Replacing bad battery improved the spec's of the rest.

softdown
softdown Solar Expert Posts: 3,898 ✭✭✭✭
in Off Grid Solar & Battery Systems #1
A 2015 8D developed a bad cell. Of course it was in the most difficult location. And 110 pounds is heavier than it used to be.

Was surprised to find the specs for the rest of the batteries improve after replacing the defective battery. Resistance went down and power went up.

Time and time again I find resistance to be one of the best indicators of battery health and quality.
First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #2
    Amazing how as batteries age, they gain weight from all the dead electrons they accumulate !
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,167 ✭✭✭✭
    #3
    110 lbs. is pretty darned light for a deep cycle 8D!
    I always have more questions than answers. That's the nature of life.
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  • softdown
    softdown Solar Expert Posts: 3,898 ✭✭✭✭
    #4
    Marc Kurth said:
    110 lbs. is pretty darned light for a deep cycle 8D!

    They are not deep cycle. They were a mistake. An experienced acquaintance told me they worked as well as his Rolls batteries.

    I was able to rejuvenate the dead cell and bring up CCA by charging at high voltage. Then I got distracted with so many projects.

    The temperatures this time of year makes measurements of voltage and power and resistance more difficult to evaluate.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,167 ✭✭✭✭
    #5
    softdown said:Marc Kurth said:
    110 lbs. is pretty darned light for a deep cycle 8D!
    (Partial clip)

    The temperatures this time of year makes measurements of voltage and power and resistance more difficult to evaluate.

    I know that you already know this, but don't forget that battery voltage and power are often totally disconnected from each other. And temperature does not necessarily impact battery standing voltage.
    Marc

    I always have more questions than answers. That's the nature of life.
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  • softdown
    softdown Solar Expert Posts: 3,898 ✭✭✭✭
    #6
    Marc Kurth said:
    softdown said:Marc Kurth said:
    110 lbs. is pretty darned light for a deep cycle 8D!
    (Partial clip)

    The temperatures this time of year makes measurements of voltage and power and resistance more difficult to evaluate.

    I know that you already know this, but don't forget that battery voltage and power are often totally disconnected from each other. And temperature does not necessarily impact battery standing voltage.
    Marc


    You should know. But I swear that really cold batteries show lower voltage. By really cold I mean less than 10F. A temp that is rare in Texas generally speaking.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,167 ✭✭✭✭
    #7
    Yes, Sir, it is warmer here. It is 19F here now - but most of my projects are not in Texas. I do a lot of projects in Alaska where we have to design for very low temperatures. A quote from Concorde's Tech Manual: "The open circuit voltage (after at least 4 hours of rest) will be
    2.17 volts per cell or higher (13.0 volts for a 12-volt battery), regardless of the battery temperature."
    I always have more questions than answers. That's the nature of life.
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  • softdown
    softdown Solar Expert Posts: 3,898 ✭✭✭✭
    #8
    Think I figured out why it seems like cold batteries have lower voltage. The vast majority have some type of load on them even if it just the constant drain of being hooked up to the computers on modern cars. That drain combined with significantly less power capacity (at low temps) will act to drain a batteries voltage more quickly.

    A newish battery barely achieved viable cranking speeds in my 488 cubic inch gas engine: at -10F. Voltage was high but output is pretty low at those temps.

    My battery banks get pretty cold (around freezing) during the winter months. It is amazing how quickly the voltage drops under drain and how quickly it shoots back up under charge.

    Perhaps too much talk about voltage and not enough about real battery output whether that be CCA or aH capacity. But voltage is so very easy to check and understand. It is quite useful but not quite the holy grail it is often treated as.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,167 ✭✭✭✭
    #9
    And yes of course, I always start by checking voltage :D
    I always have more questions than answers. That's the nature of life.
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  • Saggys
    Saggys Solar Expert Posts: 189 ✭✭✭
    #10
    Soft down, what type of test equipment are you using to measure battery internal resistance?
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  • softdown
    softdown Solar Expert Posts: 3,898 ✭✭✭✭
    #11
    Saggys said:
    Soft down, what type of test equipment are you using to measure battery internal resistance?
    I believe it is an early red Ancel model. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • Saggys
    Saggys Solar Expert Posts: 189 ✭✭✭
    #12
    Thanks
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