Nope, sadly I have no way to recharge the Alkalines and yes that does bother me. I thought I could use the old 12V from my wife's Prius 2 years ago but it wouldn't hold a charge at all. I replaced the one in mine a few months ago when the very misleading "Put the transmission in Park" message started coming up. At least in the 2004-2009 Prius, that means "your 12V is failing" which would be a MUCH more useful bit of information. I replaced it with a Yellowtop Prius kit battery from eLearnAide within a week of the message first showing up so maybe it will still hold enough charge for the auto door. If it does, I'll use it when the two 6Vs die. Since the 12V in a Prius doesn't have to crank the engine, it is a pretty small battery. I could get the grid or solar power charger and the battery from the PulletShut people but that would be much more expensive than what I am doing now.
The one thing I DIDN'T like about the Pullet-shut is that if you want the door to be automatic, you have to reset it at whatever frequency you want to account for the seasonal daylight changes. It isn't hard but you have to do both the same day because when you cancel one you cancel both. So you HAVE to be available at both times in a single day to change it. Not a problem if you live at the equator but up here the birds are awake at 5 AM this time of year and head back in around 7 - 7:30. Mid December, they get up around 8 and are back in by 3-3:30. So I got the photo sensor. Works great and cost only $15. Wish I have gotten it when I got the door, could have saved the shipping cost. If we get home after dark or if I don't feel like getting up at 5 AM, their door still works for them.
Um .... MHP ... um .... And one could certainly use a PulletShut door to let the chicks under the MHP out of the brooder area during the day!