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Recommendations for a timer switch 12V boat pump

David.Bundy

Mar 16, 2023
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Mar 16, 2023
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Hello, I'm new to the world of electronics and looking for some advice. I have a boat that is parked about 30mins away from where I live in the UK, it rains a lot here and therefore my small boat fills up with water. Its kept up on a trailer so with a 12V bilge pump and a long hose I can prime a syphon.

As the pump only needs to run 5-10 seconds to prime the hose, a simple float switch on its own will use too much power on my leisure battery. I was thinking of using a timer switch so run in a series with the float switch to create the syphon and once the next timer goes off the boat will be empty (no circuit from the float switch).

Is there a 12V timer switch on the market for my needs? lets say every hour it turns on for 5 seconds.

Thanks
Dave
 

kellys_eye

Jun 25, 2010
6,514
Joined
Jun 25, 2010
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6,514
As the pump only needs to run 5-10 seconds to prime the hose, a simple float switch on its own will use too much power on my leisure battery.
Really? Most simple bilge pumps chuck the water out at 500 to 1000 gallons per hour (2-4000 litres/hour) equivalent to a minimum of 0.5litres/second.

Assuming a 20 litre 'flood' it will take 40 seconds i.e. under a minute and at a current draw of typically 2-3A.

Assuming worse case (3A) this represents 1/20th of an ampere-hour...... a typical leisure battery would be (say) 70 to 120Ahr so you could drain a 20 litre 'flood' some 700 to 1200 times and only discharge the battery to HALF its capacity.

It must rain a lot where you are!!!

PS - I'm in Argyll, I know what 'rain' is!
 
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