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*URGENT* Replacing 12V sump pump dc battery with 12V DC power supply

*URGENT* Replacing 12V sump pump dc battery with 12V DC power supply


  #1  
Old 04-09-24, 11:35 PM
J
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*URGENT* Replacing 12V sump pump dc battery with 12V DC power supply

Greetings:
I have a battery backup sump pump that I want to disconnect from the battery and put it on 12V Power Supply 30A 360W AC to DC Adapter 12 Volt 30 Amp Switching Power Converter Transformer. See details below:







Please confirm:
  • I can connect the red lead to 12VDC + and black lead to 12VDC – terminals in the powersupply
  • I can connect the two leads from the AC outlet to AC Live and AC Neutral (and it doesn’t matter if I switch the live and neutral)
  • Can I leave this running near the sump pit? Can it overheat and become a firehazard?


Thanks
Joe


 
  #2  
Old 04-10-24, 05:30 AM
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The big problem will be if the power supply can provide the current needed for starting the motor. The 21 amps listed is likely it's running current draw but starting the motor causes that to spike for a second. Batteries can easily handle that spike but electronic power supplies can sometimes have trouble if they are not powerful enough.

Instead of adding a 12VDC power supply I would get a new AC powered pump. You avoid the hassle of 12 volts and you get a much more powerful pump that can move a lot more water.
 
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  #3  
Old 04-10-24, 05:30 AM
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BTW I have a whole house generator now that will automatically kick in if I loose the power. So won't need to be connected to battery anymore and hence the question about connecting it direct to a DC power source
 
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Old 04-10-24, 05:36 AM
J
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Thank you PilotDane, Can you please send me a link of a DC powersupply that will support a running motor
Is there a chance of the powersupply overheating and causing a firehazard if used with a running motor?
 
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Old 04-11-24, 05:19 AM
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I do not recommend using a DC pump. AC is more reliable and has a higher pumping capacity.
 
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Old 04-11-24, 07:10 AM
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Thanks!
 
  #7  
Old 04-11-24, 07:12 AM
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PilotDane,
I want to try and keep the dc pump that is already hooked up without changing to an AC Pump.
Is there a way that you can recommend with a link of a powersupply that will support a running motor of my dc pump

Thanks!
 
  #8  
Old 04-11-24, 07:15 PM
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You could use a transformer type 30A power supply but the cost would prohibitive.
The bulk of power supplies today are the switching type.
You should use at least a 50A switching supply...... power supply.

I would highly recommend a high water warning alarm too.... just an example.
 
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Old 04-12-24, 05:05 AM
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I don't know much about DC motor starting load but looking online I did find a formula but you have to test the motor and it gets a bit like a 8th grade science/math problem. From what I found the starting current might be about 1.6-1.7 the running current. Nothing like the huge spike an AC motor produces but it's enough to think your power supply should be capable of at least double the motors draw. So, PJ's recommendation for a 50amp power supply seems spot on.
 
  #10  
Old 04-12-24, 02:55 PM
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It may be less expensive to use a 25 Amp power supply that charges a battery. The excess starting current is drawn from the battery. Haven't read the entire thread, but I learned to not load a power supply past 75% of its rating; they lasted much longer that way.
 
 

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