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5kW SunSynks in Parallel withSolarMD Batteries


Shortcircuit
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Good day, Looking for help on the attached planned install.  I think that I have everything puzzled out except for the comms between the batteries and the Sunsynks.

An extract from Sunsynk's Instructions are:  (See https://www.sunsynk.org/post/copy-of-paralleling-inverters?postId=60857b09ac8dee0015cf260d for the full post.)

  • 3) You only need one CT coil per master.

  • 4) Only the master can communicate with the battery array. However, suppose you are using more batteries than the number allowable for the inverter. In that case, the other batteries can be connected to the other inverters set to voltage only, and therefore there is no need for communication.  This is one statement that confuses me

  • 5) If the inverters are connected to the communication of the same battery array, the master will control the charges in the other inverters. 

  • And then the following:  In theory, you can connect up to 16 inverters on a single-phase configuration, but be very careful about inrush current when switching on. You may need to add an additional contactor. The single-phase configuration only requires one master, and all the others are slaves. In addition, keep communication cable as short as possible. Check if all inverters have the same operating system and the latest software version and are the same model. On the multi-inverter page, select 'parallel' and choose the master, which is normally the central inverter. Ensure that you have good quality communication cable between the inverters. Set all the other inverters to be slaves. Each inverter needs its own unique MODBUS number. Each inverter needs its own data logger. You only need one CT coil, which is connected to the master. All batteries are wired in parallel. The master is the only one that communicates with the battery BMS.   This is another confusing statement as they should all be on one CAN bus with different addresses.

  • After checking and setting all this, you are good to go. As previously mentioned, the most common fault is a communication error between the inverters. Please study the previous Section 7 of this training manual.

Can anyone offer advice on the CAN bus interconnection between the Inverters and the V2Logger.  Do I simple connect the two CAN buses together or what?

Any other comments on the proposal will also be welcome as I am new to Sunsynk but have been using Axperts for years with and without solar.

 

Sunsynk Installation.pdf

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21 hours ago, Shortcircuit said:

Good day, Looking for help on the attached planned install.  I think that I have everything puzzled out except for the comms between the batteries and the Sunsynks.

An extract from Sunsynk's Instructions are:  (See https://www.sunsynk.org/post/copy-of-paralleling-inverters?postId=60857b09ac8dee0015cf260d for the full post.)

  • 3) You only need one CT coil per master.

  • 4) Only the master can communicate with the battery array. However, suppose you are using more batteries than the number allowable for the inverter. In that case, the other batteries can be connected to the other inverters set to voltage only, and therefore there is no need for communication.  This is one statement that confuses me

  • 5) If the inverters are connected to the communication of the same battery array, the master will control the charges in the other inverters. 

  • And then the following:  In theory, you can connect up to 16 inverters on a single-phase configuration, but be very careful about inrush current when switching on. You may need to add an additional contactor. The single-phase configuration only requires one master, and all the others are slaves. In addition, keep communication cable as short as possible. Check if all inverters have the same operating system and the latest software version and are the same model. On the multi-inverter page, select 'parallel' and choose the master, which is normally the central inverter. Ensure that you have good quality communication cable between the inverters. Set all the other inverters to be slaves. Each inverter needs its own unique MODBUS number. Each inverter needs its own data logger. You only need one CT coil, which is connected to the master. All batteries are wired in parallel. The master is the only one that communicates with the battery BMS.   This is another confusing statement as they should all be on one CAN bus with different addresses.

  • After checking and setting all this, you are good to go. As previously mentioned, the most common fault is a communication error between the inverters. Please study the previous Section 7 of this training manual.

Can anyone offer advice on the CAN bus interconnection between the Inverters and the V2Logger.  Do I simple connect the two CAN buses together or what?

Any other comments on the proposal will also be welcome as I am new to Sunsynk but have been using Axperts for years with and without solar.

 

Sunsynk Installation.pdf 7.4 kB · 1 download

I do understand #3. What he is probably saying is that the master has can-bus comms with one set of batteries. If you wish to connect other battery sets to the other inverters, you can do so, but you must use battery voltage settings on the inverter to control charge / discharge to these batteries. May be good to confirm with Keith.

There is a comment section below the link that you gave, perhaps raise your questions to Keith there?

 

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4 hours ago, YellowTapemeasure said:

I do understand #3. What he is probably saying is that the master has can-bus comms with one set of batteries. If you wish to connect other battery sets to the other inverters, you can do so, but you must use battery voltage settings on the inverter to control charge / discharge to these batteries. May be good to confirm with Keith.

There is a comment section below the link that you gave, perhaps raise your questions to Keith there?

 

Thanks, I've posted the question so I'll see what Keith says

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