Genetry Solar 'Parallel (AKA Daisy Chain) Mode

[Sean Genetry Solar]

This thread will house all the info regarding our parallel mode. This mode allows you to string together multiple inverters to share the same load. The pros currently being that you can effectively double or triple the output or more depending on how many you string together. We have yet to determine factors like efficiency or surge capabilities in this mode as it is still being tested and tweaked for optimal performance. 

'Split Sync' would be the preferred method with running no more than 2 inverters. 

 

This thread will be updated as more info comes along such as testing results and how to hook up.

 

Those of you waiting on your daisy inverters should see them popping in the mail soon here.

 

 

[Sean Genetry Solar]

Doing more testing over thr weekend and it's working great. Added another video.

[Tim]

Wandering can you switch from daisy to split sync or. Vi. Cell versa?maybe try split sync if panel to unbalanced go to parallel?probably already been asked.

[Sid Genetry Solar]

4 hours ago, Tim said:

Wandering can you switch from daisy to split sync or. Vi. Cell versa?maybe try split sync if panel to unbalanced go to parallel?probably already been asked.

No, this is not electrically, programmatically, or technically possible. 

• Firstly, "daisy" backfeeds power out of the AC input terminals.  You should never under any circumstances connect the AC Output terminals of any inverter (Genetry Solar or otherwise) to a live AC source.
• Secondly, split-sync requires the AC input for a sync and power on signal...and the AC output is separate from this signal
• Thirdly, most "daisy" setups are 240v split-phase.  Split-sync requires 2 inverters hardware configured for 120v single phase for an output of 240v split phase.

System setup is not fluid.  It has to be decided...well...at system setup.

[Tim]

Ok I bought 2 anyway I didn't know you would have to go inside to switch from one to the other.i have looked in my breaker box I'm not positive if it's balanced enough without taking most of the breakers out.i thought it was just a diff of rewiring on the outside.thanks for getting back to me.

[Tim]

Yes I would never wire two hots or mix neutral to a hot line I just thought you rewired them on the outside not internal.learned something new on them already. Decisions?

[Sid Genetry Solar]

I would presume then that you ordered them for split-phase "daisy" configuration?

[Tim]

Just wandering does daisy work with surge like for well pump or moter appliances?or is that's what you're working on -$@%& just went back and saw the answer for surge problem sorry.   Yes I did sorry I know you're busy but while I have you here what would I gain by adding a newer 1.1r3 board I'm not sure what mine are exactly.i preordered at the start they came on ship.thank you.Tim

[kuhrd]

A single GS-6K inverter starts my 120v well pump, sump pump, 15CuFt fridge and my 8000BTU Window AC unit without an issue.  If you are concerned about a load like an AC unit check to see what the LRA (locked rotor amps) on the unit is as that will kind of give you a rough idea what it needs for surge.  Most electric motors will require somewhere between 2 and 7 times the rated running current to start under load.  I have my inverter running pretty much my entire house except for the water heater and range at this point.  Sid and Sean are still testing things a bit with the 6k to see where the max surge limit is so they don't have any hard numbers but Sean was able to start his smaller 3 Ton, 13 SEER Air Conditioner with a single GS-6K inverter running as master when the slave inverter errored out during testing.  His smaller AC unit uses 1.2A for the fan and has a rated load amps of 14.1 and locked rotor amps of 77 for the compressor which should give you a rough idea what it can do assuming of course you have a big enough battery bank to supply it.

You won't really gain anything by going to the rev C control board.  All that changes is the voltage reading won't be affected by changes in temperature like it is on Rev A and Rev B boards (only moves by a few volts) and the AC input relay on the Rev C control board switches both L1 and L2 rather than just L1.  This is important for preventing back feeding in neutral ground bonded systems.  The best way around this if you have grid power that you are planning to connect to the input of the inverter for charging is to use a second panel and set it up for critical loads.  You can then wire the second panel as a sub panel for the inverter, keeping the neutrals and grounds separate  (not bonded) which eliminates the chance of a back feed issue.

All of the GS control boards support the same firmware at this time so they all can run 1.1r3 and will support 1.1r4 when Sid is finished tweaking, testing and ready to release it.  

[Sid Genetry Solar]

8 hours ago, Tim said:

Yes I did sorry I know you're busy but while I have you here what would I gain by adding a newer 1.1r3 board I'm not sure what mine are exactly.i preordered at the start they came on ship.thank you.Tim

Probably are Rev. A.1 or Rev. B boards...which are basically identical, except for changing the AC input relay design and a bit of associated support circuitry on Rev. B.

Like @kuhrd said, the Rev. C board largely is an iterative improvement (adding more sensors, fixing several design challenges, and changing AC input relays yet again)...but the core design is identical.  Without going to the complicated "parallel harness" method used by other inverter manufacturers, there really isn't a great way to handle surge capability in parallel mode--that is, surge beyond what 1 inverter can handle.  Surge is the Achilles heel of parallel mode unfortunately. 

I'd say that ideally a split-sync setup with 2 single-phase inverters would be the best way to achieve a doubled surge rating.  But that requires an internal inverter rewiring.

 

Be careful not to mix up hardware reversion vs software/firmware version.  The 1.1r3 is the current latest firmware, and I'm working towards 1.1r4 after working a few bugs out.  This firmware works on all GS control boards--A.1, B and C (latter in the prototype stage right now).

[Tim]

Thanks fellas I think I've kinda got a problem.i have several 230 and 220 units a 220v 9.8a well pump.a 18000btu ac window unit 230/208v 7.3/7.8 wired 230 a 220 dryer a 220 water heater and yes I know the inverters can't run them together.im not going to connect them to the grid.i think I should be able to charge from my 10.000 watt generator correct me if I'm wrong.a couple of the breakers are double but are 4 pole 2 on inside of each connected and 2 on outside connected.one on each side of the panel.120 are close to balanced but 220s are way off .dissapointed.when I first saw Sean's videos I liked the setup y'all were making.i like toyroidal coil and adding proper wiring and Sean was pushing how they were going to run parallel and they had a neutral I was happy.ok any suggestions?I know you reconfigure the coil and a couple other things on the board.will they work and surge together I don't think so.i would like to have close to 12grand with some surge (when needed)possibly at times certainly not long.any ideas? I've got to get a couple or 3 hrs.of sleep.

[Sid Genetry Solar]

1 hour ago, Tim said:

Thanks fellas I think I've kinda got a problem.i have several 230 and 220 units a 220v 9.8a well pump.a 18000btu ac window unit 230/208v 7.3/7.8 wired 230 a 220 dryer a 220 water heater and yes I know the inverters can't run them together.im not going to connect them to the grid.i think I should be able to charge from my 10.000 watt generator correct me if I'm wrong.a couple of the breakers are double but are 4 pole 2 on inside of each connected and 2 on outside connected.one on each side of the panel.120 are close to balanced but 220s are way off .dissapointed.when I first saw Sean's videos I liked the setup y'all were making.i like toyroidal coil and adding proper wiring and Sean was pushing how they were going to run parallel and they had a neutral I was happy.ok any suggestions?I know you reconfigure the coil and a couple other things on the board.will they work and surge together I don't think so.i would like to have close to 12grand with some surge (when needed)possibly at times certainly not long.any ideas? I've got to get a couple or 3 hrs.of sleep.

The 10kw generator sounds nice and big, but if I understand correctly, you have 2 GS 6kw inverters right now. 

Adding up the loads comes to some really steep numbers...let's assume the water heater is 4,500W (pretty common size) + dryer at 4,800W (guessing, could be as high as 6,000W), the window unit at 1,800W + the well pump at 2,400W...adds up to 13,500W continuous possible total.  Bit of an issue that.

Considering the 6kw limitations of the design, wiring and internals of the 6kw GS inverters, I'm thinking that the best way to handle this sort of power draw would be with 2 separate load panels, balancing out the loads on each panel, and one inverter per panel.

Panel A:

• 220 water heater (~4500W assumed = 18.75A)
• 220 well pump (9.8A)

Panel B:

• 220 dryer (20A?)
• 230 A/C window unit (7.3A)

Since the use of any sync mode (parallel, split-sync, 3-phase, etc.) renders charge unusable on any "slave" inverters, the only way to utilize the full capacity of your generator (or avoid melting the input wires on the GS inverters) will be to have separate output panels, and both inverters running in normal system mode.

If you didn't plan on being able to run >6kw on a generator, the inverters could be internally rewired to 120v single-phase each (preventing use of 240v charge), and they could be split-synced together for a full 12kw (pretty well balanced) output.

[Tim]

Hi Sid I didn't mean for you to do all that figuring I don't think I made myself clear.i know I can't run hardly half of that stuff not to mention the other a/c unit on the other side of the living room just smaller but with heat also only run 1 at a time but also all the 110 circuits. I've had the generator for a long time works well but if used several day means at least 2-3 trips to town for gas.if I needed to use it to charge batterys accasionaly it has a 120v 30a and couple reg 110s 2-6000w inverters with some surge would work fine.but over the last month or 2 I've seen that that may not be possible even as good as you are.you can only get so much out of anything I've made or built enough things in my life to realize that but I don't quite see tearing out the wall and rewiring 2 boxes down to eye level of the 2 very nosy granddaughters that live here.6.000 isn't.quite enough 11-12 occasionally shortly wouldn't be long with(some)surge if needed would be ideal.BUT not sure what to do.and world chaos could be around the corner never know.sorry to long better get off of here.

[Sid Genetry Solar]

1 hour ago, Tim said:

Hi Sid I didn't mean for you to do all that figuring I don't think I made myself clear.i know I can't run hardly half of that stuff not to mention the other a/c unit on the other side of the living room just smaller but with heat also only run 1 at a time but also all the 110 circuits. I've had the generator for a long time works well but if used several day means at least 2-3 trips to town for gas.if I needed to use it to charge batterys accasionaly it has a 120v 30a and couple reg 110s 2-6000w inverters with some surge would work fine.but over the last month or 2 I've seen that that may not be possible even as good as you are.you can only get so much out of anything I've made or built enough things in my life to realize that but I don't quite see tearing out the wall and rewiring 2 boxes down to eye level of the 2 very nosy granddaughters that live here.6.000 isn't.quite enough 11-12 occasionally shortly wouldn't be long with(some)surge if needed would be ideal.BUT not sure what to do.and world chaos could be around the corner never know.sorry to long better get off of here.

So I'm still guessing/trying to figure out what is the best option here...

IF we reconfigure the inverters for 120v single-phase each (i.e. split-sync for 240v 12kw total output)...the charge input will be limited to 120v input only (from one inverter), and basically 30A on the internal wiring limitations (possibly could hit 50A if internal wiring was beefed up). 

Output could be expected to be a solid 12kw continuous.  To reconfigure the inverters for 120v single phase, you'd also have to run the software unlock--and then you could disable the output wattage limit (for better or worse!), and probably get 13kw continuous if the ambient temps are low enough.

The issue here is that if you are expecting to charge the batteries through the one GS inverter...the total loads will have to be LESS than the maximum input power (say 120v @ 30A = 3.6kw) in order to be able to switch over, to say nothing of charging.  240v charge isn't possible with split-sync inverters.

Unless you have a separate battery charger...which would alleviate that issue altogether.  Assuming you have a pretty significant solar array?

 

IF the inverters are used in "parallel" mode with 240v input, the Neutral line has to not be connected on either inverter.  "Master" inverter could have the generator, but there must be no Neutral / ground bonding from the generator (just L1 / L2 for 240v).  "Slave" inverter just L1 / L2, no Neutral.

I will admit that the "parallel" mode has not been fully tested--as I don't have the means to test it, and Sean was running half-load tests or so on it.  Probably will need tweaking for ideal operation.

 

[Tim]

Ok I have no problem with 120/30a or reg 110 or 120 can't remember just now wether 15 or 20a believe it's 20 for charging 1 inverter I want a versatile system  I can shut down the inverters if needed to charge or use generator and let solar charge.i will not have enough panals to begin with for total solar to run constantly. this way I will basically have whatever I need also can turn grid off sometimes to save on current elect.bill. I don't plan to max the systems out that's why I want something other than just the generator also cheaper once operational.the reason for enough surge as you know is for the pump the a/c fridge freezer etc. I cook w/gas have wood heater when gets low 20s or teens.cant work job anymore just want to keep it simple.Does this make it easier for you I guess I have never fully explained my system and what I need.just an old(er)  country boy so to say.ok hope this helps.

[Sid Genetry Solar]

53 minutes ago, Tim said:

I can shut down the inverters if needed to charge or use generator and let solar charge.

Almost wonder if a 3-way transfer switch (or 2 cascaded 2-way transfer switches) for your house would be something you might want to consider?

1. AC Mains Grid
2. Inverters
3. Generator

So you could run on grid if you wanted...or if there's enough power in your batteries, you could switch to Inverters.  And if you need to charge your batteries + run your house, you could switch to Generator (house on 10kw generator), and the "master" inverter could charge the batteries at full power (with no load on the output).

 

Maybe that'd be a solid start for the system?

[Tim]

Yes now we're getting somewhere I have a heavy..cord not just a drop cord that plugs into the generator going to the panel double breaker I have room for one more double breaker on opposite side just to say also can build a heavy receptical box in generator building putting solar in a larger building 20'or so from house.now you know what I need can we make it work.id bet you can.

[Sid Genetry Solar]

My hesitation with breakers and plugs is...well, yes, they are cheap, and you probably have 'em...BUT if someone doesn't know what they're doing (or simply has a foggy moment), it's very easy to destroy both the generator and/or the inverters if they're accidentally connected to AC Mains by accident.  As it sounds like you'll likely be switching between all 3 options depending on the solar/house demands fairly frequently, there's a much higher possibility of mixing something up.

Transfer switches might not be the cheapest, but they'll render it pretty much impossible to accidentally direct power somewhere that it's not supposed to go.

[dickson]

Transfer switches might not be the cheapest, but they'll render it pretty much impossible to accidentally direct power somewhere that it's not supposed to go

 

Too bad my city  do not allow  transfer  switch  as permit  and inspection  cost  at least 900  dollars .   I  use a  suicide  extension  cord  and plug  in to wrong outlet  and could of burn my house down   if I did not unplug  immediately .   

[Tim]

Sure I understand Sid I'm.not known for just cobbling things once I get to that point if I think that I can't properly mount and label the system simply and neatly I will of course I will get a transfer switch.all we-you have to do is tell me is it workable for what we have discussed and how the inverters need to be set up these are your and Sean's baby's.wiring and connections will be done safely.

[Tim]

Yes I understand if you have ever been bolted by a lot of current or seen someone burn or even seen a car burn because of cobbled wiring you tend to be cautious with it.

[Sid Genetry Solar]

SO, if we use transfer switches or the like (kinda sorta bypassing the inverters' internal transfer switch!)...I think it should work.

Thinking then that if we internally rewire both of the inverters for single-phase output, and run them in split-sync mode to get a full 12kw with surge ability....then it should work for you.  (Would have to handle that via video call with you.)

Unfortunately, there would be no automatic switching, as the internal wiring and terminal blocks of the 6kw inverters aren't rated for 12-14kw.  Using external transfer switches (or whatever!), you'd have to manually switch between AC grid, inverter, and generator (and when switched to generator, the inverters could use some of the generator power to charge the batteries.)

Thoughts?

[Tim]

Sorry I've been busy med and especially my wife now it's Dr.dr.dr do you think that they will work better this way?I must have missed something did you all try dif circuits or just the a/c to have an idea of at what current it would go to before slave error out?you know the inverters better than I do.wander what Sean would charge me to re wire them?any chance of them having warranty if he wires them?I've been up all night this may have sounded strange sorry I need to get a few hours sleep&take my wife to phy.thearipy later thanks sid.

[Tim]

I forgot I know there probably best of course breakers or fusses but wanted to ask do you use a bms I have one but it's only 2ooa thanks again.

[Sid Genetry Solar]

On 8/17/2021 at 7:29 AM, Tim said:

I forgot I know there probably best of course breakers or fusses but wanted to ask do you use a bms I have one but it's only 2ooa thanks again.

I do not use a BMS on my system.  Properly-rated DC breakers for overcurrent protection, and set the inverter's UVP to a safe discharge voltage for the batteries (i.e. if batteries run too low, it'll shut off).  GS balancers on the LFP bank.  To each their own, though.