Need into for battery mod, lipo charger ?

I want to install some nice long life batteries and have a charger port added to it so I won't need to open to remove and recharge separately. But I am not sure what are the right stuff to get started with lipo.

I am planning to do Lynx, Game Gear, and TurboExpress. I do know Lynx draws an average of 300mA (probably about same for other color LCD systems) and I would like to know of:

which lipo is good for more than 300mA draw (maybe 500mA minimum?), has more than 20o0mAH to last me a few hours per charge, and what charger circuit to use to handle the recharging? Atari Lynx arraigned the batteries in 2 parallel rows of 3 in a single compartment while Game Gear has 2 separate compartments holding 3 batteries each compartment. TE has all 6 batteries in same compartment but all are parralel like 2 of Game Gear's compartment combined.

I was thinking of a pair of 3.6v lipo in series, each about the size of 3 AA in parallel. Atari Lynx has lots of empty space inside so I could just get rid of the old compartment and use double sided tapes to hold batteries in place.

 

Li-po cells come in different sizes and different amperage; although usually 3.7v each. Problem is the quoted amperage is not always correct (Chinese ones typically) and also even if correct the amperage draw from the console can cause the li-po cells to not work as well as stated too. As far as a charger is concerned, go for whatever you use for the batteries, ie if you have one cell, charger suitable for 3.7v, if two cells in series to get 7.4v then you need a charger for 7.4v . The other issue then is the voltage you need for your system, probably using a step-down regulator.

These links might be useful?

http://www.bacman.co.uk/home/wiring-protection-circuit-to-cells/
http://www.bacman.co.uk/home/charging-and-powering-system/
http://www.bacman.co.uk/home/good-voltage-regulators/

 

I've got some solutions. Been dealing/working with LiPO batteries for 5 years now, so I know what I'm doing pretty well, lol. And if you want 7.2 volts to be delivered, you should go nickel metal. But as far as LiPOs go, most (if not all) come at 3.7 volts like Bacman said. You want a 2S pack. You will also need a step-down regulator. But here is a LiPO (7.4) that will work well. Venom does not fluff its amperage and specs. Each battery has a real rating on it, unlike 95% of the other brands out there.

Battery; http://www.atomikrc.com/collections...h-7-4-lipo-battery-with-universal-plug-system

Charger (slow but cheap); http://www.atomikrc.com/collections...atomik-2-to-3-cell-ac-dc-lipo-balance-charger

 

The voltage needed for the systems are based on 6x alkaline batteries (about 9v) and I do know my Atari Lynx with 5v mod* will work as low as 6.5v Game Gear and TE not sure, depends on the regulator. MB3775 used in GG seems forgiving with low power so it's likely it will be fine with 7.2v. I can't find schematic for TE or GT.

Some useful links for me to check out, thanks you 2!!

*The 5v mod was done because of crappy design in stock Atari Lynx. It uses emitter-follower design with a transistor and a zener diode to pull voltage rail to 5v but if that part fails, there is nothing to prevent 9v from getting dumped into entire system. A mod removed that transistor and zener diode and adds a real 5v CD switching regulator (a r78E5 for example) which generally will stop power if it breaks down and runs cooler than conventional 7805 regulator.

 

A fair number of older systems that claim to need up to 12v run fine on 7.2v cells; as many will actually use a 7805 to run the system off 5v anyway. Surprising on the Lynx they didn't use a 7805 as they are cheap.

Just beware with li-po cells, they can explode if they swell, either because they get punctured, old or faulty - and by explode I mean explode or at least can cause a fire. That's why I use Li-ion cells rather than Li-ion packs, they are thicker, and still use similar Lithium however the battery cells are in a metal case so safer.

 

Not sure if this helps but there are 2 official rechargeable battery packs for the Game Gear. This one clamps onto the back of the GG and this one is carried in your pocket.

 

Game Gear packs will likely need to be rebuilt. They originally used NiCd and after more than 20 years, it's probably beyond dead and NiCd is somewhat hard to get because cadmium is toxic and are restricted or banned in some countries. In many cases NiMH can be used straight in place of NiCd with no problem.