XXX
07-01-2003, 04:37 PM
I have sucessfully run my 233/512 (384 ram, 30g hd, OS 9.2) Wallstreet off a
12v, 7.2 amp-hour gel cell battery:
http://www.ibsa.com/estore/view_product_detail.asp?mscssid=7NAV3TTLCWN18JUFAE4M9F
6U9L0V9NF9&part_number=SLA1075&category_id=0&find_spec=power%20patrol&js=1
The battery cost $26 at an Interstate Batteries store (they had it in-stock in
Omaha, NE) and weighs 6 pounds. Instead of buying a bunch of
soon-to-be-defective replacement wallstreet batteries at $200 apiece, I will
carry this battery inside my hard-shell foam-lined case which I keep my
wallstreet in. It's a perfect fit in the side pocket.
http://images.canadiantire.ca/media/images/Workshop/ToolStorage/HandBoxes/Metal/0
580925_450_CC_ba96.jpg
Usage in the field is not too often, but when I do, it's basically to unload
photos from my digicam during a photoshoot, so a dead battery is an annoyance.
My original wallstreet battery is one of those that dies after ten minutes, even
after all the tricks - new power adapter, power manager reset, pram zap,
PowerBook G3 Battery Reset application, etc. Can't bring myself to spend $200 on
a replacement, which would probably fail in the same way.
With regard to the plug configuration, since I had a spare older power adapter
that came with the wallstreet (still works fine, but I got the free upgrade to
the yo-yo) I took off the outer ring, which revealed the center portion of the
plug to be simply a 3-conductor 3.5mm miniplug.
The outer ring on the original plug does nothing but keep the plug firmly in
place. Not needed if you're free of kids, dogs, carelessness, and other things
which may jerk the plug out of the machine. Then again, maybe if you do trip
over the power line, it's probably better if the plug comes out easily, rather
than put a bunch of force on the power manager card.
The center portion was physically identical in every way to a 3.5mm diameter
stereo miniplug, except that the power adapter's miniplug is about one
millimeter shorter at the shank. This required fabrication of a thin flat
plastic ring shim which I slid down onto the 3.5mm stereo miniplug purchased at
radio shack. I used the modified stereo miniplug for the power connector.
The arrangement of power in the plug is as follows (measured with a DVM on the
Wallstreet's original power adapter):
Tip: Nothing, nada. Probably just trips a switch that lets the powerbook know
that it's plugged in.
First ring: Negative conductor.
Second ring, furthest from tip: Positive conductor (24v from the adapter, but
12v runs the powerbook, what gives here? Is the extra 12 for charging the
onboard battery?).
The battery came with spade lugs, and I soldered on a short two-conductor lead
attached to a polarized molex connector. I assume that reverse polarity would
destroy the computer, so be diligent in this regard. This lead I will only leave
on for testing, as I plan to put a fuse block inside this short lead for obvious
reasons. If this battery was shorted, it would melt the lead in a very short
time.
Probably also a good idea once the lead is secured is to glob the exposed
portions of the spade connectors with epoxy or cover them in plastic, so that it
will be practically impossible for the battery to short itself if it manages to
turn upside down on a metal surface, shorting the spade connectors. I would not
take it on a plane until I was SURE it could not short itself.
From there, I made an 8-foot lead which had at one end the other half of the
molex connector, and at the other end the 3.5mm miniplug. This way, if I decide
to power anything else with the battery, I merely need to make another lead to
hook to the molex. I also made another molex lead to plug into the 12v battery
charger I got at Wal-Mart. Takes about 7 hours to charge it.
Testing:
I made the first endurance test last night, and it was not as good as I had
hoped, but then again I had not topped off the battery's charge when I bought
it. The battery started off with about 12.4 volts (measured across the leads
while powering the wallstreet) and the powerbook's screen started doing some
weird flickering when the voltage got down to about 11.1 volts, so I unhooked it
then and put it back on its power adapter. It appears to be unharmed. The
voltage appeared to descend from 12.4 to 11.1 at a smooth rate, but in the ten
minutes leading up to this flickering, the voltage started fluctuating fairly
randomly from 11.1 up to 11.4 volts.
The time elapsed was 3.5 hours for this change in voltage while powering the
wallstreet, which had no power-saving functions engaged at all. I was doing
basic websurfing. Also did at least one reboot.
Maybe it will last a good while longer after I get a full charge on the battery,
and engage some power-saving features when running from the SLA.
I'll post pictures later if you want, and let you know how long it runs on the
SLA after a full charge and engaging some mild power saving features.
Is there any way to physically damage the powerbook by running it with
undervoltages? I don't see any way I could exceed 24 volts with this
arrangement. I could see instability and crashes happening, but real damage?
Comments welcome.
12v, 7.2 amp-hour gel cell battery:
http://www.ibsa.com/estore/view_product_detail.asp?mscssid=7NAV3TTLCWN18JUFAE4M9F
6U9L0V9NF9&part_number=SLA1075&category_id=0&find_spec=power%20patrol&js=1
The battery cost $26 at an Interstate Batteries store (they had it in-stock in
Omaha, NE) and weighs 6 pounds. Instead of buying a bunch of
soon-to-be-defective replacement wallstreet batteries at $200 apiece, I will
carry this battery inside my hard-shell foam-lined case which I keep my
wallstreet in. It's a perfect fit in the side pocket.
http://images.canadiantire.ca/media/images/Workshop/ToolStorage/HandBoxes/Metal/0
580925_450_CC_ba96.jpg
Usage in the field is not too often, but when I do, it's basically to unload
photos from my digicam during a photoshoot, so a dead battery is an annoyance.
My original wallstreet battery is one of those that dies after ten minutes, even
after all the tricks - new power adapter, power manager reset, pram zap,
PowerBook G3 Battery Reset application, etc. Can't bring myself to spend $200 on
a replacement, which would probably fail in the same way.
With regard to the plug configuration, since I had a spare older power adapter
that came with the wallstreet (still works fine, but I got the free upgrade to
the yo-yo) I took off the outer ring, which revealed the center portion of the
plug to be simply a 3-conductor 3.5mm miniplug.
The outer ring on the original plug does nothing but keep the plug firmly in
place. Not needed if you're free of kids, dogs, carelessness, and other things
which may jerk the plug out of the machine. Then again, maybe if you do trip
over the power line, it's probably better if the plug comes out easily, rather
than put a bunch of force on the power manager card.
The center portion was physically identical in every way to a 3.5mm diameter
stereo miniplug, except that the power adapter's miniplug is about one
millimeter shorter at the shank. This required fabrication of a thin flat
plastic ring shim which I slid down onto the 3.5mm stereo miniplug purchased at
radio shack. I used the modified stereo miniplug for the power connector.
The arrangement of power in the plug is as follows (measured with a DVM on the
Wallstreet's original power adapter):
Tip: Nothing, nada. Probably just trips a switch that lets the powerbook know
that it's plugged in.
First ring: Negative conductor.
Second ring, furthest from tip: Positive conductor (24v from the adapter, but
12v runs the powerbook, what gives here? Is the extra 12 for charging the
onboard battery?).
The battery came with spade lugs, and I soldered on a short two-conductor lead
attached to a polarized molex connector. I assume that reverse polarity would
destroy the computer, so be diligent in this regard. This lead I will only leave
on for testing, as I plan to put a fuse block inside this short lead for obvious
reasons. If this battery was shorted, it would melt the lead in a very short
time.
Probably also a good idea once the lead is secured is to glob the exposed
portions of the spade connectors with epoxy or cover them in plastic, so that it
will be practically impossible for the battery to short itself if it manages to
turn upside down on a metal surface, shorting the spade connectors. I would not
take it on a plane until I was SURE it could not short itself.
From there, I made an 8-foot lead which had at one end the other half of the
molex connector, and at the other end the 3.5mm miniplug. This way, if I decide
to power anything else with the battery, I merely need to make another lead to
hook to the molex. I also made another molex lead to plug into the 12v battery
charger I got at Wal-Mart. Takes about 7 hours to charge it.
Testing:
I made the first endurance test last night, and it was not as good as I had
hoped, but then again I had not topped off the battery's charge when I bought
it. The battery started off with about 12.4 volts (measured across the leads
while powering the wallstreet) and the powerbook's screen started doing some
weird flickering when the voltage got down to about 11.1 volts, so I unhooked it
then and put it back on its power adapter. It appears to be unharmed. The
voltage appeared to descend from 12.4 to 11.1 at a smooth rate, but in the ten
minutes leading up to this flickering, the voltage started fluctuating fairly
randomly from 11.1 up to 11.4 volts.
The time elapsed was 3.5 hours for this change in voltage while powering the
wallstreet, which had no power-saving functions engaged at all. I was doing
basic websurfing. Also did at least one reboot.
Maybe it will last a good while longer after I get a full charge on the battery,
and engage some power-saving features when running from the SLA.
I'll post pictures later if you want, and let you know how long it runs on the
SLA after a full charge and engaging some mild power saving features.
Is there any way to physically damage the powerbook by running it with
undervoltages? I don't see any way I could exceed 24 volts with this
arrangement. I could see instability and crashes happening, but real damage?
Comments welcome.