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Rewiring from 12v to 24v

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  • PhotonJack
    replied
    Originally posted by Mike90250 View Post

    "...A 2kw inverter with proper wiring and decent batteries, should be able to start a fridge..."
    Update: I moved the inverter to within 3 ft. of the batteries (was about 8 ft.) and upgraded the wire size to 1/0 (was 4) and now all is well, the fridge starts and runs fine. Thanks so much for all the helpful suggestions!
    Jack

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  • Mike90250
    replied
    Originally posted by PhotonJack View Post

    The present inverter is a SW2000 Xantrex pure sine wave. While it does work with our present setup, it won't allow the new fridge to start unless the sun is out. Apparently, the compressor surge load is too much for it. I'm considering the 4000w upgrade so that it will hopefully handle the surge. While the new fridge is running, it only pulls between 60-80 watts.......
    A 2kw inverter with proper wiring and decent batteries, should be able to start a fridge. Is this a frost free or energy star fridge ? Perhaps a energy star fridge is going to be your answer too.

    Beware with "search" or energy saver mode, some fridges, will, on application of fresh power, enter a defrost cycle. This would be overall, bad, running 7+ defrost cycles a day !!
    An inverter in saver mode, shuts off it's output power and waits for a load demand (turning on a light, or a thermostat closing), but electronic thermostats will cease functioning and never be able to trigger a load request.

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  • bcroe
    replied
    The problem with the inverter is of course, an inverter large enough to handle an induction
    motor startup surge draws a huge idle power all the time. Best fix is get a fridge/freezer that
    operates directly off a 24V battery. Bruce Roe

    Leave a comment:


  • PhotonJack
    replied
    Originally posted by Mike90250 View Post
    What size inverter are you using now ? it works, why go to a larger size - it's idle loss will become a lot larger, maybe even larger than your loads 4Kw is a large inverter, likely too large.

    And it needs to be a pure sine wave inverter, since it's running a motor.
    The present inverter is a SW2000 Xantrex pure sine wave. While it does work with our present setup, it won't allow the new fridge to start unless the sun is out. Apparently, the compressor surge load is too much for it. I'm considering the 4000w upgrade so that it will hopefully handle the surge. While the new fridge is running, it only pulls between 60-80 watts. The idle loss is indeed larger with the 4000W inverter, (about 30 watts in power saver mode) but if I don't do some sort of an upgrade, we can't add the fridge, or at least not let it run at night. We presently have an under counter 3 or 4 cubic foot old RV type propane fridge and get on our hands and knees to get stuff out and it's really too small. Initially, we considered a largish propane fridge, but at around $2K, it made more sense to put that money into upgrading the system. For about the same money, I can add the larger inverter and 4 more batteries. I will continue to monitor the battery bank voltage carefully and if needed to keep using only the top 25% - 50% max of the bank, I will add another 4 batteries.

    The larger inverter will also allow us to use more appliances during the day as well as allowing the fridge to run at night. With it, I will also be gaining a 4 stage smart charger, a 30A transfer switch and a connection to auto start the genset (whenever I upgrade it, which I hope to do). We've only been off-grid for about a year and don't mind throwing some (hopefully wise) money at the system to make it run nicely in the background.

    I will definitely wire 6 of the current panels to make them 24v input to the controller.

    Hope that adds more info, I greatly appreciate the input and expertise, please keep it coming!

    Thanks, Jack

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  • littleharbor
    replied
    With your new MPPT charge controller you should series 3. 12 volt panels per string if going to a 24 volt system.

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  • Mike90250
    replied
    What size inverter are you using now ? it works, why go to a larger size - it's idle loss will become a lot larger, maybe even larger than your loads 4Kw is a large inverter, likely too large.

    And it needs to be a pure sine wave inverter, since it's running a motor.

    Leave a comment:


  • Paul Land
    replied
    Originally posted by SunEagle View Post
    To charge a battery system of X volts your panels need to provide about X + 6volts. So IMO you would need to wire the 12V panels in pairs to charge a 24V battery system which unfortunately leaves you a spare 7th panel.
    Agree

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  • SunEagle
    replied
    To charge a battery system of X volts your panels need to provide about X + 6volts. So IMO you would need to wire the 12V panels in pairs to charge a 24V battery system which unfortunately leaves you a spare 7th panel.

    Leave a comment:


  • PhotonJack
    started a topic Rewiring from 12v to 24v

    Rewiring from 12v to 24v

    Greetings from a newbie in Colorado who knows just enough about solar to be dangerous.

    I have a rewire/upgrade question. I recently added a 120v AC fridge (specplate says 0.65 amps) that oddly will start and run fine while the sun is out, but when on the battery bank alone, the inverter beeps and rejects the startup compressor load. Looking to rewire the battery bank from 12v to 24v and go to a 4000 watt 24v AIMS inverter charger. The question is this: Do I need to rewire the panels to 24v as well? A tech at a supplier says the present charge controller (12v or 24v EPEVER Triron 3210N - LINK to manual) separates input and output and that I don't need to rewire the panels. Does that sound right? If possible, I'd rather not, because I have an odd number of panels and I'd have to drop one presumably, and I won't have to get on the roof. I will attempt to attach hastily drawn present and proposed schematics (Proposed shows if panels are rewired also). The schematics identify the various components. If you see anything out of whack, please bring it to my attention. Help and advice greatly appreciated! ~PhotonJack

    Proposed-Revised.jpg
    Present Setup.jpg
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