12 volt timer - would it work !

[CRM]

I need a 12 volt timer and have seen other Forum members ask for same. The only one that appears available is something to make chickens lay more eggs in winter !!!

I have a 240volt security timer - the electronic timer side is 'driven' by a separate AA cell. and just switches the 240v side. Could this be 'knobbled' to switch 12 volts.

With a 'safe' arrangement to stop any accidents on the 240v plug side.

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[muchy_]

Yes it can switch 12v. Its just a beefed up switch that can handle 240volts so 12volts shouldn't be a problem. You would only have a problem if trying to switch 240volts with a 12volt timer.
However, the amps drawn through the switch should also looked at....

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[pvb]

What\'s it for?

You could certainly convert your security timer, but you might need to add a relay to switch the current - what's it for? And do you want to switch something on at the same time every day, or different times on different days? There are some very cheap battery-powered devices available in the plumbing/heating industry which could well do the job.

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[Jools_of_Top_Cat]

I am sure my cental heating timer is 12v or lower, I had never thought about it as I did not fit it, bit a couple of weeks ago manweb came round to change my electric meter, and the clock on the central heating did not shut down when he killed the power.

It must be charging from the mains but that is easy to fix over. This has the ability to turn of and on many times with different settings per day....worth a though?

only about £30 from screwfix I think

<hr width=100% size=1><font color=blue> Julian </font color=blue>

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[Heckler]

if you are sure the battery is driving the timer, sure it will work on 12 volts, BUT, you will have to put a relay in cause the switch contacts will probably not be man enough to carry the 12 v amperage or handle the spark as the contacts switch, straight forward enough to set up though
s

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[oldsaltoz]

G'day Colin,

A safety note for all.

The 12 volts on you boat is Direct Current (DC)
The 240 volt, or domestic supply is Alternating Current (AC)

DC will ark / spark when power is switched, DC switches have larger contacts and a bigger gap to between the contacts to cater for this:

If you run DC through a switch designed for AC, at best it will not last long, the contacts will burn out, at worst it will fail and may not turn off or on.

You would have a safer and more reliable system if you Add a 12 volt DC relay to avoid any problems.

Take care.........

Andavagoodweekend. Old Salt Oz /forums/images/icons/cool.gif

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[DavidTocher]

The relay may be controlled by a SCR or triac which latch when switched 'on'. With AC the volts go to zero every 1/100 sec permitting the SCR to switch 'off' when the control signal is 'off'. With DC it will stay latched until the battery goes flat!

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