beam would be handy
on the good runs.

I like Moz's bent bicycle spoke attachment methods for the MR?? halogen,
or you can pick up a pair of halogen driving lights from cheap auto
stores.

I actually use garden lights taped to the bars. I had a big crash
today at about 60km/h on a steep rocky slope. im all cut up, ow, and i
had to cycle on a bad kneww for 5 km back home. the front wheel was
bent and so wer erthe handlebars, but the lights fine 🙂 I just cut it
off though, the bikes a write off.

On 11 Sep 2003 16:13:54 -0700, [email hidden] (Random Data)

Quoted message said:

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

Quoted message said:

Can I suggest a SLA 12V 18AmpHr battery instead. Weighs 6kg. Modify a
battery holder to camp it to a back rack (I brazed a support plat onto
mine). My racks are proper touring racks (test for side sway).

Even 18Ah is big. 7A gel cells are easily available and should run a
single 20W for around 2-3 hours, which is enough for most night rides.
A decent 20W with a narrow beam is fine for the bars - something using
Jaycar cat SL2729 for example. I find that's good for around 50kmh on
the road, so should be similar off road (given that tar is
considerably less reflective than most dirt tracks)

I use a 7amp hour battery at the moment driving a 50 watt, its pretty
good. but you arent supposed to run them anywhere near flat, and they
are rated for 7 amp hour at basically trickle use, not 2-4 amps.

Quoted message said:

The guy who was using the driving light knew it was going to run out,
and didn't care. Anyone riding a DH bike probably wasn't taking it too
seriously anyway, and given the amount of silliness in the Southside
Mafia's compound there's even more evidence that he was there for fun.
Yes, I was laughing at/with him beforehand.

I'm a big fan of having a helmet light as well, since it lets you look
around corners off road. Still playing with helmet lights, since my
current one is far too expensive to ride into low branches...

Not bright enough tho 🙂

Quoted message said:

If anyone hasn't seen it, I've got some stuff up on
http://www.hired-goons.net/lights regarding home made lights. Needs
some updates, but I've been playing around with building rather than
documenting lately...

Nice 🙂

Quoted message said:

Dave - who has nearly got the nice 6.5V regulator working

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

Quoted message said:

Im becoming more and more serious about off road riding on my kmart
bike. At the moment, I have a 50 watt halogen light with a 60 degree
spread. Im planning to add onto this 4 20 degree 20 watt halogen spots
pointed much further away. Ive worked out that a car battery would be
an easy way to power these. Yes, it'll be heavy, but 15 kilos or so
isnt much compared to a human's weight. Plus it'll make me go faster
downhill 🙂 Im thinking about mounting it on a rear rack, panniers i
think they are called. WIll a cheap one be strong enough to hold it as
im bouncing over rocks?

FYI, the Fat Hippy says no to mounting a battery on the back rack:

"Tim Jones" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

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

Quoted message said:

Im becoming more and more serious about off road riding on my kmart
bike. At the moment, I have a 50 watt halogen light with a 60 degree
spread. Im planning to add onto this 4 20 degree 20 watt halogen spots
pointed much further away. Ive worked out that a car battery would be
an easy way to power these. Yes, it'll be heavy, but 15 kilos or so
isnt much compared to a human's weight. Plus it'll make me go faster
downhill 🙂 Im thinking about mounting it on a rear rack, panniers i
think they are called. WIll a cheap one be strong enough to hold it as
im bouncing over rocks?

FYI, the Fat Hippy says no to mounting a battery on the back rack:

http://members.iinet.net.au/~fathers/rack.htm

And that was with just a 3kg battery - I don't think your 15kg one would
last too long!

Maybe it would go better have one in a pannier bag, that way a lot of the
bounce would be take up by the material rather than the rack itself. But
that then precludes the full car battery...

Tim

"Tim Jones" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

I'm thinking of creating one with a 12V halogen and 8 rechargable
batteries - if I went for 8 2100mA hour 1.5V batteries, this should give me
about 2 hours use right?

You'll need 10 to get 12V, since rechargeables are 1.2V. In fact, it's
worth getting 11 and running a 13.2V pack - you get around 20% more
light, at the expense of about 50% bulb life. Given most MR16 bulbs
have a rated life around 5000 hours and cost around $7, I'm willing to
do that...

Given a voltage and a wattage, you can calculate the current by
dividing watts by volts - a 20W bulb at 12V draws 1.7A. Your 2.1Ah
cells will last a bit over an hour. From memory, the spec sheet for
the 2Ah cells I saw implied that at 2A draw you'd get 50 minutes life
(the 2000mA is the full life at a more moderate load - NiMH batteries
are pretty good at high currents, but nothing's perfect).

Quoted message said:

What sort of batteries do you use? I saw at [censored] smith they have a RC car
battery (9.6V 650mAH) for $20 that would be probably suitable for a night or
two of commuting, and at that price can afford two or so. Are there halogen
lights that would suit this sort of battery?

Not really. You could make a Pulse Width Modulation regulator to drop
it to 6V, and get around 1Ah equivalent. But that's fiddly, and 6V
stuff is a little tricky to get hold of. It's easier to just get 12V
globes, and then a bunch of NiMH AAs from Jaycar - 10 2Ah ones will
set you back around $60 off the top of my head.

Dave - who commutes with 11 AAs in a Topeak mini saddle bag.

--
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

<snip>
That's a great site ;-)

It's made me interested in creating my own light set for commuting.

I'm thinking of creating one with a 12V halogen and 8 rechargable
batteries - if I went for 8 2100mA hour 1.5V batteries, this should give me
about 2 hours use right? My thought is that I could create the light and a
flexible mount for the batteries that I could wrap around the top stem near
the light with velcro.

Any thoughts?
<snip>

Tim, I reckon that you are onto a winner in making your own lights. I have
also posted some info on my home made lights at
http://members.ozemail.com.au/~drgagnon

<snip>
The batteries would be very expensive however.

What sort of batteries do you use? I saw at [censored] smith they have a RC car
battery (9.6V 650mAH) for $20 that would be probably suitable for a night or
two of commuting, and at that price can afford two or so. Are there halogen
lights that would suit this sort of battery?
<snip>

I would say that the RC batteries at 650mAh would probably be OK if you were
making a light using white LEDs, but from experience with the set that I
made, they are not as good for off-road adventures as the 20W halogens. If
you look on my sit at the V3 lights, it is the dual 20W setup that I reckon
is ideal for off-road. One 35 degree and one 12 degree globe to give a low
beam/high beam setup. (see web site for details). They are easy to make and
very cheap.

My recommendation with batteries is to start off with a Sealed Lead Acid
(SLA). They are relatively cheap (I recently bought two 12V, 3.2Ah
batteries for $30 each for some lights that I am making for a mate and his
missus). They are also pretty tolerant to abuse and not too fussy about
charging techniques. You can get away with a wall plug type charger (I just
bought a couple from Radio Parts Group in Melbourne for $20 each) that
basically use a constant voltage to charge initially at the max rate of the
charger (500mA for the ones that i bought), then tapers off to a trickle
charge as the battery nears full charge so that you can leave them
connnected for long periods of time without worrying about overcharging
them.

NiMh and NiCd batteries, although lighter and smaller are a bit more
expensive and a bit more fussy when it comes to charging. They are
generally charged using a constant current and so you need to be careful
with the cheap and nasty type chargers as they don't switch to a trickle
charge and you will shorten the life of thebatteries if you accidently leave
them on charge over the whole weekend (as I am known to do on a regular
basis). i am planning on building a PIC controlled "smart charger" for my
NiMh pack soon, as at the moment I am using a constant current charger that
I made up as an interim measure so I need to remember to take them off
charge before they get damaged.

Anway, good luck with making your lights......give me a buzz if you need any
technical advice.

Cheers,

Gags

"Random Data" <[email hidden]> wrote in message
news:[email hidden]...
<...>

Quoted message said:

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

Thanks for the info, much appreciated!

Tim

"Gags" <drgagnon@nospam_ozemail.com.au> wrote in message
news:[email hidden]...
<...>

Quoted message said:

Anway, good luck with making your lights......give me a buzz if you need

any

Quoted message said:

technical advice.

Thanks for the info! I am thinking about combining a 20W 12V light setup
with an 8 LED swirling light (a kit pack from JarCar) - would give me good
visibility on the road and decent sight on darkish bike paths...

Cheers,

Tim

Quoted message said:

My recommendation with batteries is to start off with a Sealed Lead Acid
(SLA). They are relatively cheap (I recently bought two 12V, 3.2Ah
batteries for $30 each for some lights that I am making for a mate and his
missus). They are also pretty tolerant to abuse and not too fussy about
charging techniques

The funny thing about lead acid batteries this size is, they cost more than
the next size up. A 7Ah batteries costs $21, figure that out
l have a 7Ah one on my bike and have got 3 hours out of it with a 20w bulb.
No idea yet how long the battery will last going that depth of discharge,
but they are only $21 each and l don't do 3 hour night rides very often, so
it should last awhile

stu said:

Quoted message said:

My recommendation with batteries is to start off with a Sealed Lead Acid
(SLA). They are relatively cheap (I recently bought two 12V, 3.2Ah
batteries for $30 each for some lights that I am making for a mate and his
missus). They are also pretty tolerant to abuse and not too fussy about
charging techniques

The funny thing about lead acid batteries this size is, they cost more than
the next size up. A 7Ah batteries costs $21, figure that out
l have a 7Ah one on my bike and have got 3 hours out of it with a 20w bulb.
No idea yet how long the battery will last going that depth of discharge,
but they are only $21 each and l don't do 3 hour night rides very often, so
it should last awhile

where do you get them for 21 dollars? mine cost 25

radio parts
http://www.customer-self-service.com/radioparts/
Yasa 12V
2.6Ah $42.97
7Ah $38.68
Doss
2.3Ah $20.46
7Ah $21.64

so it looks like they have fixed the prices up a little since l bought my
battery a couple of months again

I was lucky enough to buy some surplus NEC Lithium Ion batteries from
Oatley electronics. Nothing beats them for power to weight. All that
is needed to charge them is a current and voltage limited power supply.
A friend uses a benchtop PSU from jaycar. I have some other
batteries pulled from dead laptops. I just bought a new Dell laptop and
the battery has 95 watt/hours and probably weighs just over a 1 Kg.
I'll have to bring it into work to weigh it. My guess is around 1.2 to
1.5 Kg.
The major problem with lithium Ion batteries is the discharge curve is
quite step so a voltage regulate is needed. If you email me (remove
pants) I can give details on a pretty simple 555 timer circuit to do
this. One day I'll get around to using a microcontroller with an A to D.

Arpit said:

Im becoming more and more serious about off road riding on my kmart
bike. At the moment, I have a 50 watt halogen light with a 60 degree
spread. Im planning to add onto this 4 20 degree 20 watt halogen spots
pointed much further away. Ive worked out that a car battery would be
an easy way to power these. Yes, it'll be heavy, but 15 kilos or so
isnt much compared to a human's weight. Plus it'll make me go faster
downhill 🙂 Im thinking about mounting it on a rear rack, panniers i
think they are called. WIll a cheap one be strong enough to hold it as
im bouncing over rocks?