About to buy new Batteries - not sure if my set up is correct to start with

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  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: About to buy new Batteries - not sure if my set up is correct to start with

    we've gone down that road many times before on that subject. you already bought them didn't you, so why ask now?

    my opinion is snake oil, but some others may say they work.
  • obbaobba Registered Users Posts: 14
    Re: About to buy new Batteries - not sure if my set up is correct to start with
    niel wrote: »
    we've gone down that road many times before on that subject. you already bought them didn't you, so why ask now?

    my opinion is snake oil, but some others may say they work.

    I got them both for $10 each. So no great loss.
    It's funny how some say they work and some say they don't.

    On the reading i have done they send out a very high freq pulse that is supposed to 'knock' off any sulphation. And AFAIK, sulphation occurs when the batteries are not being charged - which is just over half a day.

    I wonder if Wet lead acid Batterys sulphate when being discharged, as my setup always has a constant discharge, humm!
  • BB.BB. Super Moderators, Administrators Posts: 30,485 admin
    Re: About to buy new Batteries - not sure if my set up is correct to start with

    One thing to watch with desulfators--They do output a high frequency pulse that has been seen to "confuse" at least one brand of MPPT charge controller (Outback in the reported case).

    With the desuflators attached and running, it significantly reduced the output Amp*Hours of both attached charge controllers. When the desulfators where removed, they output went up significantly.

    From late 2010:
    PhilS wrote: »
    I pulled the fuses on both Desulfators to 'turn them off', weekend before last.

    As I mentioned above, when I put a new FM60 onto a 1020 watt bank (48V? three pairs of Mitsubishi MF170) that did have an MX60, I got consistently less output than the MX had given on that bank . I had moved the MX to a new set of panels with 780 watts (54V, I think, 3 Sun HS130 panels in a string, two strings). I did this to put the better cooling fan on the bigger solar bank since I'm pushing the limits for a 12V battery bank. (OK, Bill, "exceeding" the limits" :roll: )

    I posted at the Outback forum, and Outback contacted me after reading my post. She asked if I had a Xantrex inverter (yes, SW2512MC) and she mentioned there were conflicts with the earlier Revs and some Xantrex inverters. Because I had an earlier Rev than the 2.0, Outback shipped me a new one with the Rev 2.0.

    The problem was better but not perfect. Randomly, the MX would outperform the FM. Also randomly, at the end of the day, the total KWH from the MX would be more than the FM. All panels together in a line, ground mount, no shading or other things that should cause that. Some days the FM did better and some the MX did better. I just accepted it because... I felt I had to.

    Since deactivating the Desulfators, the FM always has more KWH at the end of the day.

    Watching them occasionally this last weekend, the FM always outperformed the MX. And it seemed that both did much better (no measurements, just years of experience looking at the readings... it was like both the FM and MX had slurped down a Red Bull!). At the peak of the day, the FM was cutting off at 60 - 61 amps, as it's s'posed to but I haven't seen that since the FM was installed. The MX was hitting 58 amps, which it never did on this new set of panels. (It didn't seem to make any difference on my 3rd MX60 tied to 780 watts of panels but at 12V.)

    So my unscientific conclusion is that the two DeSulfators DID interfere with the Outback controllers. They will remain "off" and THANK YOU WisJim for asking the question!!

    Phil

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: About to buy new Batteries - not sure if my set up is correct to start with

    Lead-acid batteries sulphate. They do it if they are kept charged. They do it if they are discharged lightly and immediately recharged. They really do it if discharged heavily and left to sit before being fully recharged. You can not stop it, you can only slow it down.

    As such it is impossible to say if desulphators work because ordinary charging will achieve the same effect; it's a matter of "extent". And since no two batteries are truly exactly alike it is virtually impossible to set up a test that would conclusively prove if the device (and they are not all the same) works or not. Some claim to see better results using PWM charge controllers rather than MPPT type because the PWM 'pulses' when at the appropriate Absorb Voltage level. Well guess what the MPPT does to control Voltage?

    Some also claim that their desulphators will recover a sulphated battery. Not to 100% of course. In fact no more than standard charging procedures would do (see previous paragraph re: the difficulty in setting up a definitive test).

    My opinion, for what little it's worth, is that they are a waste of money. I come to that conclusion from decades of using lead-acid batteries in many applications and getting quite long life (longer than the manufacturer expects) out of those that were properly maintained. Ergo the desulphator would not add anything to a proper charge regime.

    Feel free to disagree. It's not my money you're spending.
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: About to buy new Batteries - not sure if my set up is correct to start with
    Some claim to see better results using PWM charge controllers rather than MPPT type because the PWM 'pulses' when at the appropriate Absorb Voltage level. Well guess what the MPPT does to control Voltage?

    Well, in theory an MPPT controller could just go to a non-optimal input tracking setting to reduce the available output current. And any pulse width modulation on the input will not necessarily cause matching pulses on the output.

    Also some desulfators claim to use energy storage capacitors to allow *really* high current short pulses, which neither a PWM nor an MPPT controller can do.

    That does not meant that desulfators work, just that your arguments are weak in that particular area. :-)
    SMA SB 3000, old BP panels.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: About to buy new Batteries - not sure if my set up is correct to start with
    inetdog wrote: »
    Well, in theory an MPPT controller could just go to a non-optimal input tracking setting to reduce the available output current. And any pulse width modulation on the input will not necessarily cause matching pulses on the output.

    Also some desulfators claim to use energy storage capacitors to allow *really* high current short pulses, which neither a PWM nor an MPPT controller can do.

    That does not meant that desulfators work, just that your arguments are weak in that particular area. :-)

    What a coincidence; so are yours. :p
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: About to buy new Batteries - not sure if my set up is correct to start with
    What a coincidence; so are yours. :p

    I keep hoping that someday we will see real data with controlled conditions instead of just a lot of anecdotes about "this worked/did not work for me".
    Of course the desulfation fans will argue that any experiments that show no effect were just done incorrectly.....
    Kind of reminds me of cold fusion. :-)
    SMA SB 3000, old BP panels.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: About to buy new Batteries - not sure if my set up is correct to start with
    inetdog wrote: »
    I keep hoping that someday we will see real data with controlled conditions instead of just a lot of anecdotes about "this worked/did not work for me".
    Of course the desulfation fans will argue that any experiments that show no effect were just done incorrectly.....
    Kind of reminds me of cold fusion. :-)

    It does, doesn't it? :D

    Batteries have this bad habit of being inconsistent in performance over lifespan even under controlled conditions. That's what mucks up the testing. :p
  • BB.BB. Super Moderators, Administrators Posts: 30,485 admin
    Re: About to buy new Batteries - not sure if my set up is correct to start with

    Add inconsistent humans and weather/power usage to the mix--And who knows what is controller/human/battery/conformation bias/actual results that are "above the noise" for some of these things.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: About to buy new Batteries - not sure if my set up is correct to start with
    It does, doesn't it? :D

    Batteries have this bad habit of being inconsistent in performance over lifespan even under controlled conditions. That's what mucks up the testing. :p

    Right, so any reasonable test will have to use a few thousand batteries.

    I do not plan to fund such testing any time soon, although it would be easier to do with smaller batteries!
    SMA SB 3000, old BP panels.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: About to buy new Batteries - not sure if my set up is correct to start with
    inetdog wrote: »
    Right, so any reasonable test will have to use a few thousand batteries.

    I do not plan to fund such testing any time soon, although it would be easier to do with smaller batteries!

    right, and if it doesn't work then they say you needed to do this with bigger batteries or some other parameter wasn't right. believe me, we heard it all here in the past.
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