Mysterious Power Frain

[fastjeff]

1986 Mercruiser 5.0 Alpha One. If I leave the Batt switch on it drains the battery overnight. Happened twice. I put a meter and a test light between every disconnected "red" wire and the battery and found nothing, yet something is draining the battery.

Recently changed the alternator (though it was when I first got the boat, so I don't know its history). Is it possible the field is staying energized somehow?

Anyone got a clue where to look? I'm at a loss.

Jeff

 

[kghost]

Remove the positive battery cables.

How many do you have going to the battery +??????

Get a digital volt meter, plug leads into AMPs

red to amps and black to the normal black connection.

now connect meter leads between battery + and each cable one at a time to see if there are any amps bieing drawn.

If I remember correctly ANYTHING over .02 amps is an issues.


Example.
I had a stereo head unit in my boat years back. Had the memory lead connected to remember my settings and + connected thru a fuse to a Battery + connection under dash.

Battery died over night twice after full charge.

I did as I described and thru process of elimination found the stereo head unit when turned off and the face place was off the unit was still drawing .24 amps.

So I through that head unit away and bought a new one.

Son I would say anything over .025 amps is going to kill a battery overnight or within a couple of days.

 

[fastjeff]

Excellent advice. Thanks.

Jeff

PS: There is an old, junk radio installed by the PO. I found a couple of mysterious white wires going the Batt sw that MAY have come from it. They are now disconnected.

 

[johnnygjr]

Fastjeff that is called a parasitic amperage draw,very common in the automotive industry with the modern age of computers screwing thing up! Good luck with her.

 

[fastjeff]

Thanks. Getting sick off flipping the Batt Sw on and off all the rime!

Jeff

 

[kghost]

Jeff
I can leave my boat, in the water, with a mechanical clock in the dash (running) for 2-3 weeks with no issues starting and I DO NOT HAVE a battery switch.

Just so you know it is possible not to kill the battery.

So if yours continues to die in a day or so then you have an issue.


I will also add I once trouble shot a battery drain issue and it turned out to be the Alternator..............I had the engine harness disconnected and only the Battery plus and minus connected to engine. NO other accessories.........Once alt was disconnected from engine wire harness the drain was gone. Determined this with a DVM (digital volt meter) set to amps as I described.

 

[RicardoMarine]

1986 Mercruiser 5.0 Alpha One. If I leave the Batt switch on it drains the battery overnight. Happened twice.
I put a meter and a test light between every disconnected "red" wire and the battery and found nothing, yet something is draining the battery.
If you cannot find a draw, it may be possible that your battery itself is bad..... perhaps one cell that is causing the depletion!

Recently changed the alternator (though it was when I first got the boat, so I don't know its history). Is it possible the field is staying energized somehow?
I'm thinking (given that this is a 1986 boat) that your alternator field is powered via the key switch circuitry.
Plus, you would have seen the drain during your testing.

Anyone got a clue where to look? I'm at a loss.
With the battery charged and after having been at "rest" for 6 to 8 hours, take a voltage reading.
You should see approx 12.6 volts from a good and fully charged battery.

Now disconnect the POS cable from this battery, and check the voltage after it has set for the same duration (over night).
If it remains charged, then you have a system drain.
If the voltage has dropped, then you have a battery issue.

Jeff

Johnny in post #4 is correct....... this would be a parasitic amperage or current draw.


*********************************

I spent approximately 24 years doing Volvo Penta AQ series service work and Marine Electrical.
In my opinion, all boats should have a means of disconnecting 12 vdc power for when the boat is left unattended and/or stored.

Two means of doing this:
..... a BS (battery switch..... ON/OFF only) typically used for one battery bank only.
..... an MBSS (main battery selector switch........ OFF/#1/ALL-BOTH/#2) typically used for multiple battery banks.

The MBSS allows for a dedicated cranking battery (usally on #1), and a dedicated HLBB (house load batt bank..... usually on #2), whereas the BS does not.

For boats that are moored, the main bilge pump float switch's Un-Interrupted 12 vdc can be taken from one of the battery bank terminals at the rear of the MBSS. Likewise for any radio Pre-Set memory circuit.

All other 12 vdc demands would be Cut-Off during the time that the boat is unattended.


Additionally, any BS or MBSS should be located where it is easily accessible...... and NOT from within the Engine Bay!


Good luck Jeff...... I hope that you find the issue!


.

 

[o2batsea]

Gawd how many boats are out there with a single DieHard battery taken out of a car?
Fastjeff, you must learn about "house"vs "start" banks of batteries. So you know, you will need at least two. One of them must be a marine deep cycle, the other can be a regular start type battery ( but I recommend a deep cycle too). You want to set up your boat in such a way that you NEVER run the start battery flat.
If you keep your boat on a trailer, you can use any old battery charger, but if you are always in the water, you'll want a good quality on board charger. There are many gazillion choices out there, so buy as much as you can afford and don't be cheap.
Same goes for the batteries. Buy Deka (east penn), or Odyssey marine deep cycle. These are the best-made ones out there and you cannot go wrong choosing either brand (made in USA).
Now here's the part where I lose people, making the proper connection between the start bank and the house bank. BTW they are called banks because you are "withdrawing" and "depositing" amperes. Anyway, you will want to keep them separate. Well, most of the time anyway but I'll get to that in a moment.
You want something called a VSR, or Voltage Sensing Relay. This goes between the charger (and alternator) and the two banks of batteries. What this does is fill up the START battery first, then when that is topped off, begins to fill the HOUSE battery. Again there are about ten million various vendors selling these, but the easiest to install and use for my money is the one by BEP Marine. This handy little panel gets rid of your (useless) 1,2,BOTH,OFF switch, and allows for emergency parallel. Wait what's that? you ask. It's what I was referring to earlier when I said you want to keep the banks separate, until you don't.
If for some reason your start battery goes flat, dies, blows up, falls overboard...whatever, you want to be able to use the house bank to start the engine. Who wants to be fooling with undoing battery cables in a pitching sea especially if its a critical moment? Not you, for sure. So with the emergency parallel switch you bring the house battery into the start circuit and bingo off to home. You won't be surprise to learn that there are automatic switches (I have one) that will put the house bank in parallel when it senses the start bank has gone flat. If you want to get super nerdy about marine 12V systems i am your man.

Anyway I hope you sort out the electric problem. And then you'll be shopping for Balmar alternators...

 

[kghost]

1. He has a simple one battery boat. He does not state anywhere he has more than one so all info regarding more than one is not needed. Just confuses the issue. 2. The only way to properly troubleshoot a drain on the battery in this case is as I described in my first post. YOU MUST use an amp meter and through the process of elimination find what is drawing current.
3. the important part here is what the meter reading is and as I described anything greater than .024 amp or 24 milliamps +/- will drain a battery in short order

 

[RicardoMarine]

Fastjeff, you must learn about "house" vs "start" banks of batteries.
So you know, you will need at least two. One of them must be a marine deep cycle, the other can be a regular start type battery ( but I recommend a deep cycle too). You want to set up your boat in such a way that you NEVER run the start battery flat.

I could not agree with you more!

A starting or cranking battery should be just that....... a cranking battery, and we should have a means of keeping this bank in "reserve".
A good HLBB should be made up from Deep Cycle batteries (plural). Deep Cycle batteries offer the AH that are required for HLBB usage.

The VSR or ACR is nice (I have a system that uses an ACR)...... however, if the banks are managed correctly it is not completely necessary.

Whether using an Automatic selecting system or not, start the engine on bank #1.
(it should take no more than 6 seconds (if that) to fire up a good starting engine)
6 seconds @ a 200 amp draw equals approximately .34 AH of current (that's only 34/100 of one Amp Hour).
During engine warm-up, an alternator will easily replace this in short order. Our cars/trucks do this all the time.

Now switch to #2 (the HLBB) and allow the alternator to continue charging this bank while you continue underway, anchor out, dock, etc.

When starting again, simply switch back to #1...... or, if your HLBB is large enough, there is no issue cranking from it as well.

(I crank my Port engine from a dedicated cranking battery, and I crank my Stbd engine from my large HLBB..... no issues at all)

The important aspect is having the #1 bank in RESERVE at all times.

1. He has a simple one battery boat. He does not state anywhere he has more than one
A boat out on the water with only one battery bank does not offer any "reserve".
Being on the water without a "reserve" battery bank is rather silly in my opinion.
I have never been able to "rope-start" a V-8 engine!

so all info regarding more than one is not needed. Just confuses the issue.
Let's allow Jeff to decide whether or not the info is confusing to him!


2. The only way to properly troubleshoot a drain on the battery in this case is as I described in my first post. YOU MUST use an amp meter and through the process of elimination find what is drawing current.
3. the important part here is what the meter reading is and as I described anything greater than .024 amp or 24 milliamps +/- will drain a battery in short order
Understood, and it has been covered here!

.

 

[kimcrwbr1]

Do you have a fuse block for accys? Pull the battery pos terminal off of the battery and turn the battery switch on then check for resistance from the posative cable to engine ground. Then start disconnecting components until the short goes away. If your accys are connected to battery pos at the ignition switch pull two 10g wires from the battery to the fuse block and isolate the engine circuit. Put a inline fuse for the accy circuit at the battery and a master power switch at the dash with a light. If you add a circuit always use marine grade tinned wire with soldered connectors.

 

[sandkicker]

Given all the above which is all well and good....
Do you have an automatic bilge pump? There is a particularly poorly conceived (IMHO) technology for "floatless" automatic bilge pumps that work by periodically turning on the bilge pump briefly and measuring the current flow ( no water in bilge, low current. Water in bilge, higher current and pump runs until current drops)

I work in a marine big box store seasonally, and we get a fair number of failed pumps of that technology that still work, but drain the battery unacceptably.

In my experience most reliable bilge pump "auto" operation is via a good quality pump and a separate float switch with a built in cage. These float switches usually have a "test" lever on the side. Wire this directly to your battery with a water proof fuse holder ( I prefer blade type), using tinned marine grade wire of the CORRECT size using heat sealed butt splices. Check that the pump float moves freely a couple of times a season. This is especially important if your bilge has grunge (soap residue plus engine oil or fish "residue" ) in it.

 

[o2batsea]

1. He has a simple one battery boat. He does not state anywhere he has more than one so all info regarding more than one is not needed. Just confuses the issue. 2. The only way to properly troubleshoot a drain on the battery in this case is as I described in my first post. YOU MUST use an amp meter and through the process of elimination find what is drawing current.
3. the important part here is what the meter reading is and as I described anything greater than .024 amp or 24 milliamps +/- will drain a battery in short order

We diverge in our opinions here. Sure, we can fix the drain issues, but those are not the droids he is looking for. A simple one battery boat is a tow waiting to happen.
And while 24 milliamps is a fine number, a properly charged battery with reserve capacity of, oh, let's just say conservatively 8 hours at the 20 amp rate, should not go flat at 24 milliamp discharge for at least...wait, let me get out the calculator...6666.6 hours. Not exactly my idea of short order. Something else is at work, and I suspect the battery itself is probably the culprit.
Jeff I'd start not by getting out the meter, but by having the battery load tested. Most auto parts stores will do this for you at no charge. That way you can eliminate the battery as the source of the problem. if it is indeed in good order, then you should start testing circuits.

The two battery set up should be mandatory on every boat that has an engine. Just trying to make his boating experience less troublesome and safer for him and his guests.

 

[kghost]

I run a one battery boat always have.

Have been since I purchased it in 1995 and its a 1987 and always had ONE starting battery.
When I had my issue I solved it the exact way I described. And many other boats with similar issues. Didn't go adding a second battery of any battery switch of any kind. Just fixed the problem.

On a side note, I do however have two 1000 CCA batteries but they are dedicated to my sound system. Totally separate from the start battery But have not always had these until the last 6 years ago when I seriously upgraded my sound system!!

Of course you cannot anticipate an electrical problem if one occurs but no need for additional batteries unless you are running off shore or in an extremely large lake like the great lakes Or you just desire two. Some boats don't have the space. A lot of you guys are running larger than typical boats for the average boat owner. The practices you use really don't apply to the smaller boat crowd.

Why take a simple issue and over complicate it with all kinds of "add ons"?

He has a problem.
he asked how to troubleshoot it

if and when he asks what to do to preempt this from possibly leaving him dead in the water, then let all the add on info roll out.

Until then

KEEP IT SIMPLE STUPID

 

[RicardoMarine]

Jack, in my opinion, and from how you see things and operate, you are perhaps not a seasoned mariner! A well seasoned mariner would not have his batteries set up as you have implied.

 

[kghost]

Do you have a fuse block for accys? Pull the battery pos terminal off of the battery and turn the battery switch on then check for resistance from the posative cable to engine ground. Then start disconnecting components until the short goes away. If your accys are connected to battery pos at the ignition switch pull two 10g wires from the battery to the fuse block and isolate the engine circuit. Put a inline fuse for the accy circuit at the battery and a master power switch at the dash with a light. If you add a circuit always use marine grade tinned wire with soldered connectors.

Nice schematic

But not many smaller pleasure boats have a dedicated power switch for the entire power distribution panel.

they have the aux power switches for lights, pump, blower, bilge like the diagram shows.
They may have a fuse/breaker vs a power switch but not all.

Battery + in those cases simply goes to the + side of the power distribution. NO fuse or switch. Especially a 1986...........many boats back then were very much lacking in there electrical design..................Especially Checkmates............they did the bare minimum.........

Also when testing for battery drains it is best to disconnect the MAIN plug connector at the motor wire harness and eliminate the entire dash and controls from the circuit. if the drain is not at the engine side of the wire harness then plug it back in and test upstream by means as you suggest.

 

[o2batsea]

Sorry Jack, I respect your knowledge and expertise in most areas, but in this case you are promoting unsafe practice. In this, "simplicity" is like doing a Bangkok hooker without a condom. A female one, not one of those ladyboys that you like. ;-)
Besides you just revealed that you have a discreet battery bank for the audio system so you shot yourself in the foot dood.

Even an 18 footer has room for two batteries. There's just no good argument against a two bank system. The reason you don't see them on smaller boats is that it costs money. If smaller boat manufacturers like Ranger or Lowe put a two bank system on their 16 or 18 footers, it would add another 5-700 bucks to the boat. That's millions of dollars in costs they choose not to carry on the price tag.
Thinking that it is sufficient to leave the dock with one battery is just plain wrong. Sure, you can get away with it but...

Anyway Jeff, go load test the battery, then get back to us.

 

[kimcrwbr1]

Good point on the bilge pump if it is wired for full time power it could easily drain the battery fairly quick. Another thing to check is with your hand just touch everything as you go resistance almost always creates heat if the bilge pump is warm but not running it needs replaced.

 

[RicardoMarine]

...................
In my experience most reliable bilge pump "auto" operation is via a good quality pump and a separate float switch

Yes, I agree.
I have seen and have worked on some of the integral pump/float switch units and the water sensing units........ they are problematic!

We diverge in our opinions here. Sure, we can fix the drain issues, but those are not the droids he is looking for. A simple one battery boat is a tow waiting to happen.

Yep!

Sorry Jack, I respect your knowledge and expertise in most areas, but in this case you are promoting unsafe practice. In this, "simplicity" is like doing a Bangkok hooker without a condom. A female one, not one of those ladyboys that you like. ;-)
Besides you just revealed that you have a discreet battery bank for the audio system so you shot yourself in the foot dood.

Even an 18 footer has room for two batteries. There's just no good argument against a two bank system. The reason you don't see them on smaller boats is that it costs money. If smaller boat manufacturers like Ranger or Lowe put a two bank system on their 16 or 18 footers, it would add another 5-700 bucks to the boat. That's millions of dollars in costs they choose not to carry on the price tag.
Thinking that it is sufficient to leave the dock with one battery is just plain wrong. Sure, you can get away with it but...

I understand your respect for his knowledge. I too can appreciate that. However, I disrespect him for his rude, disruptive and less-than-adult-like forum behavior.
Two or more of us should be able to express our differences in opinions in an adult like manor. If an error is pointed out....... we should Man Up and be OK with it.

Good point on the bilge pump if it is wired for full time power it could easily drain the battery fairly quick.

Agreed!
As we all know, the main bilge pump is there for an emergency situation, whether handling a leak while out at sea or a leak while being moored.
In order to be ready, the bilge pump's "float switch" must be supplied via an Un-Interruptible power source, meaning that even when the MBSS is turned to OFF, the float switch still receives un-interruptible power.

Many dock-side moored boats will have Shore Power available that will allow the On Board Battery Charger to keep the battery banks up to snuff.

 

[kghost]

Yes, I agree.
I have seen and have worked on some of the integral pump/float switch units and the water sensing units........ they are problematic!



Yep!


I understand your respect for his knowledge. I too can appreciate that. However, I disrespect him for his rude, disruptive and less-than-adult-like forum behavior.
Two or more of us should be able to express our differences in opinions in an adult like manor. If an error is pointed out....... we should Man Up and be OK with it.



Agreed!
As we all know, the main bilge pump is there for an emergency situation, whether handling a leak while out at sea or a leak while being moored.
In order to be ready, the bilge pump's "float switch" must be supplied via an Un-Interruptible power source, meaning that even when the MBSS is turned to OFF, the float switch still receives un-interruptible power.

Many dock-side moored boats will have Shore Power available that will allow the On Board Battery Charger to keep the battery banks up to snuff.

Well see now you are going down another RAT hole.

I do not even think he has this boat in the water. I believe it is on a trailer???

So if this is so then it is very highly unlikely the bilge pump is a factor here............also not all boats of this size/age have a auto bilge pump. Many especially of that year vintage have a simple ON/OFF bilge controlled at the dash. This would depend on boat company and or previous owners upgrading.


Also many smaller boats do not have room for a second battery. especially the ones where the gas tank is above the floor level and against the transom..........
Barely enough room for a seat.......

What the hell does shore power have to do with any of this..............Again another RAT hole. information not needed and causes more confusion.

As far as two battery boats, cant compare fishing type designs to pleasure designs. Apples to oranges. Fishing uses many auxiliary components like bait well pumps and a host of electronics that a simple pleasure boat does not have.

Of all the boats I have worked on ranging from 15' to 24' pleasure boats single engine (I/O, inboard, outboard) Virtually none have ever had two batteries until getting close to the 24' size as the amount of accessories necessitated it.

Now if we go to Salt water and or fishing boats then the need for two batteries is absolute!! No argument there.

 

[fastjeff]

Jack is spot on with one exception: I do have two batteries. (Since I take out my grandkids in this boat, no way would I have only one battery--knowhatimean?)

The bilge pump IS wired directly to one battery, but it's not that one of those dopey float-less thingees--had one of those on my last boat. Never again.

Right now I'm having so much damn trouble with the power steering that the battery issue is on the back burner. Blew two return hoses before I found out the oil cooler needed cleaning out. Then had another damn leak at a hose clamp on the cooler since the hose is 30 years old and is kinda hard (I guess). It's surprising how much pressure is in that return line! Gonna install new stuff this morning, then start cleaning the boat.

SOB blew a quart of oil all the way to the helm!

Jeff

 

[RicardoMarine]

Jack, in the text that you quoted, I was responding to o2batsea, sandkicker and kim. It is quite common for a forum thread to have
become somewhat expanded from the original topic.

Jack is spot on with one exception: I do have two batteries. (Since I take out my grandkids in this boat, no way would I have only one battery--knowhatimean?)
Jeff, you are a smart man and you are concerned about your grandkid's safety!
As some of us have indicated in this thread...... it is un-wise to NOT have two battery banks w/ an MBSS.

The bilge pump IS wired directly to one battery, but it's not that one of those dopey float-less thingees--had one of those on my last boat. Never again.
Jeff, food for thought...... it is best to power the float switch from your largest battery bank, and from the rear #2 terminal of your MBSS.
This is the same schematically, and it eliminates any direct battery connection and the Rat's Nest that can occur from doing so.


Right now I'm having so much damn trouble with the power steering that the battery issue is on the back burner. Blew two return hoses before I found out the oil cooler needed cleaning out. Then had another damn leak at a hose clamp on the cooler since the hose is 30 years old and is kinda hard (I guess). It's surprising how much pressure is in that return line! Gonna install new stuff this morning, then start cleaning the boat.

It would be best to start a new thread on your Power Assist steering pump hose problem!

 

[kghost]

Jack is spot on with one exception: I do have two batteries. (Since I take out my grandkids in this boat, no way would I have only one battery--knowhatimean?)

The bilge pump IS wired directly to one battery, but it's not that one of those dopey float-less thingees--had one of those on my last boat. Never again.

Right now I'm having so much damn trouble with the power steering that the battery issue is on the back burner. Blew two return hoses before I found out the oil cooler needed cleaning out. Then had another damn leak at a hose clamp on the cooler since the hose is 30 years old and is kinda hard (I guess). It's surprising how much pressure is in that return line! Gonna install new stuff this morning, then start cleaning the boat.

SOB blew a quart of oil all the way to the helm!

Jeff

Dont feel bad on that, two summers ago after a full spring tune up on my own boat when putting in for the first time that season I got about 1/8 mile form ramp and lost power steering.......popped engine hatch only to find the return line at pump had cracked enough to leak out the whole pump of fluid.....this occurred about 2 weeks between tune up and launch...........SH!T happens...........

 

[guppy]

Lots of good information on battery banks in this thread. Could he possible use a 12 volt test light, disconnect neg battery cable, use light between battery and cable and start disconnecting power to circuits? Light goes out problem located? Was taught this simple procedure way back in High School Auto Shop when things were simple and everything ran points.

 

[kghost]

In some cases yes if the drain is high enough in amps.

But like I posted, my experience tells me that anything greater than ~.024 (24 milli amps) will kill a battery over a short period of time and I dont believe a test light will accurately show this. Only a AMP meter and a digital one works best. An AMP clamp if it is for lower amp levels will also work.

I derived the ~ .024 amp baseline from my own experience testing known good simple (small pleasure boats) electrical systems

 

[fastjeff]

A test light--and I did use one--is no where near sensitive enough for such a minor 'leak'. Near to use my meter, as Jack suggested.

I'll be trying it again today if the temp ever gets above 40 degrees. Sheesh! What a weird Spring.

Jeff

 

[fastjeff]

BINGO! It was the crappy radio hiding in the glove box (that I don't even use 'cause it doesn't work). The red wire for lighting, bilge blower, horn etc. was showing 3 milliamps. I opened the glove box door and the *#^$%# radio was lit up. But no freakin' more!

Jack, buddy, I owe you BIG time.

Jeff

 

[kimcrwbr1]

A master power switch with a indicator light will cure those issues.

 

[sandkicker]

I've owned boats for a long time. They are always kept in a slip . If I leave the boat, not intending to use it again that day, I always shut off the master battery switch and fuel valve. Once in 1990, a cop knocked on my door @ 730 am telling me that they had just caught someone trying unsuccessfully to start my boat and presumably (no one steals a 21 yo boat) joyride it.

 

[fastjeff]

I, too, shut the Batt Sw off when I leave the boat, but if I forgot it to do it....Dead battery. Now, that's not a problem anymore thanks to Jack.

Jeff

PS: If one has a cruiser with a water hose hooked to it, one better shut that hose off before leaving the slip or else. Guy at my old marina found his Carver on the bottom when a fitting popped in the galley.