Growatt SPF5000ES Issues

[CătăDR]

Dear all, I’m having a hard time with my Growatt SPF5000ES. It keeps burning the Mosfets from the DC-DC converter and DC-AC inverter from the main board with no warning or fault before. Just after that it gives error 52 ‘low bus voltage’, bus voltage start failed’. It does it every time after the battery gets to 100%. The setup is 12 x 455w Longi panels, 2 x Pytes 5.12kw/h, 20 amps fuse and 20 amps breaker on the panels input, 100amp fuse in the battery input, 32amps breakers on the input from the grid and on the output from the inverter to the house. After the first inverter failed after 8 months I bought another one witch failed after one month and was replaced with the first one witch I repaired and failed again after almost one month. The problem appears during the summer. Didn’t have any issues during the cold season. I’m tired of replacing mosfets . Hope I was clear enough. Any ideas? Thanks

 

[B-Mod]

What is input voltage of the solar panels measured before hooking to growatt, using a digital meter? How are panels hooked up, series? Parallel?

 

[CătăDR]

What is input voltage of the solar panels measured before hooking to growatt, using a digital meter? How are panels hooked up, series? Parallel?

Panels are 2p 6s voc297vdc

 

[drbytes]

Did you figure it out ?

 

[AntronX]

It does it every time after the battery gets to 100%.

My guess is battery BMS disconnects while high charge current is present and causes voltage spike inside inverter that kills the FETs. You have to program inverter battery float and absorption voltage to 55.5V to allow inverter to taper the charge current before BMS does hard disconnect. Also have make sure cells stay top balanced to prevent a runner cell from tripping the BMS.

 

[CătăDR]

Did you figure it out ?

Yes, the problem is that the cooling fans are programmed to run at full speed only over 200w load and if you have a big load running witch generates a lot of heat in the inverter and then the load gets under 200w the fans go to minimum speed and due to thermal inertia the mosfets get overheating. It is stupid

 

[NCislander]

Yes, the problem is that the cooling fans are programmed to run at full speed only over 200w load and if you have a big load running witch generates a lot of heat in the inverter and then the load gets under 200w the fans go to minimum speed and due to thermal inertia the mosfets get overheating. It is stupid

That does sound stupid, glad you found the cause. Has additional cooling external to the units possibly helped? Keeping a Fan blowing air across the Growatt unit(s)?
I run (2) Growatt 5000 units. In open air shop, no air conditioning, but plenty of circulating air flow. Not a problem yet.

 

[CătăDR]

That does sound stupid, glad you found the cause. Has additional cooling external to the units possibly helped? Keeping a Fan blowing air across the Growatt unit(s)?
I run (2) Growatt 5000 units. In open air shop, no air conditioning, but plenty of circulating air flow. Not a problem yet.

I’m still trying to figure out a solution on how to add extra cooling to the unit

 

[Quattrohead]

Are you sure you have the correct charging voltage setup on the Growatt, I thought those batteries were 48 volt not 51.2 volts. An over voltage would make the BMS disconnect the battery and puff would go your mosfets.

 

[CătăDR]

Are you sure you have the correct charging voltage setup on the Growatt, I thought those batteries were 48 volt not 51.2 volts. An over voltage would make the BMS disconnect the battery and puff would go your mosfets.

The battery and the inverter are connected via a CAN cable so the charging voltage and all other battery parameters are controlled by the battery bms. I can’t change anything. After the temperatures dropped in August didn’t have any problems

 

[AntronX]

and due to thermal inertia the mosfets get overheating

How did you determine that being the cause of failure?

 

[CătăDR]

How did you determine that being the cause of failure?

I have Solar assistant installed and i can see on the temperature graph a spike every time the load suddenly drops below 200w (eg. from 2000w) and the cooling fans go to idle

 

[AntronX]

That's normal. More likely it's your BMS disconnecting under high charging current. What do you have your bulk charging volts set to? Closed loop BMS comms or user mode?

 

[CătăDR]

Every time it failed the batteries were charged up and there was a minimum load on the inverter (around 150w). It happened only during summer