PF Battery Box with Li-Poly Rechargeable
I decided to modify a Lego Power Functions Battery Box and fit with an 11.1 Volt Li-Poly Rechargeable Battery Pack & use a Regulator I.C. to provide the regulated 9Volts required by Power Functions type Devices. The modification was easy, but time consuming to remove the excess plastic in order to get the Li-Poly Rechargeable Battery Pack to fit inside the battery box.
Front of PF Battery Box fitted with 11.1V 900mAh Li-Poly Rechargeable Battery Pack & the 9Volt Regulator I.C. with Heatsink attached at the top of photograph.
Back of PF Battery Box fitted with 11.1V 900mAh Li-Poly Rechargeable Battery Pack, the 9Volt Regulator I.C. with Heat-sink attached at the bottom of photograph & also showing the Li-Po Pack Charger Connection Plug.
The whole installation is rather fiddly to get the 11.1V 900mAh Li-Poly Rechargeable Battery Pack and the 9Volt Regulator I.C. with Heat-sink attached to fit comfortably within the Power Functions Battery Box. This said, it was definitely worth the hour spent modifying the battery box. The finished Power Functions Battery Box works very well and drives two Large Power Functions XL Motors with ease. The result is also considerably lighter at 120Grams, when compared to having the usual 6x AAA's Batteries as the power source in the Battery Box.
I could have went out and purchased a Rechargeable Power Functions Battery Box, but I wouldn't have had a 9volt output and the commercial one is harder to mount to Mindstorms & Technics models. My modified PF Battery Box, cost a total of less than $20.00 including the Li-Po Battery Charger, which is considerably cheaper than buying the Rechargeable Power Functions Battery Box here in Australia. All that's left to do is convert another Power Functions Battery Box, so I have a charged spare ready when required.