I used these very well reviewed tenergy batteries, (https://www.amazon.com/gp/product/B0040Z...) i find that the batteries being a little bigger helped to secure everything in place…. i used electrical tape and just squeezed in the bottom battery tab using pressure and a small flathead screwdriver, that was prob the toughest part. Haven’t had a problem yet, have used about an hour total since the repair and have recharged the unit with no problems either a couple times. Here’s the link, these worked well for me and seem to hold a charge even better than the seemingly low quality factory batteries. Although any standard AAA rechargeables would prob work just as well in terms of fit.