Door Bell push button battery or mains?

[ericmark]

I have installed a new door bell for my mother Response Electronics Ltd WIRELESS DOOR INTERCOM SYSTEM (CL6011B) which seems to work well, but the bell push is at the moment powered by two C cells. These can be replaced with a 12VDC power supply but the instructions says replace so it would seem I can't fit rechargeable cells to replace the primary cells now fitted.

C cells are big I know but it is working an intercom so may not last that long. Has anyone used one of these units if so how long do batteries last? Is it worth hard wiring?

Also when the button is pressed there is about a 4 second delay before bell rings is this normal or is there a fault? It buzzes at the door twice before hand set rings.

I have been told by the councils electrician that the door release can't be fitted to back door as not enough frame to mount it on and can't be fitted to front door as it opens outwards. At the moment not an issue but may be as my mother gets older. I can easy change key safe number so once she gives it out I can change it but door release would be easy option. And of course if anyone runs off with key it's a lock change job.

She is very pleased with it she says it saves her answering door to god salesmen/women it seems she gets loads far worse than double glassing salesmen. She is in a wheel chair and it's not easy answering the door.

 

[stillp]

How does a 12 V transformer replace 2 X C cells? Does it need 12 V or 3 V?
Why can't you just replace the C cells with rechargeables, and keep a spare set on charge?

 

[bernardgreen]

The 12 volt supply will be regulated down to 3 volts or there abouts inside the unit.

 

[OwainDIYer]

C cells are big I know but it is working an intercom so may not last that long. Has anyone used one of these units if so how long do batteries last? Is it worth hard wiring?

Also when the button is pressed there is about a 4 second delay before bell rings is this normal or is there a fault? It buzzes at the door twice before hand set rings.

The batteries in the door unit will probably last for a good while - the unit will be in sleep mode most of the time until the button is pressed.

The 4 second delay will be due to the unit waking up, turning on its transmitter, and sending a signal to the handset unit, before the handset rings.

 

[Chri5]

I'd use fixed power over batteries, its a small cost (unless the supply for the transformer is a mare) against the hassle factor of cells running down (without any real warning other the the unit no working), charging and changing. Then there's a new set on rechargeable cells every few years, the set on charge while a set is in use and the charger purchase.

 

[bernardgreen]

Door bells are better on batteries if power cuts are a problem and getting a response is important provided there is someone to replace batteries.

The old chestnut of the electricity board officials ringing door bells to apologise for the power cut and explain why nothing was working, including some door bells.

 

[HERTS P&D]

Get one of these:

http://www.ebay.co.uk/itm/Large-Chi...den_Decorative_Accents_LE&hash=item20d267bee9

It even has a troll on it.

Andy

 

[ericmark]

The 4 second delay will be due to the unit waking up, turning on its transmitter, and sending a signal to the handset unit, before the handset rings.

That's a good point maybe 4 seconds delay will go away on mains?

Door bells are better on batteries if power cuts are a problem and getting a response is important provided there is someone to replace batteries.

The old chestnut of the electricity board officials ringing door bells to apologise for the power cut and explain why nothing was working, including some door bells.

This was also my worry. If an RCD trips then no power and my mother can't get under the stairs to reset.

How does a 12 V transformer replace 2 X C cells? Does it need 12 V or 3 V?
Why can't you just replace the C cells with rechargeables, and keep a spare set on charge?

I also re-read the instructions. Think the 12vdc is so it can also power a door release if used.
As to rechargables I find it hard to find out which are LSD and which are not. If always on trickle charge it would not matter but swapping on regular basis I have found at home using non LSD the batteries don't last long. The demise of NiCad and move to NiMH has resulted in two types with same labels being on the market you can get those which say ready to use and they should be LSD but not so sure on that.

I suppose a lead acid like used in alarm panels by transformer in way to go. Original door bell was hard wired and hope to swap transformer 8vac for power supply 12 vdc and short out bell and use original wires.

One method is to leave the previous wireless door bell next to it with note please push both so retaining one system which is wireless.

 

[bernardgreen]

An external ( but inside the house ) battery on trickle charge would be a near fail safe supply to the door unit. It is what I have used for wired door bells where high reliability was needed.

Flat batteries in the mobile unit are the other weak point. Having two mobiles that respond to the door bell with one kept permanently in its charger unit would be a safe guard.

Ensuring privacy can be a problem. It is easy on some door intercom systems for the mobile to be accidently left in speech mode allowing people at the door to hear conversations in the house.

It can be a help to people with restricted movement if, in emergancy, the mobile can be put into speech mode without the door bell having been pressed. While it is in no way certain a passer by will hear a call for help from the door it is a possibility.

 

[ericmark]

Interesting ideas. I have not tried to listen in to the intercom but may be worth having a go my FT50R Yaesu should be able to receive at that frequency.

The conversion to mains power is being done by the disability people from council so I will leave it to them to do.

As to help she has a wrist button which connects to call centre which is a better option. They will respond in some way.