PzS vs OPzS for off grid systems

liamgliamg Registered Users Posts: 43 ✭✭
Hello,

I've seen that almost everyone recommends the OPzS as the best choice for an off grid application (taking into account the 20 yrs life claimed by most of the manufacturers). 

Anyway, looking at the detailed specifications, the OPzS has a 20 years life span in float operation and its electrolyte has a lower density (1.24 vs 1.29) in regard to PzS version.

Moreover, the OPzS are recommended for backup applications (UPS/telecomm), where the battery is actually spending the most part of its life in float operation. That means the electrolyte concentration will stay high for a very long time hence there is an increased chance of plate corrosion (that's why they choose that lower (1.24) electrolyte density).

Well, the float operation it's not exactly an off-grid/solar scenario, where you have to cycle the battery on daily basis. For that matter, this scenario is closer to a forklift/golfcart operation (though the discharge current is usually lower).

So, why should I choose OPzS instead of Pzs? The transparent case it's not the answer.. ;)

Comments

  • mvasmvas Registered Users Posts: 384 ✭✭✭
    edited June 2017 #2
    Batteries design for long term float may not be the best choice for daily deep cycles.

    What does Trojan (biased?) report ...
    http://www.trojanbattery.com/pdf/Trojan-Battery_Industrial-Line-vs-2V-OPzS.pdf

    We need an unbiased "Consumer Reports" type test for Deep Cycle Batteries.
  • liamgliamg Registered Users Posts: 43 ✭✭
    mvas said:

    Batteries design for long term float may not be the best choice for daily deep cycles.
    That was my point, too. Then why everybody (well, except Trojan!) recommends OPzS for PV applicatons?

    mvas said:

    We need an unbiased "Consumer Reports" type test for Deep Cycle Batteries.
    That's true, I don't believe the linked Trojan report neither. Who are those "OPzS1", "OPzS2", "OPzS3"? What SG do they have? 

    Apparently, there's no constructive difference (both using tubular positive plates) between the OPzS (float operation) and PzS (heavy duty deep-cycle) batteries, except for lower SG and (maybe) the Pb alloy used (to avoid plate corrosion during prolonged float operation).

    Then why is Trojan putting the blame on tubular (vs flat) positive plate construction??
  • mvasmvas Registered Users Posts: 384 ✭✭✭
    edited June 2017 #4
    PzS    means                                         Pz = PanZerplatte (tubular plate) S = Flüssig (flooded) "MOTIVE"
    OPzS means  O = Ortsfest (stationary) Pz = PanZerplatte (tubular plate) S = Flüssig (flooded)

    I've read "OPzS vs PzS" ...
    More electrolyte in OPzS (stationary) and Enersys uses 1.28 SG in OPzS (stationary)
    Same efficiency
    Same chemistry
    Same electrical characteristics 

    But larger quantities of PzS type are produced for motive applications, this brings down the unit price of PzS vs OPzS.
  • liamgliamg Registered Users Posts: 43 ✭✭
    Still the OPzS are mainly recommended for telecomm use (mostly float) and their SG are usually around 1.24 (to avoid plate corrosion during extended float operation).

    Anyway, my question was: isn't the off grid operation more similar to a traction scenario (daily (deep) cycling)? Beside, a SG of 1.28-1.29 (PzS) means a more efficient conversion, which means more available energy using the same amount of lead plates.

    Last but not least, like you've pointed out, the PzS are cheaper (mass production).

    So, should I go with PzS for my off grid setup?
  • EstragonEstragon Registered Users Posts: 4,495 ✭✭✭✭✭
    Lower SG means lower capacity for a given size battery, but (all else equal) likely longer life.

    Personally, I'd go for the PzS if they're significantly cheaper, but the trade-offs are yours to assess.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • mcgivormcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    liamg said:

    Still the OPzS are mainly recommended for telecomm use (mostly float) and their SG are usually around 1.24 (to avoid plate corrosion during extended float operation).

    Anyway, my question was: isn't the off grid operation more similar to a traction scenario (daily (deep) cycling)? Beside, a SG of 1.28-1.29 (PzS) means a more efficient conversion, which means more available energy using the same amount of lead plates.

    Last but not least, like you've pointed out, the PzS are cheaper (mass production).

    So, should I go with PzS for my off grid setup?

    Was looking into Hoppecke OPZS which were the recommended battery/cell  for off grid, according to the distributor I was talking to, the price was 2.5 times that of GC batteries, perhaps they are more robust and better quality??
    https://www.hoppecke.com/en/product/opzs/
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • mvasmvas Registered Users Posts: 384 ✭✭✭
    edited June 2017 #8
    liamg said:
    Still the OPzS are mainly recommended for telecomm use (mostly float) and their SG are usually around 1.24 (to avoid plate corrosion during extended float operation).

    Anyway, my question was: isn't the off grid operation more similar to a traction scenario (daily (deep) cycling)? Beside, a SG of 1.28-1.29 (PzS) means a more efficient conversion, which means more available energy using the same amount of lead plates.

    Last but not least, like you've pointed out, the PzS are cheaper (mass production).

    So, should I go with PzS for my off grid setup?
    I disagree with the conclusion that "stationary" implies only Long Term Float applications.
    Initially, I thought that too but I have changed my mind.
    After much research, I posted message #4, where I stated "The Electrical characteristics of OPzS & PzS batteries are identical".
    Yes, the OPzS type is recommended for Telecom, but they are also recommended for all stationary float and deep cycle applications.
    OPzS (stationary) means - do not install in a moving vehicle, ie Tow Motor, Electric Car, etc.
    The OPzS (stationary) battery does have more electrolyte which helps with Long Term Float stationary applications.
    But that, in no way, implies that OPzS is ONLY for Long Tern Float Applications.
    I charge my batteries until they bubble (100% SOC & Equalize), so my electrolyte does get mixed.
    The electrolyte in the PzS (motive) is constantly mixed due to the motion of the vehicle.
    Supposedly, the PzS (motive) is designed "stronger" to handle the forces of motion ( not really important to us, unless you drop it ).

    I would purchase the less expensive / more common PzS (motive) battery, even though we have a stationary application.
    We gain nothing in a PV Solar application, by paying more, for the less common, OPzS battery.
    You must bubble the electrolyte in the tall battery to mix the electrolyte since it is a stationary application or install a bubbler.
Sign In or Register to comment.