Water Pump Load on Circuit

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Water Pump Load on Circuit

Postby Alex888 » Wed Apr 24, 2019 5:43 pm

I have a Paragon fresh water pump. When the pump cycles on I noticed that my Simrad heading sensor temporarily deviates about 20 degrees then returns to an accurate heading once the pump cycles off. Does anyone know of a simple solution to maintain a constant voltage to sensitive instruments when large loads are temporarily applied to a circuit? I am hoping to avoid installing more batteries or do significant rewiring.
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Alex888
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Re: Water Pump Load on Circuit

Postby Charlie0 » Wed Apr 24, 2019 7:27 pm

Are you sure it’s a voltage problem? How close is the sensor to the pump? Is the wire harness for the pump routed near the sensor? Maybe as simple as changing the routing / location of the harness.
Charlie O
Grand Banks 36
Hull 715
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Re: Water Pump Load on Circuit

Postby Alex888 » Thu Apr 25, 2019 5:01 am

Thanks Charlie. The heading sensor is forward in a stateroom under a bed and the pump is aft in the engine compartment about 25 feet apart. I will try to follow the wires to see if they cross paths. Thanks for the idea.
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Re: Water Pump Load on Circuit

Postby wkearney99 » Thu Apr 25, 2019 6:41 am

Check the voltage levels at the devices, both when idle and when operating. If there's any dip then you have something to check. Start with removing and cleaning the connections to them. A bad ground or corrosion will cause them to consume more power than usual. A device suddenly draining a lot more power can cause a dip that affects other devices. Pumps that are failing will likewise consume more power than usual.

If you've got a portable clamp-style amp meter you should use that to check how many amps the pump is pulling. Compare that against the vendor's specs for it. If it's more than spec then the pump could be suspect.

That and if the wire gauge isn't large enough it'll contribute to voltage drop. Boat wiring is notorious for under-sized wiring. Both on the positive and negative sides.

Assuming the you've checked the pump amp load, check the voltage level at the battery. Then check it at the pump (while it's not running). If there's any more than a ~.3 difference then the wire gauge might be a problem (assuming you've already check/cleaned the connections). Then check it while the pump is running. If it dips then it might be worth considering replacing/upsizing the wire to/from the pump.
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Re: Water Pump Load on Circuit

Postby Alex888 » Thu Apr 25, 2019 5:12 pm

Thank you for the detailed advice!
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