Am I overcharging?

Discussion in 'Start here' started by David Anderson, Jan 14, 2022.

  1. Afternoon all - I have a dual 12v 100w panel set up in parallel wiring connected to a p20L - this feeds a single marine-deep Cycle DuraStart battery [182 RC Mins @ 25A/105Ah Cap 20Hr rate]. This set up is providing battery power to LED light signage - has worked fine for about a year, then I went to check it out and it had clearly leaked all over the place. I was concerned with Overcharging, but filled it with distilled water (and put it into a battery box for the mess) checked the p20L settings - everything seemed to be fine: Float Charge 13.0v low voltage reconnect 12.6v low voltage disconnect 9.0 battery b03. After filling it with water, it ran the longest we've ever seen, from about 5pm to 5am. Then two days later, dropped to 5pm to about 130am so I checked it - again clearly water leaked, and now the battery is pretty clearly swelling on the sides. Any suggestions to possible causes? Do I have something set incorrectly? Wondering if Wx is playing a factor - this set up is out of direct weather in an insulated box. Any suggestions appreciated.
  2. TomT

    TomT WindyNation Engineer

    If you have a voltage meter.
    Check that the P20L controller is showing the same voltage.
    I would change reconnect to 12.4 and flood to 13.
    14.2-14.4 will cause alot of off gassing on lead acid batteries.
    Full Charge is 12.6 volts resting anyways.
  3. Great thanks for the information - I do have a voltage meter, I dont understand "Check that the P20L controller is showing the same voltage." Not sure what you mean? How to check the P20L?
    I will change the other settings as recommended.

    Thanks again for the information and response!
  4. Tuicemen

    Tuicemen Solar Guru

    Keeping your lead acid batteries maintained requires you to monitor the water level inside reguarly. You should add water after a charge not before. It sounds like you've failed to monitor the water level often enough. A swelling battery is a sign of poor maintenance. It also sounds like your running your battery down too low before a recharge. This will reduce the batery life significantly and require water more often. A daily drainage of the battery means you need a bigger Ah one, more batteries, or turning your sign off before it can drain the battery (maybe with a timer)
    Is your sign 12v or do you power it with a inverter?
  5. To Check the P20L - would that be to just put the multi-meter on the positive and negative terminals for the solarpanel connection screws and make sure the multimeter reads the same as the display?
  6. Very likely that I was not maintaining the water level properly - After the swelling, I have moved to maintenance free AGM batteries.
    As for running too low - I was under the impression that the controller would handle that and disconnect when the battery gets too low.
    The Sign itself is using a pair of 12v LED flood lights - these are instant on 10W 12V DC Super Bright 800-900LM Real 10W Watt, Working Current 0.83A(12V) 0.42A(24V) and again - I was under the impression that the Controller would disconnect these lights if the battery got too low to avoid complete drainage.
    Everything is 12v and only the controller is being used to turn the lights on at dawn and off at dusk.
  7. Also I see Low Voltage Reconnect setting and will change to 12.4
    I do not see Flood - was that meant to be Float charger voltage setting moved to 13?
    Thanks again for all you time and assistance.
  8. Tuicemen

    Tuicemen Solar Guru

    I'm not sure where your located but AGM batteries are more sensitive to cold weather. You may need to insulate your battery box. I'm unfamiliar with the charge controler your using. The ones I have only act as a charger they don't stop a battery from discharging.
  9. TomT

    TomT WindyNation Engineer

    Thanks Juiceman for the info.
    But when I had a small battery bank.
    To keep from overcharging.

    Lithium battery setup only charges to set voltage and then disconnects.
    I set it for Lithium battery,12.6 volts max and I left it unattended for a long time.

    This was a setup for a car alarm system I used for smoke alarms. in our building.
    I had the outputs on a circuit in parallel. Hooked to car alarm relay .
    It had a 5 mile range with a 5/8 antenna.
    Only had it go off 1 time. Neighbors building was on fire. Smoke Damage to ours.
    We got there the same time as the Fire Dept and they were 1 block away.
    And someone called them by phone. We were at the lake and drove a mile to the store.
    Last edited: Jan 26, 2022
    Tuicemen likes this.
  10. Tuicemen

    Tuicemen Solar Guru

    Not all batteries are the same. Flooded lead acid are the cheapest but require more work. It is always best to follow manufactures recomendations for charging and maintenance.

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