Solar charge controller question

Discussion in 'Charge Controllers' started by rake1, Oct 28, 2012.

  1. rake1

    rake1 WindyNation Engineer

    I have wind and solar my question is my solar charge controller. I just added another solar panel so I now have 265 watts of panels putting out about 17 amps on a good day. My question is any way to keep the amps up longer before my controller starts cutting the amps to my batteries? My controller is showing 17 amps but being that my batteries are about 80% charged it is only allow 4 of the 17 amps to my batteries.These are still charging but very slowly and most times the clouds roll in and I lose the amps and don't get fully charged.My controller is set from the factory at 14.2 volts anything I can do to make better use of that high amperage when it is available to charge my batteries? Would an MPPT controller help this situation?
  2. windyguru

    windyguru WindyNation Expert

    Well, it appears that you have a PWM controller and it is slowing down the charge to the battery as the battery gets more charged. This is done to protect your battery, increase its life expectancy and to maintain its ability to store the maximum amount of amps for use.

    Additionally, I have noticed that a "dead" battery acts as a larger load than a nearly fully charged battery. Therefore, a battery low on charge will pull more amps than a almost charged battery. This could be contributing to the lower amps as well.
  3. windyguru

    windyguru WindyNation Expert

    And to and to answer your question, I don't think an MPPT controller would not help in this case as they also controller the rate of charge based on charged state of the battery.
  4. NEOH

    NEOH WindyNation Engineer

    What is the Make & Model of your Charge Controller?

    Usually a 3 Stage Charge Controller will go through these 3 stages:
    Stage #1 = Bulk Charge with full amps and rising voltage
    Stage #2 = Absorb Charge with fixed voltage and continuously dropping amps
    Stage #3 = Float Charge with reduced voltage and very small constant amps

    Can you change the Voltage at which your Charge Contoller transfers from Bulk Charge (full amps) to Absorb Charge (reducing amps) ?

    It is very important for the Charge Controller to hold the Battery Voltage constant for one-hour (+/-) during the Absorb Charge as the amps drop off. You do not want to skip this Absorb Charge (reduced amps) phase. This gets the battery 100% charged without chronic over-charging or chronic under-charging. Chronic over-charging and chronic under-charging are both are bad news for your battery. Treat your battery properly by feeding it a properly configured 3 Stage Charge daily and your battery bank could last 4 - 8 years.

    You may need to find another use for the excess power. Maybe, dump the excess power into a Diversion Load for Hot Water???

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