Any way to test if my device will handle over voltage or will I just need to wire it and hope for the best?

I want to use a lithium polymer battery in a controller I have, but I do not know if it can handle the voltage difference. It uses two AA batteries (3V) and I want to put a 3.7V lipo battery. Is there any way to test if my device will be ok with it or will I just need to wire it and hope for the best? Thanks.

Davetech was successful in replacing the 2 AA's with a li ion battery here: 
https://www.instructables.com/id/MODIFIED-MOUSE-RUNS-ON-LITHIUM-ION-CELL-PHONE-BATT/?comments=all#C6JJWSPGO8DBSTK

I want to be able to test, before I fry my device.  Any help will be appreciated.  Thanks

If it takes less than 1A to run it, just stick a 1N4001 or similar 1A diode in series with the battery - it will drop 0.7 V for you
Nilson13 (author)  steveastrouk6 years ago
Thanks for your input.

It is for a wii remote. I have no idea how many amps it takes to run it. Sorry for asking more of you, but how can I find out?
Its going to be a lot less than 1A, don't worry, use the diode.

Steve
Nilson13 (author)  steveastrouk6 years ago
Thank you so much!!!