Depending on what your budget and weight restrictions are, why not look at
the batteries for cordless power tools. 12V NiCad are common and aren't that
heavy (I don't have a scale so I can't tell you exactly). After that I would
look at laptop batteries. 12V NiMH are the standard, with Lithium Ion being
the best overall, but at the highest price.
My advice would be find someone with a cordless drill and ask to borrow it.
>We are building a mobile robot and are planning to use the HC11evbu and
>stepper motors. We need a light 12V rechargeable power supply. I was told
>there are batteries that are lighter and more powerful than lead-acid, but
>can't find any in the cataloges I have.
> If anyone knows of a better kind of battery and where I can find one I
>would greatly appreciate it.