I have a Moose Z1100 alarm panel that’s about 35 years old. I recently got a blinking light warning for low battery, which is not unusual. Happens about every 4-5 years. I charged the current battery with my 10/2 battery charger. Charger gave a “battery charged” signal, but when I plugged the battery back into the panel and did batt test, I’m still getting the batt low error. I thought maybe that battery was bad, so I purchased a new one. Same result, after plugging in the new battery, still getting low batt error. I checked the voltage on both batteries and both appear to have good voltage (yes, I should have checked that to begin with). So I dug a little deeper and stumbled on a post that suggested the AC adapter may be going bad. I climbed in the attic and unplugged the AC adapter and it does look a little discolored and there is some black stuff on the plug cover. The current AC adapter shows SEC 18VAC 35VA. All of the articles I can find regarding the AC adapter replacement says to use a 16.5VAC/20VA or 16.5VAC/40VA adapter which are readily available on Amazon. Is it OK to replace the old 18VAC/35VA with the 16.5VAC/40VA?
You should be safe to use a 16.5 VAC power supply if that’s what the spec says to use. When it says 16.5 VAC, that usually means it will work anywhere within a range around 16.5 and 18 is pretty close to 16.5. So the original installer was able to get away with 18 VAC because it was within the acceptable range but your best bet is to use exactly what the spec says.
If the wire from the transformer to the control panel is very long or thin, there would be some voltage drop across the wire. It’s possible the installer used a slightly higher voltage power supply to compensate for the voltage drop. Do you know what gauge and how long the power wire is? What really matters is the voltage at the control panel end after voltage drop across the wire. But the manufacturer already accounts for that, assuming the wire gauge and length are within spec.
20VA or 40VA should both work but between them, 40VA is the safer choice. But it only really matters if you have a long thin power wire.
I’m not sure what gauge the wire is. The alarm panel is in the laundry room and the AC adapter is plugged into an outlet in the attic almost directly above where the panel is. I’m guessing the power wire is about 6 foot, give or take a foot.
The Z1100 manual does specifically say to use an 18V/35VA transformer. I did find a 18VAC/50VA transformer on Amazon.
Thanks for your help!!!
6ft is not long. But yeah if the panel spec says use 18V then that’s what you should use.