would 12v batteries help?
http://www.amazon.com/GP-High-Voltage-Alkaline-Batteries/dp/B004SK9P0O/
Here are some links for the product in the above comment for different countries:
Amazon Smile Link: http://smile.amazon.com/GP-High-Voltage-Alkaline-Batteries/dp/B004SK9P0O/
| Country | Link | Charity Links |
|---|---|---|
| USA | smile.amazon.com | EFF |
| UK | www.amazon.co.uk | Macmillan |
To help add charity links, please have a look at this thread.
This bot is currently in testing so let me know what you think by voting (or commenting). The thread for feature requests can be found here.