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Is there a formula that will give me a ball park idea of how much power I will lose when I run my DC battery bank through a power inverter? Is this something that varies depending on the inverter? Are some brands better quality than others with regards to this? Is there anything else I need to factor in or is it just as simple as saying for every V/A being drawn through inverter X you lose n%?

What do I need to know to make a smart decision about the inverter to buy? Without starting a religious war about inverters are there certain things to know about particular brands/inverters that might not otherwise be obvious?

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  • \$\begingroup\$ It definetely depends on the inverter you use. Most (probably all) of them have a couple of efficeny graphs in their datasheets from which you can figure out how many power you will lose at a specific input. \$\endgroup\$ – Golaž Feb 15 '15 at 15:00
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    \$\begingroup\$ Usually yes it is that simple. Actually the way it's specified is that you keep (100-x)%, that figure is called the efficiency. You should be able to compare efficiency figures for different inverters, but they tend to list efficiency at the load that makes their inverter look its best, so be slightly skeptical. \$\endgroup\$ – Brian Drummond Feb 15 '15 at 15:01
  • \$\begingroup\$ Any recommendations for how to interpret said graphs? Are there any brands to avoid? What do I need to know to make a smart decision about the inverter to buy? \$\endgroup\$ – BenAlabaster Feb 15 '15 at 15:17
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The short answer is no.

And the long answer is that there are no general formulae that can define the power conversion efficiency of an inverter for the simple fact that design of one inverter is different to that of another. But yes, if you can ask from the vendor you bought it from it is possible you find your self an equation but that is highly unlikely.

yes, depending on the brand power loss will be different as their electronic designs are different and their lossy points are different.

To explain more, there are just different places energy can be lost in converting from one form to another. In this case, DC power to AC power (I suppose its what your inverter does). So its not possible to come up with an equation that has a place to incorporate all different types of losses. But sure, may be your vendor may have one.

Should you really need an idea, try measuring the voltage current of battery and at the inverter load and performing basic calculations, you will be able to figure which brands are better and their efficiency too. But you have to be careful, these characteristics vary from one level of output power to another.

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