• fine_sandy_bottom
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    15 hours ago

    I thought AGM were considered “deep cycle”, as in designed for their full capacity to be used between charges.

    • Gayhitler@lemmy.ml
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      1 hour ago

      There are some possibly inaccurate and definitely confusing statements in the reply you got, but the first part, that agm is a physical structure of the lead acid battery that can be tipped over without making a giant mess and that deep cycle is another function of design as opposed to a function of the lead acid chemistry is correct.

      What’s left unsaid is that lead acid batteries which are damaged and not working right anymore have a much safer and lower tech recycling process than lithium ones do and that’s saying something because one of the parts is lead!

      • fine_sandy_bottom
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        20 minutes ago

        Thanks! The other reply obviously meant well but was a bit mansplainey !

        My situation is, I’ve recently purchased a camper trailer. It’s wired up but needs a battery. I haven’t had time to “research” other than seeing what batteries people are selling second hand. It seemed to me that everyone was using AGM batteries for this purpose and while I knew that AGM referred to the physical structure of glass mesh I had assumed it was synonymous with deep cycle batteries.

        Now I’ve read about it a bit more I realise that LiFePO4 batteries are superior but more costly.

        I guess, the reason why I was seeing AGM batteries everywhere is because everyone’s buys them because they’re cheap and then realises they really needed LiFePO4 so they try to sell the AGM and upgrade.

    • SnoopBob@lemmy.ca
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      14 hours ago

      AGM just means the acid is held inside a glass mat, like fibreglass structure so instead of liquid it’s like a sponge. This gives it less maintenance and more shock absorption, can also be turned or tipped over without issue. It’s still lead acid just not held in liquid form.

      A lead acid based battery can be deep cycle or starter or both. Being deep cycle basically means the plates inside the are battery thicker, which allows it more tolerance for being depleted as well as generally more reserve.

      A real easy way to understand it that I found (when explaining it to customers without a technical background.)

      Imagine instead of electricity it’s water. A deep cycle battery is simply a larger tank of water with a regular size pipe to get the water out. A starter battery is a regular size tank with a large pipe to get the water out.

      So if you need to start a engine that needs a chunk of water(electricity) all at once to start it , a starter battery can provide it but doesn’t have alot of reserve behind it so the pipe cant stay open very long.

      The deep cycle can’t provide the large rush of water at once(cca) but does have lots of reserve so the pipe runs longer.

      Both suffer from reduced flow(voltage drop) as the tank empties. Imagine the pipe not able to be completely filled as the tank drained, you still get water but the rate is reduced as the pressure behind drops. Both suffer damage if left too empty or are drawn too low, a deep cycles design just gives it far more tolerance to that depleted state, allow it to be cycled more( charged from empty) more times before the battery fails.

      Dual purpose batteries are basically large tank, large pipe.

      It’s worth noting that DC voltage only draws what it needs, you can hook up the largest battery bank to the smallest load with no issue as far as the size of the bank etc if everything is setup and function correctly.

      Lithium suffers from none of these drawbacks. (As well as many more advantages) Gotta use the newer tech that is far safer though. Early Lithium and most cheap none reputable stuff is using the riskier tech with substandard QC.