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I have a small 230v 650VA generator capable of producing generating 450w. I also have a deep freezer rated at 230v 110w running power. I feel the reason why the generator doesnt power the deep freezer is because of the huge startup wattage required by the freezer. So I am considering using the generator to power a 12v 15amp battery charger which charges a 12v 40ah battery connected to a 1.5Kva inverter which powers the freezer. My assumption is that the Inverter-battery combo will handle the startup surge which lasts a few seconds while generator-charger combo handles continous charging of the battery while the freezer runs. My question to the house is will this work? Is it efficient? What other ways are there to optimise the set-up?

thanks

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    In my experience inverters are not very good at handling this kind of load. It might work or it might not, or it might just work sometimes and your food might spoil (or beer get warm) some cold or hot day. Commented Dec 17, 2016 at 8:10
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    True sine inverter unless you like hot motors. And the efficiency will be kinda lousy.
    – Ecnerwal
    Commented Dec 17, 2016 at 19:44

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A 12V generator would be more efficient than a 230V generator running a charger.

eg; a small engine driving a re-purposed automotive altenator

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Honestly it sounds like you're on the right track. Freezer powered by inverter, powered by large battery bank, recharged any which way you can.

Use the genny when attended, but throw some solar panels on there too. The "off grid" people do this all the time, they don't even bother using special $2000 hyperinsulated freezer units, the common residential grade freezers are now so efficient that they're within reach of solar+battery.

As far as battery sizing, the amp-hour rating on a lead-acid battery is a lie. If you use it to spec, your battery will last maybe 40-50 discharges before failing utterly. You actually need 4-5 times the amp hour rating you actually intend to use. So if you need 40AH depth of discharge on a daily basis, get a 150-200AH battery. Otherwise you will have very short service life from the battery.

When I hear "40AH", that's a bit smallish so it sounds like an SLA, which are rather expensive per the amp-hour. You'll get more AH for your buck going to a large wet cell battery in the "car battery" form-factor, though you should use a deep cycle or golf cart battery. (i.e. 2 6V golf cart batteries).

Plus, sealed batteries rely on perfect charging. They are not magic batteries impervious to every charging issue; they are only used in applications with excellent charge control (i.e. UPSs). If you are horking together your own charging system, you want a wet cell. If you charge it sloppy, it'll lose some water, and you just pop the caps off, check it periodically and add some distilled water.

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