Dying Battery - Can't find cause

[lipinski]

I recently purchased a used boat (new to me).

I encountered some mechanical problems, e.g., bellows, carb, etc. Took to marina, they repaired everything, and they claimed that the battery died twice while they had the boat, so they replaced it.

After getting the boat back, I had it in the water. It has a slight leak such that the bilge pump probably kicks on once every 4-6 hours for about 5 min.

After two days of not running the boat, I could not get it to start - not enough juice from the battery, so I had to charge it. This is the new battery..

Few questions:
- New battery, not marked, but I could probably safely assume 40-60 Amp Hours (AH), right?
- If Bilge pump has 4A fuse, I can safely assume it uses <4A, right?
- By my simple math, and being conservative, I should be able to run the bilge non-stop for roughly 10 hours, right?
- If so, being real conservative, my battery should last easily 10+ days...

So, what else could be causing my battery problems?

I have 3 wires coming off the positive side of the battery. With an Ammeter, I show essentially 0 on two of the wires, and ~32mA on the third. That third wire feeds the "dash" which houses all the switches for everything (radio, manual bilge pump, lights, etc.). That is quite a rats nest of wiring, so I haven't been able to find the cause. I have checked everything that's switched - e.g., lights, radio, horn. None of those are using any power (best I can tell).

What's next? Any ideas would be helpful. Having a slight leak in a boat whose battery dies in 2-3 days is not a good combo.

Here's a secondary ques - how do I find the leak? I am 75% sure it is coming from the stern. I have had the shift bellows (and cable) replaced. I was told the drive? bellows is in good shape and probably replaced not too long ago, and the exhaust bellows doesn't matter because of a baffle. How can I find a leak in the stern when I can't see a darn thing because of the motor blocking view of almost everything back there...?

Thanks in advance for help on any of my many ques...

 

[Bondo]

Re: Dying Battery - Can't find cause

Here's a secondary ques - how do I find the leak?

Ayuh,... There's Only 1 way...
Ya gotta LOOK...

Use mirrors, or a camera, Whatever it takes...

 

[emoney]

Re: Dying Battery - Can't find cause

Anywhere and anything that's gone into the hull is a culprit. I had a boat that the PO drilled brackets into the "deck" for a cooler seat and then couldn't figure out why she took on water when he used it???? Tow hook in the front, if it's got one, swim ladders, through hulls, transducers, drain plugs, etc. etc. "All the above" can leak. As for the battery drain, it's not that hard to find, just use the process of elimination. Although, sometimes those bilge pumps draw a lot more on a boat that's sitting than you think.

 

[mkast]

Re: Dying Battery - Can't find cause

Disconnect the amp meter for a couple of days, see what happens.

 

[lipinski]

Re: Dying Battery - Can't find cause

Disconnect the amp meter for a couple of days, see what happens.

I don't understand... I'm using a hand held Fluke multimeter/ammeter to determine the current. It is not normally connected.

 

[mkast]

Re: Dying Battery - Can't find cause

My mistake, I thought you have an amp meter in the boat's gauge package.
To find the current draw you will have to disconnect each electrical accessory until it's found.

 

[Silvertip]

Re: Dying Battery - Can't find cause

The only draw you found was something on the order of 32ma. That's 1/3 of an amp or 8 amps/day which is a fairly large "electrical leak". Couple that with another 4A draw every few hours and you can see that a relatively small battery will not hold up long. The 32 ma draw by the way would likely be (at least in part) for the clock and station memory in the radio. To eliminate any current draw, install a battery disconnect switch that kills all power to the boat except for the bilge pump(s) which would be wired directly to the battery. By the way, if you have a single battery serving this boat, you want the largest capacity your wallet can afford.

 

[Randy J]

Re: Dying Battery - Can't find cause

auto bilge pump will run a battery down if any rain water etc activates it to cycle. ignition switch off take a test light undo positive battery post and hook test light to post and hot wire if test light is on shows something is using voltage.. sorta like a trunk hood light on a car on when closed due to bad switch etc.. then either can start pulling a fuse at a time to see if test light goes off... way to find power draw.. check if radio is on?? and etc

 

[Fireman431]

Re: Dying Battery - Can't find cause

Regarding your leak, I would look first at the gasketing for the outdrive. Especially underneath the outdrive. Also check for transom rot if you haven't already.

 

[lipinski]

Re: Dying Battery - Can't find cause

The only draw you found was something on the order of 32ma. That's 1/3 of an amp or 8 amps/day which is a fairly large "electrical leak". Couple that with another 4A draw every few hours and you can see that a relatively small battery will not hold up long. The 32 ma draw by the way would likely be (at least in part) for the clock and station memory in the radio. To eliminate any current draw, install a battery disconnect switch that kills all power to the boat except for the bilge pump(s) which would be wired directly to the battery. By the way, if you have a single battery serving this boat, you want the largest capacity your wallet can afford.

Isn't 32ma 1/30th of an amp?
How do you calculate amps/day?
What's a typical draw for a radio clock and memory?

FYI - the line that is pulling the 32ma "sparks" when I connect/disconnect from the battery terminal. It reminds me exactly of a car battery when the under-hood light is on or whatever.

 

[Doernuth]

Re: Dying Battery - Can't find cause

The only draw you found was something on the order of 32ma. That's 1/3 of an amp or 8 amps/day which is a fairly large "electrical leak". Couple that with another 4A draw every few hours and you can see that a relatively small battery will not hold up long. The 32 ma draw by the way would likely be (at least in part) for the clock and station memory in the radio. To eliminate any current draw, install a battery disconnect switch that kills all power to the boat except for the bilge pump(s) which would be wired directly to the battery. By the way, if you have a single battery serving this boat, you want the largest capacity your wallet can afford.

This, see if the battery is still dying.

As for the leak get a good mirror, flashlight and camera and look for the wet spot.

Make sure all of your engine drain plugs are tight. If not they will drip.

 

[FreeBeeTony]

Re: Dying Battery - Can't find cause

Isn't 32ma 1/30th of an amp?
How do you calculate amps/day?
What's a typical draw for a radio clock and memory?

32ma = 0.032 amps = 32/1000amps

 

[bruceb58]

Re: Dying Battery - Can't find cause

If this is not a deep discharge battery, you have already damaged the battery enough that it probably doesn't have much capacity left. Even if it was a deep discharge battery, you never want to discharge them more than 50%.

Also, 32mA draw will be 0.8Ah/day....not 8.