Re: [AFMUG] Calculating battery bank size

Wed, 02 Dec 2015 13:53:13 -0800

Only peripherally related to this thread, but I tripped across another nice document that talks about the advantages of AGM over flooded and gel. The good part is on pages 10-12. It discusses freezing, stratification, loss of electrolyte and all sorts of other fun stuff that ruins your batteries. 
http://www.lifelinebatteries.com/manual.pdf


On 12/2/2015 3:49 PM, Adam Moffett wrote:
Right.....a single discharge doesn't automatically destroy them. Some battery vendors publish charts that show the number of expected charge/discharge cycles compared to depth of discharge. There's a dramatic difference in lifespan, but one complete discharge isn't killing you.
Another consideration is you don't want the electrolyte to freeze. According to my reading, freezing the battery probably will destroy it, and the temperature required to make them freeze is much lower when they are charged vs when they are dead. There's a nice chart in table1 here: 
http://www.trojanbattery.com/pdf/WP_DeepCycleBatteryStorage_0512.pdf

That might make a good case for that 75% LVD.


On 12/2/2015 3:29 PM, Sean Heskett wrote:
i have run our solar sites down to dead (well, at least low enough voltage that everything shut down) a few times over the years and the batts just keep working. i wouldn't want to do it all the time tho lol 

it's not really a one and done situation.

YMMV
On Wed, Dec 2, 2015 at 12:56 PM, That One Guy /sarcasm <[email protected]> wrote: 

    so how dead does it make the battery for fully discharge, the
    rhetoric, is run em down, throw them away, is there a rule of
    thumb for damage?

    On Wed, Dec 2, 2015 at 12:49 PM, Bill Prince
    <[email protected]> wrote:

        He didn't indicate how the 400 ah were configured. Is it one
        12V 400 ah battery, or one 24v 400 ah battery, etc. But as
        you noted, once you convert the battery voltage and amp-hours
        to watts, it eliminates any confusion.

        If I had 4800 watt-hours of battery (assuming 12V X 4 at 100
        amp-hours), I would estimate 9 hours of run time until the
        batteries are dead as a doornail. If you want to use them
        again (and most people do), then cut that time in half.

        On the other hand, if you have a 48 volt battery with a 400
        amp-hour rating, then you actually have 19,200 watt-hours of
        capacity, and you could multiply the above by 4.

        If you configure the four 12V/100 ah batteries in series,
        then you don't have 400 ah, you have 48V/100 ah. The
        watt-hours are the same.

        bp
        <part15sbs{at}gmail{dot}com>

        On 12/2/2015 10:23 AM, Mathew Howard wrote:

        watt-hours stay the same - 200x24 and 100x48 both equal 4800
        watt hours. In other words, unless you have some horribly
        inefficient voltage converters in the mix, it makes little
        difference.

        On Wed, Dec 2, 2015 at 12:05 PM, Bill Prince
        <[email protected]> wrote:

            wrong.

            bp
            <part15sbs{at}gmail{dot}com>

            On 12/2/2015 10:04 AM, Josh Luthman wrote:


            If you do 4x 12v 100ah batteries and do 24v it's twice
            the time as 48v

            Josh Luthman
            Office: 937-552-2340 <tel:937-552-2340>
            Direct: 937-552-2343 <tel:937-552-2343>
            1100 Wayne St
            Suite 1337
            Troy, OH 45373

            On Dec 2, 2015 1:01 PM, "Bill Prince"
            <[email protected]> wrote:

                What voltage?

                bp
                <part15sbs{at}gmail{dot}com>

                On 12/2/2015 10:00 AM, TJ Trout wrote:


                    How long will 500w load last on 400ah?
-- If you only see yourself as part of the team but you don't see 
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