Pylontech batteries are stuck in alarm mode.

AlexSR

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Dear all,

Could someone give some directions on what could have happened with my battery array?
My system is composed of a 3000W PV array, a Growatt SHP4000 inverter and a 3x Pylontech US2000C battery array.
The system was running without any issues for the last 7 months, yesterday mid-morning the batteries were being charged from an overnight use and at 42% of charge all of them came up with the red alarm LED steady on and a "battery open" message on the inverter display.
From the batteries manual, it seems that this means that they are in protection mode, from the inverter manual the "battery open" says to check the battery terminals.
I disconnected everything and let it rest for 30 minutes to see if something would reset, didn't work.

Additional troubleshooting done:
Cables and terminals were inspected, but nothing was found.
Disconnecting the battery cables to the inverter if I turn the batteries on they go to run mode and operate normally.
I have measured the voltage in each battery module and for each one, I got a 49,5V reading.
If I reconnect the battery cables to the inverter and turn the batteries on without powering up the inverter the batteries jump immediately to protection mode, if I connect only one battery module to the inverter the same thing happens.
When I turn the inverter on a start cycle is done on the batteries but they jump back to protection mode.
The inverter itself is working fine without the batteries.
The batteries themselves seem to also be working fine if they are not connected to the inverter.

Any ideas or troubleshooting tips will be appreciated.
Thanks!
 

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Don B. Cilly

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Have you tried disconnecting the CAN/inverter-comms cable? Might be worth a try.
I vaguely remember when I was playing around with comms, I got a red light - everything working, mind you, but red.
Disconnected the cable, everything went back to normal after a few seconds - IIRC.
Those LEDs aren't very good at specifics ;·)
-
 

AlexSR

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Have you tried disconnecting the CAN/inverter-comms cable? Might be worth a try.
I vaguely remember when I was playing around with comms, I got a red light - everything working, mind you, but red.
Disconnected the cable, everything went back to normal after a few seconds - IIRC.
Those LEDs aren't very good at specifics ;·)
-
Thanks for the tip Don,

I have tried your suggestion and in fact, the batteries came out of the protection mode with the CAN cable disconnected but they immediately go back to it, then when I reconnect the cable they came out of the protection mode again for a few moments and the same thing happens, they go back almost immediately to protection mode.
 

Don B. Cilly

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Well, I don't know... but it's beginning to look like a "comms" error, isn't it.
Try just getting rid of the cable for the moment (it's not of much use, is it?), maybe try resetting the batteries...
-
 

AlexSR

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Do you have a procedure to reset these batteries?
I try to find it but apart from disconnect wait and reconnect I didn't find anything else.
 

Don B. Cilly

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Yeah, no, by "reset" I simply mean, switch them off, wait a minute, switch them back on.
Maybe disconnect the circuit breaker to the inverter/loads before - if you have one - and reconnect it after.
-
 

AlexSR

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Everything was turned off during the night. And I have already tried to do what you described a couple of times today.
What is really bugging me is the fact that if I turn the batteries on with the inverter off, I also get the protection mode triggered, but if I turn the batteries on without the cables connected to the inverter they start ok.
 

timselectric

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It's possible that the load, when connected. Pulls the SOC below the parameters of protection mode. Maybe the readings are off. Do you have a way to charge the batteries, separately?
 

Don B. Cilly

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Do you have a way to charge the batteries, separately?

Well, I do. I have a separate SCC, and a stand-alone 24V battery charger, if needed.
If the only way to recharge your batteries is via the "inverter", well, maybe you don't.

Or maybe you can turn off the inverter part and just leave the SCC charging. Quite likely, actually.

[EDIT] Yeah well. We don't need the OP flag plugin after all, do we? icon_smile_firuli.gif
-
 
Last edited:

timselectric

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Well, I do. I have a separate SCC, and a stand-alone 24V battery charger, if needed.
If the only way to recharge your batteries is via the "inverter", well, maybe you don't.

Or maybe you can turn off the inverter part and just leave the SCC charging. Quite likely, actually.
-
Sorry, that question was meant for the OP.
I guess that I could have tagged them.
 

AlexSR

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It's possible that the load, when connected. Pulls the SOC below the parameters of protection mode. Maybe the readings are off. Do you have a way to charge the batteries, separately?
Hi Timselectric,

No, I don't have a way to charge them separately. About the readings, well looking at the data from yesterday it charged 2.5kW until it start giving the error.
Today it is still saying that they are charged to 41%.
 

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AlexSR

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Is there any available software around from pylontech that I could use to check internal batteries logs?
 

AlexSR

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Just came across some details for the error on the inverter side. Well, there is a low battery entry there between others... not sure what to think anymore.
 

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timselectric

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You may want to raise the SOC setting for back to grid. At least until you get it sorted out.
 

timselectric

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Signature solar has a 14a one, I believe.
Or you can find a lower output option on Amazon or ebay.
 
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