Deep Cycle Draw Down Data

Captain Decent

The Bert makes ‘em Squirt
Nov 2, 2017
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Covington, wa
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Ryan
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The Bert Makes ’em Squirt
Does anyone have any data or experience with drawing a deep cycle down to <5volts and if it csn recover to near full performance thereafter? I don't mean 0% charge (~10.5v), I mean near 0 volts.

I recently (6mths) replaced my 2 house batteries (group 27) but due to a couple issues (faulty acr and also blown charger fuses) I let the house battery on the one side get drained to around 0 volts on 3 occasions. I am leaning towards replacement because that irritates me and I don't want to cut any corners but wondering if anyone has any data thst can back it up?
 
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Wild Bill

Not Blackmouthing
Aug 4, 2010
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Camano Island
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Steve
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Otter Craft
I bought my current boat with the lead acid house batteries in the state you refer and I was able to bring them back and get a couple good years out of them. These were newer batteries before the deep discharge so probably not a history of this kind of abuse so the were able to be brought back. I think if they are older batteries and this has happened once or more in the past they are doomed. Certainly worth a shot.
 
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OceanSun

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  • Mar 26, 2013
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    Snohomish WA
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    Dan Meyer
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    Ocean Dancer 21' Trophy
    I've had a set of brand new [lead acid] batteries (Les Schwab) go bad without being able to resurrect them after unintentionally drawing them down to 0 just a single time. Happened again before I found/fixed the draws/shorts and I resurrected the 2nd new set of batteries but never really trusted them after that and replaced them.
     
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    G-Spot

    Captain
  • Mar 14, 2008
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    John
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    53’ Hatteras STEEL N TIME
    It was my understanding that it is not a problem and you will get full charge and use, that’s why you get deep cycle over a regular starting battery. Electric wheelchairs, golf carts, and other toys that use these deep cycle batteries draw them down real far and recharge over and over…

    I have no data… 😃
     
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    fishing fanatic

    I Should Upgrade My Account
    May 12, 2008
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    Alger, WA
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    jason
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    28’ almar sounder //16' lavro
    Once drawn down(worked to that extreme level and pushed to that extreme) they can come back but never have the “guts” and will have a shortened life by extreme amounts. Also to get them to come back and then put them through even a 50% draw down can stun them and deem them gutless. In the marine environment I’d go new.
     
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    MYNomad

    Heading South
    Dec 12, 2007
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    Yes
    Years ago, I had to replace all of my FLAs because they were drawn down way below 12v -- maybe to 5 or even closer to zero. A wharf rat guy I knew wanted them and (using my equalizer) was able to restore them to "useful" life. Equalizing may be worth a shot.
     
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    danny warren

    Almost A Member
    Jun 1, 2014
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    I thought the point of a deep cycle battery is designed to be drawn down to zero and was good to keep them from creating a memory. Unlike regular batteries that need to stay fully charged at all times
     
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    G-Spot

    Captain
  • Mar 14, 2008
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    53’ Hatteras STEEL N TIME
    The below info is listed on several different sites for batteries. Sounds like if you did it much it will decrease life of the battery, but if it only happened once, I’d charge them and see how they hold.


    “Another thing you can do to protect your battery is to learn about the depth of discharge specifications of your battery. Most deep cycle batteries are built to handle a 50% depth of discharge, but some can handle up to 80% discharge. If you are always recharging your battery in a complete cycle, you could expect to get just over 220 complete cycles when you drain the battery 80% each day, whereas you would get almost 750 complete cycles if you only discharge 50%. On the other hand, you also don’t want to constantly charge your battery when it has been discharged less than 10%. Like opportunity charging mentioned above, this will prevent your battery from ever completing a full cycle, and will cause damage.”
     
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    eldplanko

    got the skunk off
    Jun 18, 2012
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    My other boat is a piece of...
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    Does anyone have any data or experience with drawing a deep cycle down to <5volts and if it csn recover to near full performance thereafter? I don't mean 0% charge (~10.5v), I mean near 0 volts.

    I recently (6mths) replaced my 2 house batteries (group 27) but due to a couple issues (faulty acr and also blown charger fuses) I let the house battery on the one side get drained to around 0 volts on 3 occasions. I am leaning towards replacement because that irritates me and I don't want to cut any corners but wondering if anyone has any data thst can back it up?
    It would be interesting to test it yourself… I’d charge it up properly (bulk/absorption/float), then load test it to see home many Ah you can pull before it drops to 10.5V, you’ll probably find it’s some degree less than the rated Ah capacity. Replace or not depends on how you use your deep cycle, how many Ah you need per cycle, how deep you cycle, how often you cycle, etc.
     
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    Genie Aye

    FISH BOSS
  • Sep 25, 2008
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    Cap't Paul
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    V-20 Wellcraft w/200 G2
    Ryan, what has happened with the deep discharge is the sulfuric acid has literally left the fluid and penetrated the lead plates, you have to push the sulfuric acid out of the plates back into the water. This is called decalcification of the plates. Do you have a big automotive charger with 200amp boost?
    If so, do a 15 minute max amp charge, then go to 40 amp charge for several hrs and then finish it off with a 4 to 2 amp trickle charge. Then let sit for 24hrs before load testing.

    If they don't make it, you know who to get your deka batteries from...lol

    You got my number, have load tester and 200amp charger.

    Any doubt, ask Darrell about me kick starting his 1 yr old 6v house batteries ..

    Just a fyi for all...fully charged 12v is 12.67v, a 12v at 12.2v is already 60% discharged.
     
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    liltrouble

    Member
    Jun 9, 2012
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    Shari
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    Mr. Buttercup
    Also, if you are desulfiting your FLA batteries with a 200 amp charge like Paul mentioned, make sure you are doing it in a well ventilated area, add distilled water as necessary so you don't boil them dry.

    I bought a big old charger with the 200a jump start function specifically for this purpose. Well that and cleaning cast iron pans.
     

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