Crown Battery and Kohler Generator upgrade

Rngr275
Rngr275 Solar Expert Posts: 127 ✭✭
You know the saying when it rains it pours. A month or more ago my Gererac 6Kw EcoGen generator crapped out and at about the same time I discover that 2 of my Trojan L16RE (370Ah) batteries had dead cells. Removed the parallel string and made a single 48V series with the best batteries but obviously lost half my storage.
I got my new Kohler 12Kw Res installed and really really like it! It is a little bigger than I need(ed) but it had the off grid warranty. What's really interesting is that with the old Generac our clocks would start running fast... Run the generator and by the time it turned of the clocks could be an hour fast (Hz measurements looked ok)? Also when it turned off, anything like the TV or other electronics would turn off. Not so with the Kohler.

I have ordered 16 6V Crown 350 Ah batteries. Got a great deal on them so I'm happy about that. I wanted to get the 390Ah batteries but they were unavailable and wouldn't be in stock for quite some time! So I lost a little storage (40Ah) but it should be ok since I was border line with charging with my 4 Kw of panels. I got their spec sheet for charging and it's a little more involved that the one I got from Trojan back in 2012. maybe some of you smart guys can explain. First, it says that the batteries should be fully charged after each discharge. This kind blows the 2-3 days autonomy thigh up doesn't it? Voltages are different from the Trojans which I can understand but here are a couple things that got my attention:
- The total input amperage from the charging source is at least 10 amps per 100 Ah (c/20) of battery bank

In the first 2-4 weeks after installation, spot check specific gravity readings every few days after system has gone to “float”. Specific gravity readings that fail to attain at least 1.275 at “float”, may / will result in modification of charge control settings. Please contact supplier for information. 

Suggest equalization charge of battery bank every 30 days, for batteries that are subjected to DOD of 50% or less.
Now Trojan suggested only equalizing when there was a big difference in SG between cells. I'll follow their directions... it's just different. 

One concern is the 10amps per 100Ah of battery. I have 4Kw of panels (Solar world 255W Vmpp 31.4V, Impp 8.15A, 16 panels) and my inverter Outback VFX 3648 says 60amps max AC input current. So I could use a little help figuring out how my charging will be and is it sufficient.

One last thing... thinking of adding a couple Kw of panels to help out in the winter. Will this put me in a better charging  percentage for the batteries? And what are your thoughts on Trina or Panasonic panels?

Thanks all... let me know if you need more info.

McD

Comments

  • MichaelK
    MichaelK Registered Users Posts: 234 ✭✭✭
    The maximal optimum charge rate for Trojan L-16s is ~13%, or 0.125C.  Assuming you have two parallel strings of 350s then your optimal charge rate would be 350Ah X 2strings X 0.125C X 52V charging X 1.25fudgefactor = 5688W.

    You don't focus on the amps coming into the inverter, you should be focusing on the amps of your charge controller.  Since you need 350Ah X 2strings X 0.125C = 87.5A, you need a controller that can handle that much amperage, or two paralleled controllers of lesser amperage.

    You could likely get by with an Outback 80A controller, but you'll want charging in the 70+ amps range.


    System 1) 15 Renogy 300w + 4 250W Astronergy panels,  Midnight 200 CC, 8 Trojan L16 bat., Schneider XW6848 NA inverter, AC-Delco 6000w gen.
    System 2) 8 YingLi 250W panels, Midnight 200CC, three 8V Rolls batteries, Schneider Conext 4024 inverter (workshop)
  • Rngr275
    Rngr275 Solar Expert Posts: 127 ✭✭
    S you are say an extra 2Kw of panel to my current 4Kw would be good/OK? I currently have 2 MidNight Classic 200's each rated for 79 amps out so I'm good I think. It was suggested that run my old panels through one controller and any new panels through the other controller because of the efficiency of the new panels compared to my old ones.
    Thank you for responding!
    McD