cant get pcm6048 to charge batteries past 13.8...

davodavo Registered Users Posts: 21
Hello all I have 3x290w hosun linked in series through pcm6048 charge control,I also have 2x100w 18v panels going throu solar30 pwm charge control,both are going into 2x6v 240ah batteries in series to make 12v..my problem is Trojan recommend 14.8v charge,when battery voltage gets to 13.7-13.8 pcm6048 goes to float charge,my batteries arent getting fully charged! a typical day today 10amps for 2ish hours then down to 1.5a for the rest of the day,batteries staying at 13.8 even tho its sunny all day pcm6048 only uses it for two hours!so now my telly has been on 3 hours,(12v 2.5a 30w) and battery is down to 12.4....only way I can get batteries to charge above 14 is to run the engine then alternator dors upto 14.4..
hope all this makes sense,my questions are as follows:
1.can pcm6048 be adjusted to provide sufficient charge(14.5v+) ?
2.if I cant adjust can I add some piece of equipment to make it charge higher?
3.any ideas how I can get to the magical 14.4+volts?

many thanks in advance!

Comments

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: cant get pcm6048 to charge batteries past 13.8...

    You have 290 Watt panels that are likely 30 Vmp so you are wasting some of their power potential running through a PWM type controller. That much panel (870 Watts) should be on an MPPT and making you about 55 Amps peak on 12 Volts. 10 Amps is about the output of one panel, so check to make sure one of them isn't wired in backwards.

    Get rid of the controller and buy one that will make use of the panels' full potential and can be programmed for the proper Absorb Voltage.
  • davodavo Registered Users Posts: 21
    Re: cant get pcm6048 to charge batteries past 13.8...

    hello they are 43v panels and this is through pcm6048 mppt charge control,the two 100w are through pwm.Im in the uk currently no sun per day 7.5hours daylight perday and when it does shine its very low in the sky and panels are mounted horizontally...hence 10amps...do you know of any way I can get charge voltage up without replacing charge control?
    thanks.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: cant get pcm6048 to charge batteries past 13.8...

    Nope.

    But if that controller really is an MPPT type and does not allow you to program the Absorb Voltage to 14.8 then it is not a very good one.

    That 43 Volt rating is probably Voc, making the Vmp around 35 which is a normal "24 Volt" panel. The current would then be around 8 Amps. They won't produce much of anything without sun directly on them, though.

    Still none of that changes the controller's inability to be set for the right Absorb Voltage.
  • davodavo Registered Users Posts: 21
    Re: cant get pcm6048 to charge batteries past 13.8...

    ok so time to spend more money I guess!.thanks for the advice,just to clarify there is no piece of equipment I can add the system to contril/raise the charge voltage?thanks
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: cant get pcm6048 to charge batteries past 13.8...
    davo wrote: »
    ok so time to spend more money I guess!.thanks for the advice,just to clarify there is no piece of equipment I can add the system to contril/raise the charge voltage?thanks

    Dropping Voltage is easy. Raising it is difficult. You would need a buck booster circuit and it would have to be design to work with the battery charging and calibrated to give just the needed rise at the appropriate charge stage. In other words you'd end up building an MPPT controller that "works backwards" so you might as well get one that does the job right way 'round.
  • RybrenRybren Solar Expert Posts: 348
    Re: cant get pcm6048 to charge batteries past 13.8...

    Taking a quick peek at the user manual I don't see any method to change the charge settings, nor do I see a reference to the actual charging voltages used by the CC.

    Even the spec sheet doesn't mention the voltages.

    As 'Coot said, it's time to get a different CC.
  • westbranchwestbranch Solar Expert Posts: 5,142 ✭✭✭✭
    Re: cant get pcm6048 to charge batteries past 13.8...

    You also need to change the orientation of those Horizontal panels, to something more Vertical. Horizontal panels will produce near zilch at this time of the year as you are finding...
     
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  • SolInvictusSolInvictus Solar Expert Posts: 138
    Re: cant get pcm6048 to charge batteries past 13.8...

    On page 14 of the manual, what is the Battery Over-voltage Limit Setting?

    The default value seems to be 27.3 V / 2 = 13.65 V for a 12 V battery array which is close to the value you are reporting. You need to manually change it.

    You should probably increase the Battery Under-Voltage Limit Setting because the default value for a 12 V system appears to be 9 V. For a 12 V wet lead-acid battery array it should be higher than 10.7 V which is considered a complete discharge.
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