Electrical What size of dc to ac inverter?

[pauljygrant]

Hi All,
I know it's almost like asking how long is a piece of string, but considering the merits of buying a DC to AC inverter for use in the caravan but also when we get the occasional power outage like this week in SA.
I have 200ah battery capacity in the camper and the same as 2nd and 3rd batteries in the rear of the ute....so in theory have 400ah to use. They are AGM.
Not sure what devices I would run via the inverter but if I was to restrict to say 100w, for how long do you think the batteries would last before the inverter cuts out or the batteries drop to critical levels.
Does anyone have experience of eBay quality inverters, or should I stick with known brands?
FYI - we don't have solar to top up the batteries but hoping that total battery capacity will be big enough for a weekend away without power connection.

 

[NoWorries]

The only thing I use my inverter for is the coffee machine and frother
rule of thumb is check the 240v units Max wattage and triple it for good measure

ie: A 600w milk frother you should get a 2000w inverter

Inverters are power hungry monsters, If you are going to charge Phones\Tablets or laptops then make sure that the one you buy is a Pure Sine Wave unit not Modified Sine Wave.

If you are using a 100w at 240v via a inverter then you will be using about 10a so if you have 400 a/h the you actually have only about 180 usable a/h so you will be able to use that appliance for 18hrs before you are running low on battery.

I think my calculations are right but I have not had coffee yet

 

[Drover]

I just use plunger coffee when out bush.............................sounds easier than needing a bankroll and calculator....

So you would need a bigger fridge to carry the extra milk therefore need more power....lol.

 

[NoWorries]

Gas Fridge