Thread: Battery loss through inverter

By some very loose calculations 1.5 hours.

800w is heaps.

Power loss is 2 - 10 % depending on type of inverter. Type of load, how much load......etc etc.....

Sent from my GT-I9305T using AULRO mobile app

Inverters waste up to 15% of the power going through them, so for 800W output its drawing around 950W out of the battery or around 80A.

A 105Ah battery won't last very long if you're drawing big power off it as you can't discharge then all the way to zero. Your computer and monitor ratings sound like peak values to me and should be checked for accuracy perhaps with a simple plug in power meter such as this one:

240V Volt Power Energy Usage Consumption Analyser Meter Monitor Watts P8133 | eBay

Inverters vary a lot and good ones "go to sleep" when the load is switched off. Cheap ones can draw 20W easily just idling away or around 2A. A good inverter is this one:

Inverter Selectronic LD600 12 Sine Wave 2 Outlet Works Great Caravan Camping | eBay

The seller has sold a few of these (including one to forum member Bacicat last week) so may have another one to sell later.

Try and get some detailed specifications on the inverter. Inverter efficiency is usually stated at 90-95% efficiency, but a look at detailed efficiency curves for typical inverters shows that this is usually only at rated maximum output. As the percentage of the rated output of the inverter drops, so does the efficiency, probably for typical uses to around 75-85%, but it varies widely.

Yes, 800w inverter should work, but I would avoid switching both on simultaneously, although most inverters will stand a very substantial overload for at least a few seconds (my house inverters, rated at 2kVA will supply 6kVA for several minutes, 3kVA for half an hour).

Yes, inverters draw a minimum current, even when no power is drawn from them, but this minimum varies widely. Again, looking at my house inverters, these draw 0.6A at no load. This is further reduced to 60mA after a few minutes, with a pulse of output several cycles long once a second to check for a load. But inverters vary.

John

Just bought a selectronic inverter the same as Bee Utey just linked. It is a kick arse unit and it will go to sleep when there is no load on it, saving your battery. It's not small compared to some, but it is built like a brick ****house. After killing 2 others recently, I'm looking forward to a long life from this one.

Originally Posted by ROAMER_AUS

By some very loose calculations 1.5 hours.

It is just a fraction over 1.5 hours but 1.5 hours as Roamer says is all.

It seems a lot of power the PC and display are going to consume. Can you check again those figures. My laptop chews up 5.5 amps an hour at 12volts DC.

I'm reading the figures straight off the power supplies....so I suppose that is MAX output.

1.5 hours does seem quite low!

see this file for more accurate info [ame]https://www.batteryweb.com/pdf/inverter_battery_sizing_faq.pdf[/ame]

Originally Posted by PAUL200

I'm reading the figures straight off the power supplies....so I suppose that is MAX output.

1.5 hours does seem quite low!

You're right, it would be the maximum wattage when you power it up. Best not to power up both at the same time as mentioned before. Is there anything on the web that may indicate what the working typical wattage is?