Has anyone here bought those packages of inexpensive batteries on eBay for Pioneer and Voyager models? What is your experience with them. I suppose they don't last as long but, even if they lasted half as long as name brand batteries, they'd still last, what, 9 years in my 15C??

Those batteries are alkaline batteries. They are great for devices that consume those types of batteries rather quickly like laser pointers or toys. But, alkaline batteries tend to leak after a few years, possibly causing irreparable damage to the device they are in.

Those alkaline batteries are fine for short term use in a calculator, but I wouldn't leave them in a valuable calculator like a Pioneer or Voyager. Spend the extra money on silver oxide batteries.

I think that thise batteries aren't so inexpensive... $3.33 plus $2.42 shipping is $5.75 for 10 units ($0.57 or $0.58 each).
Here in Brazil I just bought 6 units of Maxell LR44 (original) silver-oxide for my HP11C and HP42S for about $0.84 (R$2,50) each in a common photo-store. I think that if you search for those Maxell LR44 there in the US you can find it for even lower prices.

Regards,

Nelson

those batteries on eBay.

First, there is such a thing as shelf life. These are likely ones that can't be sold retail any longer.

Second, why risk a valuable piece of equipment with old, possibly defective batteries.

Third, they are not that cheap in the first place.

I suspect that they are fresh cards Vinnic batteries from China. I have not used the Ebay ones becuase I can get them locally for less. They work great and are a bargain... 25 cents a cell. Some places charge up to $2.00 each for an LR44! I had a set in a digital scale for 5 years and another in a 12C for the same amount of time. No leakage. I usually replace ALL my batteries (smoke alarms, thermostats, cameras, calculators, etc) yearly on "battery day", but these two items were lost in the back of a drawer.