# Need a time delay circuit for my float switch and 12v pump?

The ones we use are supplied with a metal retaining clip which holds the relay into the base.
Saying that they are not subject to that much vibration stuck in the back of a panel.

Simply use two relays one works pump and other does latch.

Simply use two relays one works pump and other does latch.

I have set up and tested the above schematic
Using a domestic car charger as the power source
The sequence has work and it has not blown the float switch but I could only get the chargers to show a maximum of 2 amps and I wanted to put a heaver load through it just to test it properly relay
Plugged stuff like kettles into the charger but that would only draw about an amp
Any thoughts

thanks

james

Plugged stuff like kettles into the charger but that would only draw about an amp
How much current do you expect a 240V kettle to draw from a 12V supply?!

Plugged stuff like kettles into the charger but that would only draw about an amp
How much current do you expect a 240V kettle to draw from a 12V supply?!

I was hoping 13amps
I suppose your going to tell me it dose not work like that

Plugged stuff like kettles into the charger but that would only draw about an amp
How much current do you expect a 240V kettle to draw from a 12V supply?!

I was hoping 13amps

but if a kettle draws 13 Amps at 230v, how is it going to draw 13 Amps at 12v?

It cant, but it takes me back to what i said since you do not really know what you you are doing, (no offence, and nothing personal) I still suggest you get a company to make this unit for you, since you have been told what to do and still get it wrong.

Kettle ratting 2.8Kw at 230v = 2800/230 = 12.17391 amps
230/12.17391 = 18.89286 ohms
12V at 18.89286 ohms = 0.635161 amps so about right at 1 amp.

Corrected as missed a stage out.

I would use a 12 volt head lamp bulb as 60/12 = 5 amp reasonable load.

Isn't it V²/W = R, ends up somewhere around 18.9 ohms (ignoring temperature changes)?
I = V/R therefore I = 12/18.9 = 0.6A

Ups your right too many pain killers I was not thinking straight.
Yes is should be 0.635161 Amps

Might be about an amp - the resistance will be lower at room temp, and IIRC a charger puts out more than 12V....

I have set up and tested the above schematic
You had that design (well - a functionally equivalent one) 5 days and 4 pages ago - think of the time you and everybody else could have saved.....

I have just got a reply too.
I did think you could get relay with duel outputs retail at £7.10 but could not find on internet. From Durite.

I have set up and tested the above schematic
You had that design (well - a functionally equivalent one) 5 days and 4 pages ago - think of the time you and everybody else could have saved.....

I don’t belive we ever had a duel relay circuit
The only other chematic I tried welded the switch together

I think ericman’s circuit has done the job
But I have used 2 cigereeete lighters to create a load and I managed to get the load to about 5 amps and the switch has not blown so I’ve orderd a new one and fingers crossed it should work when I test it on Friday

I have just got a reply too.
I did think you could get relay with duel outputs retail at £7.10 but could not find on internet. From Durite.

That’s just a standard 5 pin car relay
I’ve been using the 87 and 87a one
You should be able to buy them for about 4.50 from an auto electrian car parts wholsalers and ebay est.
If you by a bulk load of them from the states they are about 2 quid each

spark123
I've re drawn your schematic Im worried about the load from the pump on to port 87 and there being a positive from live on to port 30 and then onto the float switches
Surly one of them is going to be overloaded
Just wondered why you drew your diagram so the switches wear the other way round

wear are you from

i cant see two relays on that scematic
as i said to you before the above blew the switch

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