Sega Nomad internal rechargeable battery mod

[turbokon]

Quick run down of the genesis nomad internal rechargeable battery mod.

Parts used:

Two 2000mAh 3.7V lipo battery
http://www.ebay.com/ulk/itm/181812259852

3.7V to 5v booster
http://www.ebay.com/ulk/itm/130918041193

Charging circuit
http://www.ebay.com/ulk/itm/301695884093

[NightWolve]

Looks good!

[geise]

That is awesome.  I will have to try it.  I still need to replace the old tft screen.

[Desh]

I've done 2 of these.  One with (2) 3.7v 2500 mah batteries from a digital cam and one with 4 of the same batteries for double capacity.  The 2 battery setup would last about 2 hours and the 4 battery setup would last about 3.5 hours.  I used the same charger for both (could have gone bigger with the 4 battery setup).  My charging times weren't great because I played it conservative.  About 45 minutes on the 2 battery and basically double that on the 4.  The batteries were nothing special but the charger was fancy with built in overcharge protection etc. Etc. 

I used the stock DC in location as the charging port for a factory look.  The only downside is it disabled my ability to use the standard wall plug.

What is your battery life and charging times out of your design?

P.S. both of the ones I did had modern LCD's.

[turbokon]

I've done 2 of these.  One with (2) 3.7v 2500 mah batteries from a digital cam and one with 4 of the same batteries for double capacity.  The 2 battery setup would last about 2 hours and the 4 battery setup would last about 3.5 hours.  I used the same charger for both (could have gone bigger with the 4 battery setup).  My charging times weren't great because I played it conservative.  About 45 minutes on the 2 battery and basically double that on the 4.  The batteries were nothing special but the charger was fancy with built in overcharge protection etc. Etc. 

I used the stock DC in location as the charging port for a factory look.  The only downside is it disabled my ability to use the standard wall plug.

What is your battery life and charging times out of your design?

P.S. both of the ones I did had modern LCD's.

I will test the run time and charging time and will report back.

[Desh]

DELETE... totally botched an edit.

[Desh]

Well, I was looking back through my old notes on the Nomad mod and it turns out my memory is only as long as my weiner.  My charging times are accurate but my pack ratings were way off base.

The 2 battery setup had 1400 mah total.  The 4 battery had 2800 mah total.  The charger I used charged at 8v 1200 mah.  I just obtained 7.4V by wiring a pair in series and powered the Nomad directly from that (through the voltage regulator).  The 4 battery setup was another pair wired in parallel. 

Something else I dug up from my notes about li ion charging was that they like to charge at around "1c" meaning if the pack is rated at 2000 mah it's ideal to charge at around 2amps.  Your ability to "quick" charge mainly depended on how much voltage you could safely charge the battery at without over heating it.  Since your setup charges at .5c I wonder how the charge time will be.

Maybe some real life, trained engineers can chime in on this stuff.

[tool]

love Nomad  so sexi bitch

[pdiggitydogg]

Nice work. My Nomad is slated for this as well - I was going to mock it up like what is on portablesofdoom.

Edit.
I would love if you did a little more detailed write up for this. My main question is where you made contact for the charger/AC adapter circuit... Did you remove the ground pin from the original jack? Can you take some pictures of that with labels?
Does your low battery indicator light still work?

[turbokon]

I'm getting about 3hr 40mins run time.  Charging time is a lot longer, i can you tell it's over 4 hours (went to bed before it finished charging).

pdiggitydogg, yes, I separated ground and positive of the ac jack from main mother board and wired them to step down convertor.  The low battery led on the nomad doesn't blink on low battery with this mod.  It stays lid.

[pdiggitydogg]

Thank you.
This is the idea I was going to use, utilizing this same charger listed here
.http://portablesofdoom.org/?p=286
It runs the batteries in series instead of using a step up transformer... I haven't tried running the system an anything lower than 7.5v from a phone adapter.

[Jason_dicarlo85]

Dude that is pretty fkin cool

[Elder]

Thanks again for the Game Gear turbokon.  It has been absolutely awesome!  I am seriously impressed with your modding skills my man.

[Desh]

I'm getting about 3hr 40mins run time.  Charging time is a lot longer, i can you tell it's over 4 hours (went to bed before it finished charging).

pdiggitydogg, yes, I separated ground and positive of the ac jack from main mother board and wired them to step down convertor.  The low battery led on the nomad doesn't blink on low battery with this mod.  It stays lid.

That is some good usage time!  I think bumping up the charging circuit to 2amps and maybe a bit more voltage would cut down that charging time.  I like your ideas for this.  I actually have another Nomad I've been thinking about tinkering with so maybe I use some of your ideas.

Also, I had wired my setup (since I was basically using just the batteries and all of my safeties were external) directly to the factory battery prong locations (removed the prongs).  The battery light still worked correctly when done this way.  However, there was not a ton of warning.  I think I would only get maybe 60-90 seconds more usage after the light would come on.  Just enough to hopefully save your game if you were playing Beyond Oasis or something like that.

[turbokon]

Thanks again for the Game Gear turbokon.  It has been absolutely awesome!  I am seriously impressed with your modding skills my man.

Thanks Elder, glad to hear you're enjoying the gamegear.