Posted 8th Feb 2023 (Posted 10 h, 53 m ago)
Anyone able to advise on how to achieve the following:

I have a 240V device which pulls 250 watts which I want to get up in a shed with no mains power.
There is a small 300W solar setup connected to 2x 12V 180ah batteries.

My idea is to install an inverter to run overnight (leaving the batteries to charge during the day).
However from what i've read, you cannot connect the Inverter input to the Load Output of the solar controller (which I can schedule) due to the amount of amps the inverter and 240V device will pull.

The inverter is supposed to be connected directly to the battery with a fuse in between. But the issue with this method is that the Inverter is permanently connected to the batteries and will drain them just in standby.

Is there any timer device (with 25 amp load) that can connect between the 12V battery and the inverter, so that the inverter and device only comes on at a time I specify?

I want a fully automated hands-off solution, so some kind of scheduler between battery and inverter would be ideal but I can't find anything which can handle 25 amps.

Any help appreciated
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    Sonoff SV 12v Smart switch or 12v Dc timer.…sv/ (usually les than £10)
    You can then set any timings or length of time in the Ewelink app but you need wifi for it.

    OR One of these 12v DC model (Similar price)

    300w of Solar won't charge very much during the winter months and you are likely to run down the batteries quite quickly if drawing 250w for long. You may need to suitable 12v car relay operated by either of these devices to handle a larger load. (edited)
    Already checked, they don't rate anywhere near the 20-25 Amps needed
  2. Avatar
    Sounds to me like you need somthing like a contactor controlled by a 12v timer relay or smart devie.
    ie at midnigt the timer would output 12v onto the contactor shunting accross the high current 12v to the invertor.
    Something like this may siffice, you might even find a smart home wifi version.…682
    Would this work?
    1 x 12V Timer Switch Timer Controller LCD display,program/programmable 25A amps | eBay

    12V from the battery into this, set the time on this, then output to 12V inverter to 240V to power said device?
    Granted it would only be for a few hours (taking into consideration battery charge/drain), but i'm just experimenting at the moment and well aware this would only run a couple of hours a day at best. Hence the need for a timer
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