Chris Wilkson wrote:
>> Erm, what? The energy capacity? I think this depends on the capacity of
>> the cells you use. You can't say in general "the capacity of lead-acid
>> batteries is higher than that of NC ones" or vice-versa. Both are
>> available in different sizes and capacities. I don't know what you're
>> comparing here.
>
>Yah, I should have said energy density. Of course the CELL density is a
>lot higher too ;) So if the energy density is higher then the energy
capacity
>will be higher for cells of the same size. Good point.
The CELL density? Per what? If you need 4 lead-acid cells to reach over
7 volts, but 6 NC cells, the NC are more, so the cell density is higher
(?!)
>The cells I use are 2.0AH, BTW. About the size of a "D" cell, a little
longer.
Hmmm, that gives about 4 Wh per cell for a D+ size. The NC D cells I
recently bought have 1,2 V x 4 Ah, so that's 4,8 Wh. So I think also the
energy density of the NC cells is higher than the one of lead-acid.
By the way, how much do these little lead-acid cells cost? My NC cells
costed about $4 each - but that was an occasion, normally, they would
cost $8-$12 each.
>>(...)
>> Note that the voltage
>> will stay ABOVE 7,2 volts during most of the time, unlike
>> one-way-batteries, saying 1,5 Volts on it, but going below that very
>> soon.
>Yes, Nicads have basically a piecewise linear voltage/charge function.
>It's relatively flat until they discharge to a certain point, then they die.
>Quickly. Lead acids cells have a simple linear voltage/charge function.
>So as soon as they start discharging, their voltage starts dropping. But
>this is A LOT slower than carbon/zinc or alkaline batteries. When I ran it
>for the 5 hours, I had experienced the early stages of color loss. But it
>was only noticable by looking at an o'scope. I'm guessing I probably
>could've squeezed another hour out of them. I'll try to test it this
weekend.
Looking forward to it... but you need not damage your cells for that
reason!
>> Of course, you need additional batteries for the screen...
>
>Yep. What I'd really like to do is hook up a color LCD screen. But that's
>way too time consuming at this point.
Arm, not for me... I've got a "Game Gear" at home (which I won at a
Karaoke contest), with TV Tuner. If you connect the middle pin of the
2600's antenna outlet with the tuner's antenna, it should work. The
other problem could be, then, that this combination isn't very handy
anymore (4 Units- 2600, Joystick, battery, screen - and 3 cables -
power, joystick and antenna). This is also what prevented me to do
open-air Karaoke until now (here you need a good - that means heavy -
speaker too...).
>> There this "portable 2600 clone" comes to mind. I think it had a battery
>> compartment. Does anybody know what type of cells, and how many, were
>> used, and when this one would "give up", or if they did something to
>> reduce the current it needed?
>
>I don't know anything aobut it, but I suspect that they would have done some
>re-engineering while they were at it. There are a couple of places that the
>2600 could save on power. One really nice thing about nicad batteries is
>the fact that 4 of them together can make up a well regulated logic power
>supply. At 300mA, that saves 1.2 watts just from the internal regulation!
>The video circuitry can be cleaned up some, but there's a limit. You're
stuck
>with the TIA, 6507, and RIOT. Although you could probably use a super low
>power 6502 successfully.
>
>Hmm...I see one of my 2600 jrs undergoing some major surgery pretty soon. :)
That leaves the question at which voltage range these three chips would
be able to work without regulation.
With love (and many songs to write and sing - sorry there's no Karaoke
Version of Watching the Wheels)
Kurt Woloch
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