Dear All,

My current setup:

3 x Axpert King 5KW (Full Circle Solar) in parallel (Firmware 71.97 + 02.66) 

1 x Bluenova HC 37.5 Lithium

1 x Bluenova BMAC

28 x 370w panels (string 2sx5p X2 + 2sx4p) 

ICC 4.9 on Pie

 

I recently upgraded from 16 x Narada AGM batteries (+Victon BMC 702) to the BluenovaHC battery. Removed the Victron BMV 702 and replaced with Bluenova BMAC. 

Current connection:

3 x Axpert inverters in parallel (single phase) - correctly setup with 1 x HS and 2 x SL

Bluenova HC connected to BMAC via RJ45(battery) to BMS CAN port on BMAC

BMAC connected to master inverter via RS485 (BMAC) to battery port on inverter with correct wire (pinout 1->5;3->3)

ICC via USB running from one of the Slave inverters. 

 

Master inverter set to LiB, Slave inverters set to Use. 

Inverters running in SBU setting. 

 

There is successful coms between BMAC and Master inverter as the battery icon is flashing (and also on the 2 slave inverters ==> so most likely successful pass-on from Master) 

I keep on getting intermittent Error 61 / Connection errors on the Master inverter. 

Randomly, I am also experiencing low voltage (04) errors, although the battery voltage is fine and SOC on battery display is 80% or above. 

 

The BMAC does update the charge settings of the inverters (Max charge current, float, bulk, etc) - curiously, these values are different from the proposed values in the battery manual. Bulk and float is set at 55.2V and cannot be changed when in LiB battery setting. 

Also Low DC cut-off value is fixed under the LiB program to 48V (I presume this comes from the BMS / BMAC) 

 

I have manually set parameters:

12 = 50V (to comply with FAQ rule 2 => set value 12 to 2V above 29)

13 = Full

 

I cannot explain why I keep getting the 04 / low voltage warnings. Also, communication error (61) also appears intermittent.

I noticed error 04 especially late afternoon when PV was dropping and PV values below supply for the house. The battery was 100% charge. 

Battery warning would only occur if BMAC was communication with inverters. When Slave 1 + 2 was not showing BMAC communication, the also no error 04 (low battery voltage) warning on Slave 1 +2, even when the Master was showing error 04. 

It would seem that the BMAC is somehow passing the wrong battery voltage to Inverters - although battery voltage values in the BMAC monitoring page appears stable and well above limits. 

Sometimes the errors would resolve spontaneously, but a couple of times the inverters went into bypass mode due to low battery error. 

 

Any insight / advice would be much appreciated. 

Edited January 15, 20223 yr by Roentgenzap
Correction

14 hours ago, Roentgenzap said:

Master inverter set to LiB, Slave inverters set to Use. 

Hi Roentgenzap,

that setting doesn't make sense. Why not setting them all to USE? They all are (must be) connected to the same battery. I could imagine that your problems come from that.

14 hours ago, Roentgenzap said:

Bulk and float is set at 55.2V and cannot be changed when in LiB battery setting. 

Also Low DC cut-off value is fixed under the LiB program to 48V

There you have it. These settings are way too high. My 2 Axpert/Synerji MKS 5K run smoothly with following settings (LiFePh batteries):

01: SBU, 05: USE, 06: LtE, 07: ttE, 12: 47V, 13: 50V, 16: CSO, 26: 54V, 27: 52.5V, 29: 42V, 31: SbE.

No connection from BMS to inverter - I don't see the necessity or benefit.

Edited January 16, 20223 yr by Beat

Hi Beat

3 hours ago, Beat said:

Hi Roentgenzap,

that setting doesn't make sense. Why not setting them all to USE? They all are (must be) connected to the same battery. I could imagine that your problems come from that.

I want to Main inverter to use LiB - that way the BMS / BMAC can more efficiently (well, supposed to) regulate the charging, etc. 

3 hours ago, Beat said:

Bulk and float is set at 55.2V and cannot be changed when in LiB battery setting. 

Also Low DC cut-off value is fixed under the LiB program to 48V

The minimum discharge voltage according to the battery documentation is 48V. So I cannot go any lower than that - that is why the value is fixed in the LiB program. 

 

3 hours ago, Beat said:

No connection from BMS to inverter - I don't see the necessity or benefit.

The benefit is accurate SOC information. The Axperts are dismal at SOC estimation when just using voltage parameters / USE setting. I know I can look at the BMAC for the SOC, but would like the SOC and charging info passed on to the inverters in order to better control with ICC. I can then use SOC as control between SBU and SUB. 

 

Hopefully, today so far no error messages since I have changed setting 12 to 2V above setting 29. 

Let's hope for the best

 

4 hours ago, Roentgenzap said:

The benefit is accurate SOC information. The Axperts are dismal at SOC estimation when just using voltage parameters

I get that SOC information directly from the BMS to a laptop with PodmodbusToos, a software delivered by the battery manufacturer. It is clear that the Axpert cannot deliver accurate SOC display from the voltage measurements as it doesn't have the corresponding  V/SOC characteristics in its database. I just ignore the inverters SOC display.

My view is that with reasonable parameter settings in the inverter I can handle the batteries requirements adequately.

Edited January 16, 20223 yr by Beat