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kingsley
July 4th 03, 10:24 AM
Have you ever seen the discharge graph for NiCd batteries?

It goes roughly:

|...............
V | :
| :
+====================>
time

I can tell you that NiMH feels about the same.

The problem is that, as Murphy would have it, that
abrupt turn in the graph corresponds to the curve
you're riding down, in the rain, on the commute
home from work. You've just about got time to to
think "Hmmm, that light is looking a bit dull", and
then a minute later it's just about out. Maybe it
had been a bit duller earlier, but riding in those
dawn/dusk times it's impossible to tell.

This has led me to thoughts of other batteries. IMHO the
vistalight 'nitestick' is not too bad, and I think
for it's price it's good, I'm happy with mine anyway.
I must remember to charge it every couple of days though.

But each battery is only 2200mAh at 7.2V. Why is it
such a bulky battery supplies only 2200mAh? I must be
missing something. I know a photo shop that sells 2000mAh
'AA' batteries - admittedly AA is only 1.5 volts (which is
really 1.2V talking NiCd/NiMH).
Wouldn't 6 of these ganged together give me 12000mAh and
probably weigh the same as a nightstick?
Have I missed someting here?
Can someone suggest a better SLA alternative?

A nightstick battery (NiMH) costs about $70,
a pack of 4 2000mAh AAs (IIRC) about $50 with a charger.

cheers,
-kt

stu
July 4th 03, 02:11 PM
yes you are missing something
6 2000mAh AA batteries
can give you
12000mAh at 1.2V or
6000mAh at 2.4V or
4000 mAh at 3.6V or
2000 mAh at 7.2V
maybe it would help if you work it out in w/h
12000mAh at 1.2V or =14.4w/h(l think l have this right)
6000mAh at 2.4V or =14.4w/h
4000 mAh at 3.6V or =14.4w/h
2000 mAh at 7.2V =14.4w/h

stu
July 4th 03, 02:11 PM
yes you are missing something
6 2000mAh AA batteries
can give you
12000mAh at 1.2V or
6000mAh at 2.4V or
4000 mAh at 3.6V or
2000 mAh at 7.2V
maybe it would help if you work it out in w/h
12000mAh at 1.2V or =14.4w/h(l think l have this right)
6000mAh at 2.4V or =14.4w/h
4000 mAh at 3.6V or =14.4w/h
2000 mAh at 7.2V =14.4w/h

kingsley
July 5th 03, 12:23 AM
On Fri, 04 Jul 2003 23:11:43 +1000, stu wrote:

> 6 2000mAh AA batteries
> can give you
> 12000mAh at 1.2V or
> ...
> 2000 mAh at 7.2V

Ahhh, of course... damn laws of physics.
So I'd be wantin' 8 of "7000mAh size 'F' 1.8v"[1]
to give me 14000 mAh @ 7.2V.
And maybe a trailer to carry them, how big is 'F' anyway.

[1] http://www.onlybatteries.com/showitem.asp?ItemID=10661.25

-kt

kingsley
July 5th 03, 12:23 AM
On Fri, 04 Jul 2003 23:11:43 +1000, stu wrote:

> 6 2000mAh AA batteries
> can give you
> 12000mAh at 1.2V or
> ...
> 2000 mAh at 7.2V

Ahhh, of course... damn laws of physics.
So I'd be wantin' 8 of "7000mAh size 'F' 1.8v"[1]
to give me 14000 mAh @ 7.2V.
And maybe a trailer to carry them, how big is 'F' anyway.

[1] http://www.onlybatteries.com/showitem.asp?ItemID=10661.25

-kt

stu
July 5th 03, 02:03 AM
l wonder if 1.8V is a typo on there part. l thought all ni-cd batteries were
1.2V and that was it.
l just finished building lights for my bike, you know the ones, 2*20W quartz
halogen down lights
plus a 12V SLA battery.
l used a 7.0 amp hour battery(it does weigh 2.5 kgs so it isn't for weight
weenies)
http://www.customer-self-service.com/radioparts/ProdView.aspx?popup=1&Produc
t=03294155
when for my first long night ride last night and it seems to be good for 3
hours or more with one light on.
cost me less then $50 including the rear light, but l had all the wire and
stuff. best $50 l ever spent!!!!!!!
great fun

stu
July 5th 03, 02:03 AM
l wonder if 1.8V is a typo on there part. l thought all ni-cd batteries were
1.2V and that was it.
l just finished building lights for my bike, you know the ones, 2*20W quartz
halogen down lights
plus a 12V SLA battery.
l used a 7.0 amp hour battery(it does weigh 2.5 kgs so it isn't for weight
weenies)
http://www.customer-self-service.com/radioparts/ProdView.aspx?popup=1&Produc
t=03294155
when for my first long night ride last night and it seems to be good for 3
hours or more with one light on.
cost me less then $50 including the rear light, but l had all the wire and
stuff. best $50 l ever spent!!!!!!!
great fun

Gags
July 5th 03, 12:43 PM
"stu" > wrote in message
...
> l wonder if 1.8V is a typo on there part. l thought all ni-cd batteries
were
> 1.2V and that was it.
> l just finished building lights for my bike, you know the ones, 2*20W
quartz
> halogen down lights
> plus a 12V SLA battery.
> l used a 7.0 amp hour battery(it does weigh 2.5 kgs so it isn't for weight
> weenies)

Good to see that someone else has decided to build their own lights.......I
still reckon they are the best value for money. I have recently finished my
fifth set of lights for which i machined up an aluminium housing for a 35mm
halogen globe (20W). I made up a NiMh battery pack in an old water bottle
using 10 x 4500mAh batteries which are 4/3 AA size (basically a bit longer
and bit fatter than standard AA batteries). These are in series which gives
me a 12V, 4.5Ah battery.

I am also currently repacking a Vistalight nightstick for a mate whos old
one was pretty well had it. I am using 5 x sub-C NiMh cells (as per the
original) but I have bought 2700 mAh ones from Jaycar (www.jaycar.com.au)
that cost around $9 each. This means my mate gets a new nighstick for
around $45 bucks that has around 25% higher capacity than the original!!!!!
It is a pretty simple process that only involves some basic soldering.

If you are interested in having a look at my lights, they are at
http://members.ozemail.com.au/~drgagnon/lights_5.htm

Cheers,

Gags

Gags
July 5th 03, 12:43 PM
"stu" > wrote in message
...
> l wonder if 1.8V is a typo on there part. l thought all ni-cd batteries
were
> 1.2V and that was it.
> l just finished building lights for my bike, you know the ones, 2*20W
quartz
> halogen down lights
> plus a 12V SLA battery.
> l used a 7.0 amp hour battery(it does weigh 2.5 kgs so it isn't for weight
> weenies)

Good to see that someone else has decided to build their own lights.......I
still reckon they are the best value for money. I have recently finished my
fifth set of lights for which i machined up an aluminium housing for a 35mm
halogen globe (20W). I made up a NiMh battery pack in an old water bottle
using 10 x 4500mAh batteries which are 4/3 AA size (basically a bit longer
and bit fatter than standard AA batteries). These are in series which gives
me a 12V, 4.5Ah battery.

I am also currently repacking a Vistalight nightstick for a mate whos old
one was pretty well had it. I am using 5 x sub-C NiMh cells (as per the
original) but I have bought 2700 mAh ones from Jaycar (www.jaycar.com.au)
that cost around $9 each. This means my mate gets a new nighstick for
around $45 bucks that has around 25% higher capacity than the original!!!!!
It is a pretty simple process that only involves some basic soldering.

If you are interested in having a look at my lights, they are at
http://members.ozemail.com.au/~drgagnon/lights_5.htm

Cheers,

Gags

Gags
July 6th 03, 11:34 AM
"stu" > wrote in message
...

> do you really mean 35mm globes? l could only find 50mm.

Yep......you should be able to get the 35mm globes from a specialist
lighting store. I have also seen them in Jaycar. They are a bit more
expensive than the 50mm globes (close to $10) but I reckon they are worth it
for the reduction in size (Especially as the aluminium rod offcut that i
used to machine my housing was less than 50mm in diameter). I guess that
the downside is that they get a bit hotter than the 50mm globes (as they are
both 20W globes) but I don't seem to have a problem given the big aluminium
housing/heatsink that i mounted it in.

Cheers,

Gags

John Doe
July 6th 03, 11:48 AM
"Gags" > wrote in message
...
: housing/heatsink that i mounted it in.
:
: Cheers,
:
: Gags
:


Dont suppose you have pictures

Pete

stu
July 6th 03, 12:26 PM
l must be going blind they are on jaycars web site, missed them when l
looked. l wish they made them in 10w but stuff it l am not a weight weenie l
will just get another battery.
thanks

stu
July 7th 03, 03:46 AM
thanks for that dave
l will pick up a 10W one next time l am at kmart.
"PWM set up at a 50% duty cycle" did you build this yourself? l have see the
light brain on hippys site but while l could put it together, l couldn't do
the code(l dont think)

now, is 3 lights to many?
l am also working on an mounting a couple of leds so l can see my HRM and
speedo, and maybe even what gear l am in(but l think that would be a little
over the top, but how much could 4 leds and 2 AA batteries weigh?)

stuart

AJS
July 9th 03, 06:23 PM
I have spent a few hours and some $$ on lighting lately. Here are some of my
thoughts.

Try and get Phillips, GE or Osram. The Jaycar bulbs and light assembly are
quite poor. Poor light output, Poor colouring. Basically junk. If anyone is
looking at using bi pin bulbs (I haven't tested assemblies yet) then GE is
the
way to go (34715 Is what I tested). Nice white light. I would then go for
Phillips and Osram in that order. How do I know this ? Well I have just
finished building some lights using small car spotlights (Don't waste your
money of cheapies) and custom bulb holders. It works very well. I spent MANY
hours testing differing bulbs, filament types Ect. side by side. I am
currently looking for some projector bulbs to test them. If they can cope
with the vibration
then I will probably stick with them. 25% brighter than the brightest bulb I
can find with the usual reduced life.

I know that Osram make a assembly that uses an Xenon bulb (IRC). I was not
overly impressed with these (Actually disappointed). Not as bright as they
should have been until over voltaged. (I know that someone in Adelaide is
currently looking at using these to take a product to market with.)

There is a HUGE different in light output, colour and quality between
different bulb's/housings. For the people who have built them I would
recommend looking at what they are using and if they can get an additional
performance increase for little outlay.


I hope this is of interest and help to a few of you. It was not posted to a
relevant post in this thread as I could not decide which one.




AJS



P.s I am looking at setting up an light meter and measuring the output and
spectrum of different lights. If I do I will post URL for interested
parties. If anyone know where I can get HID 10-20W bulbs for a decent price
let me know, this is my pet project that is just a little to expensive to
finish at the moment :(




"kingsley" > wrote in message
news:pan.2003.07.02.21.46.21.258743@maddogsbreakfa st.com.au...
>
> Have you ever seen the discharge graph for NiCd batteries?
>
> It goes roughly:
>
> |...............
> V | :
> | :
> +====================>
> time
>
> I can tell you that NiMH feels about the same.
>
> The problem is that, as Murphy would have it, that
> abrupt turn in the graph corresponds to the curve
> you're riding down, in the rain, on the commute
> home from work. You've just about got time to to
> think "Hmmm, that light is looking a bit dull", and
> then a minute later it's just about out. Maybe it
> had been a bit duller earlier, but riding in those
> dawn/dusk times it's impossible to tell.
>
> This has led me to thoughts of other batteries. IMHO the
> vistalight 'nitestick' is not too bad, and I think
> for it's price it's good, I'm happy with mine anyway.
> I must remember to charge it every couple of days though.
>
> But each battery is only 2200mAh at 7.2V. Why is it
> such a bulky battery supplies only 2200mAh? I must be
> missing something. I know a photo shop that sells 2000mAh
> 'AA' batteries - admittedly AA is only 1.5 volts (which is
> really 1.2V talking NiCd/NiMH).
> Wouldn't 6 of these ganged together give me 12000mAh and
> probably weigh the same as a nightstick?
> Have I missed someting here?
> Can someone suggest a better SLA alternative?
>
> A nightstick battery (NiMH) costs about $70,
> a pack of 4 2000mAh AAs (IIRC) about $50 with a charger.
>
> cheers,
> -kt
>

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