How to build a new battery for a NightSun Team Issue?
DCheung
a new battery for it?? The factory battery is listed as "30 watt hour",
but it doesn't have a voltage or amp rating. Don't I need to know this to
get the right kind of batteries?
I read the FAQ, and from what I've been able to infer from the postings is
that someone built a homebrew light, compared it to the Nightsun, and
figured it used 12V, 2000 mah batteries. What is mah?
doland
MSchadAPI
>but it doesn't have a voltage or amp rating.
I would guess that this means 30 hours at 1 watt, which is not a common unit of
measuring current. Watts is a measure of power.
>the Nightsun, and
>figured it used 12V, 2000 mah batteries. What is mah?
>
Mah is milliamperes/hour. Since 1000mah=1ah, those batteries are 2 apere-hour
batteries. They will last 2 hours at a 1 amp load, which would mean a 12 watt,
12 volt lamp.
Mark
Matt O'Toole
DCheung <dch...@spl.usace.army.mil> wrote in message
news:01bf1595$c3af01c0$9e6f...@SPL111-158.spl.usace.army.mil...
> Anybody out there got any specs for the Nightsun Team Issue so I can build
> a new battery for it?? The factory battery is listed as "30 watt hour",
> but it doesn't have a voltage or amp rating. Don't I need to know this to
> get the right kind of batteries?
> I read the FAQ, and from what I've been able to infer from the postings is
> that someone built a homebrew light, compared it to the Nightsun, and
> figured it used 12V, 2000 mah batteries. What is mah?
mAh is milli-amp-hours, or amp-hours divided by 1000.
The system runs on 12V, and the amperage depends on whether you're running
the high or low beam. However, we know the low beam is a 10W, which means
it will run for 3 hours with a 30 watt-hour battery. That sounds like the
advertised runtime, eh? 30 watt-hours (Wh) divided by 12V is 2.5 amp-hours
(Ah). The cells in your battery are 2.5Ah, or 2500mAh.
Which sounds about right. 2500mAh is a very common, widely available,
inexpensive size, selling for about $4 each. Usually, these are C cells,
but they can be slightly different shapes as well. Nightsun used 10 of
these 1.2V cells to build your 12V battery. You can do this again, or
"upgrade" to higher capacity cells. C cells are now available in 2800mAh,
or even 3000mAh. BTW, Cannondale and Nalgene water bottles have large
mouths, making them best for battery building. After wiring the cells
together and stuffing them inside, you can fill the voids with instant foam,
or just plain old candle wax.
There are other options, too. You could use bigger, 5000mAh D cells, but 10
of those won't fit in a normal water bottle, so you'd have to use some other
kind of battery holder. Another (recommended) option is to add one cell,
yielding a 13.2V battery. This will make your lights much brighter, at the
expense of some bulb life. Most lighting companies are doing this now,
including Nightsun, with their new Trilight system. You could also build a
NiMH battery, with greater capacity, that's also lighter and smaller. But
NiMH cells are more expensive, don't last as long, and should really have a
"smart" charger, which is also expensive.
Finally, companies like Turbocat or Beam Adventures will build you the
battery pack of your dreams, maybe cheaper than Nightsun.
I also have a (really) old Nightsun system, with the early 8.5W low beam,
and the funky plexiglass tube LED tailight. It's been used with all kinds
of bulbs and batteries, rewired a couple of times, and it still kicks butt.
For even more info, read through the Bikecurrent mailing list archives.
Matt O.
Jon Isaacs
>a new battery for it?? The factory battery is listed as "30 watt hour",
>but it doesn't have a voltage or amp rating.
I built a battery from two 6 volt gel cells which I purchased at radio shack
for my NIGHT SUN Team Issue. It has worked for about 3 years now. These were
2000mah batteries
Since the light/battery is rated at 25 watts for 1 hour using a 12 volt supply,
this indicates that you need a 2 amp-hour battery. I did this using the 2
Camcorder batteries wired in series to get the 12 volts.
While it is not recommended to use a Nicad charger on Gel Cells, I have done it
and it has worked well for me.
I built the battery pack and put it in a large seat bag so that I still have
the two water bottle cages if I am on a long ride and need the light and water.
Jon Isaacs