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  • New Victron Controller questions.

    I purchased a Victron 100/50 w/ Bluetooth controller and have been using it for a bit now with my 200 watts of portable panels . The manual is a bit sparse on info, most of it is just other language translations. I am researching grid tie panels of approx 300 watts each as I find they will put out the 50 amps when cold and in "perfect" conditions. (which I will never see) But it seems we need to size the controller to numbers we will never see.

    RV Specs 520Ah LA battery (4@ 6v 260 Ah Crowns S&P)
    Magnum 2800 watt PSW inverter w/ 125 amp charger. 4/0 Cables from Inv to Battery.
    Victron 100/50 controller with 12" 6AWG cables to the inverter 4/0 cables. 50 amp inline circuit breakers
    7500 watt Generator
    Want to replace about 200 Ah per day. I am assuming I will need to run the genny to get it out of Bulk most days as the panels will be flat mounted and probably warm in the southwest US. But all that is just speculation till after i buy and install them and see what really occurs.


    Here are my "hopefully" not stupid questions:

    1. If my panels get really cold and surpass the 100 volt maximum input voltage will that hurt the Victron controller or do they limit it like the output? I can only find reference to the output being limited, if it tries to put out 51 amps it will only put out 50 amps to the battery. Nothing about the incoming voltage. The panels I am considering put out very close to 100 volts with two panels @ 10 degrees C.

    2. Currently I have setup the controller with User defined battery settings per my battery manufacturer recommendations. 15.5 EQ, 14.5 Absorb, 13.5 Float. EQ is not enabled. The BT app shows the device is in Bulk charging my 520 Ah battery pack @ around 15 amps with my current portable panels, but doesn't show what voltage its charging at. Nor does it show that in Absorb or Float. It does show the battery voltage, in what looks like real-time. My thought was it should be providing 14.5 volts during Absorb and 13.5 during float, my guess is that is what the battery voltage should show those voltages during charging from the controller. But what shows is batt voltage slowly going up, from say 12.67 to 12.68 then 12.69 etc. That doesn't make a lot of sense to me if the controller is putting out the higher voltage needed to charge the battery.

    3. Maximum absorption time 6 hours is default. When charging my batts via my magnum inv/cnv i use 120 minutes for absorb time. Should I use the same for the Victron? Or since its solar should it be longer possibly due to lower amperage? I am really not sure why we have to specify absorb time at all, and nothing for bulk or float.

    Thanks in advance for any helpful information to clear up my cloudy vision of whats going on!

    -Bill



    Last edited by Bigbillsd; 05-30-2018, 01:06 PM.

  • #2
    Originally posted by Bigbillsd View Post
    I am researching grid tie panels of approx 300 watts each as I find they will put out the 50 amps when cold and in "perfect" conditions. (which I will never see) But it seems we need to size the controller to numbers we will never see.
    Hold the bus my friend, the size of the panel does not determine how many amps of charge current is produced. Not sure where you got that from, but is nonsense in any respect. MPPT Charge Current is determined by total panel wattage and battery voltage. The charge controller does not care if you have 10 x 60 watt panels or 2 x 300 watt panels connected either way is 50 amps maximum.

    MPPT Charge Current = Panel Wattage / Battery Voltage

    600 watts / 12 volts = 50 amps all day long
    1200 watts / 24 volts = 50 amps all day long
    2400 watts / 48 volts = 50 amps all day long.

    Originally posted by Bigbillsd View Post
    1. If my panels get really cold and surpass the 100 volt maximum input voltage will that hurt the Victron controller or do they limit it like the output? I can only find reference to the output being limited, if it tries to put out 51 amps it will only put out 50 amps to the battery. Nothing about the incoming voltage. The panels I am considering put out very close to 100 volts with two panels @ 10 degrees C.
    Think we have already covered this ground before and you are going to get the same answer every time whether you like it or not is of no concern to me. You risk damaging the controller period. Being in an RV there is absolutely no reason to risk anything. If you are using 2 x 300 watt panels, wire them in parallel and all the risk are gone. The wire distance is so short between panels and controllers voltage loss and expense becomes a non issue. Dance with the devil if you want, but quit asking the same question over and over again.

    Originally posted by Bigbillsd View Post
    2. Currently I have setup the controller with User defined battery settings per my battery manufacturer recommendations. 15.5 EQ, 14.5 Absorb, 13.5 Float. EQ is not enabled. The BT app shows the device is in Bulk charging my 520 Ah battery pack @ around 15 amps with my current portable panels, but doesn't show what voltage its charging at. Nor does it show that in Absorb or Float. It does show the battery voltage, in what looks like real-time. My thought was...
    Well thinking has you confused because if you can see the battery voltage, then you know what the charge voltage is. You have it in your mind just because you have a set point set to say 14.5 volts you are going to see 14.5 volts at the battery which is a false assumption and lacks a complete misunderstanding how a battery charges. The only time you will ever see the voltage set point equals the battery voltage is when there is only during the Constant Voltage phase with low charge current or no charge current. In otherwords the battery has to be saturated and charged. Try reading the Stickies like this one.

    Originally posted by Bigbillsd View Post
    3. Maximum absorption time 6 hours is default. When charging my batts via my magnum inv/cnv i use 120 minutes for absorb time. Should I use the same for the Victron? Or since its solar should it be longer possibly due to lower amperage? I am really not sure why we have to specify absorb time at all, and nothing for bulk or float.
    Now you have discovered the irony of solar. It is not possible in most cases to ever fully charge a working battery with solar. There are not enough hours in a day. Absorb phase is not a times event. It is a Current event and full charge is reached after charge current taper to 1 to 3% of C and that can take 10 to 12 hours. You do not have the luxury of time. Read this sticky.
    Last edited by Sunking; 05-30-2018, 03:00 PM.
    MSEE, PE

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    • #3
      Thanks Sunking, The parallel suggestion lit up the bulb! That will allow me to put out the portable panels too assuming that the flat mounted roof panels won't max out the output due to their angle to the sun most of the time.
      Thanks for that answer about the voltage on the charge side, I did not understand that, I thought the controller was supposed to put out 14.5 volts at whatever amperage it could muster to charge during the absorb phase. That part about taking 10-12 hours to fully charge makes me think this might be a fools errand and will just kill my batteries if they can't ever be fully charged.

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      • #4
        Originally posted by Bigbillsd View Post
        Thanks for that answer about the voltage on the charge side, I did not understand that, I thought the controller was supposed to put out 14.5 volts at whatever amperage it could muster to charge during the absorb phase.
        It is possible to have a charger take a discharged battery to set point voltage. If you followed the sticky example of a 12 volt 100 AH battery discharged down to 12 volts, it would take a 240 amp charger to take it 14.4 volts initially. But with a 10 amp charger the recommended charge rate only goes up to 12.1 volts. But even if you had the 240 amp charger, and the battery did not boil over and over heat will still take 6 to 12 hours before charge current tapers down to 3% or 3 amps.

        Get a hydrometer as it is the only way to accurately measure and determine SOC.
        MSEE, PE

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