Wanted: Pure sine wave 48VDC inverter (only) > 2,000W

[sidpost]

I can get another Samlex PST-1500W 48Vdc inverter but, I'm really looking for something bigger and low frequency to tap my ~35Kwhr of usable battery. High frequency is nice but, the durability of low frequency is attractive on its own in addition to its surge capacity and dealing with sustained surges.

Signature Solar out of Texas has some nice Growatt options but, they are all 230Vac which is great for my clothes dryer and welder but, those are at best very infrequent loads and I have a direct drive 230VAC inverter driven by 10 solar panels that I can use during the day.

TIA,
Sid

 

[John Frum]

48 Volt Inverters with built-in charger | DonRowe.com

Go high efficiency with a 48V inverter/charger. These high quality inverter/chargers have a full range of features such as built-in charger, transfer reply, remote capability, and more.

www.donrowe.com

To the best of my knowledge there are no discrete low frequency inverters only inverter/chargers.

 

[sidpost]

I have looked at the Midnite Solar DIY models which are as you describe. Not a total deal breaker but, my experience with Chinese Charge Controllers has generally been bad. That's why I don't run them on anything that matters and so far have only run Samlex PST series inverters. 1500W is just a bit low for my needs.

 

[toms]

LAtronics, an Australian company, make what you are looking for.

If my life depended on an inverter - this is the one i would choose. No bells or whistles, they just go forever!

 

[PeSCaLo]

Maybe This?

 

[Hedges]

SMA Sunny Island is a low-frequency inverter/charger.
4.5kW or 6kW at 120V, and up to four can be stacked for 120/240V.

You can get them for around $3000.

 

[Hedges]

I have looked at the Midnite Solar DIY models which are as you describe. Not a total deal breaker but, my experience with Chinese Charge Controllers has generally been bad. That's why I don't run them on anything that matters and so far have only run Samlex PST series inverters. 1500W is just a bit low for my needs.

That was our first thought too, but the guys at Midnight have 50 years experience in the industry and have designed some of the most reliable charge controllers and inverters. After looking into the OEM designs and requesting some changes, they have decided to rebrand the units as Midnight DIY, support and warranty them.

Midnight is just about now introducing their own design "Rosie the Inverter" which might meet your needs. They demonstrated it starting four air compressors simultaneously (I pointed out those were brush-type motors not induction motors) and one well pump (in an above ground tank for demonstration.)

Both high-frequency designs. One of them might be good for your application.

Or the SMA units. New in the box are sometimes still at <$3k prices on eBay and Craigslist. I'm also seeing the European model 8.0H, which wouldn't be what you want. The 6048US or 5048US or 4548US would be the model to get. Sunny Island is particularly famous for how well it maintains lead-acid batteries and AC couples to GT PV inverters which implement frequency-watts. For lithium batteries, it is best to have a BMS (e.g. REC) which communicates with the inverter.

 

[Hedges]

I'm really looking for something bigger and low frequency to tap my ~35Kwhr of usable battery.

If that means a battery bank with other loads and charge sources, if you use Sunny Island then connect a battery shunt. That lets it track state of charge so it can control loads and shut down based on SoC. If it is fed from grid or generator, it can also charge battery properly.

At least with lead-acid. In the case of lithium, some people configure Sunny Island by customizing VRLA parameters; I don't know how well that works. It wants to communicate with a BMS on lithium battery and just do as it's told.

 

[sidpost]

I have a JBD BMS system for the LiFeP04 batteries so, tying that back to the Inverter is a good idea. Regarding high-frequency inverters, I'm really thinking a low frequency is best for a lot of my loads. My welder runs at a ~10% duty cycle so a low-frequency inverter seems like a much better option for something like that but, that is used infrequently so isn't a driving factor. My well pump, clothes dryer, and other things would likely benefit from a low-frequency inverter too.

 

[Hedges]

Inverter welder or buzz box?

Clothes dryer should be a particularly benign load, other than a 1/3 hp induction motor.

Well pump, determine the surge current. One of the members has posted a charge of running starting amps for a range of motors.
Midnight demonstrated their Rosie high frequency inverter starting a well pump. Don't know if they arranged representative backpressure or not.
Sigineer may be high frequency, but lists a good and long surge output.
Sunny Island, I think you can't go wrong if you're OK with the cost. A couple of the old big iron brands like Trace/Schneider too.