I'm specing out an inverter for my bus.
Here are the details on what i'm looking for and what I have already.
Appliances to run,
Microwave (1100 W)
Electric griddle (1300W)
T.V (~~ 70 W )
Laptop ( ~~ 150 W )
9000 BTU air conditioner ( Draws 900W )
Obviously Im not going to be able to run all this at once, but the big hitters here are going to be the microwave, and the Airconditioner.
For my thoughts on the A.C skip to the end.
What I want is about 700-900W of solar power.
2.5KW of battery storage
Charging from the bus alternator would be nice but not essential at this time.
I already have several batterys out of a totaled Fiat 500E.
These are 6 cell Li-Ions and rated at 65AH each. I plan to use two ( 130AH @ 25.2V )
What I need now i the inverter.
Cost is obviously a factor here, but I also want a unit with good longevity, as a 300$ inverter that dies in two years is less valuable to me than a 800 inverter than lasts 10+ years.
Here are the options I am looking at.
Chinese 5000W ( Obviously over rated )
3KW "FuelZero" ( Never heard of them ) Low Frequency inverter
High Power, High Output Pure Sine Wave Inverter, Low Frequency, AC Charger, 24v Input, 110v Output, 3000 watt Continuous, 9000 watt Peak
Those last two are Low Frequency inverters.
The word on the street is that the LF inverters have longer longevity because they are more resistant to large surge currents, and use a single large heavy transformer rather than high frequency small transformers.
The Cotek is the only one with a reputation, the other two are unknowns.
Im looking at a Pure Sine Wave inverter, Mostly for that microwave, but people have run microwaves on Modified Sine Wave successfully so if you have a suggestion and it's not PSW then I'll still take it into consideration.
Other details for consideration.
Most of my non-appliance stuff is going to be run of 24VDC ( Fans, lights, water circulation pump, USB charger for phone, etc )
These items are irrelivant to my purchase of the inverter
Im O.K with having to often replace MOSFETS in an inverter if they die. So if you know of an inverter that eats a few mosfets now and then requiring a bit of soldering skills to replace them that's not a big deal to me at all. If the motherboard dies or it blows up capacitors often that's not cool.
I live in Utah. It's sunny every day and often over 100 degrees. I need A.C, not negotiable.
Thoughts on the A.C. The unit in the link is a VFD driven air conditioner. This means that it's more efficient than a regular A.C, and likely has a way lower, if any start up current.
If you are not familiar with VFD ( Variable Frequency Drive ) it takes your AC, converts it to DC, then uses a variable frequency drive to deliver power to the motor.
This DC stage means that the high inrush current that typically faults out your inverter wont be there. What this also means is that I can probably hack the electronics and feed DC directly into the DC bus of the VFD and bypass the AC Inverter stage altogether. This would mean I can run the airconditioenr directly off the DC batteries using just a DC to DC boost converter.
The DC bus is probably 200+V but Im a electrical engineer by trade and have experience with VFD's Motor's and DC conversion circuitry. I have wanted a DC run Airconditioenr but those things are several grand. Forget it, The VFD units have potential to be direct DC operated and I think I can make it work.