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Changing AGM 8D batteries for Lithium Ion

Discussion in 'Electronics' started by enproep, Sep 21, 2022.

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  1. enproep

    enproep New Member

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    Sorry, posted the same on General Yaching...
    Hello, I carry 4 Lifeline AGM GPL-8DL house batteries on board. Unfortunately it's time to replace them. They are ~10 years old and I know battery technology has changed immensely over that time. Any suggestions on Lithium Ion replacements...how many, AH's required, etc. I assume i'd need to change out charger as well, how about inverter?
    Any advise would be helpful.
    Thank you in advance.
    Bob
  2. Capt Ralph

    Capt Ralph Senior Member

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    Well you are changing your battery charger also.
    Are these to be cranking batteries?

    OTOH, Why change something that has worked 10 years for you. Lifeline batteries are still current.
    KISS!!
  3. Pascal

    Pascal Senior Member

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    I m sticking to lead acid batteries on my boat because they re easy to top off very 2 to 3 months. AGMs are fine if they re hard to reach and you don’t want to have to call a chiropractor everytime you top them off.

    in my experience AGMs don’t last significantly longer than lead acid

    as to lithium ? Hell no! I think I ll take the red flu vax before I ll let lithium batteries on my boat :). Well maybe not…. Seriously there is still too much Unknown about lithium battery fires for me to put them on a boat especially since it s so hard to know where they re made.

    On a boat? 200,300,400 lbs of batteries really make little difference so why risk it.
    SplashFl and Capt Ralph like this.
  4. DOCKMASTER

    DOCKMASTER Senior Member

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    Personally, I like AGM’s. I prefer not having to deal with checking water levels and such. I got 10 years out of my big AGM battery bank at my off grid vacation house. I also use AGM in my house and starting banks on the boat. On my first set of AGM house bank batteries they twice recovered from accidentally fully discharging them. Don’t think wet cells would do that. Still got 5 years out of them after the full discharge. I like the Full River AGMs. They are not quite as good as the Lifeline batts but also less expensive. Hard to go wrong with Lifeline if you don’t mind the cost. If you got 10 years from those I would go back with the exact same set up if the capacity serves your needs.
  5. Capt Fred

    Capt Fred Senior Member

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    counter point. I have helped two people change their lead acid to lithium. They are very pleased with their conversion. In most cases the battery charger and inverter can handle lithium batteries with some slight changes like settings and in one case a control head for the inverter. The lithium iron phosphate are the best for the application. They are the safest chemistry and the batteries chosen had internal battery management systems to prevent over charge and over discharge. You basically need the same amount of amp hour you currently have. There is a lot of info on the net saying you need to increase your alternator because the lithium batteries can take so much charge which can over heat the alternator at low rpms. Both vessels had large alternators and we did not need to change them. On the first conversion, I added a Victron device to help manage the alternator output, my fear was than on a long run, the alternators would overcharge the lithium batteries but as it turned out this was not necessary and again the batteries have their own protection.
  6. gr8trn

    gr8trn Senior Member

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    I know enough to know I don’t know nearly enough for such a conversation. I also know I would not allow someone to make the switch that was not Lithium Iron Phosphate experienced master electrical installer.

    Sure it may be doable without catching fire, but…
  7. DOCKMASTER

    DOCKMASTER Senior Member

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    If you decide to go with LiPo please make sure you do your homework. There are numerous Youtube videos where these batteries are taken apart only to find that you may not be getting what you think you are. Internal battery management, internal heaters and other devices are often claimed but not always real. Yes, there are reputable battery manufacturers out there that deliver what they say. Just make sure you know exactly what you are getting.
  8. enproep

    enproep New Member

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    Thanks all for the advise...I guess the message is; if it's not broke, why fix it. Sticking with replacement Lifeline AGM's.
    Bob
    gr8trn likes this.
  9. enproep

    enproep New Member

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    Sorry, one last question; I have 4 of the Lifeline 8D's and if i load test and find 2 are good and 2 are bad, can i only replace the 2, or, since all are pretty old, do i need to replace all 4?
    Thanks again.
  10. Capt Ralph

    Capt Ralph Senior Member

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    You may have more purchasing power if you can negotiate for 4 batts.
    You know the other 2 are going to fail some time,,,, soon ?? Murphy will prevail on this...
    While you have the strong backs* to move them around, do them all now.
    It is usually not beneficial to mix new/bad batteries.

    I have a question, I'm guessing the 2 banks of 2. Was it the top or bottom battery that failed first?

    * Always use somebody else's back when moving batteries.. o_O
  11. DOCKMASTER

    DOCKMASTER Senior Member

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    Never a good idea to mix new batteries with old. The weaker batteries will pull down the new ones and cause premature failure. You also cause an uneven charging that tries to occur across the stronger/weaker batteries.

    And to be clear on LiPo I'm not anit-LiPo. I feel they have a place where space, weight or capacity issues drive the need. But in a case like this I just can't see where it makes sense.
    gr8trn likes this.
  12. enproep

    enproep New Member

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    Thanks again for all the advise. 4, 8D replacements it is.
  13. ranger58sb

    ranger58sb Senior member

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    You might have some options depending on the setup. Can't tell your boat, but looks like it could be one where the manufacturer has combined start/house functions, perhaps two banks of two batteries each, one bank for port engine and half of the house, one bank for starboard engine and the other half of the house.

    If so... and if you find two bad, two good...

    You could shuffle the two good old batteries to one side, then replace only the two bad old batteries on the other side. If you need to spread your expenditures out a little.

    Other comments above still apply, though.

    -Chris
  14. Pascal

    Pascal Senior Member

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    If all Four are in the same bank, then yes you should replace all four. The only time you can get away with it is if one battery fails early and the others are way 1 year old.

    if the batteries are in two different banks, then you can replace one bank and keep the others
  15. Capt Ralph

    Capt Ralph Senior Member

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    I was thinking all are 10 years old. Past their prime. The sposed good batteries MAY fail at any time.
    An event that happened to me a couple of times, trying to keep up ole 8v battery banks and 12v/24v AGM house banks.
    Last edited: Sep 22, 2022
  16. Capt Ralph

    Capt Ralph Senior Member

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    Some old guys here may remember my questions why the top battery always failed first.
    That's why I was asking here if it was the top 12 of 24v that failed or the whole bank failed evenly.
  17. gr8trn

    gr8trn Senior Member

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    Do tell, I don’t have any stacked but curiousness has me asking.
  18. Capt Ralph

    Capt Ralph Senior Member

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    In a 32v system, 4 x 8v batteries are used. On our boat, it was always the top 8v battery that would fail long before any of the others.
    I started a 2 x 12v bank for an inverter, seemed the top battery always failed first.
    In looking at our customers and other batteries, most of the time it was the top battery also.
    So I was just asking enproep what batteries failed in his banks. Just to either enforce or lower the numbers in my hypothesis.
    gr8trn likes this.
  19. Capt J

    Capt J Senior Member

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    The battery the positive comes off of is the one that always fails first, due to it running hotter temps than the other ones.