The thing that's the problem here is two-fold:
1) Brand new batteries should give 100 full power flashes, so the specs state. But I am getting only 25 or so flashes out of them before the low battery warning shows up.
2) These batteries that fail in the 900 will fire the 800 many times

So I don't think the batteries are dying or dead. I think there is something wrong with the 900 killing them because I have used this 900 for many years and it has never done this until yesterday. It has always fired continuously using a Quantum auxiliary battery pack and the AA batteries have habitually lasted a long time since they don't have much power draw (because of the Quantum).