HQRP3.6V Lithium Thionyl Chloride D-Size Battery Compatible with DSC ER34615M-T1 WT4911 WT4911B WT8911 ALEXOR Wireless Outdoor Siren WT4911BATT ADT

This battery was just what I needed. Before you just put it in and connect it like any other battery, be sure to follow the steps for depassivation if your siren requires it or else the battery will not register and charge correctly.

So glad this battery is still available from the same supplier. Previously I had bought this one from them and it lasted more than 2.5 years: https://a.co/d/6e1Cj80The new one I got depressivated in just about 30 seconds so it was fresh! Just as I did with my previous review of the one linked above, I will continue to come back and update my experience with this battery. Before finding this brand and seller, I had gotten very frustrated trying to source quality replacements for my outdoor siren. The included instructions were great to have included so I didn't have to dig up my directions for starting the depassivation cycle.

I tried 3 times to depassivate this product in my outdoor siren unit (each of my attempts timing out at 30 min). The strobe turned off followed by a single beep which indicates that the battery is dead or defective.Furthermore, after attempting to contact customer service, I received no reply.

The battery works, but it was a year and 2 months old. The first one lasted 3 years.

It's worked

It looks exactly like the picture and is exactly what I needed for my outdoor siren

This battery works well with the ADT outside alarm. It last about a year and half.

While this battery did work for our security alarm system, it ran down to 20% in less than one year. Also, the battery is not marked with a date to determine how long it had been on the shelf before being sold to us.