Bell transformer queries

[Observer]

I am planning to replace existing plain vanilla doorbell with a wired video doorbell. I want to retain the existing chime, which requires 8-16V AC supply.

The video doorbell requires 16-24V and 10VA.

Existing doorbell setup includes a Honeywell remote chime that specifies 8-12V supply.

I have replaced previous 8V transformer with one that has 8V, 12V and 16V taps and rated 8VA.

Actual voltage from the transformer on the 16V tap is around 18V, 14V from the 12V tap and 10V from the 8V tap.

So:

- the transformer is under-powered (8VA) for the video doorbell (10VA)
- the remote chime is receiving 18V instead of 12V maximum

The doorbell and remote chime are actually working fine as far as I can tell.

My question is, are the noted discrepancies within a range that, although 'less than ideal', will probably be okay, or should I expend more time and money trying to eliminate them (I don't have a clear solution anyway).

As a possible mitigation, can I take a second feed from the 8 or 12 V tap on the transformer for the remote doorbell? Is this likely to make a difference?

My priority is to have the new video doorbell working. I could sacrifice the remote doorbell if unavoidable.

Thanks

 

[Taylortwocities]

As a possible mitigation, can I take a second feed from the 8 or 12 V tap on the transformer for the remote doorbell? Is this likely to make a difference?

You can, providing the rating of the transformer is enough to drive both doorbells. It doesn’t look like it has enough grunt.

 

[bernardgreen]

A door bell transformers only needs to supply power for a few seconds while the door bell is being rung.

They are designed for this purpose,,

If a door bell transformer is used supply power continuously then there is a significant risk of the transformer overheating . Some have thermal fuses and disconnect before they become dangerously overheated

 

[Jackrae]

Door bell transformers generally provide an AC voltage which is all the chime requires. In all likelyhood your video system will require a DC supply.

 

[Observer]

A door bell transformers only needs to supply power for a few seconds while the door bell is being rung.

They are designed for this purpose,,

If a door bell transformer is used supply power continuously then there is a significant risk of the transformer overheating . Some have thermal fuses and disconnect before they become dangerously overheated

Hmm. I see the argument but the installation manual is quite clear that existing transformer can be used if 16-24V. The video is not recording continuously, only when activated by motion detector or bell push.

 

[bernardgreen]

A typical data sheet for a door bell transformer.
https://www.doepke.co.uk/assets/pdfs/Control/Technical-Data-09--RK-3U--0520v1--en.pdf

Nennlast translates as rated load.

 

[Observer]

A typical data sheet for a door bell transformer.
https://www.doepke.co.uk/assets/pdfs/Control/Technical-Data-09--RK-3U--0520v1--en.pdf

View attachment 289742

Nennlast translates as rated load.

Fair enough. But this is data for the transformer I've installed.


0V, 10V, 12V,16V Output Voltage (NEST / RING Doorbell Compatible) Bell transformer is for use in consumer units with an operating voltage up to 250V 50Hz. and has a power capacity of 8VA. It complies to the following standards EN61558-1 & EN61558-2-8 Safe electrical separation between primary and secondary circuit. Provides extra low voltage up to 16V Low temperature rising High output accuracy Extra overload capacity up to 25% within 24 hours Technical Detail Rated input voltage: 240V AC Rated output voltage: BT8: 4,6,8,12,16 Rated freq: 50/60Hz Rated power output: 8VA Consumption: 1.15W Service period: Continuous operating Pollution class: 2 Connection terminals: pillar terminal with clamp Connection capacity: rigid conductor 10mm2 Installation: On symmetrical DIN rail 35mm Panel mounting Terminal connection height: H=15.5mm Enclosure MaterialPlastic (Insulated) Height (mm)135 Width (mm)50 Depth (mm)73 Usable Ways2 Suits Video Doorbells that require voltage up to 16V

 

[Why Not Indeed]

Door bell transformers generally provide an AC voltage which is all the chime requires. In all likelyhood your video system will require a DC supply.

Presumably video doorbell manufacturers are aware of this common scenario and design the products accordingly.