Mission Impossible? Recharging a 2019 AGM 12V battery showing 1.3 volts.

softdown
softdown Solar Expert Posts: 3,896 ✭✭✭✭
in In the Weeds--Member's Choice #1
Transmission fluid change on Prius went sideways - rounded out extremely tight 10mm female hex. Amazon took full month to ship removal tool. Lowes wanted double the price of Amazon. Seat belt prevented door from closing - I thought it was flex from being jacked up. This killed the battery.

2019 AGM 12V starter battery discharged to 1.3 volts. Four modern chargers failed to initiate the charge process. A 1990's 10 amp charger is slowly bringing up the voltage however. It is feeding the battery a 16ish volt charge with, I would guess, very low amps. After approx. 8 hours the battery is showing 5.3 volts with the charger disconnected. The voltage did not plummet while the charger was disconnected overnight.

It gets far more complicated than that of course - this is my life we are talking about. It is - interesting. This battery reconditioning is supposed to be futile. But why not persevere - see what happens.
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: 1,166 ✭✭✭✭
    edited May 2020 #2
    Our standard deep discharge recovery procedure for Sun Xtender and Lifeline AGM batteries:
    1) Using a constant current charger set for 5% of the battery C/20 capacity, with the maximum voltage set to 18v.
    2) When the charge voltage climbs to 15.5v, continue for 4 more hours.
    3) Discontinue if battery temp exceeds 130F. Allow it cool, then continue where you left off.
    4) Run a capacity test.
     Fully recharge the battery, then equalize at 15.5v for 6 hours if needed.
    We have brought back 100's of batteries that were condemned as unrecoverable.  About the best that I see, is 80% of original capacity, which is better than zero. Yours may well be recycle material.
    I have seen customers "redneck" this procedure using a large old school farm/ranch type manual charger. The 200 amp boot setting will often get you close to 17.5v, but you have to babysit it.

    Marc

    I always have more questions than answers. That's the nature of life.
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  • softdown
    softdown Solar Expert Posts: 3,896 ✭✭✭✭
    #3
    The old charger bought it up to 9 volts before I switched to a 4 amp charger set on AGM charging. So I don't have to worry about cooking the battery while I sleep. Seem to have cooked a little ATV AGM battery using a charger set on lithium charging. The little battery was 7 years old and worse for wear. Thought I could maybe rejuvenate it a bit. Instead a couple sides bulged and the battery died.

    I'll try the lithium setting (higher voltage) if I can get the battery over 12.6 volts resting. Think it has a slim chance being a 2019.
    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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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #4
    With the battery below "charging setpoint" (like below 14.x volts), the actual charger voltage does not matter... Just the rate of charge. Following Mark's C/20 5% rate of charge, the battery's actual voltage will not rise above 14.x volts until it is near full (i.e., if 18 volt charger and battery is only at 5% current and 10 volts--It is charging at 10 volts).

    Many chargers will not start charging until there is ~9+ volts on the battery. A "simple" charger may not care and will start at 1 volt...

    I did have a "simple" 1 amp cube 12 volt charger and it worked... HOWEVER, when charging the (at the moment) "dead" battery (only a few volts), the charger itself overheated and popped open the plastic case (still worked, surprisingly).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • softdown
    softdown Solar Expert Posts: 3,896 ✭✭✭✭
    #5
    Charged up to 12.9 volts with charger freshly disconnected. Not great but OK.

    Battery tester advises me to REPLACE if a FLA and GOOD if an AGM. Curious since both settings call the battery 44% Healthy. A 500CCA battery showing 367CCA - enough for a Prius I think. But how long will it last?

    Internal resistance is quite high - 8.1.

    Now I debate putting a 4 amp charger using Lithium (high voltage) setting. Or simply replacing the AGM with the same size FLA - which I bought for the genset. Then the genset battery decided it was still "GOOD" once the temperatures warmed up.


    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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  • softdown
    softdown Solar Expert Posts: 3,896 ✭✭✭✭
    #6
    Trying a compromise at the moment - A Duracell 4 amp charger set for FLA batteries. Not going to be here to babysit it for a bit. This charger considers the battery less than 75% charged. May be interesting. Or not.

    I think Marc is accustomed to working with ~$600, or more, Deep Cycle batteries. That are worth babysitting. I'd place the value of this battery at closer to $40 or so. Could be no more than scrap value in fact.
    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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  • softdown
    softdown Solar Expert Posts: 3,896 ✭✭✭✭
    #7
    Couple hours with the Duracell:
    13 volts
    396 CCA
    51% HEALTHY
    7.8 Internal Resistance
    Still less than 75% charged according to this lil magic box.

    Slight improvements across the board. It is warm inside the car - that also improves battery stats of course.
    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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  • softdown
    softdown Solar Expert Posts: 3,896 ✭✭✭✭
    #8
    Lithium (higher voltage) charge setting has bought CCA up to 426. I'll leave it charging at that higher voltage for another hour. Then see what we have tomorrow. Don't want it to go sideways while I am sleeping. Looks like the battery is retrievable - if the voltage doesn't fall too much overnight.

    This has been quite interesting. Almost everything I have been taught eventually proves to be - wrong. More or less.

    I don't know how many times I have read that sub 10 volts destroys the battery - but the number is high. Then again, this battery may be dead in the morning.
    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 ✭✭✭✭✭
    #9
    It will last till you are ready to leave the mall to go home tomorrow. and then will be dead.  Will test fine in the AM.   Have fun.
    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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  • softdown
    softdown Solar Expert Posts: 3,896 ✭✭✭✭
    #10
    mike95490 said:
    It will last till you are ready to leave the mall to go home tomorrow. and then will be dead.  Will test fine in the AM.   Have fun.

    You are way optimistic. This is what I foresee. Somewhere in Georgia - in between my Colorado residence and my Florida rentals that are constantly getting torn up - the battery fails to a point that the hatchback won't even open. Hundreds of pounds of maintenance supplies prevent access from the side door. I see a congregation of alligators and eagerly feed them - by running into the swamp and flailing wildly. 
    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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  • softdown
    softdown Solar Expert Posts: 3,896 ✭✭✭✭
    edited May 2020 #11
    40F at 6am - battery shows 424CCA. It was 500CCA when new.  Nothing significant happened overnight. Will complete charge at lithium (higher voltage) setting. I think it will be OK though service life will be shortened.

    For some reason this battery size has a high internal resistance. Even the new model has high internal resistance. The resistance is coming down with further charging.
    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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  • softdown
    softdown Solar Expert Posts: 3,896 ✭✭✭✭
    #12
    Done some driving - 500CCA battery now shows 495CCA and is rated 80% healthy. Resistance has declined to 6 - it was likely ~5 when new. Being a 2019 - think I'll be OK.

    Still can't believe it discharged to 1.3 volts. Took a very long time to recharge.
    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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  • softdown
    softdown Solar Expert Posts: 3,896 ✭✭✭✭
    #13
    Prius are weird. Hooked up the teardrop camper yesterday for a trial run. Turn signals work but running lights do not. Suspecting a ground issue. I installed trailer electronics made for the Prius so this issue comes as a surprise,

    Was startled to see the dash lights still on this morning. Accidentally brushed the gas pedal while trying to get the lights to turn off. The engine instantly roared to life. I can't hear a thing when it is idling.

    Turns itself off when I leave for a few seconds to open or close the gate. But not last night! Prius are weird.
    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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