New Sunny Island and JK PB BMS set up - problem and solution.
We’ve had a US 6048 Sunny Island 12kw split phase set up for many years now. It was set up as back up for when grid power was lost with a lead acid forklift battery. That set up worked well for years. We recently upgraded to the JK PB BMS because it’s supposedly has closed loop communication that works with the Sunny Island. Thanks to some forum members here, we got some really nice CATL 12 V battery packs that we wired together for 48 V packs. Built in heating pads, welded, busbars, compressed metal case, etc. Total of 93 kWh and 8 JK PB 2A BMS boards.
The short version.
We set everything up and kept getting LOBAT1 warnings W755, W756, and external BMS communication loss warnings. The warnings were due to a can bus communication failure on the Sunny Island part. Updating to the latest SMA firmware for the Sunny Island fixed the problem. There is a new firmware version available as of May 2024, 7.304 that among other things addresses can communication error that we had. This completely fixed the problem. I can say with high confidence that the Sunny Island works and communicates well with the JK PB BMS. There are others issues that I’ve heard such as the JK factory making firmware that creates problems as well as solves them so pick firmware you like and try to stick with it if possible.
The longer version.
We kept seeing W755 and W756 and some other warning messages. External BMS communication loss was another error we saw. Depending on the circumstance, when you get these messages, the Sunny Island thinks the battery is at 0% SOC and potentially shuts the whole system down. One shutdown was so serious that we had to disconnect everything from the inverter for half hour before it would boot up again. The 755 is LOWBAT1 warning. Normally, for lead acid these are set at say 40% for number one, 20% for number two and say 5% for low battery level three warning. Warnings are, of course, a bit less severe than failures. Warnings just tell you what’s happening failures actually would lead to a shut down. Anyway, this is supposed to be the short version. We installed a raspberry pie and some monitoring software so that we could monitor all the Sunny Island parameters on Home Assistant. We were able to see that we kept getting these low battery warnings sporadically in the evenings and at night. Generally. First, we lowered those parameters to 20% 10% and 3%. That did not solve the problem. Got the same error messages. We ended up setting all the battery protection levels to 0%. But that did not solve the problem either.
At one point, we swapped the master and slave Sunny Island to see if the problem was in the master only. That did not solve the problem.
There’s also a thing where the Sunny Island uses 100 ohm terminating resistors and the JK uses 120 ohm terminating resistors. We made new resistors to match what the Sunny Island had. That did not solve the problem.
We used a normal ethernet cable with an RJ 45 for communication to Sunny Island from the JK master in BMS. It was running in the same path as the AC and DC cables and was just fractions of an inch away from those. Thinking that the cable may be too close to those AC and DC wires and getting interference, we move the communication cable away from those AC lines. That did not solve the problem.
Thinking it still may be the cable, we replaced it with a shielded ethernet cable and ran it far away from the AC and DC lines. That did not solve the problem.
Thinking maybe the master JKBMS might be the problem we swapped the JK master and the slave. That did not solve the problem.
Thinking that also the BMS to BMS communication cables might be the problem. We also swap those out for short shielded cables. That did not change anything either.
Another option was that we were using firmware on the JK that was slightly newer than other users. We downgraded the firmware to that older version on the JK. That did not solve the problem. You need to have a code generator to install older firmware. Here’s a link below for Google that will generate those codes that are valid for one hour. With that code generator, you can install any firmware old or new.
Info below on how to set up Sunny Island communication with the Home Assistant.
https://diysolarforum.com/threads/s...-6048us-monitoring-with-home-assistant.91280/
With the raspberry pie, we can get the following data from Sunny Island. Home Assistant: see below.
LINK COMING
JK bms code generator to downgrade/force update firmware.
https://mirofromdiro.github.io/JK-firmware-code/
We’ve had a US 6048 Sunny Island 12kw split phase set up for many years now. It was set up as back up for when grid power was lost with a lead acid forklift battery. That set up worked well for years. We recently upgraded to the JK PB BMS because it’s supposedly has closed loop communication that works with the Sunny Island. Thanks to some forum members here, we got some really nice CATL 12 V battery packs that we wired together for 48 V packs. Built in heating pads, welded, busbars, compressed metal case, etc. Total of 93 kWh and 8 JK PB 2A BMS boards.
The short version.
We set everything up and kept getting LOBAT1 warnings W755, W756, and external BMS communication loss warnings. The warnings were due to a can bus communication failure on the Sunny Island part. Updating to the latest SMA firmware for the Sunny Island fixed the problem. There is a new firmware version available as of May 2024, 7.304 that among other things addresses can communication error that we had. This completely fixed the problem. I can say with high confidence that the Sunny Island works and communicates well with the JK PB BMS. There are others issues that I’ve heard such as the JK factory making firmware that creates problems as well as solves them so pick firmware you like and try to stick with it if possible.
The longer version.
We kept seeing W755 and W756 and some other warning messages. External BMS communication loss was another error we saw. Depending on the circumstance, when you get these messages, the Sunny Island thinks the battery is at 0% SOC and potentially shuts the whole system down. One shutdown was so serious that we had to disconnect everything from the inverter for half hour before it would boot up again. The 755 is LOWBAT1 warning. Normally, for lead acid these are set at say 40% for number one, 20% for number two and say 5% for low battery level three warning. Warnings are, of course, a bit less severe than failures. Warnings just tell you what’s happening failures actually would lead to a shut down. Anyway, this is supposed to be the short version. We installed a raspberry pie and some monitoring software so that we could monitor all the Sunny Island parameters on Home Assistant. We were able to see that we kept getting these low battery warnings sporadically in the evenings and at night. Generally. First, we lowered those parameters to 20% 10% and 3%. That did not solve the problem. Got the same error messages. We ended up setting all the battery protection levels to 0%. But that did not solve the problem either.
At one point, we swapped the master and slave Sunny Island to see if the problem was in the master only. That did not solve the problem.
There’s also a thing where the Sunny Island uses 100 ohm terminating resistors and the JK uses 120 ohm terminating resistors. We made new resistors to match what the Sunny Island had. That did not solve the problem.
We used a normal ethernet cable with an RJ 45 for communication to Sunny Island from the JK master in BMS. It was running in the same path as the AC and DC cables and was just fractions of an inch away from those. Thinking that the cable may be too close to those AC and DC wires and getting interference, we move the communication cable away from those AC lines. That did not solve the problem.
Thinking it still may be the cable, we replaced it with a shielded ethernet cable and ran it far away from the AC and DC lines. That did not solve the problem.
Thinking maybe the master JKBMS might be the problem we swapped the JK master and the slave. That did not solve the problem.
Thinking that also the BMS to BMS communication cables might be the problem. We also swap those out for short shielded cables. That did not change anything either.
Another option was that we were using firmware on the JK that was slightly newer than other users. We downgraded the firmware to that older version on the JK. That did not solve the problem. You need to have a code generator to install older firmware. Here’s a link below for Google that will generate those codes that are valid for one hour. With that code generator, you can install any firmware old or new.
Info below on how to set up Sunny Island communication with the Home Assistant.
https://diysolarforum.com/threads/s...-6048us-monitoring-with-home-assistant.91280/
With the raspberry pie, we can get the following data from Sunny Island. Home Assistant: see below.
LINK COMING
JK bms code generator to downgrade/force update firmware.