Selecting an Invertor

[HelloImDavid]

When selecting the capacity of a small 12 vdc to 115 v. Inverter....do we want to run the Invertor near the maximum capacity level or have it work sayyy at 75% capacity or even 50% capacity of the total load ? The loads would consist of a 15" FlatScreen TV / a VHS Player / and Laptop Computer ....possibly all running at the same time. Thanks. (Ive often wondered about this) .

Also, how does it apply to a cars alternator capacity versus max. expected load ?

[mena661]

X2 smk and MEX

[Ron3rd]

Good advice above. Make sure it's a pure sine wave inverter (PSW) or it might not play nice with some electronics.

[RoyB]

I followed the same rules that SMKETTNER says but it wasn't long before I was wanting to add one more item, then another item...

I have three GP24 Interstate batteries in parallel and that gives me a whopping 255AHs capacity. Lets me run my 600WATT PSW Inverter drawing around 300WATTS load just fine thru the night. By 8AM the next morning I am down to somewhere around 50% charge state on my batteries so this is when I recharge my batteries running my 2KW generator. Here on the East side of the US we have all these generator run time restrictions so being able to re-charge my batteries to their 90% charge state in as little as three hours generator time usually fits in with everyone rules.

Inverters love lots of battery power...

Roy Ken

[time2roll]

50% may put the wattage higher than you need. I would prefer to be in the 70% to 90% range. My 300w GoPower has run fine at 100% for extended periods.

I suggest 150w to 300w for running a tv/dvd/satellite/games/phones/laptop/netbook/ipad etc.
I only recommend sine wave.

Another beauty of small is the ability to use existing wires.

[MEXICOWANDERER]

How to apply the most efficient charging rate to a battery using a car alternator, in theory, paradise is when you start the engine and voltage immediately rises to 14.8 volts across the house battery terminals. Of course the voltage is going to decrease as the voltage regulator operates.

BUT BUT BUT BUT BUT

Many inverters TRACK

12.2 volts in, 115 VAC out

14.8 volts in, 138 VAC out

I would go right to the inverter engineering department and ask them "Does This Model Inverter Track Voltage?"

If they say "yes" or hesitate answering, then everything of mine gets disconnected when charging batteries via alternator or generator.

Some inverters may not "track". I have no idea which ones do and which ones don't.

[MEXICOWANDERER]

So many inverter ads are so full of hyperbole it makes a person's head spin.

You need something clean so it does not disrupt the television picture, quiet so it doesn't sound like a 767 on the waiting ramp, dependable and efficient. I sure would not ignore reading customer reviews of whatever first catches your eye.

Use ridiculous overkill planning when furnishing battery power to the inverter. Meaning wire size larger than what the manufacturer suggests or supplies.

I would make sure nothing is connected to the inverter when charging the batteries.

[MrWizard]

loaded question

a 300 or 400 watt is big enough for your intended use, total up the rate power wattage of your devices

most inverters are most efficient in power conversion in the 70~90 % range

you can't hurt an inverter running at LOW LOAD

but you can work one hard running at 90% all the time

if its going to see hours of use, the 50% or less loading will give it a cooler longer life

[1492]

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