Battery drain...

[luvmyi36]

Hello everybody,
Last Saturday, I took my first offshore fishing trip of the young season. I left the harbor at 4:30 AM, and pointed to the 182 high spot about 35 miles from Oceanside. I motored until about 11:30, and all ran fine. Nice constant temperature of 165, oil pressure of 35 after 6 hours... All is well, right? Well, I sailed for a while, and then the wind died down and I am still 20 miles offshore so I try to start the motor with the house battery that I had been running the stereo and autopilot on, like I always do, and no go. Switch to batt 1 and she fires right up. I motor for about 2 hours and then notice that all my motoring has left me a little gasoline challenged, so I shut her down and ride the tide for the last 10 miles or so. Get into the harbor, and no juice from batt 1 or 2! I was on batt 1 when I motored, and batt 2 when I sailed thinking I could save batt 1 for starting. Sailed into the slip with just a minor bump... My question is this, what could drain the battery while running? (In case you are curious, no fish, just one BIG biter, think it was a Mako because we we're trolling at about 6 knots and he broke off the 60 lb. almost immediately.) Thanks for any replies.

[Mark S]

Loose belt? Loose or disconnected wire? Bad batteries? Bad regulator? Bad alternator? Don't think it could be anything else.

Mark S

[Dave Neptune]

Drain?

luvmi36, sounds like a charging problem and or a shorted battery which probably wouldn't allow you to motor for so long. Do you have an amp meter? If so was it showing a positive charge? I ran mine back from Catalina before with a dead alternator at night and she wouldn't start when I got back to the slip and that was on my start battery (100 amp.) with the A-pilot radios and lights for 5 1/2 hours.
Check the belts and the alternator. Most rebuilders can redo the alternator for a reasonable price.
How old are the batteries?

Gud luck!
David

[luvmyi36]

Thanks for the quick replies.

Loose belt was my first thought, and it might just be that it is old. I have never changed it, but the bracket is extended all the way so that I can not stretch it any more. It still feels fairly snug. I think batteries can be ruled out. They are only 2 years old, gel type, no maintenance, big bucks, etc.... Plus, when I went to the boat on Sunday, I found them fully charged again off shore power. I do have an amp meter, not sure if it has ever worked properly. How do I test that? It never seems to move off center of the guage. As for a voltage regulator, what is it, and where would I look to find it? The other thing I did not mention was for the last 4 hours the motor was on, (or so), I was basically just idling. Could the low RPM's cause the alternator to not fully charge?

[Dave Neptune]

Charging?

Jim, your amp meter should show both charge and discharge. You should be able to at least maintain voltage at idle, mine does at 600 rpm and that is the std delco 35 amp model. Perhaps your new batteries have been covering for an alternator related problem.
Get out a volt meter preferably a digital one. Check the voltage and start the engine and bring to about 1000 rpm. Check voltage again on the orange output wire on the back of the alternator or it may be red and see if it rises. When charging you may see as many as 14.7 volts and should see more than you did without the engine running.
That wire should run directly to the amp meter then to the power distribution panel or battery bank. Check the connections at the meter, batteries, battery switches and alternator. Your meter should show discharge if the engine is not running and you have a bit of stuff on or charge if the engine is running.
Lets worry about the regulator and the aalternator after a voltage check.
If you find anything loose belt, wires or nuts clean and reinstall then recheck.
Do you know what alternator you are using? The std delco has the regulator on the back side and is usually replaced during rebuilding. There are many "smart type" available especially for the gel type batteries.
After you get some numbers there are some members that are very good with electronics, I can help with the basics and that is where most problems of this sort lie.

Gud luck!
David

[sastanley]

more data?

The quickest test is a volt meter on the battery posts when the engine is running. You should see 13.8 volts from a stock 35 amp Motorola alternator.

[hijack]A new belt is $11. If you think it might be the belt try a new one. I just put a new belt on because I managed to wear my other new-this-season-belt out in about 15 hours of motoring due to an alignment problem. It was still too loose at max tight and slapping into other stuff. [/hijack]

Other things that would help is: do you have any charge controllers, or battery charge isolators, etc.etc.. A bad wire in the ammeter circuit could cause a no charge situation. I eliminated mine this spring as a precaution and occasionally (when I have the battery compartment open) just stick the volt meter on the battery when the engine is running to make sure it is charging. I plan to add a gauge type volt meter in the future up in the panel..if you see 13+ volts it should indicate a decent charging circuit..if you only see 12, something is up..(or going down in this case)

There is a bright side..it is a good thing our boats have sticks and rags to get home with when the engine quits and we don't have to call a Tow Boat

[luvmyi36]

Thanks a bunch!

Gentlemen,

Thank you very much for the detailed responses. I will print out, and will take with me to the boat in the next couple days to test the insight's. I must say, as handy as I am with all things mechanical, electricity has always remained somewhat of a mystery to me. I have spent hours on this forum reading the likes of Steve Markowski, Rigspelt, et al, and come out of the readings even more confused. But then, I have never tried to put the words in action.... Maybe that is what I have been lacking. Any way you slice it, I think I will take a new belt with me when I go just for giggles, and then work down the list from there, reporting back as I go. Again, I appreciate the thought you put in your replies. Fair winds.

PS. Yes, Shawn, thank God for the sticks and rags!

[rigspelt]

I have spent hours on this forum reading the likes of ... Rigspelt ... and come out of the readings even more confused.

Heh-heh. Well, that explains your confusion: I am no expert and was only posting here to get things figured out, not give advice to others (blind leading the blind and all that).

Qualified expert opinion is best when working on boat electricity. As backup, Nigel Calder's Boatowner's Mechanical and Electrical Manual and Charlie Wing's Boatowner's Illustrated Electrical Handbook are never far from me when I'm messing with electricity on our boat. The AYBC specs are very useful if you can get access to them, and look for authoritative (not opinionated) posts on the likes of http://www.cruisersforum.com/forums/ and http://www.sailnet.com/forums/gear-maintenance/. This, by the way, is not an authoritative post, just an amateur boater's suggestion.

Nice constant temperature of 165, oil pressure of 35 after 6 hours... All is well, right?

I monitor four key parameters when running: those two, plus engine RPM and electrical charging. If the ammeter needle never moves, I'd wonder about the wiring or the gauge and pay close attention to that situation until satisfied. Has a connection become disconnected between alternator and ammeter?

Some use an ammeter to ensure the alternator is putting out charge, others use a voltmeter to check for both that and the state of the engine start battery. I switched our old boat's setup from ammeter to voltmeter in the cockpit in part for that reason. But the change requires rethinking the charging setup.

When I rewired the boat this winter, I installed a voltmeter in the cockpit ignition panel so I could check whether the alternator is charging, overcharging or undercharging while running on the engine. I also have a switchable voltmeter and ammeter in the new Blue Sea house DC distribution panel in the cabin. That meter lets me check both the engine and house batteries for voltage at any time, just by flipping a toggle switch. The ammeter function is on the house circuit, telling me how much amperage we're drawing from the house loads (stereo, etc) while sailing or anchored. There are lots of other ways of setting up a boat to monitor the state of the charging system and batteries.

[rheaton]

Sir, as was mentioned above, use a meter accross the battery terminals to check voltage. Do this before you start the engine, then after started. If it does not increase when started, you know it is not charging. Also the charging isolator mentioned above allows both batteries to be charged regardless of your a/b battery selection. If you dont have this isolator, you might think about getting one. The Niegal Calder book mentioned above is a great one.

Best of luck to you,

Russ

[sastanley]

Gentlemen,

I have spent hours on this forum reading the likes of Steve Markowski, Rigspelt, et al, and come out of the readings even more confused.

Hahaha...you are not the only one. My eyes glaze over when the two of them get to hypothesizing about electrical systems

Russ's suggestions are good and a simple first step. Check the volts before start and after start..it should change..That is the biggest issue right now to determine. We can dig into each little piece from there.

A healthy battery at rest should read ~12.6 or a little higher if recently charged.

[luvmyi36]

Giving it a try tomorrow night.

Alright, I have now printed out all responses, and will get to the boat tomorrow night to check it all out. Thanks again to everybody, I will let you know how it turns out. Rigspelt, I am then truly impressed by your comprehensive understanding as an amateur electrician. I figured you for and electrical engineer!

[sastanley]

rigspelt knows what he is talking about...he just doesn' t want to take credit (or the liability) for it.

He is much more thorough than most of the rest of us (at least me)

[luvmyi36]

Notes from testing...

Well, I spent about an hour poking around on Saturday with a volt meter, and this is what I found. With engine off, across battery posts I read 13.60 volts. With engine running across posts, 12.74 volts. At orange output wire with engine running, I read 13.67 volts. Where did that volt go? I did not replace the belt yet. I also believe that my amp meter is faulty. It registers only the slightest of decrease from "0" when I kick on the blower, but that is all. When I start the engine, it moves back to "0". Is there something in that circuit that could drain the voltage off? I do have a battery isolator switch, and use it on batt 2 almost all (99%) of the time. I did check all visible connections, and all look to be in good order, tight and clean. Thoughts?

[luvmyi36]

Bump for thoughts on volt meter test results...

[Dave O]

I would seriously question the first two readings 13.6 volts engine off and 12.74 volts engine running. If anything it should be the other way around. If there is any question about the meter (I believe there is) I would check the results with another.
Dave O