Best practice

[Dgrblu]

Greetings all,

This forum is full of people that are a whole lot smarter than I so I'm here for guidance.

The system. Off grid. Two 48v battery banks of eight 6v agm, 424ah in series with the banks wired in parallel. Two classic 150's, both with wizbang's. Two, Magnum ms4448pae operating in master/slave configuration with one BMS.

I have purchased a Generac 20k HSB propane fired generator and am wondering how others or the best practice would be to configure the auto start/Stop of the generator.

 I was thinking that I could use the SOC of the Classic 150 through the aux 1 contact to initiate the transfer switch at a SOC of 60%. To terminate the generator,  I was thinking of using the Magnum Absorb time termination,  2.5 hrs to switch back to solar charging.

Wondering if this doable. Will I need a piece of Magnum hardware or other piece of hardware to accomplish my task? How are others doing this? I'm wanting to have a KISS approach for this function of the system.

TIA,
Bruce

[boB]

Hi Bruce.

As long as the Classic's aux output turns on and off according to the minimum and maximum SOC%, it should be able to start and stop the generator.  It is only one wire though.  On or Off.  It can also turn its aux off and on by battery voltage. 

Are you using lithium or lead acid batteries ?

I don't know about that Generac but I would think it works like you want.  Maybe it even has some warm up and cool down smarts built in ?

Best practices should say there is a warm up period for the generator and a cool down time for the generator.  There will be some amount of warm up time (seconds ?) before the Magnum starts to charge.

Someone else here may have some more insight and experience with this particular setup.

boB

[LilMT]

Personally, I use the Magnum AGS along with their BMK.  You can then program the AGS very easily to perform a gen warmup run a programmed cycle, gen cooldown, and shut off.  You can program it easily and it is pretty intuitive.  Lots of option for basic start run stop based on SOC, or Bat voltage, quiet hours, run exercise cycles etc.

I have mine set to start at a specific voltage - runs it cycle until float, float for a bit and then shutdown.

I also have a safety on cycle programmed so that it will auto start and run a cycle if my SOC gets below 60%

I use that for when I am getting enough sun that I am getting a higher bat voltage but my SOC is still dropping.

Just one way of doing it, but I would recommend some kind of setup that allows for warmup and cooldown.

Slamming dirty startup gen voltage into the inverter is not real good.  And neither is power off a gen while under load.

Of course, all of that is my humble opinion. 

Hope you get it figured out and let us know what you came up with.  If you have any questions, let us know.

[boB]

Thank you LilMT.  I was going to suggest the Magnum AGS but I did not know if it was still available.

There are other third party AGS management systems available or at least there used to be.

Here is the Magnum one.  Gary, who works with us now designed this many years ago and is proven to work great.

https://www.amazon.com/Magnum-Energy-Automatic-Network-ME-AGS-N/dp/B00A6XGLKO

But The aux output should work temporarily at least until a better method is chosen.

boB

[Rob Linschoten]

The Magnum AGS is still available and we use one all winter. One useful aspect to that AGS is the ability to add external on/off control to it to overrride the auto programming.

In our case we have added a WiFi controlled override switch to start stop with a phone app when away from home. It triggers the Magnum's warmup and cooldown cycle as per normal. Graham's Android app keeps us informed.

In absolute repudiation of the KISS principle I tried to include the aux output of my master CC so that when I reached 98% SOC (using the WBjr)it would initiate a shutdown in series with the on/off overide.  It does do that but I have not figured out how to keep it from restarting when the SOC drops...trying not to buy the Magnum BMK.