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Topic Title: 12 volt timer
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Created On: 04 February 2007 08:13 PM
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 04 February 2007 08:13 PM
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deleted_16kw

Posts: 2
Joined: 04 February 2007

could you please tell me how to make a 12 volt timer, i have a large solar panel (80w) to charge 2x12 volt batts. i power 3x 20 led lamps for the garden i want them to come on for 3 hours. at the moment i have a invertor (12 vvolt to 240)240 volt timer then a drop down trasformer to 12 volts, the trouble is im using all my free power to power what i dont need , or could you tell me where to buy one , thank you
 06 February 2007 06:13 PM
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amillar

Posts: 1918
Joined: 28 May 2002

The simple answer is a 12V timer relay, RS and Farnell both have several, the 12V ones tend to be the 'multifunction' type. But they are fairly expensive - 30 to 40 pounds.

How much curent are the lamps drawing in total? And is this work or a 'homer'?

-------------------------
Andy Millar CEng MIET CMgr MCMI

http://www.linkedin.com/in/millarandy

"The aim of argument, or of discussion, should not be victory, but progress." Joseph Joubert
 07 February 2007 08:38 AM
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deleted_16kw

Posts: 2
Joined: 04 February 2007

hello, thank you andy, i have 3 led clusters that are 4.5volt each i joined them up ann run them off 12volt. they take less than 1 amp, i use them in the garden for 2 hours a day. keith
 07 February 2007 10:06 AM
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amillar

Posts: 1918
Joined: 28 May 2002

Hi Keith,

I've sent you a private message.

Cheers,

Andy

-------------------------
Andy Millar CEng MIET CMgr MCMI

http://www.linkedin.com/in/millarandy

"The aim of argument, or of discussion, should not be victory, but progress." Joseph Joubert
 09 November 2007 03:26 PM
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mattnewell

Posts: 3
Joined: 09 November 2007

Hi Andy,
Can I jump on the back of this thread and ask for the circuit diagram/instructions for this timer please. I've been searching for answers for the reason my 38Ah battery keeps discharging so quickly in my shed, and now I know why.

Many thanks,
Matt.

matt_newell@hotmail.com
 10 November 2007 09:10 PM
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amillar

Posts: 1918
Joined: 28 May 2002

Hi Matt,

What is it you need it to do?

Cheers,

Andy

-------------------------
Andy Millar CEng MIET CMgr MCMI

http://www.linkedin.com/in/millarandy

"The aim of argument, or of discussion, should not be victory, but progress." Joseph Joubert
 12 November 2007 11:32 PM
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mattnewell

Posts: 3
Joined: 09 November 2007

hi andy. it is to light my chciken shed for a few extra hours per day. currently have an inverter with 240v mechanical timer attached. this set up is sucking battery dry in a few days, not even that (38ah bat). have looked at units available and they cost a fortune.

many thanks,
matt
 19 November 2007 01:11 PM
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amillar

Posts: 1918
Joined: 28 May 2002

Hi Matt,

Did we chat many months back? Then I got sucked ionto 5,000 different things...(note: must learn to say 'no' more often!)

I will try again to send you a circuit diagram and a chip asap...I'm pretty sure I've already written the software for this.

Cheers,

Andy

-------------------------
Andy Millar CEng MIET CMgr MCMI

http://www.linkedin.com/in/millarandy

"The aim of argument, or of discussion, should not be victory, but progress." Joseph Joubert
 19 November 2007 10:30 PM
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mattnewell

Posts: 3
Joined: 09 November 2007

hi andy, thanks for reply. no, we didn't chat in person, must have been the other person asking for details of the same device.

would be grateful for the circuit diagram etc, when you get time.

If you want me to call, or vice-versa, drop me a pm. Otherwise, my email address is

matt_newell@hotmail.com

Many thanks and kind regards, matt
 22 December 2007 11:02 AM
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bheideman

Posts: 2
Joined: 22 December 2007

I'd like to get in on the act here as well, though for a slightly different application. I'm putting together an automatic watering system for my greenhouse and poly tunnel. The system will be either solar or wind powered but I need a timer circuit which will control a 12 volt water pump, I'll probably only need to run the pump for a couple of times a day and for only a few minutes at each period. I need a timer that isn't going to suck all the life from the battery at night and that can be controlled quite finely. Do you know of a timer that is available on the market for a reasonable price or could you help with a circuit design?

Bruce Heideman
bhent@widgets-uk.com
 10 January 2008 10:41 PM
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Genaa

Posts: 5
Joined: 10 January 2008

Hello,

Like the above poster I am also on the hunt for an affordable 12v timer solution for an automatic watering system, rechargeable through a solar panel.

I did see a link elsewhere on this forum to a site : Link removed/timers.htm which appeared to be precisely what I am after but sadly the email addy for the guy in question returns as undeliverable

What I am ideally after is a SPDT 5 contact relay timer, running off 12v, that can be set to preferably min timing intervals of a minute on a 24hr time clock so as to be able to flood a "flood and drain" chilli hydroponic setup for say 5 minutes every 3 hours... hard to believe that digital 12v timers are so hard to come by and so expensive

Any ideas welcomed!

rbmiddleton@yahoo.com

Edited: 10 January 2008 at 10:43 PM by Genaa
 11 January 2008 03:04 PM
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AlanKay

Posts: 232
Joined: 09 July 2002

Originally posted by: Genaa

SNIP
... but sadly the email addy for the guy in question returns as undeliverable
SNIP

A "Whois" for the guy's email domain (www.hmh.co.uk) gives a registrant's address in North London. Have you tried writing to him?

HTH

-------------------------
Alan Kay, CEng MIEE
 11 January 2008 06:15 PM
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Genaa

Posts: 5
Joined: 10 January 2008

Hi,

No I haven't written but I certainly shall - thanks for the steer
 14 January 2008 01:56 PM
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amillar

Posts: 1918
Joined: 28 May 2002

Very good link to several solutions at http://www.reuk.co.uk/12-Volt-...mable-Timer-Switch.htm

-------------------------
Andy Millar CEng MIET CMgr MCMI

http://www.linkedin.com/in/millarandy

"The aim of argument, or of discussion, should not be victory, but progress." Joseph Joubert
 14 January 2008 05:53 PM
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Genaa

Posts: 5
Joined: 10 January 2008

Hi Amillar,

Thanks for the link although I had already visited that prior to locating the IET site. It seems that one of the limitations with such a chip device is that it would be difficult to programme it to activate for say 5 minutes every 3 hours, as opposed to 3 hours on, 3 hours off, which would be straightforward but not suitable for my requirements.

I tried to track down the owner of the skinflinters site - who does not appear to be the person to whom the domain is registered. I did however find a further link to a Mark Huddart who I believe is the individual in question and am hoping he will pick up the message I have left for him at Ecademy site.

Any further suggestions welcome - Am looking for something which can be run from solar panel recharged 12v batteries if possible avoiding any need to run mains electricity down to greenhouse.

Cheers
 15 January 2008 12:46 PM
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amillar

Posts: 1918
Joined: 28 May 2002

Are you sure that the modified central heating controller on that site won't do what you want?

Otherwise, making a circuit similar to that on the site that gives out a 5 minute pulse every 2 hours 40 minutes (or a 5 min 38 sec pulse every 3 hours) is pretty straightforward using a 32 bit shift register - what you could do is find a starving electronics student and take him out for a meal in return for designing and building it

-------------------------
Andy Millar CEng MIET CMgr MCMI

http://www.linkedin.com/in/millarandy

"The aim of argument, or of discussion, should not be victory, but progress." Joseph Joubert
 15 January 2008 11:06 PM
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Genaa

Posts: 5
Joined: 10 January 2008

hehe am working on it. Am now in email conversation with the guy from reuk and also the guy from skinflinters site who is going to check to see what, if any, stock he has left in his workshop so fingers crossed.
 24 January 2008 04:34 PM
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bheideman

Posts: 2
Joined: 22 December 2007

I've come across some interesting information relative to this topic on the Net, have a look at this link.

Link removed/12-Volt-...able-Timer-Switch.htm

I'm going to have a go with a programmable central heating controller as a test, picked up one on eBay for less than £15.00.

Bruce Heideman
 07 April 2009 08:01 PM
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maddiman

Posts: 1
Joined: 25 July 2008

Link removed
seem to have something of intreast

-----------------
John PhD MBA BEng CEng MIET
 15 July 2009 06:17 PM
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essex3lv6

Posts: 2
Joined: 15 July 2009

Hi there there is a little more to just using a timer or 12v programmer as i also have pv panels, wind turbine charge batterys you also need to sense battery level and also remember after load has been removed the battery recovers slightly.. I have developed a control system to cover all these problems and are available on ebay ..serch for wind turbine and battery manager my ebay id is essex3lv6 kind regards Geoff
IET » Electronic engineering » 12 volt timer

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