Growatt 3000 - 'Solar/Battery/Utility' firmware issue?

[wingedlizard]

I have a growatt 3000 SPF LVM with 6.5 KHW battery. I have my inverter set to 'Solar/Battery/Utility' but when my battery hit's 100%, I don't think it's trying to pull any solar, because it reports '0 W' solar PV on solar assistant.

Does it draw on the battery and not use solar when the battery is full? Changing to 'solar first' doesn't seem to change anything.


Using a clamp meter seems to verify this conclusion.

>Specification
>Driver Growatt SPF
>Serial number BNJ2BKU04B
>Firmware version 502.10
>Secondary firmware version 002.07
>Max AC output apparent power 3000 VA
>Max AC output power 3000 W

Does a later firmware fix this?

Brett

 

[Mattb4]

A SCC job is to charge the battery. Once charged (CC and CV done) it can go into float (lower voltage than boost/bulk usually) or trickle charge depending on battery chemistry and settings. Or it can say the battery is charged and stops all PV input until battery voltage drops to a recovery voltage set point and begins charging again. During charging loads have first call on any PV generated and the surplus goes towards the battery. Say you are generating 20a at battery voltage. Your loads demand 18a of that which leaves 2a to charge up the battery. Eventually your batteries voltage rises up to the SCC charge voltage setting.

So your system seems to be operating appropriately.

You do not want a charge controller that ignores the battery.

 

[wingedlizard]

Understood.. but why won't the growatt AIO switch to solar when there is an AC load?

At the end of the day, my battery is down 10 or 15 percent, even.though the sun has been out all day.

I would expect the day to end with a larger charge.

 

[sparrowhawk]

Understood.. but why won't the growatt AIO switch to solar when there is an AC load?

At the end of the day, my battery is down 10 or 15 percent, even.though the sun has been out all day.

I would expect the day to end with a larger charge.

I had the same issue until I set me bulk charging voltage and my float charging voltage to the same value. My inverter is the 24 volt version so for me it's 27.4 volts.

 

[Mattb4]

Understood.. but why won't the growatt AIO switch to solar when there is an AC load?

At the end of the day, my battery is down 10 or 15 percent, even.though the sun has been out all day.

I would expect the day to end with a larger charge.

Think of it this way. The battery and the SCC are connected in parallel. In order for the PV to charge the battery it has to increase the voltage potential to create current flow into the battery. If the voltage of the parallel DC circuit is above the SCC charge set point it must drop before charging will occur again. If you want to reach the end of the day with a full battery you need to have the right mix of loads and PV to charge the battery full, have it drop in voltage (battery charge drops) until the recovery point is reached, charging starts again, and once again reach full charge around the end of of the day.

It will never be perfect especially with a LiFePO4 battery chemistry. With FLA you can keep a constant trickle voltage that allows the PV to power other loads since FLA has a higher self discharge rate than lithium does. Some people use float charge voltage to do this with lithium but not all AIO's have a float stage for LiFePO4. You can also adjust the CV absorption time which might allow more PV production.

One other thing is adding an additional PV array and SCC. I find that with two SCC with slightly different charge settings (one lower than the other) feeding the same battery bank you can have the situation where one can begin a new charge cycle after the other finishes.

 

[wingedlizard]

So Solar/Battery/Utility is not really solar first. It does not use solar first -- it uses Battery if it's above the 'float' voltage, and only pulls solar if it trying to charge the battery.

 

[Mattb4]

So Solar/Battery/Utility is not really solar first. It does not use solar first -- it uses Battery if it's above the 'float' voltage, and only pulls solar if it trying to charge the battery.

It does use the energy from solar to power loads one of which is the battery. It is a bit hard to explain (at least for me) but regular loads grab the solar power first and any left over feeds the battery. Or if there is insufficient solar the battery acts to make up any difference. It is a function of them being in parallel (SCC output and the battery) just like you get with two batteries in parallel. That is until the battery reaches the charge voltage set points.

The video you linked did a good job of explaining this although it left out that not all SCC and AIO's will have a float voltage when they are operating in a lithium battery selection. They may have a float setting but it is ignored. Instead the SCC must drop below the recovery setting voltage (with the offset if any) before constant current starts over.