Battery pack for a PC Engine and an LCD screen - what voltage do I need?

[soop]

Hello, long time no see!

I'm thinking about continuing a mod I started years ago, then put away.  I got stuck at the battery stage after buying 2 li-ion batteries I was going to wire together.  From what I know now, this is a terrible idea, because I don't have the expertise to limit the charge properly in any way.

So basically, the next step is to get a new battery that will be able to supply the screen and the PC engine.  I know that I can wire the screen to take the power directly from the console, and the screen is only 5v.  What can I get away with for the PC engine?  I know it says 9v, but in practice I remember it was less.

I've found this 12v battery which I should be able to uncase, and it would also solve the problem of charging:
http://www.ebay.co.uk/itm/Professional-4000mA-Polymer-Lithium-Ion-Battery-12V-Plastic-Shell-And-Charger-F7-/222304228894?var=&hash=item33c25d561e:m:mRP4EW7A60z95keQbeqfLjg

But I also have a 5v battery already with USB in/out ports.  If I can use that, and if I can figure out how to rewire the out part, that would be ideal

[crazydean]

I don't understand the purpose of a battery pack mod. Why not just buy some eneloop rechargable batteries instead? They'll probably last longer...

[Necromancer]

I've no idea about such techy issues, but what's the end game?  I wanna say a Switch that won't suck. 

Whatever it is, it sounds like an interesting project.

I don't understand the purpose of a battery pack mod. Why not just buy some eneloop rechargable batteries instead? They'll probably last longer...

He's not talkin' about an 'Express.  It's a PCE and separate LCD.

[soop]

He's not talkin' about an 'Express.  It's a PCE and separate LCD.

Yep - I'm making my own PCE LT, since I'll never own a real one

[SignOfZeta]

For just a PCE I'd imagine 7V 400mA would be enough to keep it going. Maybe as low as 250mA if you promise not to use a multi tap. I don't think 5V is going to do the job so you'll need to build some kind of power distribution to reduce voltage for both components, variable resisters maybe?

[soop]

One last question before I buy a new battery; once I supply power to the console via the bus, it bypelasses the power switch, doesn't it?  So if I connect a battery without a switch, it's on until I disconnect it.

[SignOfZeta]

I believe the switch still works. If you have an IFU and the PCE is switched off then it stays off no matter what you do with the IFU so I don't think you'll need a switch.

[soop]

I believe the switch still works. If you have an IFU and the PCE is switched off then it stays off no matter what you do with the IFU so I don't think you'll need a switch.

Just re-read this http://nfggames.com/games/pce/ and it features this text:

"Secret 32:
If you supply power to the PC Engine or CoreGrafx through the rear expansion port it will bypass the power switch, and you can't turn the system off. This will also bypass the regulator and fuse, so use caution! "

I'll test it when my new battery arrives, but it looks like I might need to include a switch

[Eddiesamma]

It would be alot more efficient to hit adafruit and get a charge boost circuit and then ebay a healthy lipo pack. I think turbokon has a thread about adding a lipo pack to the express that uses that idea.

[soop]

Thanks man - I only just found these exist, so I'll look up the thread.