Choosing an inverter

Choosing an inverter:

There are a bunch of different options to choose between when deciding on which inverter to buy. Here are some of the things to look out for.

Quality:
Name brand units like Victron or Outback will come with a warranty of many years, but obviously you will have to pay for it, typically they will cost twice what a cheap Chinese inverter of the same rating will go for.

One usually doesn't think of electronics as being able to wear out, but the capacitors used to smooth out the generated sine wave will wear out eventually. Cheap inverters will contain cheap capacitors which will burn out faster, especially if you run your inverter at its maximum power rating, since this will cause the inverter to run hotter, and heat kills capacitors. The switching components in very cheap inverters also might not be protected properly so these can also pop more easily due to surges.

If you go with a cheap inverter, make sure you leave a good margin spare: Don't run it at more than half of it's rated capacity for extended periods of time.

DC Voltage:
How many batteries can you string together? The more batteries you connect in series, the more efficient the system becomes.
If you have the choice, try go with the higher voltage option because this will be the lower current option for the same amount of power.
High current would mean thicker battery cables and/or more losses to heat.

Expansion:
Some inverters let you chain up more units in parallel in case you need to add more capacity. Unfortunately it's typically only larger units that let you do this in the first place.

Integration:
The inverter is only half the story- you will also need to charge your batteries. Many units have a built in charger (This makes it a UPS) and some will also accept input from solar panels.
It's probably better to keep things separate in case one breaks, but all-in-one units can be way cheaper. I paid R13000 for my 4KW inverter, 50A AC charger and 50A MPPT solar charger unit (Voltronic Axpert MKS 5K).

Monitoring:
Most larger inverters have data ports so you can fiddle with settings and monitor usage. You might want to investigate your monitoring options before choosing. You will want to be able to keep an eye on how much power you are using so you don't run into any nasty surprises.

The inverter typically won't be able to tell you very accurately how much power is left in the battery, usually only a high/medium/low sort of thing. If you want a percentage readout you'll need a separate battery monitor that counts charge flowing in and out of the battery.

Stock:
One of the main reasons I bought the inverter that I did was that I found stock. Unfortunately Eskom has caused massive shortages of Inverters and Deep Cycle batteries in South Africa. I think it's getting better though.