A lot of problems would be solved with a bigger solar system...

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softdown
softdown Solar Expert Posts: 3,822 ✭✭✭✭
in Off Grid Solar & Battery Systems #1
Time and again we read about a solar enthusiast who is unable to accomplish their goals with a couple panels, a couple batteries, and a large inverter.

Keep in mind that their exists losses, losses, losses everywhere. You only get a few hours/day of ideal sunshine on average. Your inverter is eating up energy simply by being on. The larger the inverter, the more it eats simply by being turned on.

Your batteries are suffering significant damage be being cycled below 11/11.5 volts. Especially if they stay there for several days. Your inverter will probably drain the batteries down to 10.5 volts. It may be a good idea to install an adjustable cut-off for powering the inverter.  I think 11.5 volts is a good cut off point.

Your panels need to be approximate matches. Your controller is more efficient if it is MPPT. Your inverter eats more when it is large. If you have a 12 volt system, your wires need to be significantly larger than a similar 24 volt or 48 volt system. 24 volt wiring needs to be larger than a similar 48 volt system.

Rant over...trying to help a bit.
First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) 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
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  • Johann
    Johann Solar Expert Posts: 245 ✭✭✭
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    Not to forget those used car batteries that been sitting for 2 years at the car port before they made there way into a solar system. Or that special deal found when getting marine batteries that are believed to be deep cycle batteries or that super deal when getting those used batteries that are in ''perfect'' conditions.

    Many are starting out using car batteries not realizing that they do not have the capacity and that they will not last long.
    Most Marine batteries are not to much better than a starter battery, as a matter of fact they are between a starter battery and a true deep cycle battery so they are not deep cycle batteries and not the best to use in solar applications. True deep cycle batteries are the way to go for most solar applications.
    Look at a weight of an battery. Do not expect to get the same capacity of a 30 lb battery vs a 60 lb battery vs a 100 lb battery.
    Things can get confusing at times.

    Many of us started and made mistakes, mistakes that where cheap and easy to fix and some other mistakes that became expensive.
    So, ask and search and investigate first before you buy or do anything. 


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