Charging one battery with solar panel and outboard alternator on sailboat

I'd like some opinions on the best way to connect these two charging sources to the battery.  Is it ok to run the solar panel and outboard alternator into a solar panel controller?  Would it be better to have a separate controller for each one?  Will a solar controller function correctly with input from an outboard motor alternator?

Thanks.

Comments

  • EstragonEstragon Registered Users Posts: 1,616 ✭✭✭✭
    You would connect the alternator directly to the battery. It should have its own regulation. Charge controllers aren't normally designed to handle alternator output.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • softdownsoftdown Solar Expert Posts: 1,557 ✭✭✭✭
    I second Estragons offering.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 150 watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • rporterrporter Registered Users Posts: 2
    Its a 6hp outboard with an "alternator" which looks like two coils that fit under the flywheel and there is a rectifier.  The only info I can find is that the output is about 5 amps.  Do you think the rectifier has capability to regulate the charge rate?  I don't want to over-charge the battery if I'm running the engine for 8 hours.
  • softdownsoftdown Solar Expert Posts: 1,557 ✭✭✭✭
    I should think you could measure the output from the alternator and see if it tapers off as the battery approaches full charge. If it is so simple that it does not, I should think (more often really) that one could find a simple gadget that would moderate the output. Bear in mind that I am doing some speculation here.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 150 watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • jonrjonr Solar Expert Posts: 875 ✭✭✭✭
    edited March 20 #6
    Perhaps of interest for unregulated alternators:

    http://www.boatingmag.com/converting-your-outboards-unregulated-charging-system

    You know you are unregulated if the battery voltage goes too high (eventually, with no loads).
  • EstragonEstragon Registered Users Posts: 1,616 ✭✭✭✭
    What kind of battery and bank size are you charging? Do you know the voltage on the alternator output?
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • dennis461dennis461 Registered Users Posts: 85 ✭✭
    Do you know make, model, year of outboard?  From your description it sounds like the rudimentary system used on 1960-1970 vintage two stroke motorcycles.  The main source of regulation was the battery itself. The magneto-coil-rectifier setup simply sent pulses of DC to the battery.  If the battery lost all it water (like when the dirt bike falls over) the pulses of DC would be high enough to burn out the lights in short order.
    Camden County, NJ, USA
    19 SW285 panels
    SE5000 inverter
    grid tied
  • oil pan 4oil pan 4 Solar Expert Posts: 613 ✭✭✭✭
    If you have an oversized battery for running lights at night or a secondary electric motor then 5 amps is probably not enough to come close to keeping the battery fully charged.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • jonrjonr Solar Expert Posts: 875 ✭✭✭✭
    edited March 20 #10
    In theory, a DC-DC converter (as is found in the better solar charge controllers) could take excessive voltage from a simple permanent magnet alternator and convert it into additional current.   My understanding is that most small engines use a shunt regulator (briefly shorting out the windings to reduce voltage).

    My guess is that one could connect the output of the alternator+rectifier to a solar charge controller.  But only if the peak (not rms) open circuit voltage of the alternator was less than the charge controller's max input voltage.
  • oil pan 4oil pan 4 Solar Expert Posts: 613 ✭✭✭✭
    I have seen simple magneto generators put out up to 24v OCV with the battery removed, with an otherwise functional regulator. Straight off the magneto can produce up to 48VAC at no load.
    I'm not saying every single one is like this, but I have seen a few.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • jonrjonr Solar Expert Posts: 875 ✭✭✭✭
    So for that generator, maybe 68V peak.  OK for some solar charge controllers.

    Last summer, I blew an ignition module surge protector/fuse.  Apparently because the bad battery wasn't accepting much charge (and the regulator wasn't regulating very well).
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