Inverter and onboard charger to starting battery?

smallmouth55
smallmouth55 Registered Users Posts: 3 ✭
in Caravan, Recreational Vehicle, and Marine Power Systems #1
Heres one for you intellects; 
I would like to install a new onboard charger (6 amp, single bank) to a group 27 Interstate starting battery in my bass boat. I know that's OK. The question I have is it OK to also connect a 1500 watt inverter (modified) to the same battery. The inverter has an on/off switch, and the charger only charges either while the boat motor (150 horsepower Mercury) is running, or at home plugged into 110 volt. Will anything be hurt with all things connected. Help! I don't want to fry anything. Thanks 
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #2
    Yes, you can connect an inverter to the battery as well as a charger. 

    A 1500w load on a 12v battery is a substantial load though, potentially carrying 100s of amps.  The battery won't support a load like that for long.  The connection should be made with a fuse or breaker sized for the (short and heavy) wiring used.  A bolted connection is preferable to spring clips.

    MSW inverters can run some loads (eg resistance heater) fine, but can be a problem with others.  I assume any AC loads will be portable (with floating grounds), and the DC has negative return wiring (not chassis).
    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
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  • smallmouth55
    smallmouth55 Registered Users Posts: 3 ✭
    #3
    Your assumption is correct, and will only have a load from the inverter when stopped and motor off. The use of power from Inverter would only for a minor pull.  Is there any recommended distance required from inverter to battery?
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  • smallmouth55
    smallmouth55 Registered Users Posts: 3 ✭
    #4
    Also, is there a solar item that I could carry to the lake that I could charge my battery while bassfishing?
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  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,174 ✭✭✭✭
    #5
    Your starting battery will die young if you drain it appreciably when the motor isn't running.
    There is no harm in using a deep cycle battery for starting. For a given size battery, a deep cycle version will have around 25% to 30% less CCA than a starting battery. Not an issue in Group 27 and a 150 outboard, because even a deep cycle battery will have twice the cranking amps needed.
    Everything depends on how much total power you expect to pull from the battery. A typical Group 27 has a storage capacity of around 100 amp-hours. Be aware that if you are drawing 1000 watts through your inverter, that will kill your battery in less than 1 hour. It all starts with an accurate estimate of how much power you will need.
    I always have more questions than answers. That's the nature of life.
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #6
    The distance from inverter to battery should be kept as short as practical, say a few feet.  Bow to stern on a bass boat is probably "too far".

    You can get portable solar panels up to ~100w, but I'm not sure it would be worth the effort on a bass boat.  As Marc notes, it all starts with the loads.  I don't know what a "minor pull" is.

    Speaking of pulls, I assume you know running loads off an idle starting battery risks a dead one when it's time to go, requiring a pull on the kicker motor  ;)  
    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
    · Share on Twitter

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