Charge controller voltage settings

System
System Posts: 2,511 admin
in General Solar Power Topics #1
Hello all,

I have recently purchased a 270w folding solar panel set to be used in charging my 2 - 6v (in series for 12v) Sunxtender PVX-2240T RV batteries and need opinions / recommendations on the proper voltage settings for the CC thats permanently attatched to the back of one the panels.

The CC controller is a low budget chinese made JUTO cmp24-20a that only has a few user programmable voltage settings on the digital display which are as follows;

1. Charge on - (battery voltage the CC will commense recharging at when the batteries get down to a certain voltage) - default is set at 12.6v
2. Charge off - (Max battery voltage charge the CC will shut off at) - default is set at 13.7v and can be set from 13.7v - 27.4v
3. Load off - (LVD setting)? - default is set at 10.6v
4. Load on - (LVD setting)?

I'm sure that many of you have most likely have never used or even heard of the JUTO CC that I have, but may or may have used the same Sunxtender PVX-2240T batteries and I would very much appreciate any best educateded guesses that you could provide me as to what the proper voltage settings should be on the CC in relation to the 4 parameter settings I listed above so that I can try to set this thing up for proper (or as close to proper) charging on my sunxtender's.

Not sure if this makes much difference on the CC settings or not, but I should also add that the folding panels will not be directly attached the batteries via gator clips as do most portable folding panel sets. I have installed a Trimetric 2025 battery meter in my RV that passes through a shunt (as should be) and made up a quick connect, 2-conductor cable / connector at the battery itself, that is connected to the batteries and shunt (fused positive side to the positive side of the batteries and negative side to the shunt) so that I would be able to easily connect and disconnect the panels without having to take the battery cover off each time and so that I will also be able to monitor the voltage being supplied from the panels when connected.

thanks in advance,
Bob
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Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Charge controller voltage settings

    I don't want to sound like Mr. Meanie, but that's just about the worst charge controller you could possibly have for deep cycle batteries. Let me elaborate:

    Normally a deep cycle battery is brought up to Absorb Voltage and held there either for a period of time or until current drops below a certain point. Then the Voltage should drop down to the Float set point and remain there for as long as possible.

    The charge controller you have there functions more along the lines of an automotive type: Voltage drops below set point, charge on. Rises above set point, charge off. Works for cars, but isn't going to properly replenish a deep cycle.

    So the best bet is to try and 'trick' it into behaving like a proper controller. To do this, set the 'off' Voltage to just above the Absorb set point for the Sunsavers. Probably that would be 14.2 to14.4. The 'on' setting could be anything that you're comfortable with as a minimum Voltage.

    It has separate Load terminals, yes? You probably won't be using them. If you do, crank the setting up from 10.6; you won't like that set point.

    Just my opinion. Others' may differ. Feel free to disagree.
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