Inverter Hell

[AZRoadrunner]

Hi all -- been lurking on this forum for a while, I have a question about inverters. I'm constructing my own solar generator for use at home -- the purpose is emergency backup power (and occasional use just for the heck of it) which can be rolled around the house. Will also use it to power my ham station once in a while. Using two Battle Born 100VA batteries in parallel for a 12v system, a Victron MPPT 100/20 charge controller, and the solar panels are two 195-watt panels, ground-mounted and angled up. We live in Southern Arizona and our back yard has a direct southern exposure with not a thing to block the sun -- might as well take advantage of it! Anyway -- I have every piece of my system except the inverter and am stuck on stupid trying to figure out what would cause the least amount of disappointment in performance. My ideal inverter would be a Victron Multiplus Compact, but even the "compact" version is quite large and I'm not sure suitable for a roll-around case. Other major brands (i.e. Renogy, AIMS) are getting horrific reviews on Amazon and elsewhere. And Amazon is flooded with a bunch of inverters in the 2kw range that appear to be almost knockoffs of each other -- and they're cheap, but the failure rates seem high and the specs reportedly exaggerated. What are your thoughts based upon my intended uses?

 

[snoobler]

195*2/12 = 32.5A, so a 30A controller is a better choice. With 20A, you're leaving peak solar on the table.

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Concerning exaggerated specs, ALL high frequency (HF) inverters have optimistic SURGE specs. Surges can only be tolerated for absurdly short periods of time - milliseconds. HF inverters are lightweight. Low frequency (LF) inverters have massive heavy transformers and have legitimate surges measured in many seconds (20-30 typically) and are suitable for starting power tools. HF inverters might choke on the surge.

 

[AZRoadrunner]

Thanks, Snoobler. The recommendation for the 20A controller came directly from a tech a Battle Born -- they stated that the 20A would actually outperform the 30A in my scenario. The panels have a 9.02A working current (10.83A short circuit current), and I'm installing them in series. (Have I miscalculated something here?)

The most we will probably ever put on this (during an emergency, or during regular test runs) are small kitchen appliances, some lights, etc.

 

[Bud Martin]

I would still recommend Victron inverter if yoiu want relability, it is also transformer based Hybrid inverter and it can handle surge well.

 

[snoobler]

The tech is wrong.

That's like me saying a 2000# car will go faster with a 200 horsepower engine vs. a 300 hp engine (all other things identical).

Conceptually, the 30A will get you the entire curve. The 20A will not get the red portion.

Solar Charge controller, how many amps?

I want to install 600 watts of solar on my van. After performing a basic calculation of 600/12 = 50, it seems that I would need at a minimum a 50 amp charge controller. I am a little confused as I am looking at starter kits from Grape solar and Rich solar 3 X 200-watt panels with only 40 amp...

diysolarforum.com

 

[Diysolar123]

I am a ham as well and when its time to get on the air the inverter goes off...they are really noisy.
I have an AIMS inverter/charger and its been working without a hitch for years. Avoid scrimping on the inverter buy from an established company, get a nice pure sinewave model that is double whatever load you think you will need. Make sure it has a UPS mode and you can control the the battery charging/low cutoff parameters.

Instead of trying for a roll-around handcart, try a roll-around wagon...weight is not much of an issue anymore and large wheels make uneven ground a non-issue. fyi, get flat-free wheels

 

[snoobler]

This is the equivalent of an AIMS. Sigineer makes both units:

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Heavy, a bit on the inefficient side (88% vs. 93%) and has a higher idle draw, but it will kick the crap out of most loads. Want to run a table saw? No problem.

 

[Uoavitar]

I have 2 Victron Mutliplus inverters that have always been 100% reliable. I can't speak towards other brands as I went straight to Victron but I can say I have never had not one issue and thier reliability isn't even a thought in my head, they just work.

 

[chrisski]

200 ah of Battleborn can power an inverter at the 2000 watt range, but how much use you'll get out of this really depends on your power usage.

If I plug my microwave in, it pulls 155 amps, which I've wired with 4/0 wire. My LED lights pull less than an amp to 2.5 amps, depending on the set.

For an inverter, I use a SAMLEX 2000 PST, 12 volt version, and it is UL458 certified.

The recommendation for the 20A controller came directly from a tech a Battle Born -- they stated that the 20A would actually outperform the 30A in my scenario.

I don't understand that recommendation. The Victron SCC 20 amp version can only push out 20 amps. Even though your panels are making 18 amps at 18 volts when tilted into the sun at noon, that MPPT SCC is keeping the wattage constant so 18 amps at 18 volts equals 23 amps at 13.6 volts, so your SCC would clip some production.

Best to get a 30 amp controller at least. Once you start charging your generator after usage, you'll probably want to push a lot more amps into the batteries so you can get it back in use and reel it around the house. I don't know the max charge rate of these batteries, but at "5X the charge rate of Lead Batteries," it'd be good to have those batteries fully charged after an hour with a lot more panels and bigger or more SCCs instead of taking all day with a 30 amp charger and two panels.

 

[Terrapin]

I pulled the trigger on the GoWise/Pure Sine 2000w based on Will's site saying he had a few running 7/24 for a few years. I researched them and found issues from back in 2016-17 that seem to have subsided for the most part. I hope it works out...

 

[AZRoadrunner]

I appreciate the heads-up on the 100/20 recommendation from Battle Born and will return it to Amazon and order the 100/30 instead. To be honest, I was surprised at the recommendation myself and asked twice to be sure -- and their tech stuck to his recommendation for the 100/20 instead of the 100/30. Embarrassingly, I'm a certified electronic technician, and have been for about 30 years -- however, I have little to no solar experience and not enough ego to override someone else if I sense they should be in the know.

 

[snoobler]

I'm a schmuck. I'd call back and ask for a detailed explanation.

 

[rhino]

I pulled the trigger on the GoWise/Pure Sine 2000w based on Will's site saying he had a few running 7/24 for a few years. I researched them and found issues from back in 2016-17 that seem to have subsided for the most part. I hope it works out...

Any inverter recommendations should be prefaced with the type of loads recommended for it and/or what not to use it for. I'm curious for instance if there are any videos of someone trying to start an electric motor with any of these high frequency inverters. A lot of them such as Growatt I noticed leave out any details of surge capacity.

 

[Uoavitar]

Any inverter recommendations should be prefaced with the type of loads recommended for it and/or what not to use it for. I'm curious for instance if there are any videos of someone trying to start an electric motor with any of these high frequency inverters. A lot of them such as Growatt I noticed leave out any details of surge capacity.

Good call, I use my Victron Multiplus 3000s in my RV. I have run the factory AC off of one briefly. It was able to start it without any soft start and let it run for a little bit just to test it. It's an 18btu rooftop unit.

 

[Terrapin]

Any inverter recommendations should be prefaced with the type of loads recommended for it and/or what not to use it for. I'm curious for instance if there are any videos of someone trying to start an electric motor with any of these high frequency inverters. A lot of them such as Growatt I noticed leave out any details of surge capacity.

OK. Makes sense....It's not in service yet like I indicated.... but this was for a calculated load of 1300w surge start for a 700w microwave. plus a few LEDs burning, safety monitors for LPG and CO2 operating and the LP refig. solenoid powered up open. it's a little more than 2x the rating of the 2000w constant...so like I said, my fingers are crossed.

 

[AZRoadrunner]

Now that we've settled on the charge controller (Victron 100/30) -- the inverter remains as a blank spot. The system I'm building will NOT be used continuously or frequently -- rather, it's for emergencies and for occasional use to make sure it's operating correctly. I'm shooting for capacity for running smaller appliances for longer periods of time (hence, the 200VA of capacity in the batteries). We have a Honda 3 kW generator that can run off of natural gas as well as gasoline and it will power our refrigerators and a portable AC unit just fine in the event of an emergency (although that's not nearly as nifty or as green as solar). So -- with two 195W panels feeding 200VA of battery capacity with a Victron 100/30 charge controller in the mix, what would be a good pure sinewave inverter for my intended usage? The batteries and the inverter need to fit into a rolling case that I can shuffle around the house.

 

[Bud Martin]

So what kind of loads are you going to use with inverter? if the loads are not motor/compressor type which will require high startup current then you can just use high frquency type inverter which will small and lighter than L.F transformner based inverter.

 

[AZRoadrunner]

So what kind of loads are you going to use with inverter? if the loads are not motor/compressor type which will require high startup current then you can just use high frquency type inverter which will small and lighter than L.F transformner based inverter.

Here are the example loads that we might put on the system during an emergency. The system would not be burdened with more than one of these at a time (except for some LED lights, maybe). My intention is not to have a 24/7 emergency power system, but some power to get us over the hump and accomplish some things during a power outage. We do have a gasoline/natural gas generator (Honda 3000) which works fine, but if SHTF there's zero guarantee of the continued availability of fuels.
- Small kitchen appliances (e.g., blender, toaster, instant pot, etc.)
- Microwave (draws 1400 watts continuous on high power)
- LED lights
- Kitchen range electronic controls (range is gas)
- Washing machine (new, uses even less power than dryer)
- Dryer (gas, draws 300 watts when running)
- Miscellaneous ham radio equipment (nothing high power)
- Laptop computers (maximum two - Macbook Pros)
- Internet router, firewall, and switch

 

[AZRoadrunner]

I am a ham as well and when its time to get on the air the inverter goes off...they are really noisy.
I have an AIMS inverter/charger and its been working without a hitch for years. Avoid scrimping on the inverter buy from an established company, get a nice pure sinewave model that is double whatever load you think you will need. Make sure it has a UPS mode and you can control the the battery charging/low cutoff parameters.

Instead of trying for a roll-around handcart, try a roll-around wagon...weight is not much of an issue anymore and large wheels make uneven ground a non-issue. fyi, get flat-free wheels

Thanks. I like your idea of a roll-around wagon instead of a large toolbox on wheels -- will poke around on Amazon to see if I can find something suitable. That would send me right away to a Victron inverter. However, I'd like our "emergency power cart" to not look like a high school science experiment, so hopefully there are some "carts" that would enclose the system enough to hide the ugly side of electronics.

 

[Delmar]

If you are looking for something inexpensive, small and light I recommend the Reliable WZRELB. Only downside is minimal surge capacity, but you are not running large motors so will not be an issue. For the same price of a name brand you can also upsize the capacity. There are lots of videos on YouTube.

Reliable may not be the most “reliable”, especially the older ones, but will work good enough for your backup usage. I’ve not managed to fry my 48V 2500W yet, even while pushing it hard during the great Houston freeze when running my furnace. Even the expensive inverters can fail. Show & Tell.