GroWatt SPF 5000 - some questions

[david47]

Hello,
I am just beginning my research into what parts I need to buy for my future solar system, and came across SPF 5000 inverter. Could someone please verify that it's an appropriate inverter for the following scenarios:

1. Inverter + LiFePO4 batteries
-have the inverter charge the batteries using grid energy at a specific time of day (say a 5 hour window), and then use the energy stored in the batteries for the remaining 19 hours. If battery energy runs out, need the grid to take over the house loads, but not charging the batteries outside the set timeframe. Generally want the inverter to charge the batteries up to a max of 85%, and discharge to the minimum of 20%

2. Inverter + LiFePO4 batteries + solar
-have the inverter charge the batteries using primarily solar, and grid as secondary option. Once the batteries are full, have the solar energy routed directly to the house, never back to the grid. Still keeping the same requirement as in the first scenario though, which is charging the batteries through the grid only in the said 5 hour period.



As I understand, SPF 5000 is the correct inverter for the job?

 

[AshleyL]

......get SPF 6000 ES instead.
Be warned. Voltronic is the major OEM for all those MPP, Growatt, EG etc.....except Victron.
All inverters produced by Voltronic utilizes the battery for its idle power consumption. It is not low, it is 50 - 75 watts.
Basically, you will lose 1 - 2 kWh in 12 hours just to power the inverter from the battery.
This is known as "the cost of doing business".

 

[timselectric]

Hello,
I am just beginning my research into what parts I need to buy for my future solar system, and came across SPF 5000 inverter. Could someone please verify that it's an appropriate inverter for the following scenarios:

1. Inverter + LiFePO4 batteries
-have the inverter charge the batteries using grid energy at a specific time of day (say a 5 hour window), and then use the energy stored in the batteries for the remaining 19 hours. If battery energy runs out, need the grid to take over the house loads, but not charging the batteries outside the set timeframe. Generally want the inverter to charge the batteries up to a max of 85%, and discharge to the minimum of 20%

2. Inverter + LiFePO4 batteries + solar
-have the inverter charge the batteries using primarily solar, and grid as secondary option. Once the batteries are full, have the solar energy routed directly to the house, never back to the grid. Still keeping the same requirement as in the first scenario though, which is charging the batteries through the grid only in the said 5 hour period.



As I understand, SPF 5000 is the correct inverter for the job?

Yes, It will do what you want.
But limiting your usable capacity to between 20% and 85% is wasting money. (35% of your money)
Without any benefit.

 

[david47]

Yes, It will do what you want.
But limiting your usable capacity to between 20% and 85% is wasting money. (35% of your money)
Without any benefit.

I will be cycling them daily as I have servers to run continuously, as I understand using only 60-70% of their storage capacity daily instead of 90% should greatly prolong battery's life.

 

[timselectric]

I will be cycling them daily as I have servers to run continuously, as I understand using only 60-70% of their storage capacity daily instead of 90% should greatly prolong battery's life.

That's a common misconception. Carried over from EV's (Electric Vehicles). Which are discharged and charged more aggressively. Which generates a lot of heat in the cells.
For solar storage, you can use the full capacity without concern. If you are draining your batteries completely in 2 hours. Your battery is way undersized. And with LFP batteries, you need to get into the upper knee of the charging curve regularly for balancing to occur. Without balancing, the usable capacity is continuously diminishing.

 

[kirkdis]

my conceptual planning for a PV is based on the worst days/weeks in the year. To be honest this is not the cheapest version but the most sustainable one.

IF you need 10kW per night then plan your storage at least three times bigger. SPF5000 are fine as those devices are a great proof of concept and cheap these days. The SPF 6000 I never saw physically but how I know Growatt it takes up to 2 years to fiddle out the firmware issues and therefore I would not recommend to pick the 6000 version over the 5000 as long you are not in need of 2 separate MPPT inputs.