Growatt 3000TL LVM-ES limit AC Input?

[mrfusi0n]

Does anyone know if it is possible to set the max AC input current on a 48v Growatt 3000TL LVM-ES?

Right now I have 2x Growatt 3000TL LVM-ES running split phase 240v. For cloudy days, I have a 7500w generator to keep the batteries charged. For the most part, this is working great. I can even max out the Growatt's charging capacity at 40A each (at battery voltage). The problem is, I cannot find a setting to limit the overall draw on the generator. If I set it to charge the battery at max amperage and then use the microwave, toaster oven, etc., it tries to pull that from the generator too and overloads it, tripping the breaker.

Seems like an obvious setting to have on the Growatt but I can't find it anywhere. Am I overlooking something?

I tried a lot of settings including setting the AC output priority to SBU (solar > battery > utility) but that seemed to completely ignore the generator, not even letting it charge the battery.


I see setting 11 allows me to set the max input to use for charging the battery.

 

[sunshine_eggo]

The Growatt charger is funky. It's like a tank float. It doesn't come on until battery is below the charge trigger voltage, and it turns of the instant the target charge voltage is hit. It does not act like a typical inverter/charger with bulk/absorp/float. SBU mode means solar - battery - utility priority, so with that enabled, you'll never get charging unless the battery is below the trigger voltage.

No. When connected to AC, you're charging and feeding loads with AC input. When there's surplus AC up to the charge limit specified, you get charging, but when you add loads, it pulls the extra from the AC input.

This has to to with the dual function of the transformers. There is only one set of transformers. They both invert and charge. When connected to AC and charging, they can't invert, so any additional loads are pulled from the input.

Even Tier-1 products work this way. In some cases, like Victron, they have a power assist function where if the loads exceed the AC input limit, then it stops charging with the surplus and piggybacks inverter power to supplement the AC input to prevent overloading the generator. I have this exact situation. Single phase Quattro, but I have a split phase generator, and I can only pull from one leg - 15A. If I disable power assist, loads can easily trip the generator's breaker. With it on, the inverter supplements the 15A AC input with inverter power drawn from batteries.

For your scenario, it's best to reduce the AC charge current to give you some overhead for loads.

 

[mrfusi0n]

Thanks so much for the insightful response!

I still feel like the Growatt should be able to handle this scenario by lowering the charge current when I increase load. When I set the charge current, I wish it were interpreted as the MAX charge current and it would be smart enough to lower the charge current to compensate for increasing loads.

Here's the scenario I tested out the other day. I started up the generator and started a 240v electric oven. To get things working, I had to adjust the Growatt settings to lower the charging from AC input to only 5A each. That worked but once the oven was at temperature, it turns the heating elements off. They then turn on briefly here and there to maintain temperature. During the down time, the generator power is not really utilized. Why can't it increase battery charging during that downtime? The only thing I could figure out that made sense was to run things like the oven 100% off battery. Then, once big loads are done, use the generator to charge the battery back up. This seems much more efficient but not ideal...

 

[sunshine_eggo]

Thanks so much for the insightful response!

I still feel like the Growatt should be able to handle this scenario by lowering the charge current when I increase load. When I set the charge current, I wish it were interpreted as the MAX charge current and it would be smart enough to lower the charge current to compensate for increasing loads.

Feelings and "shoulds" don't matter. Things work a certain way. You paid a cheap price for a cheap inverter. This limitation also exists on my $2200 Victron, but it has the added option of power assist, which is not on all tier 1 products. Damn spendy option.

When you have AC input and are charging, you are LIMITED BY THE AC INPUT. Period. The inverter either charges or inverts, it can't do both at the same time. Once you accept this, it will begin to make sense. When the generator is running, IT is providing the sine wave. Your unit is using that incoming sine wave to charge the battery and pass through the loads. Your charging and loads can't exceed your AC input. Period. You have to pay more money for better hardware with more options.

When power assist is enabled, my inverter STOPS CHARGING and begins to SUPPLEMENT the incoming AC when the AC input limit is exceeded ($700 means you don't get this option, $2200 means I can).

If I have power assist disabled, my $2200 Victron behaves exactly like your $700 Growatt. I know... I know, I'm beating a dead horse on pricing. It really does matter. You get so much more with Tier-1 hardware.

The cheapskate in me loves the Voltronix stuff, but the guy that wants reliability above all else won this fight.

Here's the scenario I tested out the other day. I started up the generator and started a 240v electric oven. To get things working, I had to adjust the Growatt settings to lower the charging from AC input to only 5A each. That worked but once the oven was at temperature, it turns the heating elements off. They then turn on briefly here and there to maintain temperature. During the down time, the generator power is not really utilized. Why can't it increase battery charging during that downtime?

Because the generator is providing the power, and it doesn't matter if 4500W (guessing) hits it for 1 second or 1 minute, that additional load on the generator exceeds it's rating, and you have problems.

Even if the generator had some sort of dynamic "smart" charging algorithm, the instant-on nature of the loads, particularly high surge loads like motors, would present too great a challenge to prevent generator overload.

The only thing I could figure out that made sense was to run things like the oven 100% off battery. Then, once big loads are done, use the generator to charge the battery back up. This seems much more efficient but not ideal...

Yep. You've found your solution.

 

[LukeA]

You are the man, sunshine-eggo. This answered my question too.

Seems like a possible, Frankenstein's monster medium-priced setup is to leave the Growatts for only inverting power from the batteries and get a separate charger/inverter to recharge the batteries at the same time. That way mrfusi0n, you can have your microwave (cake) and charge your batteries at the same time (eat it too).

Maybe something like this: https://www.amazon.com/Power-CON120...charger&qid=1640694258&sr=8-6#customerReviews

Or two of those to get 37 amps charging from his 7500 watt genny—and for $550.

 

[Rustic]

Have you tried playing around with setting 2, also the battery not charging is controlled by setting 12. Set that the voltage you want the batteries to start charging in line mode.

 

[sunshine_eggo]

Have you tried playing around with setting 2, also the battery not charging is controlled by setting 12. Set that the voltage you want the batteries to start charging in line mode.

This whole thread is about charging with AC input.

 

[Rustic]

This whole thread is about charging with AC input.

Yes it is, when I asked Ian about having this same problem, changing those settings fixed my charging problem and tripping breaker. Do you own a Growatt 3000 ES?

 

[mcmullen7242]

Does anyone know if it is possible to set the max AC input current on a 48v Growatt 3000TL LVM-ES?

Right now I have 2x Growatt 3000TL LVM-ES running split phase 240v. For cloudy days, I have a 7500w generator to keep the batteries charged. For the most part, this is working great. I can even max out the Growatt's charging capacity at 40A each (at battery voltage). The problem is, I cannot find a setting to limit the overall draw on the generator. If I set it to charge the battery at max amperage and then use the microwave, toaster oven, etc., it tries to pull that from the generator too and overloads it, tripping the breaker.

Seems like an obvious setting to have on the Growatt but I can't find it anywhere. Am I overlooking something?

I tried a lot of settings including setting the AC output priority to SBU (solar > battery > utility) but that seemed to completely ignore the generator, not even letting it charge the battery.


I see setting 11 allows me to set the max input to use for charging the battery.

how do you have your generator wired up to the inverter be able to charge 40 amps? does your generator have a 50amp outlet? i am looking at a generator that has 2 30A outlets and wondering if i can create a y connector between them and then wire to the ac input

 

[whuang86]

I’m stuck on ac bypass mode even tho I have the battery. When I disconnect the ac input it goes to battery and when I connect the ac input it goes to bypass. Why is that?

 

[Rednecktek]

how do you have your generator wired up to the inverter be able to charge 40 amps? does your generator have a 50amp outlet?

The amperage limit for utility charging is based on battery amps, NOT utility amps. If you've got a 24v system with a 40a utility charging, that usually wants to charge at about 27v, so 27v * 40a = 1080w / 115v AC = 9..4a coming from your generator.

i am looking at a generator that has 2 30A outlets and wondering if i can create a y connector between them and then wire to the ac input

Nope, please don't try that, you'll just end up with a dead generator at best and death and/or Angry Wife at worst.