too much battery, too little solar.

landyacht.318
landyacht.318 Solar Expert Posts: 82 ✭✭✭✭
in General Solar Power Topics #1
I've got a kyc 130 and SB2512i charging either 2 or 3 115 ah everstarts. I started noticing the voltages in the morning would be lower and lower, even when my Monitor indicated 100% at sundown and ~89% at sun up. My electrical usage was the same overnight. I figured the batteries were aging and it was normal.

Currently the vehicle is parked while I swap the rear axle, and the panel would be half shaded mid day, so I covered up the panel and pulled the fuse.

After letting the batteries fall to 60% I plugged in the car charger and brought them back up to near 100% as indicated by the monitor.

Now in the morning the monitor registers .4 volts higher in the morning than before, with the same electrical usage.

Is this because I have more battery than panel? Is it a good idea to use a wall charger every so often to pump some higher amps into the batteries in my situation?

The car charger would go into float mode when the monitor indicated 20 amp hours from full.

Should I try to use more electricity overnight to cycle the batteries a little deeper? They now rarely fall below 88%.

Thanks
· Share on Twitter

Comments

  • System2
    System2 Posts: 6,290 admin
    #2
    Re: too much battery, too little solar.

    Some quick thoughts.
    No, do not cycle your batteries deeper. With lead acid batteries, in general, the less discharge the better and when they are discharged, recharge as soon as possible to prevent sulfation damage.
    Also note that batteries will self discharge over time due to normal internal electrical leakage, so must from time to time be recharged for that reason too.
    Another note - - you mention that they are "Everstarts", which sounds to me like they're starting batteries, rather than real deep cycle batteries. If so, they will not stand up to cycling nearly as well as real deep cycle batteries will.
    Even with real deep cycle batteries, you should aim for taking no more than 20% of the power out of them (leaving them still 80% charged) before recharging, and never more that 50% as this will drastically shorten their lives.
    The term "deep cycle" is misleading, as many folk take that to mean they can be drained dead before needing to be recharged, when in reality such use is considered abuse and will murder the poor things in short order.
    Cheers
    Wayne
    · Share on Twitter
  • landyacht.318
    landyacht.318 Solar Expert Posts: 82 ✭✭✭✭
    #3
    Re: too much battery, too little solar.

    I know they are not true deep cycles, but they are labeled as deep cycle batteries. They do have a lower CCA rating than same sized starting batteries. One alone has more than enough juice to turn over my v8, but I usually keep all three in parallel.
    · Share on Twitter
  • Brock
    Brock Solar Expert Posts: 639 ✭✭✭✭
    #4
    Re: too much battery, too little solar.

    Just a guess but I bet the panel isn't full charging them. If you can get a volt meter on them in the afternoon and see what kind of voltage you’re at. You want to see 14.4+ voltage. My guess is the battery charger pushed them up so they are truly full and they were not getting truly full with the panel. Although with no loads on them that should be able to maintain them, but maybe you have some small load on them. If it were me I would leave the solar charge on and once a week or two hit them with the grid powered charger to make sure they are topped off.
    3kw solar PV, 4 LiFePO4 100a, xw 6048, Honda eu2000i, iota DLS-54-13, Tesla 3, Leaf, Volt, 4 ton horizontal geothermal, grid tied - Green Bay, WI
    · Share on Twitter
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #5
    Re: too much battery, too little solar.

    it does sound like they weren't getting charged all of the way. don't take a battery monitor for gospell all of the time as you should verify by voltage and specific gravity readings too. i would imagine sulphation has gotten a good start on the batteries.
    · Share on Twitter
  • System2
    System2 Posts: 6,290 admin
    #6
    Re: too much battery, too little solar.
    niel wrote: »
    i would imagine sulphation has gotten a good start on the batteries.

    Unfortunately, that's probably why they seem to be so rapidly loosing capacity.
    A direct result of perhaps being discharged too deeply and not being FULLY recharged ASAP after use.
    Wayne
    · Share on Twitter
  • landyacht.318
    landyacht.318 Solar Expert Posts: 82 ✭✭✭✭
    #7
    Re: too much battery, too little solar.

    Only once did I let the batteries drop to 52% according to the monitor. I hit them with 25 amps promptly.

    For a while, before I lowered my float current, it failed to stay in acceptance unless the engine was running.

    Now it will kick from acceptance to bulk shortly after my 2.7 amp fridge kicks in.

    Shortly after the fridge kicks off it goes back in to acceptance.

    When in float mode near midday the fridge kicking on will not knock it into bulk
    . It seems to adjust pretty quickly to loads.

    Today the batteries seem to be holding their voltage much longer.
    · Share on Twitter

Categories