Hi there!
So, in my first attempt to do something creative and actually learn something, I have decided to mod my Sega Nomad battery pack with an FP550 which requires 8.5v to charge (measured from the charger that comes with the battery)
Now, I am using the rechargeable battery pack and I would like to preserve the power adapter to avoid having too much of a modded 'look'... basically I want it to appear stock on the outside.
So, the Nomad mk2103 charger I have I measured with my mmeter and got a 12.5v @ 4.2a reading, even though the rating on the outside says 10v @ 0.85a.
My original idea was to shove the charger guts for the new battery into the Nomad battery housing, basically daisy-chaining the transformers to get the required 8.5v for charge, but I was told by several people this would not work as the charger for the new battery is an AC/DC transformer and would not work if given the DC input; and as it turns out the circuits would not fit into the housing anyway.
Now, my understanding from a conversation I had with my electrical engineer buddy and things I've read on the forum here, is that I can rig up a voltage regulator that would give me the clean 8.5vDC current I need for charging the battery.
Now I have a couple questions... since the reading I got on the mmeter from the mk2103 doesn't match the stats on the outside, most voltage regs I saw have a max of 1amp, will I have to do multiple in-line regs to account for the 4.2a current that I measured, or did I just measure wrong?
I also want the simple LED to light up when its plugged in; unfortunately I burned out the old one during tests, so do I have to account for the draw of volts/amps by the new LED and resistor when calculating the final output voltage, or input voltage if I tie in the LED before or after the volt regulator?
Finally, how much more difficult would it be to go the next step and make an intelligent charging circuit that would shut off when the battery reached full charge?
Thanks for any help!
So, in my first attempt to do something creative and actually learn something, I have decided to mod my Sega Nomad battery pack with an FP550 which requires 8.5v to charge (measured from the charger that comes with the battery)
Now, I am using the rechargeable battery pack and I would like to preserve the power adapter to avoid having too much of a modded 'look'... basically I want it to appear stock on the outside.
So, the Nomad mk2103 charger I have I measured with my mmeter and got a 12.5v @ 4.2a reading, even though the rating on the outside says 10v @ 0.85a.
My original idea was to shove the charger guts for the new battery into the Nomad battery housing, basically daisy-chaining the transformers to get the required 8.5v for charge, but I was told by several people this would not work as the charger for the new battery is an AC/DC transformer and would not work if given the DC input; and as it turns out the circuits would not fit into the housing anyway.
Now, my understanding from a conversation I had with my electrical engineer buddy and things I've read on the forum here, is that I can rig up a voltage regulator that would give me the clean 8.5vDC current I need for charging the battery.
Now I have a couple questions... since the reading I got on the mmeter from the mk2103 doesn't match the stats on the outside, most voltage regs I saw have a max of 1amp, will I have to do multiple in-line regs to account for the 4.2a current that I measured, or did I just measure wrong?
I also want the simple LED to light up when its plugged in; unfortunately I burned out the old one during tests, so do I have to account for the draw of volts/amps by the new LED and resistor when calculating the final output voltage, or input voltage if I tie in the LED before or after the volt regulator?
Finally, how much more difficult would it be to go the next step and make an intelligent charging circuit that would shut off when the battery reached full charge?
Thanks for any help!
