MPP solar 11kw with Pylontech US5000 - low battery error

[ns31]

I'm in touch with Pylontech, they claim that the cable supplied with the batteries may need modifying to work with the MPP inverter. Will see what comes of this and feed back once its done....

 

[SenileOldGit]

Isn't the error saying 'battery weak' totally dependent on what voltage he has the settings at? So if he set it at 50V, he would get a 'battery weak' message as soon as the battery discharged down to 50V, even though the battery wasn't near empty.

 

[Lt.Dan]

Isn't the error saying 'battery weak' totally dependent on what voltage he has the settings at? So if he set it at 50V, he would get a 'battery weak' message as soon as the battery discharged down to 50V, even though the battery wasn't near empty.

We have no idea what "Battery weak" actually means. Hence why above I suggested watching the LCD screen on the inverter and see if it throws an error code we can actually use. Battery weak could be an overcurrent alarm, or a cell imbalance, who knows.

 

[SenileOldGit]

If the 'back to utility' voltage setting is 48V, isn't that too high? My PIP5048MKX manual says the default for my inverter is 46V.

 

[SenileOldGit]

Regarding the low battery alarm, raising the setting will make the problem worse as it will happen sooner during the discharge cycle. Here is an analogy: If your car is always running out of Petrol then the solution is to just disconnect the fuel gauge wire!!

Lt.Dan, we know what 'battery weak' means, it's the error message that comes up when the battery voltage goes below the voltage you have set in Setting 12.

 

[SenileOldGit]

Even at 48V it sounds an alarm, why is this if running the battery down is intended behaviour?...

View attachment 166841

You say "even at 48V", don't you mean "even at 38V", because you said in the previous post that the lowest setting you could try was 38V?
My PIP5048MKX MPP Solar inverters only go down to 44V, and the Pylontech US5000 manual says the discharge voltage can be between 43.5V-53.5V. Have you tried setting it at 45V?

What voltage does the inverter say the battery is at, when the 04 warning displays?

 

[ns31]

You say "even at 48V", don't you mean "even at 38V", because you said in the previous post that the lowest setting you could try was 38V?
My PIP5048MKX MPP Solar inverters only go down to 44V, and the Pylontech US5000 manual says the discharge voltage can be between 43.5V-53.5V. Have you tried setting it at 45V?

What voltage does the inverter say the battery is at, when the 04 warning displays?

That should have read 48V sorry, 38V was a typo. I think what @BentleyJ says makes sense, as lowering to 46V threw an 04 error.

 

[SenileOldGit]

What does the manual say the default setting should be?

 

[ns31]

What does the manual say the default setting should be?

It doesn't. It gives a default of 46V... https://www.mppsolar.com/manual/PIP-MAX/PIP MAX 11KW manual.pdf

 

[SenileOldGit]

So the manual says the default setting is 46V.

Have you checked all of your battery cable connections, including into your MCBs and/or fuses? Are all battery cables the same length? I had a problem with a battery cable going into an MCB and it caused the voltage to be read by that inverter (I have two inverters) as 27V, when it should have been 50V.

 

[ns31]

So the manual says the default setting is 46V.

Have you checked all of your battery cable connections, including into your MCBs and/or fuses? Are all battery cables the same length? I had a problem with a battery cable going into an MCB and it caused the voltage to be read by that inverter (I have two inverters) as 27V, when it should have been 50V.

All the same length and the +ve leads are on fuses which are fine. I think more battery power is needed as voltage drop occurs under load (2x batteries isn't quite enough), and I also need to check the cable from the batteries to the inverter is wired as Pylontech recommend.

 

[SenileOldGit]

What is your setting 29? It should be 42V. If that's higher than 42V, that might explain it. What is the maximum load the inverters are giving out to the house?

 

[ns31]

29 is automatic based on PYL being selected on setting 5