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I am an inexperienced hobbyist So My Question may be obvious, but thank you for the help.

I have a 12 V battery, which is powering two 12 V pumps. It is a 100 W pump which runs at 7 A on average (Depending on required Pressure), and another Pump, which runs at 3 A on average, but both pumps can peak under pressure to a combined continuous amp draw of over 15 A, and the current load also peaks on start-up.

My aim is to have the battery powering the two main pumps, the less powerful pump to be controlled on and off by an rf relay switch and a motor speed controller, and the more powerful pump activated by a mini water level switch as well as a motor speed controller.

My problem is that the mini water level switch is listed as having a 15 watt power rating, and 1 amp contact current. It therefore does not allow the more powerful pump to start or stop when open or closed. If the pump is running and the contact switch opens, the pump will cut out, but if the relay then closes the pump cannot restart again. It simply gives off a quiet click sound. Is there a component I can use, like some sort of controller which will allow me to lower the current through the float switch, whilst allowing full power to the pumps?

Again I am aware that this is likely a very simple question but I very much appreciate your time and help as I have never studied electrical engineering and am learning as I go. Thank you so much for your time and response please let me know if you need further clarification. Joell

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Use the float switch to energize a relay. An automotive headlamp relay would work fine, normally have 12 volt coils, and can handle upwards of 25Amps current easily.

So you have 12V -> Switch -> Relay Coil -> 12V Common for the switching circuit, and then you have 12V -> Relay Contact -> Pumps -> Common for the controlled circuit.

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