Join Date: Nov 2016
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Automatic bilge pump current requirements
I am getting ready to install a new bilge pump in my N28-2. I will be installing a Rule Lopro900 automatic pump. This is the type of pump with an electronic sensor instead of a float switch. The paperwork for the pump lists how much current the pump needs when running, but not how much current the electronic sensor needs. So I got out my trusty DVM and measured the current. According to my DVM, the electronic sensor needs 1.4 milliamps (0.014 amps). The reason I wanted to know what the current requirements are, is my boat will not be hooked up to shore power at this time, and I currently do not have a solar maintainer/charger installed. The solar is a near future project, and the shore power will have to wait until I rewire the boats AC circuits. Anyway, I will be installing a new set of Optima Blue Top deep cycle batteries in the coming weeks, and the bilge pump will only be connected to the house battery, so I will only have approx. 65 amp/hrs of capacity for the bilge pump. I was concerned that there would be enough current loading from the pump electronic sensor to deplete the battery in a fairly short period of time. That will not be the case. Doing the math, and only discharging the battery to 50%, and the pump motor not running, the battery will be good for 2321 hrs or 96 days, or a hair over 3 months. That means the pumps electronic load is for all intents, a non issue. Of course, this ignores the battery self discharge, or the pump cycling.
Anyway, I figured someone in the group would be interested in the results of the test.