I ran my MD2 from batteries...

TmEE co.(TM) · Post by **TmEE co.(TM)** » Mon Jul 09, 2007 11:11 am

I recharged the batteries in my S3 cart, took them out, and used these to power my MD2( http://www.undergroundcm.com/forum/view ... 78&start=0 ). I was able to play for 1hour and then the batteries were sucked dry.

My MD2 seems to be really power hungry, I guess these extra stuff I've put in it are the reason.

Jorge Nuno · Post by **Jorge Nuno** » Mon Jul 09, 2007 12:05 pm

I can run my Mega drive model one for 5hours with a 4Ah/6Volt lead battery

The voltage of the battery never exceeds 7.15Volts to prevent Hydrogen forming which ruins a SLA pretty quickly

But I put a cmos Z80, got rid of the old-eneficient regulators, and trew in a switching one for Digital Vcc and a Low-drop linear for analog Vcc

Digital Vcc(3.7V): 68K, VDP, Bus master, Memories, Z80
Analog Vcc(4.2V): YM, RGBencoder, RF

TmEE co.(TM) · Post by **TmEE co.(TM)** » Mon Jul 09, 2007 7:21 pm

I saw your MD, it is really cool, and very ugly

These batteries are ordinary Ni-MH that I ripped out from a Nokia 2110 battery. These hold on a week or so in my S3 cart (I've not made any long run tests though). If I use something like you, it'll hold up around the same time as yours. Z80 in my MD2 seemed to be CMOS in the beginning (I've not checked, but C in the middle of type number usually means that).

Jorge Nuno · Post by **Jorge Nuno** » Mon Jul 09, 2007 7:49 pm

MD2 comes with a cmos Z80 by default but mine MD came with a Z0840004psc; @5V that z80 and VDP run very hot, the new Z80 runs cool and the VDP just keeps warm (@3.7V)

Yeah the MD2 draws much less power than a MD1 default, I think you are correct about the 5 hours of playing without messing with the vcc

You could put a solar panel in there (for the save ram), I think a panel from a solar calculator is enough to keep data in RAM or you could buy a fram from ramtron

TmEE co.(TM) · Post by **TmEE co.(TM)** » Tue Jul 10, 2007 11:57 am

Nah, I'm not going to bother, I keep backups of that RAM every once in a while, and if the power gets too low (so RAM gets garbage), I'll load the backup on it play Sonic for a day (so the batteries get fully recharged).

evildragon · Post by **evildragon** » Tue Jul 10, 2007 12:03 pm

wait, you putting in power through the controller port? isn't that dangerous?

TmEE co.(TM) · Post by **TmEE co.(TM)** » Tue Jul 10, 2007 12:09 pm

It is not dangerous unless you switch the polarity. I triple checked for that !!!

evildragon · Post by **evildragon** » Wed Jul 11, 2007 1:19 am

so then the controller ports 5v must be directly from the regulator then.. did you remove the regulator or leave it in?

i also noticed you got Duke 3D in it.. i've been looking for that cart! lol

TmEE co.(TM) · Post by **TmEE co.(TM)** » Wed Jul 11, 2007 11:00 am

I didn't do anything with the regulator, I just connected batteries to MDs 5V power lines.

That Duke3D is a russian pirate cart without SRAM (I'm planning to add some), notice the "Russkaja Versija" on the label