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Author Topic: External Battery Pack Mod  (Read 1026 times)

Offline Remzi

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External Battery Pack Mod
« on: December 16, 2018, 10:30:27 AM »
This is an experimental project.Try at your own risk

Board no 250469 (short board) the 10 ohm resistor at the R19 overheats.Needs to be disconnected before using DC only power.

I am not sure about long boards.I will test them out.

Running the C64 on DC only is not a new thing.It's been tried many times.Check out Ilker's Project.

The only thing doesn't work with the C64 is TOD chip.Which is used by very few software.It is possible to do a small modification on the motherboard by adding a 555 timer to overcome this problem.I haven't tried it myself yet so I can't say much about it just yet.

Here is the finished Battery pack,

(That 3.5mm jack is used for powering my SD2IEC so I don't have to use the cassette port.)

This is a regular power bank with standart USB 5V and 9V/12V/15V adjustable power outputs.

Idea is feeding 12V or 15V DC (depending on the C64) to AC rail on the userport output.And of course 5V DC to 5V rail.

5V output of this power bank is useless as under load it drops down to 4.5V.C64 still works with this voltage but SD2IEC is not really happy about it.

That's the reason I had to use a step down converter to get a solid 5V output from the power bank.

The photo above shows the edge connector,power switch and the converter module installed to the front panel.

I soldered the GND and the 12/15V wires to the DC socket.This power bank came with a small push switch on it's side.I couldn't find any info about the purpose of this switch,I tried everything.I came to a conclusion that this switch is useless so i converted to the reset switch for the C64.

I cut the trace on the board,soldered the reset line on the other leg.

There are a couple of issues with this battery pack.

1.Datasette doesn't work.It seems like it's not powerful enough to supply enough current.I'm testing out larger power banks.

2.You can charge the battery pack with a regular 5V 2A USB charger while you are using your C64 but power bank gets really hot after half an hour.Culprit is the inductor right next to the micro USB connector.Some sort of a heatsink or cooling fan might be an option.Or I can use a different power bank charged with a 12V power source.

« Last Edit: December 19, 2018, 06:07:37 AM by Remzi »