Growatt 3000TL LVM 48v off grid with generator setup help please

[Colorado_Al]

I have some questions about setting up the Growatt system with solar as primary charging and a manual start generator as backup.
I have a 1.9kw solar array and it seems to be charging the 2 GYLL 48v LiFePo4 correctly.
I have the Growatt set to program 01 (output source priority) SBU priority = Solar > Battery > Utility (generator powers loads only when battery is 48v or less)
Program 03 (AC Input Voltage range) set to GEN = generator
Program 05 (Battery Type) set to USE = user defined
Program 14 (Charger source priority) set to SNU = Solar and Utility - to allow solar and generator to concurrently charge the batteries if needed
Program 19 (Bulk charging voltage) set to 56v
Program 21 (Low DC cut-off voltage) set to 48v

A few questions:
Does everything above look correct?
Would I be better off selecting Program 01 as SOL so generator could power loads when either solar not avail or battery voltage below 48v?
Program 20 (Floating Charge voltage) It is currently the default of 54v. Not sure about this because I though LiFePo4 don't need float charging?
Program 12 (Setting voltage point back to utility source) should this be set to the same as the Low voltage cut-off? currently default of 46v
Program 13 (Setting voltage point back to battery mode) default is 54v - does this mean that after the battery is at 54v, the generator will no longer charge the batteries? Should this be set to 56v to match the bulk charge voltage?


Thanks for any help or tips you can provide. Thanks!
Al

 

[Markbe]

Hi Robert. Did you find a solution to this? I have exactly the same question about how to set up with a generator. Thanks

 

[Colorado_Al]

It's Al and I did get this setup.
I ended up choosing UTl as the output source priority (program 01). Since the generator will only run when I manually start it, the system defaults to solar & battery, and then uses the generator as priority when I run it.

 

[Markbe]

It's Al and I did get this setup.
I ended up choosing UTl as the output source priority (program 01). Since the generator will only run when I manually start it, the system defaults to solar & battery, and then uses the generator as priority when I run it.

Great. Thank you. That was what occurred to me to do, and I wrote to growatt to ask if that would work. They haven't replied yet and then I found this post. Glad it worked for you and thanks for sharing!

 

[marex]

Hi, I have a very similar setup except that I have a DIY LiFePo4 battery. I use SBU setting and for Program 5 you should use US2 (if available, maybe it's a new value for more recent device or maybe you need a firmware upgrade). See below what the doc says about US2. Program 19 and 20 should be the same and in my case I selected 56.8 (3.55V per cell so +- 90% SOC).

What matters is the generator you have. If it's a typical one (no inverter) then you will not get a very stable AC frequency output and that is the main cause of failure of sensitive electronic devices (many devices). They will not fail right away but I found that they died after a few weeks. My Generac 3250 produces 70 to 75 Hz AC with no load and if I connect it to the AC input of the Growatt then it will not accept it. I have to plug another load to the generator to maybe be lucky and have it work with the Growatt. If your generator works ok then maybe you do not want the Growatt to switch to bypass mode and send a more or less stable AC to your home. This is where SBU is good as long as the solar and battery can handle the load.

I decided to buy an inverted generator to get a stable signal and not worry about it. And since in my cas it's a remote chalet (more than a cabin), I want the generator to autostart when the battery gets too low to keep the Starlink Internet and camera working. For this reason I will buy the Honda EU7000IS which is an inverter generator with fuel injection thus no choke which is a must for remote start at least here in Canada where it gets very cold in the winter. Yes this model has a connector to remote start it with a contact relay and obviously I will need a large gas reservoir that feeds the basic reservoir of the Honda using a special tank cap that connects to a large tank that is higher to get a gravity feed.

If you run an inverter generator than Utility first is also a good option but not if you have a standard generator. I also do not select GEN for Porgram 3 as they state that it's only for Diesel generator or 10KVA or more... I select APL


====== DOC for US2 ======
User-Defined 2(suitable when lithium battery without BMS
communication)

If “User-Defined 2” is selected, battery charge voltage and low DC cut-
off voltage can be set up in program 19, 20 and 21. It is

recommended to set to the same voltage in program 19 and 20(full
charging voltage point of lithium battery). The inverter will stop
charging when the battery voltage reaches this setting.

 

[Colorado_Al]

Hi, I have a very similar setup except that I have a DIY LiFePo4 battery. I use SBU setting and for Program 5 you should use US2 (if available, maybe it's a new value for more recent device or maybe you need a firmware upgrade). See below what the doc says about US2. Program 19 and 20 should be the same and in my case I selected 56.8 (3.55V per cell so +- 90% SOC).

What matters is the generator you have. If it's a typical one (no inverter) then you will not get a very stable AC frequency output and that is the main cause of failure of sensitive electronic devices (many devices). They will not fail right away but I found that they died after a few weeks. My Generac 3250 produces 70 to 75 Hz AC with no load and if I connect it to the AC input of the Growatt then it will not accept it. I have to plug another load to the generator to maybe be lucky and have it work with the Growatt. If your generator works ok then maybe you do not want the Growatt to switch to bypass mode and send a more or less stable AC to your home. This is where SBU is good as long as the solar and battery can handle the load.

I decided to buy an inverted generator to get a stable signal and not worry about it. And since in my cas it's a remote chalet (more than a cabin), I want the generator to autostart when the battery gets too low to keep the Starlink Internet and camera working. For this reason I will buy the Honda EU7000IS which is an inverter generator with fuel injection thus no choke which is a must for remote start at least here in Canada where it gets very cold in the winter. Yes this model has a connector to remote start it with a contact relay and obviously I will need a large gas reservoir that feeds the basic reservoir of the Honda using a special tank cap that connects to a large tank that is higher to get a gravity feed.

If you run an inverter generator than Utility first is also a good option but not if you have a standard generator. I also do not select GEN for Porgram 3 as they state that it's only for Diesel generator or 10KVA or more... I select APL


====== DOC for US2 ======
User-Defined 2(suitable when lithium battery without BMS
communication)

If “User-Defined 2” is selected, battery charge voltage and low DC cut-
off voltage can be set up in program 19, 20 and 21. It is

recommended to set to the same voltage in program 19 and 20(full
charging voltage point of lithium battery). The inverter will stop
charging when the battery voltage reaches this setting.

I have a Honda Inverter Generator already. Thanks!

 

[rykelo]

Ahoy! Fellow Canadian here with generator struggles. My Growatt SPF 3000TLM LVM won't accept AC input from my Generac 6500 XL. The utility icon flashes, and the shows over 120 volts AC input but the diagram doesn't show that power getting to the battery or loads. Guessing I need to buy an inverter generator, will this one work?

https://www.homedepot.ca/product/generac-gp-3500w-open-frame-inverter-generator-with-powerrush/1001168356

Hoping it can power my loads (trailer lights and refrigerator) and charge my homemade LiFePo4.

For the time being my plan for rainy days is to plug my trailer directly into the generator while simultaneously charging my battery using an inverter that plugs into my car cigarette lighter. Haven't tried it yet, does anyone see anything wrong with this plan?

Thanks!

 

[marex]

Your Generac 6500XL probably does not run in the 55-65 Hz, at least mine was running at 74 without load. The inverter model should be ok, your Growatt can handle 3KW so your generator should match it assuming you’re using all the power which should not be very often. I have to set my Growatt in UTL mode to have it charge my batteries otherwise in SBU, if the batteries are not very low it won't charge from the generator AC input. I also set the AC level to GEN as I guess they may do something special in that mode like wait a bit when AC (gen) is detected to give the generator some time to get up to speed.

What you may want to check is the noise of your generator. Camping with a loud noise near the trailer may not be fun for you and neighbors. Not all models are equal. I was really really surprise by how silent my Honda EU7000is is compared to my Generac 3500. So maybe check the Honda 2000 W inverter models if that's enough for you - they seem to run quietly (for a generator). You can set the maximum Amps to charge your battery with the Growatt so you can make sure the AC input is not exceeded.

 

[rykelo]

Thanks @marex you're right about the noise, my Generac is loud. Next time I'm up, I'll take a shot at the settings you mentioned and see if I can get the Growatt to accept the Generac. Now that it's fall we're getting into more cloudy days and so more need for the generator. Hey, do you know off hand whether the Growatt has some kind of cold protection built in to prevent it from charging the LiFePo4 battery below freezing?

 

[marex]

The Growatt will not control charging based on temp. It's your Lithium battery BMS that should have a probe and settings to disable charging at a given temp (near 0 celcius) and disable discharging at another temps (near -20 celcius). The Growatt has temp requirements too. From what I recall it should not run at a low temp - check the specs. What I did is build a 4x6 isolated room within my shed where all my electrical stuff is located and added an oil filter heating pad (from amazon at 300W) that I sticked to a metal sheet and controled with a temperature controller (amazon too) that will start heating the room from 4 to 7 celcius. This will make sure my batteries and Growatt are always at safe temp. This makes sense only if the generator can be started automatically when the battery goes too low. My Honda EU7000is can be started remotely so I bough the connector and a generator startup controller because it's not just a simple relay contact to start/stop a generator. Just got all the parts for this auto start and still need to wire it up and ensure it works for a while during winter because I can only get to the chalet by skidoo! So I bought a 15 gallons fuel tank that will feed my generator through a new cap with a hose and hopefully that will last long enough for me to refuel... Or maybe my 2.4 KW solar array will do the job to extend the life of the fuel capacity but in winter sun is low in my area and there are trees and often cloudy. Worst case, the BMS will shutdown the battery and therefore the Growatt and I will have to get there to refuel!

 

[rykelo]

Wow it sounds like your setup is pretty awesome! Would love to see photos. Thanks for the input about the battery temp cutoff being controlled at the BMS. My battery doesn't have BMS communication to the Growatt but the guy who built it for me installed these little computer boards in there and I don't exactly know what those do.. hoping they have low temperature protection. I'll see if I can get an answer from him about that. But in any event, it sounds like the best bet for me is to just remove my Growatt and Battery from the shed for the winter (mine isn't insulated or automated with temp control like yours!). Over the winter, I'm planning on charging the battery once per month or so through the growatt's utility charging ability on grid power. I'm actually pretty confused as to how to even tell when the battery is full! My assumption is that the Growatt will stop trying to charge it once it reaches the 29.2 V "high voltage" setting.