44 minutes ago, sixwheeledbeast said:

Some of the earlier model bells did this type of thing before they failed completely, not seen that with the 740.

I only know of the mains or wirefree bell options never seen a 12v option, the expander would allow for most SCB option wired bells but you would need alarm cable.

The system is obsolete and only one way, I would say it's not worth spending on it and to upgrade.

The last thing I wanted to do was upgrade seeing as it is only 6 years old. Out of curiosity how much would a similar one cost now?

1 hour ago, PeterJames said:

Its one way wireless so its nothing to do with distance, or waht it has to travel through. You can add a 12vdc PSU to these bells that would stop the battery going flat 

Thanks, could you give me an example of a 12v PSU that would be suitable?

Had a Visonic Powermax Complete alarm system fitted back in 2014. This came with the MCS-740 wireless siren, but finding that the battery only lasts a maximum of 12 months and it is becoming expensive to replace every year.
Wondering if it is the distance of the alarm panel from the siren or whether it is the 20 inch walls between the two that is causing the quick depletion of the battery?
Thinking whether it would be worthwhile to go for a mains powered siren that would be compatible with the Powermax? I understand that there is a Visonic expander module that clips into the main alarm box for the cost of about £18, but what siren is compatible with it?

 

Pictured are the new batteries ready to be fitted