Hello all, 

I have an inverter that after a local storm got this board damaged. If I unplug the connector to this board, the inverter works as it should, no errors displayed, charges batteries, PV voltage is detected. Does somebody know when is this board used by the inverter? In parallel mode only or only when feeding power to the grid? It has 4 SCRs of type BT155W-1200T. If the board is plugged in, the inverter does not power on. 

Also, did anybody reverse the schematic for this board already? Thanks in advance.

Edited February 19, 20242 yr by sethmad

Seems i found an answer in this thread: https://powerforum.co.za/topic/4170-axpert-repair/?do=findComment&comment=183455

"This board basically houses some SCRs which  implement the UPS AC input range setting. It allows the inverter to switch to or from battery mode in roughly 10 ms, as opposed to about 20 ms without it. That's not something you'd typically notice unless you have sensitive equipment and/or are looking / listening for it."  @Coulomb

"Edit: another possibility: I believe that that PCB is only needed to get the fast transfer when using the faster UPS "input voltage range". I've often wondered if you can choose APL instead for setting 03 and just remove that board My understanding is that the board uses TRIACs or similar to reduce the transfer time from battery to/from line mode (less delay connecting AC-out to/from AC-in and inverter out)."

@Coulomb what do you think, is it safe to run the inverter without this board if using in APL mode and not UPS mode (in setting no 03)

 

14 hours ago, sethmad said:

is it safe to run the inverter without this board if using in APL mode and not UPS mode (in setting no 03)

Yes, I believe that it is safe. 

16 hours ago, sethmad said:

, is it safe to run the inverter without this board

These optional boards are described as a necessary addition to run the inverters in parallel. The inverter can perfectly run stand alone without this board.

To my surprise my MKS 5K inverters were delivered with the board installed and with the required cables despite the sellers description that they must be purchased separately for parallel installations. Therefor I have 2 complete sets of parallel boards and cables with no use. If anybody needs them, can have them.

30 minutes ago, Beat said:

These optional boards are described as a necessary addition to run the inverters in parallel.

Confusingly, there are two types of boards that are called parallel boards. This one is not the one for paralleling inverters; this one is to parallel the relay contacts with SCRs to make the relays switch faster.

You'll notice that yours look very different, and have different cables. This board connects to the mother board via long stand-offs, and a small white connector with ribbon cable.

35 minutes ago, Beat said:

If anybody needs them, can have them.

They will probably be very handy for someone else.

any chance to find a schematic for this small PCB board?

On 2024/02/21 at 3:39 AM, sethmad said:

any chance to find a schematic for this small PCB board?

I'm not aware of one.