A previous owner labelled one switch position house and the other as start. We've only been using the house battery, even for starting. However, I'm finding that the start battery's voltage is down to 11.5v even though we havent used it. I'm thinking the bilge pump is pulling power from it. Is the bilge pump typically wired to battery 1 or 2 when the battery selector switch is off?
Which battery is my bilge pump connected to?
- Thread starter Project_Mayhem
- Start date
Does the bilge pump run when the start battery selector is off? Need to trace the wire from the bilge pump.
Check the terminals on the house and starter batteries to see where the light weight connections are.
If by some weird chance the connection to the bilge pump is further down the wiring, pull the (+) main wire off the posts one at a time to see who powers your bilge pump.
If by some weird chance the connection to the bilge pump is further down the wiring, pull the (+) main wire off the posts one at a time to see who powers your bilge pump.
Actually, you have two issues:
1. To which battery is the bilge pump connected, and
2. why is one battery discharged.
as you have been told, trace the wiring. Nobody knows what a previous owner did to energize the pump or how he labeled the switch.
then trace how the two batteries are connected to the charger or via what interconnection, e.g., isolator, ACR, etc… they are interconnected.
1. To which battery is the bilge pump connected, and
2. why is one battery discharged.
as you have been told, trace the wiring. Nobody knows what a previous owner did to energize the pump or how he labeled the switch.
then trace how the two batteries are connected to the charger or via what interconnection, e.g., isolator, ACR, etc… they are interconnected.
Yes, I can trace the wiring but I was hoping someone could tell me how catalina wired this from the factory as the manual states that it's on even when the battery selector switch is off
Could you take the pos wire off one battery bank, and see if the pump turns on (lift the float to test)?
Do you have a bilge pump switch at the DC panel? If so, I would guess the house bank is powering the pump. But if you disconnect the pos from the house bank, and see if the pump turns on it should confirm.
Greg
Do you have a bilge pump switch at the DC panel? If so, I would guess the house bank is powering the pump. But if you disconnect the pos from the house bank, and see if the pump turns on it should confirm.
Greg
There's no telling what a PO might have done to the wiring.
And there’s no telling if the PO did something wrong (At night, in the dark, while drunk). Never trust the manual
YES !
They ran the wiring directly from the battery terminals. No ON/OFF switches in between. No battery selector. Just a breaker in between and that's likely on your DC panel.
That's what the manufacturer intended. Check post #8 as most PO's are absolutely out of their minds when it comes to things like this. Nothing is off the table when it comes to PO's. As a matter of fact, @Don S/V ILLusion has listed the conditions under which the PO most likely altered the the bilge pump wiring.
Last edited:
Which is exceedingly stupid because if the switch if OFF the pump won't run!
If you feel the need to have an operating bilge pump while you are away from the boat, you could wire a properly fused bilge pump directly to the house battery bank. That way you could turn the batteries switch Off and disconnect all the others circuits. I personally do not think the benefit of periodically expelling incidental water compensates for the risk of having the unreliable float switch getting stuck and killing the batteries. The trick is to frequently check your plumbing system and rain entry points for leaks and minimize them.
i have no independent knowledge how true this is - “more boats sink at the dock than while underway”.
if true, it’s a “no-brainer ” to have it always energized. And even if it’s not true, it is still better than relying on luck.
Unreliable float switches usually "die" in the OFF mode, meaning when they go the pump DOESN'T WORK. Which is BAD NEWS.
Of course, regular checks are always appropriate.
Hey,
I don't believe the bilge pump is draining your start battery. You wrote that you have been leaving the battery switch on 'house.' That might be the reason your engine battery is so low. You need to start the engine and see if the alternator is charging the house bank AND the engine bank or just the house bank. Many older boats have the alternator output on one line - whichever battery is connected is the one that gets the alternator power. If you have a 1 2 both off battery switch you can try starting the engine and then switching to 'both' and see if that charges the engine battery.
Good luck
Barry
I don't believe the bilge pump is draining your start battery. You wrote that you have been leaving the battery switch on 'house.' That might be the reason your engine battery is so low. You need to start the engine and see if the alternator is charging the house bank AND the engine bank or just the house bank. Many older boats have the alternator output on one line - whichever battery is connected is the one that gets the alternator power. If you have a 1 2 both off battery switch you can try starting the engine and then switching to 'both' and see if that charges the engine battery.
Good luck
Barry
While it's one way to do it as part of Barry's very good overall advice to find out, the less intrusive way to do it is to find out how your boat is actually wired. I have an old boat with a 1-2-B switch, but my alternator output goes to my house bank and I have a combiner, although using B on the switch would do the same thing.
Figure out how you're actually wired and learn how it all works.
Here are some handy links to help you:
OEM 1-2-B Switch Wiring History Alternator/Batteries & "The Basic" 1-2-B Switch BEST Wiring Diagrams
1-2-B Considerations (New 2020 - Rod finally got around to diagramming what I had done in the above link in 2009
)1/2/BOTH Switch Considerations
Basic Battery Wiring Diagrams This is a very good basic primer for boat system wiring: Basic Battery Wiring Diagrams
This is another very good basic primer for boat system wiring: The 1-2-B Switch by Maine Sail (brings together a lot of what this subject is all about)
http://forums.catalina.sailboatowners.com/showthread.php?t=137615
This is a newer primer for boat system wiring design with a thorough diagram: Building a Good Foundation (October 2016)
Building a DC Electrical Foundation
The Short Version of the 1-2-B Switch Stuff: Electrical Systems 101 This is a link to the Electrical Systems 101 Topic, reply #2
