Propeller Platform Battery Pack

Sure, your electronics project is awesome, but wouldn't it be cooler more than 10 feet away from a power outlet?

I designed this add-on Battery pack because I program my Propeller Platform around the house, and I hate having to drag a Power Adapter everywhere I go. With this module, I just drop it on and go. When I do use a Power Adapter, I don't need to remove it, I can flip the switch on the battery pack.

My design uses common AAA batteries as the power source. The Propeller Platform has very flexible power consumption capabilities, so the Battery Module can run for many, many hours:

• 40 Hours 3 cogs running @ 20MHz
• 17 Hours 3 cogs running @ 80MHz
• 8 Hours 8 cogs running @ 80MHz

Flip to the next step and I'll give you some more technical details on the Battery Module and show you how to use it. I've also put hi-res photos for this howto on flickr.

The Battery Module is also available as a kit from Gadget Gangster.

Step 1 FAQ

Design Goals
I designed the Battery Module with a few objectives;

1. It should be cheap. Cheap to buy, cheap to use
2. It should be easy to recharge / replace the batteries
3. It should be easy to build, repair, and modify.

I did a first rev. of the design and put it up for comment on the Parallax forums. Got feedback and made a few changes to get to the final version.  I think it meets all of the design objectives;

1 - Cheap
Small PCB, uses inexpensive AAA batteries so charging circuitry doesn't have to be on-board.  It takes advantage of the Propeller Platform's on-board regulator to provide 3.3v power.  Liquidware's Power shield is awesome, uses a lightweight battery, and has built-in charging, but $40 is more than I wanted to spend.

2 - Easy to charge / replace batteries
Compared to LiPo or or Li-ion, nimh AAA batteries are incredibly easy to charge and replace.  There are a million nimh chargers already available, and you could even use standard Alkaline batteries in a pinch.  It's easy to swap out dead AAA batteries with a fresh set, and when the batteries stop holding a charge, you can pick up replacements at the local 7-11.

AAA nimh cells aren't as flashy as a proprietary LiPo cell, but given my design goals, I think it's a better choice.

3 - Easy to build / modify / repair
Everything is through-hole, and the design is available under the MIT license. It's a simple circuit but I want to keep it as open and hackable as possible. Links to download the layout files are on the last page of this howto.

Is it Easy To Build?
Yes. If this is your first time soldering, it will probably take 15 minutes. If you're a seasoned pro, it should take longer for your soldering iron to warm up than assemble.

Comments

[unseenfire]

Would it be possible to use the with the El Jugador console from Gadget Gangster? I haven't actually made the console yet, but I've been looking into and I plan on making it soon, but I don't know how it gets power..

Would it be possible to put this under the platform with the controller connections then have it all in a nice little case?

[Foaly7]

Would this work the same using two AA battery holders instead of four AAA?

[Gadget Gangster]

Sort of - If you're using 2xAA's, connect them to the the V33 connection instead of the V50. You won't be able to use any 5v devices, and it won't provide a regulated 3.3 volts, either.