If you ever need to break into a small portable electric safe because you forgot the combination, try what is known as the bounce method.
The idea behind this is simple. Many cheaper electronic safes do not have counterweights for their locks. What that means is if you drop the safe a short distance while trying to open it when it lands, the door will open.
Practice makes perfect, so make sure you try this a few times to get the right feel and timing.
Here is a video that better demonstrates: