Growatt SPF 3000TL LVM Fault 08: High Bus Voltage

[rykelo]

Hey Everyone!

My Growatt is displaying fault 08: high bus voltage anytime the panels (3 x 440W bifacial in series) are in direct sun during peak hours. I don't know anything about anything but it seems like my panels are overwhelming the Growatt.

My battery is custom built LiFePo4 with no BMS (photo attached).

Is there a setting I'm missing that would prevent this fault from happening? Thanks!

Settings:

01: SBU
02: 60A
03:APL
04: Sds
05: US2
06: auto restart enable
07: enabled
10: Number of series batteries: 2 (very uncertain about whether this one is right!)
11: 30A
12: 24.5V
13: 27V
14: CUt
18: bYD ( overload bypass disabled... Maybe this has something to do with it? I don't know what "line mode" means in the instructions)
19: 29.2V
20: 29.2V
21: 24V
22: SbE
Everything else default settings. Thanks again!

 

[sunshine_eggo]

My battery is custom built LiFePo4 with no BMS (photo attached).

Fix the above first. Running LFP w/o BMS is not acceptable.

 

[rykelo]

@sunshine_eggo thanks for the reply - I should have mentioned there are computer chips and temp sensors wired in. These don't communicate with the Growatt via a BMS cable but they do provide low temperature charge protection and perhaps other things the BMS would do that I'm unaware of but my battery guy knew about when installing those computer boards.

 

[sunshine_eggo]

What's this?

Additionally, please provide tech specs for your panels.

 

[gelmjw]

Three 440s will likely exceed the Growatt's 145VOC limit. I have a 410 and the VOC is 49.

 

[acdoctor]

Take one of the panels out and let us know if it still changes. I for one am interested in it can handle pv over voltage. And what is the VOC of those panels?

 

[sunshine_eggo]

You should be fine with the 3 even in the hot coukd never hit 146 volts I’m a growatt dealer when did you buy they have 3 your warranty’s there are a few things to check first is do you have it set to solar utility abs battery it just the solar and utility of set up wrong it will try abs use a battery that is not there. There smart just not that smart the other has to do with code. 8 is a few things what did you do before

The hot is not a concern as Voc is lower than spec. It's the cold he has to worry about and 3X 72 cell panels in series is too much. Period.

I would expect a professional to know this.

 

[rykelo]

You guys nailed it - I finally heard back from my guy (they're not the best at customer support, and I no next to nothing about solar) and he said the third panel in series creates too much voltage for the Growatt to handle. He said the simple fix is to rewire the panels in parallel. When they designed the system it was originally with two panels, but when I showed up to pick up the system they had an additional panel from another job which had been damaged (superficially - still functions fine) and offered to sell it to me at a pretty heavy discount. I bought it and added it to the array - and here I am today with too much voltage on my hands... perhaps a good problem to have! I don't know anything about the differences between parallel or series wiring, but do you guys think it's a good solution?

 

[rykelo]

Also - requesting tech specs for panels and a description of that those computer boards are all about... will post here when I hear back. Thanks again everyone for your input!

 

[MisterSandals]

I don't know anything about the differences between parallel or series wiring, but do you guys think it's a good solution?

3 panels in parallel will result in an array producing the single panel voltage but 3x your panel amps (the sum of panel amps). You will need to fuse each panel anytime you have 3 or more in parallel.

An easy solution would be to add a 4th panel, if available and room for it. You can run 2S2P setup with just a set of cheap Y cables. The array would be 2x panel voltage and 2x panel amps. All easy to wire and accepted by your SCC.

Check Amazon for MC4 Y cables (assuming your panels have MC4 connectors of course).

 

[rykelo]

View attachment 71642

What's this?

Additionally, please provide tech specs for your panels.

From my supplier: "These Chips are called BMS (Battery Management system) units, their job is to make sure that the battery is only charged under safe conditions. Generally, the Growatt does the same thing but this acts as a second layer of protection in the case that the Growatt unit may fail (which is unlikely). These units look at voltage, current, and ambient temperature. They make sure that the voltage of the battery is not too low or too high, they make sure that the current flowing into the battery and out of it is also in a safe window and they make sure that the battery is only used in safe temperatures. Lastly, these units also make sure that every cell in the whole battery pack is balanced and will actively balance them if it detects that there is a difference in charge."

Panel spec sheet attached!

 

[sunshine_eggo]

My battery is custom built LiFePo4 with no BMS (photo attached).

The above conflicts with this:

From my supplier: "These Chips are called BMS (Battery Management system) units, their job is to make sure that the battery is only charged under safe conditions. Generally, the Growatt does the same thing but this acts as a second layer of protection in the case that the Growatt unit may fail (which is unlikely). These units look at voltage, current, and ambient temperature. They make sure that the voltage of the battery is not too low or too high, they make sure that the current flowing into the battery and out of it is also in a safe window and they make sure that the battery is only used in safe temperatures. Lastly, these units also make sure that every cell in the whole battery pack is balanced and will actively balance them if it detects that there is a difference in charge."

Panel spec sheet attached!

You DO have a BMS.

 

[rykelo]

Ah okay I was confused about BMS... There was a BMS wire that came with the Growatt for connecting to the battery and because I had no way of connecting that wire I was unsure as to my BMS situtation. Seems my battery has it built in - sorry about the mixup!

 

[rykelo]

You will need to fuse each panel anytime you have 3 or more in parallel.

Thanks @MisterSandals - why do I need a 4th panel? Is there a setup where I have the 3 panels wired with 2 in series and the 3rd on its own somehow? Thanks

 

[MisterSandals]

Thanks @MisterSandals - why do I need a 4th panel? Is there a setup where I have the 3 panels wired with 2 in series and the 3rd on its own somehow? Thanks

With 3 panels, there are only 2 ways to connect them: 3 series (voltage too high for your SCC), and 3 parallel which requires fuses on each panel.

With 4 panels, a very popular configuration is 2S2P. This requires a pair of Y connectors (~$15 on Amazon). This often provide a sweet spot for moderate voltage and moderate amps.

 

[gelmjw]

... Is there a setup where I have the 3 panels wired with 2 in series and the 3rd on its own somehow? Thanks

No. Your best solution is 3P, and this will require the fewest extras.

Connect with a 3-to-1 Y MC4 connector. Add the fuses as spec'ed by your panels, one for each POS input to the Y.

If you have 10GA from the Y to the controller, you will likely exceed the 30A rating. You will want to replace with 8GA.

I am installing a similar system with the 24V Growatt 3000. It took a long search to find these particular panels to max out my roof and stay within the GW limits. The panels are SunPower E20 327W to be in 3P configuration. The specs I am working with are VMP 54.7, IMP 5.98, connected in 3P which is 55V * 18A, rounded for illustration. The 18A is within the 10GA rating.

A costly option is two panel strings and two controllers in parallel on the battery bank. The GW could run 2S. A separate controller with the 1 panel would also require its own wiring.

 

[gabrielpc1190]

No. Your best solution is 3P, and this will require the fewest extras.

Connect with a 3-to-1 Y MC4 connector. Add the fuses as spec'ed by your panels, one for each POS input to the Y.

If you have 10GA from the Y to the controller, you will likely exceed the 30A rating. You will want to replace with 8GA.

I am installing a similar system with the 24V Growatt 3000. It took a long search to find these particular panels to max out my roof and stay within the GW limits. The panels are SunPower E20 327W to be in 3P configuration. The specs I am working with are VMP 54.7, IMP 5.98, connected in 3P which is 55V * 18A, rounded for illustration. The 18A is within the 10GA rating.

A costly option is two panel strings and two controllers in parallel on the battery bank. The GW could run 2S. A separate controller with the 1 panel would also require its own wiring.

I have six of this panels and today I found myself discovering this Error 08 on my SPF 3000 24v. I have two strings of 3 panels in series, so 3S2P, and has been running for maybe 3 months without a problem, but now that the summer is hitting hard here, maybe too much power is generated?

I'm guessing I would have to install some more Y MC4 connectors and have 2S3P.
What do you think?

 

[MisterSandals]

I'm guessing I would have to install some more Y MC4 connectors and have 2S3P.
What do you think?

Yes, there are MC4 3:1 connectors:

Amazon.com

Amazon.com

 

[gelmjw]

I have six of this panels and today I found myself discovering this Error 08 on my SPF 3000 24v. I have two strings of 3 panels in series, so 3S2P, and has been running for maybe 3 months without a problem, but now that the summer is hitting hard here, maybe too much power is generated?

I'm guessing I would have to install some more Y MC4 connectors and have 2S3P.
What do you think?

I can assure you that I would not configure my panels in 3S. Those panel's VOC is above 65V and three in series would equal 195V which would then exceed the GW's 145VOC limit. Poof!

I think I cannot offer anything else unless you provide your panel's VOC, VMP, and IMP.

 

[gelmjw]

I have six of this panels and today I found myself discovering this Error 08 on my SPF 3000 24v. I have two strings of 3 panels in series, so 3S2P, and has been running for maybe 3 months without a problem, but now that the summer is hitting hard here, maybe too much power is generated?

I'm guessing I would have to install some more Y MC4 connectors and have 2S3P.
What do you think?

Part deux:

As to the bolded above, you have the temperature issue backwards and wrong. The issue is too high VOC, not power. A panel's VOC is reduced as it heats. You may have already passed the critical point for the VOC issue. I can only conclude the you did not exceed the VOC limit of the GW.

What is the highest VOC you have experienced?