Long-Lasting Power: Ultralast UL129VB 9V Alkaline Battery, 12 Pack Review

I bought a bunch of these batteries less than two years ago. When I recently installed them in smoke detectors, I noticed that they had kind of died. Five of the sealed cases had an open circuit voltage of less than 5 volts. Something has deteriorated in these batteries. The expiry date (best before) was 02/2014.

These batteries were definitely worth their price. However, the connecting posts seem to be a bit off. The socket felt too tight and was difficult to fit over the adapter pin. However, the pin of the plug was too small and it came out of the socket on the adapter. I had to squeeze the adapter socket with pliers and even then the connection wasn't very tight. I believe the batteries are slightly different from the standard batteries. I don't know what the durability will be as I just received…

I bought these thinking yes they are not Duracell or Energizer or even Rayovac. Not correct! I figured this would be a good opportunity to buy a pack of 12 batteries and replace all the smoke alarm batteries in my house. Most of them still come with their original Duracell batteries that I bought the house with 5 years ago. So after everything was replaced everything was fine one day. Then one started chirping, that annoying noise they make when their battery is low. I thought, well, a bad one.