Turboexpress internal rechargeable battery mod

[turbokon]

You can also bypass using the internal 5v regulator with this mod.   The charger circuit used is only rated at ~5.25V.

[NightWolve]

Yeah, you should or probably have to since it's running closer to 5V like you mention.

It's a great time for rechargeable batteries these days, 100,000 mA USB portables on the cheap, getting better all the time!

http://www.ebay.com/itm/100000mAh-Dual-USB-Portable-Solar-Battery-Charger-Power-Bank-For-Cell-Phone-/201389176627

[in99flames]

Great job!.  Even at 4-5 hours it's a huge power saver.  Was there even an aftermarket/first party external battery pack ever made for the Turbo Express like the Game Gear, Game Boy, or Lynx?

Yes actually. As far as first party packs...the ones i know of were made for Gameboy.  sega made a game gear rechargeable pack that worked for nomad as well.  Atari has an interesting one for the lynx...it is an external battery pack but its not a rechargeable one(besides putting in rechargeable batteries in it). I believe it takes 4 or 6 "D" size batteries as opposed to the 6 AA. on the d batteries you could run it a lot longer. I can't think of any others at the moment :-P

[pdiggitydogg]

Really great. I am looking at doing the same for my Sega Nomad but am still in the shopping-around stage.

[wilykat]

So how does one bypass the original 5v in TE to power it off lipo? And what about new LCD? LCD used for car uses 7-14v and may not like running at 5.

[NightWolve]

So how does one bypass the original 5v in TE to power it off lipo? And what about new LCD? LCD used for car uses 7-14v and may not like running at 5.

No, they gotta run at 5VDC, their power adapters have 5VDC regulators in them. Think of any powerful 7" to 10" tablet these days, they all come with 5VDC 1-2 Amp power supplies which can fully run them with no drain on the battery if it's always connected! That's with powering the CPU AND the LCD!!! So yeah, you can do A LOT with 5VDC and support for 1-2 Amp draw.

[wilykat]

Ok but where does one put the 5v from lipo board to?  TE has input for 9v from AC or battery and generally the internal 5v regulator needs higher input to work.  Where do I tack on the 5v from the lipo board to bypass the original 5v regulator so TE would work off lipo?

[NightWolve]

Logically I would guess at the output leg of the TurboExpress' 5V regulator so it'd pick up the job right where it all begins. But I'll leave the question to our professional EEs/modders.

[fluxcore]

I wonder if LiFePO4 batteries could be substituted - they seem to be replacing LiPos in a few electronics projects due to being a safer technology (and having voltages more suitable to some tasks). Wouldn't be very nice to have a TE catch fire during a recharge :/

[thesteve]

with screen mod 5V works

[turbokon]

The lcd I used is easily modded to work with 5V.

[thesteve]

but the stock one doesnt

[NightWolve]

EE in the house!

So Steve, just to confirm for him, the output leg of the 5V regulator would be appropriate to bring in a 5VDC battery to ? I believe a regulator has diode properties and the output leg is forward-electrons-only, so adding 5V to that leg from another source should in no way damage it or should you add a diode between that leg and the board just to be safe ?

[turbokon]

Yeah, that's how I'm doing it.  Also this setup output ~5.12v.  I'm using a voltage divider to bring the voltage down to ~5.0v.  A diode can possibly be used as well since it cause a little voltage drop but maybe a little to much. 

[NightWolve]

Yeah, that's true, you see about a .5 voltage drop with a diode.