Batteries, Solar, Inverters Oh My!

Discussion in 'Boats, Motors, Trailers and Towing Rigs Forum' started by Rain City, Jul 21, 2020.

  1. Rain City

    Rain City Crew Member

    Anyone turn their charger off when running their inverter? I noticed a huge draw on the system when it was on and I was worried my solar was unnecessarily charging my start battery instead of my house batteries because of this. Do you switch your start batteries off when you're on the hook? How much solar charging do you need to keep you off the grid for more than a dew days? I have two 100 watts and didn't seem to get more than about 130 watts at peak times so with the fridge running I was slowly depleting. I did end up going the full week without shore power or s generator but it was on my mind for sure.
     
  2. Foxsea

    Foxsea Well-Known Member

    Your solar system will include a charge controller that should be wired directly to the house batteries. That's it. The charge controller is smart and efficient in keeping your batteries up. Many are 3 or 4 stage. Running a charger from a solar bank is unnecessary and very inefficient. Your charger should only run on shore power for house batteries. The engine will maintain your start batteries. Your inverter runs from the house batteries to supply 110 volts when needed. Also somewhat inefficient compared to using 12 volts. Keep in mind that panel ratings are under ideal conditions (never). Any dirt, cloud cover, shading, etc. reduces the output dramatically.
     
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  3. Rain City

    Rain City Crew Member

    Thanks man! Is there any chance that the fact that the battery charger is wired through my AC panel could cause it to be running while my inverter is on? As far as I can tell my inverter juices up my entire AC panel as apposed to just a few outlets. Fridge and all.
     
  4. Foxsea

    Foxsea Well-Known Member

    Yes, it's possible so shut the charger off. In fact, probably a good idea to only run the A.C. essentials when not on shore power. If your fridge has a compressor it likely needs A.C. power. A microwave draws lots of A.C. power but usually for short periods so it's a good trade-off for convenience. Avoid resistance loads like blow dryers, toasters and coffee makers. Use the stove to boil a kettle. 12 volt electronics and led lites use little power so they are okay. Inverters use power, even in standby and most are not very efficient. Add another solar panel, if you have room.
     
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  5. Rain City

    Rain City Crew Member

    Ok last one. The fridge definitely "kicked on" when I flipped the inverter on. I had assumed the fridge ran on both AC and DC as that's what the last Nova Cool I had did. While the inverter was off I was hearing a hum so I assumed the fridge was running but it clearly wasn't unless the inverter was on. What might that be?
     
  6. Foxsea

    Foxsea Well-Known Member

    Some Nova Kool models will run on both A.C. and 12 or 24 volts D.C. You should be able to switch it to 12 volts D.C. and thereby avoid using the inverter. They use a DanFoss compressor so you will hear it start and run. They draw about 6 amps so make sure the wire is sized correctly. I'm not sure what the hum is.
     
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  7. Foxsea

    Foxsea Well-Known Member

    You might like to check this out:
    http://www.novakool.com/support/default.htm
    I noted the breaker size for 12 volt operation was 30 amps on some models to allow for starting load. Again, wiring must be adequate.
     
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  8. Rain City

    Rain City Crew Member

    Maybe this was the issue. Definitely dropped below that on the trip. The lowest I hit was 11v but over the course of the day it jumped back up to 11.8 on the solar with most things off.
    Screenshot_20200721-230924_Adobe Acrobat.jpg
     
  9. BCI

    BCI Crew Member

    @Rain City , some inverters/inverter-chargers power the entire AC panel. In this case, simply turn off your large 120V loads breaker by breaker on your 120V panel.

    For example, turn off your 120V breaker for your hot water if you want to run your inverter. Any other large resistive loads like space heaters, bilge heaters, etc on 120V? Turn them off. Let us know if that helps what you're seeing.
     
  10. BCI

    BCI Crew Member

    After you try the resistive load test (including hot water heater 120V resistive loads, if equipped), try this;

    12V/120V fridge will normally auto-select 120V when it see both power sources available. With inverter off and shore power disconnected but 12V system on, try opening fridge door and see if fridge light comes on. If so (assuming bulb is good) you know your fridge sees your 12V. Turn 120V breaker off for fridge on the 120V side of your breaker panel. Turn on inverter. Confirm the bulb is still on in the fridge. Check current draw now that fridge is running off 12V intsead of 120V - See how the current draw is now through inverter. Good chance the fridge draws more load at 120V since it assumes it has shore power / generator supply. Good chance fridge is more 'electrically economic' on 12V since it assumes it's running off batteries / alternator.

    From Nova Kool Troubleshooting guide - AC will always take precedence over 12V DC is both are available and the AC/DC module is fitted. Look at the DC fuse size - 15A fuse for 12V DC - that's 180 Watts load before it blows the fuse. At 120V it's 4 amps - that's 480 Watts load before it blows the fuse.

    I see in the trouble shooting guide that the interior light is a 12V light, so you may not be able to use that being on/off as your troubleshooting component as I mentioned before. May need to use the compressor noise or an ammeter to see the unit cycle.

    PASTE;

    2. Electrical: When fitted with the optional AC/DC module, both AC & DC power can be connected to the module at the same time. The unit will always run on AC when AC is available. Should the AC be disconnected there is a 1 minute time delay before the unit continues running on DC. If AC power is reestablished there is no delay, and the unit will immediately resume running on AC. 2. Electrical: (cont’d) The DC models are 12 & 24 VDC (the only consideration is the models supplied with an interior light, either 12VDC OR 24 VDC). The AC/DC models work on both 12 & 24 VDC as well as from 100-240 VAC 50/60hz. (The interior light on the AC/DC models is always 12vdc regardless of the DC supply voltage). Both modules “auto” sense the supply voltages so no wiring adjustments are necessary other than following the guidelines for DC fuse sizing; DC breaker & fuse sizing 20-amp breaker (main switch) for both 12 & 24VDC applications 15 Amp fuse for 12VDC 7.5 Amp fuse for 24VDC AC (optional) breaker and fuse sizing (100-240VAC 50/60 Hz) 6 Amp breaker (main switch) 4 Amp fuse (included with unit)
     
    Last edited: Jul 22, 2020
  11. Rain City

    Rain City Crew Member

    So it's funny I always leave my water heater off regardless because at Burrard we only have 15 Amp shore power and if that's on with the charger it trips. I'll flip that on and see what happens next time. Re the fridge I don't have a light so I'll have to check the draw. Obviously if I just look up the model number it'll answer some of these questions. I'm honestly thinking now that it was the DC voltage dropping below 12.2 that shut the fridge down. I'm wondering now if that's why my water pump crapped out as well. My wife loves washing dishes...
     
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  12. zurk

    zurk Active Member

    rule of thumb with solar is 1/5th of panel rated power through the day. so 1 x 50W panel will give you 10W through the full 12 hour day cycle.
    size accordingly.
    this is a mono panel with PWM charger. average power not peak.
     
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  13. triplenickel

    triplenickel Well-Known Member

    If your solar charge controller is stand alone and it’s the older style look into MPPT controllers. You’ll get closer to your full panel potential.
     
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  14. Rain City

    Rain City Crew Member

    That one Resized_20200625_144703.jpeg
     
  15. Foxsea

    Foxsea Well-Known Member

    I believe that model is pulse width modulated.
     
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  16. Sir Reel

    Sir Reel Well-Known Member

    RC I have the same solar charge controller. My AC panel is split so that the inverter only supplies AC power to the 2 cabin outlets and the microwave when running off battery. The battery charger, heater, and fridge only get AC power when connected to shore power. Yours should be the same. You could test when not on shore power to see if hot water power light comes on or if start battery charger comes on with inverter on and those switches on. I also have a fridge switch on the panel that keeps the fridge running even with everything turned off. When I leave the boat for any length of time (like a week away) I need to make sure that is off.
     
  17. Rain City

    Rain City Crew Member

    No mine is definitely juicing up the whole panel. You can see the draw on the magnum panel when I switch things off and on.
     
  18. Rain City

    Rain City Crew Member

    Yah yah pulse width o_O...
     
  19. Sir Reel

    Sir Reel Well-Known Member

    Then you will just manually have to switch stuff off like charger and hot water heater
     
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