Epever 8420AN almost blew up my batteries

[Copyright2017]

Quickly before I get started, I just created this account because I'm kind of in need of some advice asap. Hello everyone! Call me "Copy" anyways, I have lurked on here for a while getting answers here and there about questions that have arose as I built my system. The system has worked great until today it scared the absolute sniezenhouerzers out of me.

This morning I woke up to a pleasant surprise of a hissing noise coming from my batteries.
For reference:

• The charge controller (Epever 8420an) is hooked to 3500 W of solar and a 48v bank with 840ah and two 16 ga dedicated wires running to the batteries for the Remote Voltage Sensor. Also the wires going to load and charge controller are all 1/0 (into the charge controller they had to be trimmed down a tiny bit to fit) for the least resistance and voltage drop possible.
• I have a raspberry pi reading all of the charge controllers information via modbus and recording it in homeassistant.io, this allows me to see what the charge controller is doing even if i am not present.

I woke up around 10:30 AM to a slight hissing noise outside. I didn't think anything of the hissing noise because it wasn't too loud. I opened up my phone and started looking at social media. After a couple minutes I opened the homeassistant app on my phone and it showed a battery voltage of 31.25v which immediately sent me into panic mode. I ran over to the controller - the alarm light was on and the voltage on the display read 31v. I grabbed my multimeter and read the actual voltage on the terminals at somewhere around 65 volts! I quickly grabbed a screwdriver and disconnected the positive solar terminal. Immediately the voltage on the display of the charge controller jumped up to 63v and then started declining where it stabilized around 56 volts.

I have a homeassistant graph(s) of the events:

Voltage:

https://imgur.com/MkS1ktd

It looks like around 8:15 AM the charge controller had an error and started reading the wrong voltage. I was still sleeping at this time. My alarm went off at 10:30 AM and it was only when I checked my phone at 10:35 ish did I see the problem.

Battery Current:

https://imgur.com/HFEhbMT

As you can see it looks like the charge controller had been steadily applying more current to the batteries to try and "charge" the batteries even though they were already fully charged.

The charge controller is currently disconnected. Please help me figure out what happened here. I do not feel comfortable reconnecting the controller.

The batteries could have easily exploded. 65v/4 is 16.25 volts on a lead acid. I would be dead right now if they had exploded.

I contacted Epever about it but haven't heard anything back. I contacted them about a month ago for another reason (to get the modbus protocol information) and recieved a response almost instantly so the fact that I am not getting anything back is worrying.

 

[gnubie]

Is your epever set for autodetection of battery voltage or have you manually set it to 48V? It looks like the recorded battery voltage roughly halved when the problem happened. I don't know about your particular epever but a lot of these things have firmware that will work on higher voltage models , and that might mean it faulted and the autodetect said the battery was 96V. It then took the base 12V figures multiplied by 8 and tried to pull the battery up to there.

 

[theotherhand]

Hi, have you made any progress in understanding what happened? Has anyone from epever been in touch?

 

[Copyright2017]

Update: epever replied and said it's the batteries fault. But the batteries are fine. They also told me that my graphs are "fake" and that there's no possible way for the charge controller to go above it's voltage disconnect which I recall is around 60 volts.

 

[Supervstech]

Update: epever replied and said it's the batteries fault. But the batteries are fine. They also told me that my graphs are "fake" and that there's no possible way for the charge controller to go above it's voltage disconnect which I recall is around 60 volts.

Wow...
Actual measured voltage... and refusal to acknowledge the results...

Ask to speak to a supervisor...