Duel Battery Bilge Pump Question -

[afarrens]

ok, so here is a good question for you guys, I still have a little while before I get to this point but I was doing some design layout yesterday and think I confused myself

my new three way switch has three posts on the back, bat1, bat2 and both. Now when I wire up my bilge pump, everywhere i have read, it is recommended that the bilge is wired direct to the battery. So000 - do I wire the bilge to the battery2 (sense that's the secondary backup battery) , or to the both outlet on the switch?

of course my worst fear is that I am camping in the boat and the battery dies from burning the radio or anchor lights and next thing i know i'm knee deep in the cuddy because the bilge didn't switch on. and ideas here?

I am in the process of restoring a 85 Bayliner - the restore thread can be found at

http://forums.iboats.com/showthread.php?t=567730

 

[tpenfield]

Re: Duel Battery Bilge Pump Question -

Battery 2 would be good.

Not sure about the switch posts, but it sounds like "bat1" and "bat2" are the leads from each battery and the 'Both" is really the common hot lead that goes to powering everything. If you hook your bilge pump up to that one, it may not work when the battery switch is in the "off" position.

 

[Silvertip]

Re: Duel Battery Bilge Pump Question -

Wired that way I can assure you it won't work when the switch is turned off. The COM switch is not the BOTH terminal. That's the post that is HOT when the switch is set to BAT 1 BAT 2 or BOTH. When set to OFF neither battery is connected so the pump won't run. You connect he bilge pump directly to the HOUSE (normally BAT 2) battery. That way only the pump will run if the switch is set to off (and then only if there is water in the bilge and then only if you have an AUTOMATIC bilge pump.

 

[afarrens]

Re: Duel Battery Bilge Pump Question -

Thats kinda what i was thinking... but I was going to go one more step - so going backwards, I was going to do the positive battery to a circuit breaker to a LED on the dash the float switch to Bilge pump, with a on/off switch wired between the bilge and the float. if that makes sense. I should be able to manually switch the bilge on/off at my pleasure, it should ALWAYS be hot, and if the float flicks on I would have an indicator...shoot, it may almost be worth while to just wire a small alarm into the cuddy. Then i'd be able to sleep without wondering if there is a light on...or wire the light into the cuddy also...here is a simple drawing that shows what i am thinking...am i close?View attachment 160949
I think i need to move my warning light inbetween the float and bilge, not the breaker and float?

 

[kahuna123]

Re: Duel Battery Bilge Pump Question -

If your manual switch has a light when it is on your already have an indicator when the auto comes on if it is wired right. As far as always hot I do not agree unless your boat lives in a slip. When I am done boating and on the lift or trailer I want to go back and turn EVERYTHING off. I don't like buying batteries. If I am sleeping over the switch is on anyways. IF you want a real alarm. Go buy a float switch and a 12v horn. Place the switch on something 3-4 inches higher than the pump switch. Our boats stay in the water 12 months a year. Sometimes being left alone too long. But that gives the dockmaster a warning that something is wrong. If you are sinking you dont want a little light to come on while you are busy or asleep. You want noise.

I am not a supreme mariner (whatever) but here is a boat I am rewiring. It has six pumps.

 

[CharlieB]

Re: Duel Battery Bilge Pump Question -

If your manual switch has a light when it is on your already have an indicator when the auto comes on if it is wired right. As far as always hot I do not agree unless your boat lives in a slip. When I am done boating and on the lift or trailer I want to go back and turn EVERYTHING off. I don't like buying batteries. If I am sleeping over the switch is on anyways. IF you want a real alarm. Go buy a float switch and a 12v horn. Place the switch on something 3-4 inches higher than the pump switch. Our boats stay in the water 12 months a year. Sometimes being left alone too long. But that gives the dockmaster a warning that something is wrong. If you are sinking you dont want a little light to come on while you are busy or asleep. You want noise...........

Nice wiring!

Personally, I prefer to pull a line off each battery post of the switch, block each with a diode, install a breaker and a switch then feed the auto bilge and alarm. The diodes prevent either battery from 'seeing' the other. This way the bilge and alarm are powered by either battery (as long as the switch is on). The battery select switch is still able to kill everything else on the boat.

I've seen boats 'sunk' on their trailers because someone forgot to pull their bilge plug, some sunk at the dock because the battery switch was 'Off'. Heavy rain can be a B........

 

[NYBo]

Re: Duel Battery Bilge Pump Question -

If your manual switch has a light when it is on your already have an indicator when the auto comes on if it is wired right.

Not necessarily. I had a lighted switch, and figured the internal light would act as an indicator for the float switch circuit too. I discovered that this particular switch shorts the negative and accessory feed terminals when turned off.

I reinstalled the non-lighted switch and added an LED from Radio Shack to the switch panel. Works perfectly now.

 

[kahuna123]

Re: Duel Battery Bilge Pump Question -

Look closely in the left of the pictures you can see the diode. I feed the whole boat from both battery banks with that diode. Its 30volts blocking and will take 400 amps. Cost 12 bucks. This one is twin outboards. You can turn off any three batteries or one side completely and still feed the whole boat.

I used to do this for a living. I know, I know the colors are incorrect but we were doing this one on the cheap. The boat got wet.

IF you take the switched side of the float switch and attatch it to the run side of the switch the light will come on when it goes into auto.

 

[NYBo]

Re: Duel Battery Bilge Pump Question -

IF you take the switched side of the float switch and attatch it to the run side of the switch the light will come on when it goes into auto.

That's what I did but it was a no-go (see my reply immediately above yours). Is there a way to tell if a particular switch will work properly? Mine caused a short; it was a cheapo from AutoZone that I bought because it fit the cutout in the switch panel. Not that i need a solution since I installed an external LED, but it could help someone else.

 

[afarrens]

Re: Duel Battery Bilge Pump Question -

If your manual switch has a light when it is on your already have an indicator when the auto comes on if it is wired right. As far as always hot I do not agree unless your boat lives in a slip. When I am done boating and on the lift or trailer I want to go back and turn EVERYTHING off. I don't like buying batteries. If I am sleeping over the switch is on anyways. IF you want a real alarm. Go buy a float switch and a 12v horn. Place the switch on something 3-4 inches higher than the pump switch. Our boats stay in the water 12 months a year. Sometimes being left alone too long. But that gives the dockmaster a warning that something is wrong. If you are sinking you dont want a little light to come on while you are busy or asleep. You want noise.

I am not a supreme mariner (whatever) but here is a boat I am rewiring. It has six pumps.


View attachment 160995

Yea nice wiring - I think just a little buzzer alarm in the cuddy will help me sleep late at night!