Most pointers use 3 silver oxide button cells and consume these
at a voracious rate. It pays to replace these by a dummy battery
and run wires to external power. Three AA alkalines are equivalent
to 15 sets of AG13 button cells and a lot cheaper. Lasers are pretty
fussy on supply voltage so it's better to avoid rechargeables -
three x 1.25 volts is not really enough and four x is too much.

As I mentioned in a previous post, Rayovac makes rechargable alkaline
batteries that put out true 1.5V just like regular alkalines. They are
perfect for intermittant use because, like regular alkalines and *unlike*
NiCad or NiMH, they do not self-discharge (i.e., they have excellent
shelf-life). They can be recharged often and can last a long time (I have
some that have been in constant use for over five years). Rayovac markets
these under the name "Renewal" and you will need to buy their special
charger for recharging (their newer recharger models will recharge Renewals,
NiCads, and NiMH batteries so they are a great value).

I have no affiliation with Rayovac (I don't even own any of their stock).
Just a satisfied customer.

Regards,
Michael