Heavy duty 12v pump relay overheating

Thread Starter

Andrew32

Joined Jan 29, 2021
6
Hello all,
I have a 20gpm pump for a big caravan for shower use etc. It's great but the included relay for the pressure is clicking on and off constantly, after a few mins it overheats and stops working. What options do I have to replace it?
I'm tempted by mosphets, solid state relays, heavy duty relays (for starter motors etc) but looking for something that actually is just able to be switched on and off really often without overheating, any ideas?
Thanks
 

Reloadron

Joined Jan 15, 2015
5,934
The On/Off constant clicking is a symptom unless it is supposed to be doing that. The question is why it constantly turns on and off? What is getting hot, the relay coil or the contacts? A relay coil designed for sustained use should not overheat.

With a known coil voltage yes, you can replace the relay with a solid state DC relay or MOSFET circuit. I would, however, try and find the cause of it getting hot. Part numbers and load data would help?

Ron
 

Thread Starter

Andrew32

Joined Jan 29, 2021
6
The On/Off constant clicking is a symptom unless it is supposed to be doing that. The question is why it constantly turns on and off? What is getting hot, the relay coil or the contacts? A relay coil designed for sustained use should not overheat.

With a known coil voltage yes, you can replace the relay with a solid state DC relay or MOSFET circuit. I would, however, try and find the cause of it getting hot. Part numbers and load data would help?

Ron
I would put it's reason down for getting hot is the spark from the high amperage, it's direct (with a fuse) to a leisure battery, so it must be consuming a lot of amps.

It's clicking on and off correctly, it's the pressure switch. Was just hoping there's a better solution than a physical contact clicking on and off quite rapidly.
I'll look up the model number and current draw now
 

MaxHeadRoom

Joined Jul 18, 2013
23,085
The relay coil should not switch on and off if the relay contacts are conducting high current, unless the load is dropping the voltage somehow.
Max.
 

Thread Starter

Andrew32

Joined Jan 29, 2021
6
The relay coil should not switch on and off if the relay contacts are conducting high current, unless the load is dropping the voltage somehow.
Max.
As it's a water pump with a pressure switch I believe it's working normally as it should, it's just as you use the pump especially not at full flow it's reaching max pressure quickly so the pressure relay is clicking on and off really fast to keep up, causing the sparks to make it overheat
 

MaxHeadRoom

Joined Jul 18, 2013
23,085
According to the Ad the pump comes in LV DC and 220AC?
Did you supply the relay or is it built in?
I see by the title it is 12vdc.
Max.
 

crutschow

Joined Mar 14, 2008
27,172
If the relay is clicking on and off rapidly to maintain the pressure, then it would seem you need a small pressure tank (one with an air bladder) to store pressurized water for a period of time.
Depending upon the size of the tank, that should greatly reduce the on/off cycling.
 
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