Wiseguy New Inverter Build Nano R6

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Joined: 21/06/2018
Location: Australia
Posts: 1088
Posted: 11:57am 08 Mar 2024      

I apologise in advance for a detailed discussion on controller start and stop.

The controller board although designed for automatic high current contactor closing, is also equally at home with a Manual pre-charge button and DC high current breaker.

I think it is time to present the two different types of operation for Manual and Auto use. I will reiterate why we have pre-charge for any newcomers.

If we close the contactor or circuit breaker with no precharge to the capacitors - it momentarily has hundreds of Amps flowing.  There is a loud splat and chunks are taken from the switch contacts or they become welded together - you only make this mistake once !

So we cause a more gentle current to flow until the capacitors are charged to the battery voltage, then we can make a high current connection, with no splat.

Now to describe the controllers operation for Manual starting up. First the main breaker switch is off, press the pre-charge button, the Nano controller is powered too by the button press but inverter is inhibited whilst the button is pressed. The Run led will light steady during the pre-charge and go out to tell you capacitors are charged.

Ok, still pressing the pre-charge button, close the main circuit breaker to the inverter and then release the pre-charge push button and the magic begins.
The inverter will slow start the mains voltage and the Run Led will flash to let you know mains is happening - be careful, and when mains is up the mains contactor/relay is driven to connect the AC to the load.

Lets look at the batteries becoming flat,  our batteries are now heading below 44V, or whatever low voltage we programmed for the inverter to gently stop.

The mains on relay opens the Run led stops flashing on and our inverter waits patiently.  Now the sun is up the batteries are receiving charge and become higher than batt low shutoff.  The inverter soft starts to bring mains up then the mains up relay is closed and the lights and fridges all start automatically.

If you wish to stop the inverter, press the pre-charge button and the inverter will gently stop - now is the good time to open the circuit breaker when the Run led stops flashing.  With the breaker open it is galvanically isolated from the batteries.

Our wives may not like this inverter much claiming it to be a complicated monster that is scary to use.

Auto Version
The Contactor version has more finesse, it just has a small toggle on/off switch. We need to close the main circuit breaker, is the inverter switch on or off - doesnt matter their will be no splat as the main contactor high current path is open.

If inverter was on, then after Vcap is pre charged, the Nano closes the contactor and ramps up the inverter and then closes the mains output relay/contactor.

If inverter was off nothing is powered, turn switch on, then after Vcap is pre charged now continue as for previous line.

If inverter is running and on off switch is set to off, there is a sequence, first, open the mains relay, ramp mains down to stopped, open main DC contactor and now inverter is off and galvanivcally isolated from the batteries.

Lastly if the inverter shut itself down it is very similar to the Manual recovery as the batteries receive charge. Contactor closes inverter ramps mains up, mains relay is driven to connect the load, lights come one fridges run etc. Wife is happier (maybe...)

Please ignore the previous Auto start PDF latest is here
4KW Nano R6 AutoStart.pdf
The manual overview PDF
4KW Nano R6 Manual Start.pdf
Finally controller schematic
4KW Nano R6.pdf
Edited 2024-03-08 22:00 by wiseguy