What Size Solar Panel to Charge a 200Ah Battery?

Answer
512 W of solar (5 sun hours)

Refilling 80% of a 12 V 200 Ah battery takes 1,920 Wh. With 5 peak sun hours and 75% real-world efficiency, that needs about 512 W of panels. Use a charge controller rated for at least 53 A.

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Battery voltage
h/day
W
%
Flat mounts, heat and shade: 70–80%.
Solar needed
–
How we calculated this

    For estimating and educational purposes only. Results are approximate and are not a substitute for a licensed professional, the manufacturer's instructions or your local code. Disclaimer

    More questions like this

    50 Ah100 Ah300 Ah400 AhAll quick answers

    Solar watts to recharge a 200 Ah battery in one day

    SunFrom 20% (80% refill)From 50% (50% refill)
    3 sun hours853 W533 W
    4 sun hours640 W400 W
    5 sun hours512 W320 W
    6 sun hours427 W267 W

    75% overall efficiency covers heat, wiring, controller losses and non-ideal panel angle. An MPPT controller harvests 15–30% more than PWM.

    Frequently asked questions

    Will a 100 W panel charge a 200Ah battery?

    It adds about 31 Ah on a sunny day, so a full recharge of a 200 Ah battery takes about 5.1 days.

    What charge controller do I need?

    About 53 A for 512 W on a 12 V battery; round up to the next size.

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