Hardcore offroad machine *g*

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: woa.com.auwoa.com.auOpen ↗ 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 hired-goons.netlightsOpen ↗ 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 hired-goons.netlightsOpen ↗ 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

Terry Collins 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.

(Random Data) 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 hired-goons.netlightsOpen ↗ 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

"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:

members.iinet.net.aurack.htmOpen ↗

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

"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:

<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 members.ozemail.com.au~drgagnonOpen ↗

<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

"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

"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 customer-self-service.comradiopartsOpen ↗ Yasa 12V
2.6Ah $42.97 7Ah $38.68 Doss
3.3Ah $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?