Pulling My Hair Out

i am currently pulling my hair out trying to solve the battery issues I am having with the flashes for my hummingbird photography. Which isn't very good because I don't have very much hair. I purchased some eneloop rechargeable batteries hoping I could save some money over the long term. So far what I have found is that the eneloop batteries initially put out too much power to the flash on the first burst and then drop too low and underexpose on the next discharge of the flash if I'm doing a sequence of images. Eventually as the batteries start to wear down it gets a little more consistent. So far I'm leaning towards going back to just paying for regular AA batteries even though it may be more expensive in the long run. Here are a few hummingbird images from the backyard this afternoon. God's love and blessings to all, chris All images created with a Canon 7D mkII and a Canon EF 100-400mm f/4.5-5.6L IS USM Lens on a Manfrotto tripod with a Bogen ballhead. Manual mode, ISO 100, F 22.0 at 1/200th of a sec. Four Canon 540EZ flashes set to 1/14th power were used for lighting.