question

Hi everyone, I'd like some help setting up my nearly 100% Victron system:

Batteries: Victron Smart Lithium 150AH/12.8v batteries. Six total, wired in serial pairs to create 25.6v and paralleled to add up to 450AH @ 25.6v

Battery Management System: Victron VE.BUS BMS

Battery Monitor: Victron BMV-712

Charger/Inverter: Victron Quattro 5kva/120a/24vdc/230vac)

Second charger: Victron Skylla-i 24/80

Generator: Onan MDKBN (11kw, 230v)

I am on a boat and trying to achieve the following:

When the SOC, as reported by the BMV-712 is below 20% OR the VE.BUS BMS charge disconnect signal goes open circuit (eg - low cell voltage condition), the BMV-712 relay triggers the Quattro to send a pulse to start the 3-wire Onan generator.

To allow oil to circulate (per Onan recommendation), I would like to have the generator run with no load for 45 seconds before the Quattro charger turns on. The Skylla charger is on AC-OUT2 and therefore is already delayed by 2 minutes, so I don't have to worry about that.

Once the SOC reaches 55% or the VE.bus BMS low voltage disconnect fault is corrected by charging, I would like the charging to continue for 15 more minutes. If the reason for the generator start is low SOC, 15 minutes additional charging beyond 55% SOC on my system is about 15%, taking me to 70% SOC, which I am fine with. If the reason for the generator start is VE.BUS BMS low cell voltage condition, I would like the charger to run for 15 minutes after the low cell voltage fault is corrected so that the fault does not return immediately upon turning off the charger.

After that additional 15 minute period, I would like the Quattro and Skylla to stop charging, WHILE the generator stays running for another 60 seconds to allow generator cool down, per Onan recommendation. After those 60 seconds of no-load generator runtime, I would like to send a stop pulse to turn off the generator.

Here's how I propose doing it, but I would like some help to ensure it should function as intended:

1. The output of each of these triggers (from both the BMV-712 and the VE.bus BMS) will be a single wire. I would put them in a daisy chain and wire them to the Aux2 input on the Victron Quattro.

   1. 
      

      1. The rationale is that, if either trigger signal goes open circuit, it would tell the Quattro to initiate the generator start procedure and when it goes to battery voltage again, it would trigger the Quattro to start the generator stop procedure.

      2. I believe the only way to daisy chain both trigger signals into the single Aux2 input on the Victron Quattro is to use two bi-stable solid state relays (one controlled by the BMV-712 and the other controlled by the VE.Bus BMS) in a daisy chain, while passing through a 24v signal to the Quattro's Aux2.

Programming via VEConfig3 Assistants

Here are the assistants, in order, that I would add:

Turning on the charger /generator sequence, when triggered by either BMV-712 or VE.BUS BMS

1. Add Programmable Relay <closes relay K1 to initiate start pulse to start 3 wire onan generator>

   1. Use secondary programmable relay K1

   2. Set Relay On

   3. Input signal

   4. (just click next, no extra drive options needed)

   5. Aux2 open for 0 seconds

2. Add Programmable Relay <sets general flag which will be used to ignore AC for a period of time>

   1. Use General Flag

   2. Set Relay On (aka flag on)

   3. Input Signal

   4. (just click next, no extra drive options needed)

   5. Aux2 open for 0 seconds

3. Add General Flag User <uses #2 above to “ignore AC” for 45 seconds to prevent Quattro charging function starting for a period of 45 seconds to allow the generator to warm up, per Onan guidelines>

   1. Use general flag to ignore AC input 1

4. Add Programmable Relay <clears general flag which was used to ignore AC for a period of time>

   1. Use General Flag

   2. Set Relay Off (aka flag off)

   3. Input Signal

   4. (just click next, no extra drive options needed)

   5. Aux2 open for 45 seconds
      
      QUESTION - WOULD THE GENERAL FLAG USER SHOWN IN #3 THEN BE CLEARED AND WOULD “IGNORE AC” BE DE-ACTIVATED AT THIS POINT OR DO I NEED TO DO SOMETHING ELSE TO DE-ACTIVATE IGNORE AC?
      
      

5. Add Programmable Relay <opens programmable relay K1 to terminate start pulse after 3-wire onan generator successfully starts>

   1. Use secondary programmable relay K1

   2. Set Relay Off

   3. AC Input

   4. (just click next, no extra drive options needed)

   5. AC1 available for 0 seconds

QUESTION - IF I USE GENERAL FLAG USER (STEP #3) TO IGNORE AC, WHICH I WANT TO DO TO KEEP THE CHARGER FROM STARTING FOR 45 SECONDS WHILE THE ONAN WARMS UP, DOES THE PROGRAMMABLE RELAY ASSISTANT #5 THEN NOT SEE “AC1 AVAILABLE” WHILE “IGNORE AC” SET IN #3 IS ACTIVE?

Turning off the charger /generator sequence

1. Add Programmable Relay <sets general flag which will be used to ignore AC for a period of time to switch off charger and allow generator to cool off>

   1. Use General Flag

   2. Set Relay On (aka flag on)

   3. AC Load and Input Signal

   4. (just click next, no extra drive options needed)

   5. Load higher than 50 watts for 0 seconds and Aux2 closed for 900 seconds
      
      IT STATES AT BOTTOM OF https://www.victronenergy.com/live/assistants:start
      “- an ON condition always has priority over an OFF condition - multi criteria in the ON ( or OFF ) list go by the OR principle”
      
      

      DOES THAT APPLY ONLY TO DIFFERENT PROGRAMMABLE RELAY ASSISTANTS OR ALSO THE MULTIPLE CONDITIONS WITHIN A SINGLE PROGRAMMABLE RELAY ASSISTANT?

1. Add General Flag User <uses #6 above to “ignore AC” for 60 seconds to stop Quattro charging function for 60 seconds to allow the generator to cool down after high load usage, per Onan guidelines>

   1. Use general flag to ignore AC input 1

2. Add Programmable Relay <clears general flag which was used to ignore AC for a period of time>

   1. Use General Flag

   2. Set Relay Off (aka flag off)

   3. Input Signal

   4. (just click next, no extra drive options needed)

   5. Aux2 closed for 960 seconds

3. Add Programmable Relay <close programmable relay K2 to initiate stop pulse for 3-wire onan generator>

   1. Use secondary programmable relay K2

   2. Set Relay On

   3. AC Input and Input signal

   4. (just click next, no extra drive options needed)

   5. AC1 not available 60 seconds Aux2 closed for 960 seconds

4. Add Programmable Relay <opens programmable relay K2 to terminate stop pulse for 3-wire onan generator>

   1. Use secondary programmable relay K2

   2. Set Relay Off

   3. AC Input and Input signal

   4. (just click next, no extra drive options needed)

   5. AC1 not available 70 seconds Aux2 closed for 970 seconds
      
      I cannot find a more elegant way to terminate the stop pulse. This method of doing it is based on the assumption that maintaining the stop pulse described in #9 for 10 seconds will be enough to turn off the generator and maintaining the stop pulse for those 10 seconds is not damaging. Thoughts ?

Finally, this is all an attempt to make sure we don't kill the batteries by allowing SOC or cell voltage to get too low if we aren't paying attention. It's a fail safe, basically. If there is a better way of doing it, I'm all ears. BTW - we have tried using the BP-220 to solve the low cell voltage condition and our boat has too high of current demands and fried the BP-220 in less than a day.

We may also start the generator ourselves, so we want to make sure the Assistants don't introduce problems or activate certain assistants when we decide to start the generator manually. Thanks in advance!