diy solar

diy solar

Help with Growatt Maximum Ac Charge Current. Low Voltage output doing Bulk Charge from Utility.

Olasitu

New Member
Joined
Aug 6, 2022
Messages
43
I have 2 Growatt 5000 ES installed in Parallel with 2 x Blue Carbon 48V 200Ah Lithium Battery Pack For Solar Home System. PVs are Mono 10 x 550W. 5 panels each in series to each Inverter. Priority is set to Solar, Utility and Battery.

We have quite frequent power cuts that results in Batteries charged to 50%. On resumption of Utility power - Battery is pulling like 2KW for Bulk charging which is resulting in Low Voltage in the rest of the house. Like in the range of 205 - 210. Once battery reaches Float charge Voltage output returns to normal.

This low voltage output does not happen under normal operation. PV, Utility or Battery only.

There are 2 related settings:
Setting 11 - Maximum Utility Charging Current set to 30A (Range is 0 - 80A)
Setting 2 - Maximum Ac Charge Current. This is a combination of Solar and Utility. This is also set to 30 A! The range is 10 - 100A.

Maximum Ac Charge Current is set to 30A. Should this be increased?

Or is there something else going on?
 
There should be 3 related settings.
Max utility charging current (DC amperage) AC is inverted to DC so remember W=VA
Max charge current (AC inverted to DC and PV)
Max PV charge current

If your Max charge current is only 30a you are severely limiting PV production from your panels.

On your AC voltage dipping low during a grid lost and recovery. This would indicate inadequate wiring to your inverter to create such a large voltage drop on startup current. Or possible your supply from the grid is inadequate.

What wire size are you using and what is the run length?
 
Thank you for the comments. I have noted the comments re. 30A. I have the Technician coming in tomorrow. However, I have attached 2 pictures. One for the Wiring from the Batteries and one for the Wiring from the Grid and the Internal distribution board. Please do note ... this issue only occurs during Bulk charge. The issue does not occur otherwise on normal Grid power.
 

Attachments

  • GW-01.jpg
    GW-01.jpg
    486.8 KB · Views: 12
  • GW-02.jpg
    GW-02.jpg
    527.3 KB · Views: 13
There should be 3 related settings.
Max utility charging current (DC amperage) AC is inverted to DC so remember W=VA
Max charge current (AC inverted to DC and PV)
Max PV charge current

If your Max charge current is only 30a you are severely limiting PV production from your panels.

On your AC voltage dipping low during a grid lost and recovery. This would indicate inadequate wiring to your inverter to create such a large voltage drop on startup current. Or possible your supply from the grid is inadequate.

What wire size are you using and what is the run length?
Replying further Battery to Inverter Run is less than 6 Meters. Inverters are at most 2 Meters from the Distribution Board. You may have a point on the Grid Voltage. I have attached additional pictures.
 

Attachments

  • GW-03.jpg
    GW-03.jpg
    587.5 KB · Views: 11
  • GW-04.jpg
    GW-04.jpg
    585.9 KB · Views: 11
When operating in AC bypass your battery is not supplying anything other than the Growatts operation circuit. So it can be ignored as a contributing factor.

You could try reducing your AC charging current to see if it helps.
 
Wow. I thought it was too low.

Setting 11 - Maximum Utility Charging Current is set to 30A (Range is 0 - 80A)

OK. Will try this out. But please explain why this could help. Sorry. Newbie.
 
It can help by reducing total load. When utility is supplying loads plus charging battery at 30a you draw that extra 2000w that you note in your first post. Say you reduce the utility charging to 20a. At that point 20a X 52vDC =1040w plus some overhead for a load of 1500w.

Voltage drop is a function of current and impedance. https://en.wikipedia.org/wiki/Voltage_drop
 
Thank you so much. One last question. Does this mean I can set PV charge current much higher than Grid charge as you've noted earlier. How come PV has a different effect compared to Grid. Many many thanks for your Time.

So PV 60a and Grid 20a. Max combined 80.??
 
PV charge current will be affected by 3 conditions. The rating of your inverter, the amount of wattage from your solar panels and finally by the safe charge current your batteries can accept (this has to be manaully set if you have too much).

Your first post said that you have 5 panels of 550w per inverter (2 inverters so keep in mind that battery charging will add both together) that is a total of 2750w each inverter. 2750w/52vDC = 52.88a

Grid charging is going to load your grid and PV charging loads the panels. Say you are running in bypass so that the inverter can use both. At that point the panels amperage and grid charging amperage adds together. In this case with setttings of G=20a and PV=60a the total will be actually 20a + 52.88a (only if panels are delivering maximum in full sun which is unlikely) 72.88a to the batteries from each inverter.
 
Last edited:
Back
Top