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ContinuousWave: Small Boat Electrical
Battery Charging from Outboard Engine
|Author||Topic: Battery Charging from Outboard Engine|
posted 07-22-2015 11:12 PM ET (US)
It is my practice to hook up a battery maintenance charger [to my boat battery] every couple of times [following use of] the boat during the summer. Generally, after [the boat has been used but before the charger is applied] the readout [of some unknown measuring device] is 95-percent. I leave [the external charger connected to the boat battery] until the readout is 100%.
The last two times I checked, and after long days on the boat, when I [connected] my maintenance charger [to the boat battery], the first time the analytics say the battery is 82% charged; I was concerned. After last weekend, [when the charger was connected some measurement then said the battery was] 77-percent charged.
We had spent about six hours in the boat, made long run through Spring Lake into Lake Michigan and about 10 miles out and back, all the way to the north end of Spring Lake for take out. The motor was almost constantly running. A nice cruise engine speed is about 3,200-RPM.
I had the battery checked under full charge two months ago and it was within 93% of battery life. It's an Interstate Battery, two-years old or maybe three-years old. I run a Raymarine A57D and Raymarine VHF, but no other electronics. I usually shut them down often. I have one battery and no switch (well, not one installed). On the way back, both times I ran Navigation lights for maybe 45 minutes. I have LED on white pole aft.
Assuming the battery is good, how do I troubleshoot the charging system? A read out on dash gauge is always just in the green, perhaps 13-Volts--I need to double check.
Any help is appreciated. Thanks
posted 07-23-2015 09:14 AM ET (US)
[Moved to SMALL BOAT ELECTRICAL]
posted 07-23-2015 09:25 AM ET (US)
The measurements you provide about the state of the battery such as percentage-of-charge or percentage-of-life are not easily interpreted. It is better to measure the battery terminal voltage with an accurate voltmeter.
To check the voltage of the battery you need a good voltmeter. Measure the battery voltage right at the battery terminals. The terminal voltage of a battery that is being charged by an outboard engine that is running and has a proper battery charging current output should be greater than 14.2-Volts.
If a boat battery is charged by an external battery charger to full-charge, and then that boat is operated for six hours with the outboard engine charging the battery continually during that time, and the loads on the battery are modest loads as you have described, the battery state of charge at the end of six hours ought to be practically the same as when the cruise began.
To assess the charging current output of the outboard engine, you just need to compare the battery terminal voltage when the engine is not running with the terminal voltage when it is running. You cannot get sufficient measurement accuracy with meters that only show red regions and green regions on their dials. Get an actual voltmeter.
posted 07-23-2015 10:25 AM ET (US)
It appears at first glance that the outboard engine is not providing sufficient battery charging current. The battery charger of an outboard engine is usually a permanent magnet alternator or PMA. A PMA consists of four main elements:
--stator coil assembly
The magnets are usually embedded into the flywheel; the stator coil assembly is usually under the flywheel and connected by wiring to the rectifier; the rectifier and regulator may be combined into one unrepairable assembly.
Give us more information about the outboard engine, such as the manufacturer, model year, type, and model number. This can be useful in lending advice on diagnosis of the problem.
posted 07-23-2015 03:41 PM ET (US)
Thanks, I have a digital Volt/Ohm meter similar to a Fluke. It is a 1995 Johnson 115 model # J115TLEO. I will check when I get home later today and see what the output is. I assume once running (on muffs) I can take a reading. Does battery have to be fully charged before testing when engine operating?
posted 07-24-2015 10:43 AM ET (US)
Dave at Lockeman's did full day (or boat and I were there all day - memorable experience) eval, fixes and scope of that motor a couple of years ago. He said great motor, great shape, low hours, put in new electronic module, scoped the cylinders. Same year I replaced impeller and thermostat and other preventive procedures. All that confirmed my decision to keep the motor instead of repowering w/ ETEC since my actual usage is quite low/year. Although Dave's words ring in my ears "you have a great motor but they are thirsty girls...."
posted 07-24-2015 12:33 PM ET (US)
Okay, Just checked with digital meter, Engine on the muffs. Readout at idle 12.72 VDC. After warm up 12.8 and a few more minutes 12.85 both idle (neutral position) and throttle up to ~3200. I put probes directly on the cables coming from the motor and on terminals no change.
Dash gauge readout in the green a nudge over 13 VDC guess 13.2.. Took iPhone photo of gauge straight on.
Battery fully charged over night 100%, charger switched to maintain mode.
posted 07-24-2015 02:07 PM ET (US)
I always like to carry a spare battery fully charged.
posted 07-24-2015 09:09 PM ET (US)
Well, Jim is correct, not that I doubted him. Motor should be putting out 14.2 at least. Dave things it's the rectifier regulator which he said is under the flywheel. Spendy little bugger at over $200 bucks at least at one dealer.
Not sure how hard it is to get flywheel off but Dave said it's a piece of cake once it's off.
BInkie is exactly right, should carry fully charged battery for backup or do two battery system which I've been meaning to do for a long time. Except with schedule there is no time.
Any other advice, info would be appreciated especially regarding that flywheel. If I wasn't 3.5 hours away I'd take it to Dave because they are so awesome.
posted 07-25-2015 04:44 PM ET (US)
If Dave Zammitt says you need to take off the flywheel, then you need to take off the flywheel.
The hardest part will be getting the flywheel retainer nut loose, followed by getting the flywheel off the crankshaft extension. You may need an impact wrench and then a gear puller.
Bad connections at the battery can cause the rectifier-regulator assembly to go. Also heat and old age can damage them, too.
posted 07-26-2015 01:31 PM ET (US)
I have an air compressor and air tools and a chain wrench but will use strap instead on that fly wheel. Puller could be a problem but my pattern maker neighbor is always ready to assist.
I don't think I'll get to it for a few weeks and not much boat time on the calendar until maybe after Aug 7th. Things break loose then - and hope the flywheel nut does too.
Meter says motor putting out about 13.2 so I'll be aware.
posted 07-27-2015 09:47 AM ET (US)
Meanwhile it may not be a bad idea to allow the flywheel nut to soak in WD-40 or PB Blaster.
posted 07-31-2015 08:56 PM ET (US)
[A] puller for the [flywheel] is about [$20] at [an] auto parts [store].
posted 08-02-2015 10:59 AM ET (US)
Thanks everybody - gonna keep battery charged up full, take a spare for now at least the next few weeks until I can make some time to dig in. Went to gyp joint boat shop yesterday asked about price of part he gave me horror story and worse. That's why if I need to I haul to Dave in Detroit. So far Camp N Cruise over here seem legit.
posted 08-03-2015 01:48 PM ET (US)
I am having the same problem with my 1992 Evinrude E60TLENE. I measured the battery terminals at 12.21 vdc with the engine off. When I started the engine and had it running about 1,100 rpm it measured 12.21 vdc. Safe to say that the regulator rectifier is not charging?
posted 08-03-2015 05:00 PM ET (US)
I am researching how to test [with] digital meter. I guess it's best to understand everything under the flywheel, about the stator, and how to test. Parts are [expensive]. Instinct is to replace them all. Budget says no.
posted 08-04-2015 03:30 AM ET (US)
The presence of a charging current can be inferred when the battery terminal voltage is seen to rise from its resting voltage. Since you measure no change, there is every reason to believe no charging current is being provided to the battery.
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