Newbie / Batt bank question

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  • bryanl
    bryanl Solar Expert Posts: 175 ✭✭✭✭✭
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    Re: Newbie / Batt bank question

    re: "so I have close to enough battery bank for 18000 watt/hours?"

    If the VoG (Niel) says so, it must be .... ;-) you are hereby given a warning of a more permanent future solution should you continue for that was uncalled for and that was aimed at me in a derogatory way. i merely agree with him and there are many posts out there from other posters that have done the same without your smart comments. you will now have a temporary ban of 1 week to remind you not to continue to discuss your nasty opinions of some people. you previously judged somebody as needing mental help here and this will not be tolerated. niel

    it looks like you have a dozen very big batteries so that sounds right. You say each one is about 3 kWh or about 3 times the size (i.e. ~180 pounds) of a typical group 27. So, for a dozen, a 18 kWh nominal target cycle depth sounds about right.

    as for currents, if you are running nominal reserves, you are using about 600 watt hours per day or an average load of about 25 watts. The distribution is probably skewed with short periods of much higher load but, still, in the overall scheme of things, you're normally only pulling less than an amp from a 48v battery bank. Getting too hepped up on a 2' vs 4' wire imbalance seems a bit of a misdirected concern.
  • keyturbocars
    keyturbocars Solar Expert Posts: 375 ✭✭
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    Re: Newbie / Batt bank question

    I wonder how temperature might be affecting your battery bank's performance. It sounds like your bank is not performing up to what you expected. What are the temperatures like where you have your bank set up?
  • dagelt
    dagelt Registered Users Posts: 24
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    Re: Newbie / Batt bank question

    I have added some comments to my album to help let everyone know what each box does and maybe how I have things hooked up.... thanks for the advice!!!!!

    My batteries are in outside temperatures. The shed is not heated so right now at night is it around 10 degrees and during the day it is around 30 degrees. I have not seen any difference in the performance in the bank from summer to winter. It really has acted the same.

    I went ahead and made all of my positive cables the same length. I also made all of my negative cables the same length. My positive and negative cables are not the same length between each other but from what I have been hearing.... as long as polarity cables are the same length I am good and everything should be balanced.

    I have not been able to get them installed yet by I should on Thursday. Will let everyone know what I find out.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: Newbie / Batt bank question

    "I went ahead and made all of my positive cables the same length. I also made all of my negative cables the same length. My positive and negative cables are not the same length between each other but from what I have been hearing.... as long as polarity cables are the same length I am good and everything should be balanced."

    from the sounds of it you should be good to go.
  • dagelt
    dagelt Registered Users Posts: 24
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    Re: Newbie / Batt bank question

    Well I finally got my cables back on my battery bank (735aH) and the TriMetric TM-2025A battery monitor system up and running. I have only had it working for 2 days but I think Cariboocoot was correct, I have not been using my batteries at all.

    Last night I set my inverter to 48.5 volts and let it use the batteries to support my house demand and according to the monitor I only got down to 96% DOD with voltage varying from 49.8 to 48.8 during the night..... (I did have some wind to help)

    I did watch the the battery voltage and from 53 to 50.5 it went very quickly but from 50.5 to 49.0 very slowly and supported my house for the night. I use to only have my inverter set at 50.5 because according to voltage readings 50.4 is 75% DOD and I was trying to make my batteries last as long as I could.

    I will post more after I have a night with NO wind to let everyone know how long the batteries last.... down to 75% DOD.

    I am getting close to adding my other string to my battery bank, another 245 Ah.. maybe next weekend waiting on a part.

    I wanted to Thank everyone for their help with my adventure in going green!!!! and will still take advice on anything in this thread.


    One thing I still need help with is how to better control my wind power to charge my battery bank. My solar the charge controller works great but unless I have my inverters sell setting at 27 amps and sell voltage at 53.6..... my wind turbine will go to over voltage and never turn back on because they do not re-set until voltage reaches 54. I am only wanting to do this because I am trying to keep my charge voltage up higher than 53.6 for extented amount of time. Maybe this does not matter but I thought it should be higher than that when I charge them each day.....???

    I will post this problem on the wind side of this forum and maybe someone with an Xantrex inverter and an HY wind controller can help.