Looking to upgrade my current Growatt 6kw inverter to 18kw: advice/questions

architekt

New Member
Joined
Aug 30, 2021
Messages
7
I currently have a few 12.8kwh 48V LiFePO4 giant batteries from bigbattery.com (appropriately named). They're the TREX model if anyone is familiar with them. They can handle a max continuous discharge of up to 150A. When I bought the kit from them, they shipped me a Growatt 6kw inverter. Which can only output a max of 25A. Not nearly enough to power what I thought I was going to be able to power, namely my AC and a few other things. My electrician suggested I look into getting a beefier inverter. I found two 18kw models which would provide 75A (18kw/240v), plenty to power the AC, my computer, and finish any dishwasher/washing machine loads that were in the middle of running. 18kw is a lot, but the price difference between 18kw and 15kw models doesn't seem to be much so I figure, I'm going to go with the higher model for just more amp headroom. I've been looking at two brands and I was wondering if anyone had any opinions on them:
1. Sigineer model HP18048D (product link)
2. SunGoldPower (product link)

My batteries have a "suggested charge current" of 45A with a max of 90A, and a "suggested charge voltage" of 59.5V. My current 6kw Growatt inverter only lets me supply 58.4V, but the manufacturer says that's fine. The batteries say that "bulk voltage", "absorption voltage", "float voltage" don't apply to them ("Not applicable to Lithium Batteries"). They have a low voltage cutoff valid between 40V-46V, suggested 46V.

Reading their respective documents, they look like they're essentially the same. They even look essentially the same with essentially the same features. They both seem to let me set things up the way I need, albeit not with the nice friendly UI that the Growatt has with it's buttons and LCD set up screen (sadly Growatt maxes out at a 12kw model). Franklin (everyone says they've talked to Franklin) at Sigineer says that their model has a fixed cut off voltage of 42V, which is within my manufacturer's listed range so I know that'll work. SunGoldPower doesn't mention this anywhere.

I have 2 questions:
1. Both of them have essentially the same battery selector knob/switch on the front. The SunGoldPower has a LiFePO4 setting which would output 58.4V: that's the same as what I have now with my current set up so I know that's fine. The Sigineer has what looks like the exact same setting, it just happens to also say "AGM 2 / Lithium Battery": this shows the exact same output voltages as the SunGoldPower unit. Here's the question: When choosing the battery type selector, does anyone know if that SOLELY affects the output voltage? The manuals seem to indicate this, as the charts just list boost/float Vdc per battery type. You use DIP switches to affect current and both have a knob to attenuate this between 0-100% so I can easily set my output amps to the suggested 45A. I just want to make sure that the battery type selector is only affecting the voltage and not some other parameters that aren't mentioned in the docs.

2. Does anyone have experience with either unit or brand and their reliability/quality? So far, the Sigineer sales rep seems to be really on the ball and communication has been great which gives me a positive feeling, whereas the SunGoldPower rep kind of gave me bare minimum info to my questions. Or, are there perhaps other models that someone would suggest instead that can output 18kw 75A? I'm really just looking for the high amp output. I have the battery capacity to run what I need for 8 hours (more than enough for our storms here in Pittsburgh) if I had an inverter that could handle the amp load.
 
Last edited:
  • Like
Reactions: feo

feo

Solar Enthusiast
Joined
May 24, 2021
Messages
36
Have you thought about the peak wattage you need to handle for dishwasher+AC?sounds like you are basing your numbers off of steady-state loads.

Regardless, very interested in your results of AC vs large inverter. How big is the AC unit? LRA?
 

architekt

New Member
Joined
Aug 30, 2021
Messages
7
I actually decided not to put the dishwasher/washer/dryer on the critical load panel. I did a test and turns out it's not a big deal recovering from them after a loss of power. Regarding the AC, LRA is 58.3, RLA 13.5. The inverter apparently can handle 300% load for 20s, according to the all knowledgeable Franklin (and the device's documentation). I already ordered the Sigineer model so I'll report back once my electrician installs it all. Oh and to answer my question, ya, setting the battery type on this device just afffects what it states on the label.
 

Supervstech

Administrator
Staff member
Moderator
Joined
Sep 21, 2019
Messages
6,227
Isn't growatt supposed to be a stackable inverter tech?
So, you could just add an additional 6KW or two... no?
 

architekt

New Member
Joined
Aug 30, 2021
Messages
7
I could add more, ya, but that would cost more than just getting this unit and selling the current one. I mean I'd have to buy 2 more to get the same as this one unit (or I guess just buy their 12kw model to add on, but still, costs more). It would also take up more space and my electrician suggested that it would overall be less hassle/be better to just get a beefy unit to replace this one with.
 

houseofancients

Solar Addict
Joined
Nov 29, 2019
Messages
550
I could add more, ya, but that would cost more than just getting this unit and selling the current one. I mean I'd have to buy 2 more to get the same as this one unit (or I guess just buy their 12kw model to add on, but still, costs more). It would also take up more space and my electrician suggested that it would overall be less hassle/be better to just get a beefy unit to replace this one with.
well it would provide youbwith redundancy , load sharing, and a much higher peek load possibility..
plus , a good low self consumtion 18k will break your bank quite happily
 

architekt

New Member
Joined
Aug 30, 2021
Messages
7
I already ordered the unit a little while ago so it's kind of a moot point, but it was cheaper to buy it than to buy multiple Growatt inverters.
 

Jgb3

Solar Enthusiast
Joined
May 27, 2021
Messages
149
I already ordered the unit a little while ago so it's kind of a moot point, but it was cheaper to buy it than to buy multiple Growatt inverters.
What is the self consumption on the 18k?
 

architekt

New Member
Joined
Aug 30, 2021
Messages
7
What is the self consumption on the 18k?
If set to power save mode (aka when there's <=25W of load) the inverter will periodically "search" for loads according to the manual and in this state will consume 60W (max it says) itself. If power save is turned off it's 250W. If it's off and just simply charging the batteries, 3W.
 

Jgb3

Solar Enthusiast
Joined
May 27, 2021
Messages
149
If set to power save mode (aka when there's <=25W of load) the inverter will periodically "search" for loads according to the manual and in this state will consume 60W (max it says) itself. If power save is turned off it's 250W. If it's off and just simply charging the batteries, 3W.
Ok I have the growatt 12k it uses 150w and just charging 12w
 

offthehook

New Member
Joined
Dec 4, 2020
Messages
10

architekt

New Member
Joined
Aug 30, 2021
Messages
7
btw, just saw this passing by, might be the thing you're looking for :

Thread 'Sigineer 48V 15KW Split Phase' https://diysolarforum.com/threads/sigineer-48v-15kw-split-phase.15484/

asks 1200
Huh, had I seen that I would have been reaaaaaaaaaaaaaal tempted to pick that up. Oh well. The 18kw model will just provide a little more juice. Like I said, I placed my order a few days ago. I talked extensively back/forth with the Sigineer rep Franklin who answered every possible question I had, which, besides answering my questions, gave me a good feeling about buying from them. That and my battery manufacturer said I shouldn't have a problem with it (they just told me to stay away from Renology or Renogy or something like that, not sure why, they just said they had issue with their inverters).
 

offthehook

New Member
Joined
Dec 4, 2020
Messages
10
Huh, had I seen that I would have been reaaaaaaaaaaaaaal tempted to pick that up. Oh well. The 18kw model will just provide a little more juice. Like I said, I placed my order a few days ago. I talked extensively back/forth with the Sigineer rep Franklin who answered every possible question I had, which, besides answering my questions, gave me a good feeling about buying from them. That and my battery manufacturer said I shouldn't have a problem with it (they just told me to stay away from Renology or Renogy or something like that, not sure why, they just said they had issue with their inverters).
Yeah. I also worked with Franklin. It's a solid design, I just went a different direction.
 

Scott LOPEZ

New Member
Joined
Jul 26, 2020
Messages
9
I currently have a few 12.8kwh 48V LiFePO4 giant batteries from bigbattery.com (appropriately named). They're the TREX model if anyone is familiar with them. They can handle a max continuous discharge of up to 150A. When I bought the kit from them, they shipped me a Growatt 6kw inverter. Which can only output a max of 25A. Not nearly enough to power what I thought I was going to be able to power, namely my AC and a few other things. My electrician suggested I look into getting a beefier inverter. I found two 18kw models which would provide 75A (18kw/240v), plenty to power the AC, my computer, and finish any dishwasher/washing machine loads that were in the middle of running. 18kw is a lot, but the price difference between 18kw and 15kw models doesn't seem to be much so I figure, I'm going to go with the higher model for just more amp headroom. I've been looking at two brands and I was wondering if anyone had any opinions on them:
1. Sigineer model HP18048D (product link)
2. SunGoldPower (product link)

My batteries have a "suggested charge current" of 45A with a max of 90A, and a "suggested charge voltage" of 59.5V. My current 6kw Growatt inverter only lets me supply 58.4V, but the manufacturer says that's fine. The batteries say that "bulk voltage", "absorption voltage", "float voltage" don't apply to them ("Not applicable to Lithium Batteries"). They have a low voltage cutoff valid between 40V-46V, suggested 46V.

Reading their respective documents, they look like they're essentially the same. They even look essentially the same with essentially the same features. They both seem to let me set things up the way I need, albeit not with the nice friendly UI that the Growatt has with it's buttons and LCD set up screen (sadly Growatt maxes out at a 12kw model). Franklin (everyone says they've talked to Franklin) at Sigineer says that their model has a fixed cut off voltage of 42V, which is within my manufacturer's listed range so I know that'll work. SunGoldPower doesn't mention this anywhere.

I have 2 questions:
1. Both of them have essentially the same battery selector knob/switch on the front. The SunGoldPower has a LiFePO4 setting which would output 58.4V: that's the same as what I have now with my current set up so I know that's fine. The Sigineer has what looks like the exact same setting, it just happens to also say "AGM 2 / Lithium Battery": this shows the exact same output voltages as the SunGoldPower unit. Here's the question: When choosing the battery type selector, does anyone know if that SOLELY affects the output voltage? The manuals seem to indicate this, as the charts just list boost/float Vdc per battery type. You use DIP switches to affect current and both have a knob to attenuate this between 0-100% so I can easily set my output amps to the suggested 45A. I just want to make sure that the battery type selector is only affecting the voltage and not some other parameters that aren't mentioned in the docs.

2. Does anyone have experience with either unit or brand and their reliability/quality? So far, the Sigineer sales rep seems to be really on the ball and communication has been great which gives me a positive feeling, whereas the SunGoldPower rep kind of gave me bare minimum info to my questions. Or, are there perhaps other models that someone would suggest instead that can output 18kw 75A? I'm really just looking for the high amp output. I have the battery capacity to run what I need for 8 hours (more than enough for our storms here in Pittsburgh) if I had an inverter that could handle the amp load.
i used sungoldpower 12kw inverter more than 2 years, it is really great. my engineer friends said sungoldpower inverter board is much better quality than the sigineer , and their 6kw inverter has passed UL 1741
 
Top