Real Battery Issues or Micro Management

DerikDerik Solar Expert Posts: 82 ✭✭✭✭
I have read many battery threads and everyone is always checking all the cells, using the hydrometer, trying to hook up a monitor either a tri metric or something else to get more readings, taking all cells and trying to equalize them, adjusting float times and absorption times and doing more measuring and calculating....

Is this the nature of the off grid solar guy or is this necessary with most systems?

This is my second solar experience and I am becoming worried I too am checking everything all the time and ending up with the same results.. it looks like I will have to make seasonal adjustments to my absorb time and keep the water full in each cell and forget the rest??

My first system was 2 Trojan T-105s so a small investment I did nothing but keep them full and 5 years later they are still working fine, this time it's 12 trojan L-16RE B's so I am into the game of keeping them healthy, but what if i just kept them full of water and forgot the rest?? Would they last just as long or close to it if the system was matched correctly??


  • icarusicarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Real Battery Issues or Micro Management

    IMHO the real value of doing a regular maintenance on a battery bank is to find problems early. Regular checking of battery condition will serve to find problems early. You now have 36 cells to maintain, enough so that if you had a bad cell you might not even know it until that battery fails, but in the process it might begin to damage other cells.

    I check the water in my about every month, and at the time check the SG. I tend not to eq very often since my SG is always pretty even. I might add, that it is very important with a battery bank that big, to make sure that the batteries are wired properly so that each cell does it's share of the work, and gets it's share of the charge current. 12 batteries, 12 sets of cables, all need to be kept clean and tight etc.


    PS If you haven't read the following links, I suggest that you might find them interesting.

    One other question is how are you keeping these batteries charged, PV, aux charger etc?

  • DerikDerik Solar Expert Posts: 82 ✭✭✭✭
    Re: Real Battery Issues or Micro Management

    I have 9 215 panels. I have posted here just a few times but the only issue I have had since May was that my charge controller was set too low as far as absorb time goes. I adjusted it and wham in just a few days my batteries were up again to spec.

    I guess it depends on where you are and in certain locations where the batteries get really low then they will require more checking. Of if you loads are really high..

    My house is a weekend house and the batteries never get below 70% and because of the high desert my house is in they will be fully charged every three days at a minimum. I have made over 13kw in the summer and over 10kw in the winter. I suspect I could have made more power but the batteries were fully charged at that point so thats all I made. I was trying to use a lot of power to see how much I could make but under normal circumstance I only use about 4-5 kw.

    People seem to worry about cells and having a bad cell. How common is this? Also some seem to really want to shock the batteries with hydrometer readings that are off the trojan charts.. Is this really necessary?? I have never seen my batteries above 1.255 and the old T0105's are always at 1.250, Trojan says this is fine.

    Some have said that you need 10% from the panels of the amp hours the batteries have so I would need to have 120amps to charge my batteries.. but that hasn't been the case.. when I bought my charge controller I don't think outback even made one that was 120 amps..

    My two T-105s never had more than maybe a few amps going through them but they still have good hydrometer readings..after 5 years and only being equalized once. They are being charged by one 65 watt panel.

    Will my L-16's life be cut by not charging them with higher amps?? if so how much, currently I am hitting them with 60-70 amps for short periods almost every day, but I am only using the top 20% or so of the batteries capacity and I never do laundry, run the dishwasher or vacume at night..& since I don't have a generator I cut my power use a lot when it rains or is cloudy to keep the batteries up.

    Do I even need a trimetric? How about if I just check the water once a month, and the hydrometer readings every couple of weeks? Will this make my batteris life shorter? I have a mate and look at it once a day to see what I made and what the voltage is, is this enough?

    Did I just get lucky with the t-105's or is battery checking and measureing and re checking something some just like to do?
  • hillbillyhillbilly Solar Expert Posts: 334 ✭✭
    Re: Real Battery Issues or Micro Management

    I don't think that you have to do a ton of work on basic battery care and monitoring, just a bit of basic checking on a monthly (or so) basis. I'm one of those guys that has WAY too much data on my batteries; mostly because I didn't know some of the basics in the very beginning and now have some battery issues. It's when you start to notice some problems that you get a lot more obsessive about trying to understand as much as you can, and looking for any sorts of trends or clues to tell you what's going on inside that battery. It also depends a bit on how much your investment is I suppose, in our case the original 2K is a pretty sizable chunk of cash ... so it's worth it if we can eek out an extra year or so on them.

    If I only knew then what I know now...
  • icarusicarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Real Battery Issues or Micro Management

    There are two reasons to have charge current between 5-13% for FLA batteries. The first is strictly to get them charged in a timely way. The second is to produce enough current to allow the electrolite to bubble so that it does not stratify. Mixing of the electrolite leads to better battery life.

    A common mistake that people make is having too much battery for charge capacity. This often leads to chronic undercharging, and potentially (since you have a big battery) chronic over drawing. With out a good battery monitor it is fairly difficult to get really accurate battery condition information in real time, since a battery may show nearly 12.6 volts even when it is significantly charged, especially if the surface charge has not been bled off.

    I too used to live with 2 t-105s charged with a single 63 watt panel, and they held up quite well. To some great extent it depends on good management.

  • DerikDerik Solar Expert Posts: 82 ✭✭✭✭
    Re: Real Battery Issues or Micro Management

    I guess I am above the minimum of 5% charge amps and because of my mizerly useage my batteries are under utilized. I'll hook up the tri metric since it's already paid for and maybe at some point add a wind turbine so I don't worry about doing laundry or running the dishwasher..

    I guess I am like Hillbilly and didn't worry about any of my solar stuff until I realized my charge controller was only in absorb for one hour and saw my batteries were low, for the past few weeks I have been reading everything and checking the hydrometer every day.. so I need a happy medium.

    The lowest voltage I have seen is 24.4 and the lowest hydrometer reading was 1.210 with only an hour absorb time so I think I really have little to worry about, just trying to figure out where others comfort level is and how much monitoring is really necessary.
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