Draining Battery Question for Techy?

[Ship Wreck]

I need some advise about a starting battery that drains dead on me every couple of days. I have on the positive terminal the main feed to the distribution block for the radios, lights, etc., the power for the outboard and the bilge pump and pilge pump float switch. I have a main kill switch installed witch kills all radios etc but not bilge pumps and motor that I turn off everytime I leave boat. And if I leave the boat for a few days I come back to a dead battery which when I jump and run for 20 minutes runs fine for the rest of the day. It is a new battery from Sept that I had inside over the winter. I think I must be getting a power drain from somewhere but am not sure how to determine from where. I do have an amp meter but am not so schooled on using it. Any thougts? Suggestions?

 

[drewpster]

Re: Draining Battery Question for Techy?

Simple test would be to disconnect the ground cable from the battery. Connect a test light between the end of the ground cable and the battery ground post. If the light comes on then you have something draining. The light may be very dim indicating a slight drain so do it low light conditions so you can see it.
If you have a drain, leave the light in place where you can see it while removing fuses from the fuse panel. When the light goes out you will know which circuit is causing the drain. If the light goes out with every fuse then it is likely that the fuse panel itself is causing the problem. Pay particular attention to the bilge pump circuits, they are a potential culprit.

 

[Scaaty]

Re: Draining Battery Question for Techy?

Yep..good advice...

 

[Ship Wreck]

Re: Draining Battery Question for Techy?

Thanks, I tried an could not get light or amp meter to read anything. So I rerouted all positive leads through battery disconnect switch exept for the bilge float switch. I also noticed a loose connection on a livewell pump that may have been the culprit. I will give it a few days and see how we do. Thanks again....

 

[bruceb58]

Re: Draining Battery Question for Techy?

A loose connection would not cause the battery to drain unless the pump was on and the loose connection allowed current to flow through it with out actually spinning the motor.

 

[gregtobin]

Re: Draining Battery Question for Techy?

Use a mulimeter to test leakage across the top of the battery. If your battery has a lot of grime on it, you can detect 3 or 4 volts running across the top of the battery. Clean it up well and this will stop.

 

[bruceb58]

Re: Draining Battery Question for Techy?

Use a mulimeter to test leakage across the top of the battery. If your battery has a lot of grime on it, you can detect 3 or 4 volts running across the top of the battery. Clean it up well and this will stop.

What are you measuring when you say 3 to 4 volts across the top of a battery?

In any case, there would be no build up of impurities that could possibly discharge a battery in two days...not possible.

 

[Ship Wreck]

Re: Draining Battery Question for Techy?

Alright, thanks for all the suggestions...Seems to have been much simpler than we all thought. Noticed some water in the battery box. Battery had a crack in the bottom that was leaking fluid. Hopefully new battery has solved the problem.