Growatt inverter choices

[GlennWest]

Been panning now that between jobs. I have decided on Growatt. They have a 3k 120v HF, a 5K 240v HF,  a 12K 120/240 LF unit. I would need 3 3k. 2 5k and an  autotransformer. 1 12K. That are my choices. Money is same either way. Thoughts. Should add I don't need 240v. Stepdown transformer on mini split.

Edited September 19, 2021 by GlennWest

[Randyretired]

The amount of inverter draw might help to decide.   Lower continuous draw is better but I would also like multiple units incase of failure.

[GlennWest]

What is your thoughts on an autotransformer. The 5k units are only 240v. I would get the Victron unit 100 amp. With the 3k units autotransformer not needed but need 3 of them.

Edited September 19, 2021 by GlennWest

[Randyretired]

I believe the auto transformer also has a continuous draw that would need to be considered but other than that those seem to work well.  The HF typically draw less and with 3, one or 2 could be disabled during times of less demand to reduce standby draw.  Hopefully others with experience with these chime in.

[Randyretired]

Just thought about 12,000 watts on an RV main panel would need to be 240v or the neutral could be overloaded.  This is assuming you have 50amp service.

[GlennWest]

Isn't 12000 watts what a 50 amp service is?  If go single unit would prefer a 10k unit but company that selling them don't stock that one. They do an 8k. Same basic unit, split phase LF.

[Randyretired]

10 hours ago, GlennWest said:

Isn't 12000 watts what a 50 amp service is?  If go single unit would prefer a 10k unit but company that selling them don't stock that one. They do an 8k. Same basic unit, split phase LF.

Yes, but it needs to be split phase 240v as the neutral is rated to carry 50 amps max.  Split phase cancels out much of the current the neutral would have to carry.  If all of the power were to be straight 120v that would be 100 amps on the neutral.  

[Kirk W]

1 hour ago, Randyretired said:

Yes, but it needs to be split phase 240v as the neutral is rated to carry 50 amps max.  Split phase cancels out much of the current the neutral would have to carry.  If all of the power were to be straight 120v that would be 100 amps on the neutral.  

Or to add just a bit, you have 6000 watts available on L1 and another 6000 watts available on L2 for a total of 12,000 watts. But there is a small catch in that the only way that you would ever see the entire 12,000 watts would be if there were exactly 50A being drawn from L1 and exactly 50A from L2, and then there would be 0A on the neutral as it only carries the difference between the currents of L1 & L2. In the real world, it would be very unusual for an RV to actually use the entire 100A/12 Kw but in a practical application you probably have about 80A/9.6 Kw useable because if either leg should exceed 50A it will cause both sides to open since they are linked together. 

[GlennWest]

So if I went 3 3k 120v inverters which at max output is 75 amps. That would overload my neutral. Had not considered that. Thanks for bringing this up. Don't believe would ever max out but could go over 50 amps possibly. So will rule that option out.

[oldjohnt]

Glenn, this in ONLY food for thought and an OPTION (Im NOT recommending it)........Since an RV rooftop AC (or even a 120 Volt mini split AC) will likely run off a 3000 Watt 120 Volt Inverter and if you had say two of them (front and rear) you could (sure that's work but doable) rewire and configure your wiring to power one AC from one Inverter, A,,,,,,Another AC from a different Inverter B,,,,,,,Use the third Inverter C to power all else. Far as I know those Inverters can be synced so you can parallel two or more but the Neutral conductor in your RV power cord (unless you modify) can only handle 50 amps.  A 50 Amp RV when plugged into a true 120/240 Volt Single Phase Three Wire service pedestal can draw up to 12,000 watts and it would be sooooooooooo much simpler to use a SINGLE say 10,000 to 12,000 Watt true 120/240 Inverter if such is available ???? 

 As you already know you can use a dry transformer to obtain 240 (if you need it ???) from 120 or 120 from 240..

 Are you building an RV that requires MORE then 12,000 watts ?? Homes can run on less

Don't forget to create a proper Neutral Ground Bond on the Inverter since your RV panel has none.

 John T

[GlennWest]

Reason I was thinking of 3 120v units was if one fails still got two. Hadn't considered overloading neutral. Big oversight on my part. Know of a lot that runs 2 3k units but that is 50 amps so they have no problem with neutral. I am over powering with inverter but all I have read running around 50% output insures long inverter life. And DW could forget and have microwave and dryer running same time. She good at not doing that but we all have those uh oh moments. The single 12k is tempting. Very simple wiring. It definitely will not be overworked. The 12k is also repairable. They stock new boards for them. $300.00. But they is a lot to be advantage with 2 inverters. Replace one and still have power while getting failed unit fixed or replaced. I currently have a 120v 48v charger I am using to keep my lithium battery packs charged now. No longer have a 12v battery. If ever need a generator would use it to charge batteries instead of feeding inverter power. We were recently hookup to a 30 amp site. To my surprise everything worked. We didn't try clothes dryer since just a day there. I might could get by with the 8k unit, 

Edited September 20, 2021 by GlennWest

[oldjohnt]

15 hours ago, GlennWest said:

We were recently hookup to a 30 amp site. To my surprise everything worked. We didn't try clothes dryer since just a day there. I might could get by with the 8k unit, 

That's a case (hooked on 30 amps) where addition of a Soft Start on AC's can help and get you by.

15 hours ago, GlennWest said:

I currently have a 120v 48v charger I am using to keep my lithium battery packs charged now. No longer have a 12v battery

  Good old 48 to 12 DC to DC use 

John T  

[noteven]

I had a bright idea I would put a 12V air conditioner on toppa my vintage camper project. 

Then I saw what they cost. 

That's a lot of perfectly good motorcycle money. 

Back to Glenn's thread now.

 

Edited September 21, 2021 by noteven

[GlennWest]

1 hour ago, oldjohnt said:

That's a case (hooked on 30 amps) where addition of a Soft Start on AC's can help and get you by.

  Good old 48 to 12 DC to DC use 

John T  

No rooftop acs. All mini splits. 

[GlennWest]

8 minutes ago, noteven said:

I had a bright idea I would put a 12V air conditioner on toppa my vintage camper project. 

Then I saw what they cost. 

That's a lot of perfectly good motorcycle money. 

Back to Glenn's thread now.

 

I seriously considered a 48v mini split. They were much more money but are more efficient. But with the new generation of mini splits at or near 30 seer no benefit now.

[GlennWest]

Have decided not to use growatt. Nothing against them except they are too noisy to put under my bed. 59 db at 5 feet. 

[GlennWest]

Reading up on Victron Multiples 2 48/8000 with an autotransformer.

[Darryl&Rita]

1 hour ago, GlennWest said:

Have decided not to use growatt. Nothing against them except they are too noisy to put under my bed. 59 db at 5 feet. 

That's into generator noise territory. Wow!

[palmeris]

On 9/21/2021 at 10:07 AM, GlennWest said:

I seriously considered a 48v mini split. They were much more money but are more efficient. But with the new generation of mini splits at or near 30 seer no benefit now.

But, if I understand correctly,  using a 48v mini split would allow you to run the mini split directly from the 48v battery bank without using an inverter as well as run directly off a 48 volt solar array?

[GlennWest]

1 hour ago, palmeris said:

But, if I understand correctly,  using a 48v mini split would allow you to run the mini split directly from the 48v battery bank without using an inverter as well as run directly off a 48 volt solar array?

True, But one likely if using 48v will have an inverter anyway. and a large one since it is 48v. There are 240v mini splits now at 30 seer. Mine were one of the highest at 21 seer. https://www.signaturesolar.us/products/mini-split-ac-heat-pump-gree-12000-btu

Edited October 7, 2021 by GlennWest