Surrettes, still trying

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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Re: Surrettes, still trying
    Another week, 582 amp hrs to be returned, 15.2 volt absorb, ( 14.9v corrected ) entered absorb @ 1.190 SG level. 13.5 hrs later 1.260 @ 12.8 amps exit to float.

    Have you thought about raising the absorb volts by 0.2? --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Surrettes, still trying
    vtmaps wrote: »
    Have you thought about raising the absorb volts by 0.2? --vtMaps
    I thought about it , but @ 91° F , I really don't know where it would take me. Unless I sit there and watch them for 13 hrs. I can unplug the RTS and let it roll, I have it set to 15.2v now.
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Surrettes, still trying
    Let's see ... hours spent trying to get Surrette batteries to work time minimum wage .... you could have bought a new set of batteries by now. :p:D (JOKE)
    Your 100% correct as usual. I added to the cost of ownership today as I am stuck with them now. I ordered a Hub & FNDC from NAWS today at the cost of $433. I have a concern about leaving them unattended with a 13 hr absorb time locked into the inverter. If I lost power for 10 minutes the voltage would dip below 12.5V and trigger a full charge and it could conceivably do it over and over, the other side of the coin is if I shut it off it could drain the batteries. I need to get them set up to do ending amps. I guess it's the cost of doing business.
  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Re: Surrettes, still trying
    I ordered a Hub & FNDC from NAWS today at the cost of $433.

    I can hardly wait to read your reports on the FNDC. There's a lot of info on setting them up over at Outback's forum. Does your inverter/charger have end amps capability? (I know the flexmax chargers can do end amps with the FNDC).

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Surrettes, still trying
    vtmaps wrote: »
    I can hardly wait to read your reports on the FNDC. There's a lot of info on setting them up over at Outback's forum. Does your inverter/charger have end amps capability? (I know the flexmax chargers can do end amps with the FNDC).

    --vtMaps
    Yes, I am using a GFX 1312 ( 70 amps ) as a finishing charging source, so the FNDC should control it. This won't change the long absorbs, but it should get me out of the babysitting business. While I have been doing 50% discharges / re-charges it won't be that way every time, thats where the fixed time ( 13 hrs ) becomes a problem. I spent a couple hrs last night on the Outback forum reading through all the posts about the FNDC. One thing I am not entirely clear on is the Temperature correction setting of the End of Charge Voltage and the RTS interaction. I don't consider this as a set and forget fix, but it should help my time if it works.

    Battery End-of-Charge Voltage: See the manufacturer recommendations or set .2 volts lower
    than the system absorb voltage for 12/24 volt systems and .4 volts lower for 48 volt or higher
    systems
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Surrettes, still trying

    If anyone is following this I changed it up, I pulled 256 amp hrs yesterday. I charged back @ 189 amps. When it exited Bulk to Absorb the SG's were 1.230 vs 1.190. The Absorb took 6 hrs and 12.9 ending amps and SG's of 1.260. So the total time was about 7.5 hrs. This is just about 1/2 of the time that 500+ amp hours takes, so I believe it's accurate. These batteries just take a LONG time to charge if your thinking about buying a set. If your planning to do deep discharges you best have some long sun hours. 250 amp hrs is only 19 % dod.
  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    Re: Surrettes, still trying
    If your planning to do deep discharges you best have some long sun hours.

    Or, I assume, a weekly full charge with a generator?

    I am available for custom hardware/firmware development

  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Surrettes, still trying
    jonr wrote: »
    Or, I assume, a weekly full charge with a generator?
    Not a thing wrong with that scheme ( 50-80% ) except you end up with a bunch capacity that you never get to use. A set of GC-2's will recharge twice as fast and cost less than half what these do. Generator costs are always a concern, don't know if you'd want to design a system with mandatory run time built in, dealing with unexpected weather is bad enough.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Surrettes, still trying
    ... dealing with unexpected weather is bad enough.

    Boy is that ever right!
    Now that the constant deluge has ended we are experiencing T-storms that come up just about the time the sun should be directly on the panels.
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Surrettes, still trying
    Boy is that ever right!
    Now that the constant deluge has ended we are experiencing T-storms that come up just about the time the sun should be directly on the panels.
    I did a 14 day stretch back in February, it is not fun.

    I started this as a grand experiment, I thought I was smart enough to make these work better than most could because once a week I can use the grid. Once you get past the first hour of Absorb at high current, your at the total mercy of the battery and how much it will accept. Yeah, you can keep on raising the voltage, but 15.2 is as far as I am willing to go on a normal charge, this is just not normal to me, lesson learned. I am already pushing the temperatures into the 90's and summer is just starting.
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Surrettes, still trying

    I'v had the FNdc and a hub a week now,it's been a process of learning it's function. It has not lowered the time to charge, but it has made my life a little easier. Getting all the settings correct is a process because the way Outback chooses to write their manuals is tricky and they leave out some details on how it functions.

    Once you add the FNdc there is a setting that allows the FNdc terminate the charge in the FX advanced menu. You answer <yes> . You would think that the FNdc has full control, not so, the FX still has to have enough time on the absorb time to allow it to terminate the charge, otherwise the FX will as normal and stop it ( short in my case ). No where will you find this in the documentation on the FX or FNdc. ( my case 13.5 hrs ). This normal with a controller, but they don't mention it or I didn't see it.

    There are 3 settings that control the charge in the FNdc, when these 3 perimeters are met it will terminate the charge.

    1) Ending amps.
    2) Set absorb voltage. (-.02 Volts )
    3) Time after ending amps are reached and holds stable.

    The next 2 settings sets the SOC tracking algorithm , but has nothing to do with the charging, it's a separate register.

    1) Bank Capacity (20 hr )
    2) Battery Charging Correction Factor. (peukert in reverse )


    Vic posted the ending amps on a post for his batteries, I wished I had used them (11.8 amps ). I trusted a Victron BMS that was 2 amps off from the FNdc read out. Once I saw the SG's were going to be low, I changed the ending amps. I used the same 15.2V ( temp corrected to 14.9v ) as the absorb. I used 2 minutes as the time that the has to be met. The amps will dance around towards the end as it tries to hold the voltage up, but still lower the amps, thats why they have the time setting.

    Is it worth $430 ? , II don't know yet. The one thing I hadn't counted on was that I still have to leave a large amount of time on the Absorb timer.

    http://legacy.outbackpower.com/pdf/tech_notes/Technical_Note_FNDC_Battery_Calibrating.pdf