Bilge pump wiring

Dean Abramson · Post by **Dean Abramson** » Dec 12th, '06, 12:27

My automatic bilge pump is wired so that I have to leave the master battery switch on. I suppose that the only downside to this is that it means I am consuming whatever juice the little red light on the panel draws continuously when I am off the boat.

Is that small draw worth worrying about, or should I wire it so that the bilge pump wiring does not go thru the panel? Is there any downside to that approach? Anything I need to keep in mind?

Dean

rtbates · Post by **rtbates** » Dec 12th, '06, 13:54

I have no idea what pump your driving so I don't know the wire size requirements, BUT if the pump manual suggests anything much bigger than 18 ga you might consider going directly to the battery, via a fuse/switch. I say this because the Jabsco pump I use and the electronic switch call for 10-12ga and the back of Seraph's panel is wired with something like 18ga. Very wimpy wire IMHO. My bilge pump is wired directly via fuse/switch to the battery with 10ga wire.

Neil Gordon · Post by **Neil Gordon** » Dec 12th, '06, 15:11

Dean,

Go directly to the battery. You get the peace of mind knowing that when the switch is off, everything on the boat (other than the bilge pump) is off. You also eliminate the chance of something shorting downstream of the switch when you're not there.

Ron M. · Post by **Ron M.** » Dec 12th, '06, 18:02

I feel Neil's suggestion is a good one. On my boat I use a bilge pump switch: auto-off- manual that has it's own fuse and is direct wired. Determine wire size by the amperage the pump draws. I always go one size larger
________
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Trawler Joe · Post by **Trawler Joe** » Dec 12th, '06, 18:40

I just did this same project on Sunday. My setup was the same as yours -- pump and float switched wired to the panel, so I had to leave main battery switch on all the time.

I just took the one lead from the float switch, which was wired to the "auto" position, and wired directly to the house battery instead, with 16ga wire and an inline fuse. 16ga was bigger than the wire on the switch itself. Wire and fuse holder totalled about $10-15. Another option is to run an always-live wire from the battery to the "auto" position on your panel, bypassing the battery switch. Downside of that is that you have to remember to leave the panel in "auto" position. I'm forgetful, so I bypassed the panel completely and went right to the battery.

Now the panel switch is effectively just "On" or "Off" -- because the "auto" position isn't hooked to anything. But that doesn't really matter...

Steve Laume · Post by **Steve Laume** » Dec 12th, '06, 18:44

The main switch should be off when you leave for all I have read and heard. You could very easily make your connection at the main switch by going to the battery side of the switch instead of the load side. That way the pump would work with the switch off. It would also allow you to run the pump off both batteries in the both position. You would still need a fuse near the connection. This may make for a shorter run with your pump wire and it keeps the small wire connections in a more hospitable environment. I am just now considering installing an electric pump and I believe this is the way I will wire it, Steve.

Dean Abramson · Post by **Dean Abramson** » Dec 12th, '06, 21:18

I really appreciate all of the input. I wasn't sure how bad it was, but it really just bugged me to have that battery switch on. Now I can re-wire it, and not feel like I am just being compulsive.

Thanks,

Dean

Mike C · Post by **Mike C** » Dec 12th, '06, 21:28

[quote="Dean Abramson"]My automatic bilge pump is wired so that I have to leave the master battery switch on.

while on the subject:
one mechanic told me I should never put the auto-bilge pump to the start battery but to the house battery. That way you will be able to start the engine even if the pump has been running bit more than it should. So I changed the wiring to reflect his suggestion. Now the only power drawn from the start battery is for the diesel, which is a much smaller battery than the house battery.

I then put a second bilge pump on a on-off switch to the start battery as back-up.

M. R. Bober · Post by **M. R. Bober** » Dec 12th, '06, 21:37

FWIW:
At RESPITE's recent survey--demanded by her insurance company--the surveyor (a savvy chappy) insisted that the auto bilge pump switch setting be wired to the battery. His reasoning: better to have a flat battery and possibly keep her floating than to have her sink with a fully charged battery. I have wired the pump/switch directly to Battery #1.

Mitchell Bober
Sunny Annapolis (where we are positively connected), MD

Gary M · Post by **Gary M** » Dec 12th, '06, 21:54

There is a product that will keep track of how many times your bilge pump comes on (cycles) while you are gone.

This way when you leave your boat you can notice that your counter is at say 30. Then you return you can check the counter and if it says 33 you may consider that normal but if it says 75, you've got a problem!

I think I saw it in West Marine but I can't find it now but I know there is one out there.

Gary

viejo · Post by **viejo** » Dec 13th, '06, 16:17

I put in a bilge pump counter when we first got the boat we have now (it's been over 10 years now).

When the counter was first installed, I went nutz. 50 or more cycles a day was the norm.

Slowly (although faster than the incoming water), I tracked down everyone of the leaks (fresh and salt water) that were causing the cycle count.

I've finally got all the leaks taken care of (the list would astound folks) and now the counter (on the average) gives me zero cycles per week.

If nothing else, the counter was allowing me to see the fruits of my efforts with stopping the leaks.

Trawler Joe · Post by **Trawler Joe** » Dec 15th, '06, 10:12

I found this diagram on the web. I think this set up is probably better than what I did (I wired the float switch directly to the battery and directly to the pump).

In the diagram, the float switch goes from battery to panel switch, so you don't need to leave the main battery switch on, but you DO need to leave the panel switch in Auto. This set up, however, lets you turn off the pump if you need to.

This is the link to the page: http://continuouswave.com/whaler/refere ... ePump.html

Mike C · Post by **Mike C** » Dec 16th, '06, 09:16

[quote="Joe Boater"]I found this diagram on the web. gram, the float switch goes from battery to panel switch, so you don't need to leave the main battery switch on,

The reasoning behind the putting the auto bilge pump on the house battery instead of the start battery is the capacity (size) difference. The start battery is only 25% the size of the house battery and its purpose to sit for long periods and then supply starting power. The house battery is designed to fit the needs of the owner (the boats use) and general is sized to have long periods of steady usage and a much higher amp hours. .

Trawler Joe · Post by **Trawler Joe** » Dec 16th, '06, 09:23

Mike C wrote:The reasoning behind the putting the auto bilge pump on the house battery instead of the start battery is the capacity (size) difference. The start battery is only 25% the size of the house battery and its purpose to sit for long periods and then supply starting power. The house battery is designed to fit the needs of the owner (the boats use) and general is sized to have long periods of steady usage and a much higher amp hours. .

Yes, I would definitely use the house battery -- not suggesting otherwise...

The Cape Dory Board

Bilge pump wiring

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Re: Auto switch with direct battery connection