Any Suggestions?

[wreck-it-steve]

Hi,

I need to make a 12v LED panel lamp turn on upon power failure. I cannot find anything to do this and just wanted to know if anyone knew of any way to do this?

I would need it to be there for any power failure without having to change any batteries (battery would need to be charged when not in use)

Thanks

 

[JohnW2]

I need to make a 12v LED panel lamp turn on upon power failure. I cannot find anything to do this and just wanted to know if anyone knew of any way to do this? I would need it to be there for any power failure without having to change any batteries (battery would need to be charged when not in use)

The simplest way would probably be to have a rechargable battery floating across an appropriate charger, and then just a simply relay, powered by the normal power, to switch the LED on in the event of a power failure.

It obvioulsy would be simpler if you didn't have to have a charger. Some types of (non-rechargeable) batteries have a very long 'shelf life' (like the '10-year batteries' in some smoke alarms).

Kind Regards, John

 

[wreck-it-steve]

I need to make a 12v LED panel lamp turn on upon power failure. I cannot find anything to do this and just wanted to know if anyone knew of any way to do this? I would need it to be there for any power failure without having to change any batteries (battery would need to be charged when not in use)

The simplest way would probably be to have a rechargable battery floating across an appropriate charger, and then just a simply relay, powered by the normal power, to switch the LED on in the event of a power failure.

It obvioulsy would be simpler if you didn't have to have a charger. Some types of (non-rechargeable) batteries have a very long 'shelf life' (like the '10-year batteries' in some smoke alarms).

Kind Regards, John

Thanks, I need to make sure it does not fail as its for a pumping system. It all needs to be mounted in a panel with just a supply cable going to it.

 

[JohnW2]

Thanks, I need to make sure it does not fail as its for a pumping system. It all needs to be mounted in a panel with just a supply cable going to it.

If it's a situation in which it's crucial to know if/when power has failed, is a mere LED on a panel going to be adequate (i.e. necessarily noticed)? - wouldn't it be better with at least an additional audible warning (just connect some sort of sounder across the LED)?

Kind Regards, John

 

[wreck-it-steve]

Thanks, I need to make sure it does not fail as its for a pumping system. It all needs to be mounted in a panel with just a supply cable going to it.

If it's a situation in which it's crucial to know if/when power has failed, is a mere LED on a panel going to be adequate (i.e. necessarily noticed)? - wouldn't it be better with at least an additional audible warning (just connect some sort of sounder across the LED)?

Kind Regards, John

Sorry should have said.. there will be a sounder connected to it also.

 

[EFLImpudence]

If you only need it to warm you of one circuit failing that is easy.

Presumably you would notice and it would make no difference if ALL power is lost.

 

[pjcomp]

Does it have to be this particular light fitting? Sounds like an off-the-shelf emergency light is already tailor-made for the job.

pj

 

[wreck-it-steve]

If you only need it to warm you of one circuit failing that is easy.

Presumably you would notice and it would make no difference if ALL power is lost.

Its only for the supply that feeds the pump control panel.

 

[Spark123]

Or something like these with a relay across the pump's control supply which will drop out when supply fails, using the contacts for the alarm and sounder:
http://www.dantech.uk.com/da391.html

 

[wreck-it-steve]

Or something like these with a relay across the pump's control supply which will drop out when supply fails, using the contacts for the alarm and sounder:
http://www.dantech.uk.com/da391.html[/QUOTE]

Thanks, I was not wanting to spend so much on it as they seem a bit on the expensive side.

 

[JohnW2]

Thanks, I was not wanting to spend so much on it as they seem a bit on the expensive side.

As I said, yiou could avoid such expenses if you just used an appropriate non-rechargeable battery and remembered to replace it every decade or so if that's consdiered safe enough for some smoke alarms. it would probably be adequate for you.

Kind Regards, John

 

[wreck-it-steve]

Thanks, I was not wanting to spend so much on it as they seem a bit on the expensive side.

As I said, yiou could avoid such expenses if you just used an appropriate non-rechargeable battery and remembered to replace it every decade or so if that's consdiered safe enough for some smoke alarms. it would probably be adequate for you.

Kind Regards, John

I am just worried that the battery will fail or I will forget to change it and then it will not work. If the battery was able to charge then at least I would know it was always going to work (providing there is no other faults)

 

[JohnW2]

I am just worried that the battery will fail or I will forget to change it and then it will not work. If the battery was able to charge then at least I would know it was always going to work (providing there is no other faults)

Fair enough, but you expressed concern about the cost, and obviously can't have a charging system without paying for it! I suppose that, given that it's virtually never actually going to be used, some form of very basic/simple 'solar' charging might well be adequate to keep a battery 'topped up'.

However, be warned. You seem concerned that you might forget to replace a non-rechargable battery, say, once evey 10 years, but I wouldn't personally want to put any money on a rechargeable one remaing servicable for 10 years, either! There is, in fact, a significant risk that, since it was rechargeable, you could easily be lulled into a false sense of confidence and fail to realise that it had 'died' after a few years. Whatever you decide, I would certainly suggest that you try to remember to test the alarm periodically, by disconnecting the power source.

Kind Regards, John

 

[wreck-it-steve]

I am just worried that the battery will fail or I will forget to change it and then it will not work. If the battery was able to charge then at least I would know it was always going to work (providing there is no other faults)

Fair enough, but you expressed concern about the cost, and obviously can't have a charging system without paying for it! I suppose that, given that it's virtually never actually going to be used, some form of very basic/simple 'solar' charging might well be adequate to keep a battery 'topped up'.

However, be warned. You seem concerned that you might forget to replace a non-rechargable battery, say, once evey 10 years, but I wouldn't personally want to put any money on a rechargeable one remaing servicable for 10 years, either! There is, in fact, a significant risk that, since it was rechargeable, you could easily be lulled into a false sense of confidence and fail to realise that it had 'died' after a few years. Whatever you decide, I would certainly suggest that you try to remember to test the alarm periodically, by disconnecting the power source.

Kind Regards, John

what none re-chargeable battery would you recommend?

 

[JohnW2]

what none re-chargeable battery would you recommend?

I'd have to look around - but, as I said, there are certainly some designed for very long-term term 'standby' service. I'll have a look and see what I can find.

Kind Regards, John