EXIDE - EPZV charging

fca1
fca1 Solar Expert Posts: 124 ✭✭
in Off Grid Solar & Battery Systems #1
Hi
I have now 12 new exide forklift epzv 255ah dryfit "gel" batteries, exide recommends the use of therir sp2100 chargers and send me this charging curve that their charge apply..

I undestantd upt to the point that i should set my MS mpp60 to a charging voltage of 2.35v and then it will switch absorption mode (constant voltage), i don't get is on this curve that final stage where it seems that the voltage could go up to 2,8v !!!!!
i always read the gel cells should not be equalized, but these "dryfit" technology..... i have a lots of doubts about it, and the supplier only point me to the their charger ...

any comments or advice on how to configure my solar charge to use these ones..

Regards


i-8HQdsvQ-L.jpg
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Comments

  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #2
    Re: EXIDE - EPZV charging

    This is the IUIa charging profile favoured by forklift chargers because it lets you charge the battery from a deeply discharged state to fully charged in the shortest time possible.
    But this is not the only way to charge a battery, you can also use an IUoU charging profile which most of the renewable energy industry uses. In fact some forklift chargers will also use the IU charging profile (Bulk and absorb, no float): but they take longer to charge the batt, so aren't as popular.

    From the battery technology handbook:
    Attachment not found.
    Attachment not found.
    So, if I were in your shoes, I'd just use an absorb of 2.35 and a looooong absorb phase then monitor the charging current. When it drops to 1mA for every Ah, note the time it took since the start of absorb to get there, that's your new absorb time.
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #3
    Re: EXIDE - EPZV charging
    stephendv wrote: »
    This is the IUIa charging profile favoured by forklift chargers because it lets you charge the battery from a deeply discharged state to fully charged in the shortest time possible.
    But this is not the only way to charge a battery, you can also use an IUoU charging profile which most of the renewable energy industry uses. In fact some forklift chargers will also use the IU charging profile (Bulk and absorb, no float): but they take longer to charge the batt, so aren't as popular.

    From the battery technology handbook:
    Attachment not found.
    Attachment not found.
    So, if I were in your shoes, I'd just use an absorb of 2.35 and a looooong absorb phase then monitor the charging current. When it drops to 1mA for every Ah, note the time it took since the start of absorb to get there, that's your new absorb time.

    I think hera are some mistmatch, fca1 speaks about "gel" batteries like a EPZV?...maybe i am confused!...;-)
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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #4
    Re: EXIDE - EPZV charging
    unicornio wrote: »
    I think hera are some mistmatch, fca1 speaks about "gel" batteries like a EPZV?...maybe i am confused!...;-)

    Yep, gel batteries EPZV used in forklifts. Where's the mismatch?
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #5
    Re: EXIDE - EPZV charging
    stephendv wrote: »
    Yep, gel batteries EPZV used in forklifts. Where's the mismatch?

    Hi, Stephen,

    I had understood that your batteries were lead/ acid ... or not? ... ;-)
    I'm sorry to have messed up! ... any way I was wrong, sorry ... :-(
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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #6
    Re: EXIDE - EPZV charging
    unicornio wrote: »
    I had understood that your batteries were lead/ acid ... or not? ... ;-)

    Yes, mine are flooded lead acid forklifts, but his are gel. My comment above is for gel batteries, and the excerpt from the battery technology handbook (good bedtime reading) is also for gel cells used in forklifts, i.e. PZV. :)
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #7
    Re: EXIDE - EPZV charging

    Clarification: gel batteries are lead-acid. It's just that the acid is suspended in 'Jello'. :D
    AGM's are also lead-acid, but the acid is contained in a fibreglass mat trapped between the plates (just enough for the electrochemical reaction to occur).
    Flooded lead-acids (FLA's) are as the name implies; plates wallowing in a vat of electrolyte solution.

    (I know you guys already know this: I put it in for any casual readers of the thread.)
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  • unicornio
    unicornio Solar Expert Posts: 217 ✭✭
    #8
    Re: EXIDE - EPZV charging
    Cariboocoot wrote: »
    Clarification: gel batteries are lead-acid. It's just that the acid is suspended in 'Jello'. :D
    AGM's are also lead-acid, but the acid is contained in a fibreglass mat trapped between the plates (just enough for the electrochemical reaction to occur).
    Flooded lead-acids (FLA's) are as the name implies; plates wallowing in a vat of electrolyte solution.

    (I know you guys already know this: I put it in for any casual readers of the thread.)

    yeah!...this is clear ...;-)
    but I got confused with batteries EPZV typical of lead /acid with electrolyte, but traction ... sorry
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  • fca1
    fca1 Solar Expert Posts: 124 ✭✭
    #9
    Re: EXIDE - EPZV charging

    Can you explain what os the diference between IUIA And IU ?
    My tristar mmpt60 do bulk, absorption and float...
    What about that 2.8v it means that the bat can go up Jo 2.8 ?
    Where can u find that book?

    Thanks

    stephendv wrote: »
    This is the IUIa charging profile favoured by forklift chargers because it lets you charge the battery from a deeply discharged state to fully charged in the shortest time possible.
    But this is not the only way to charge a battery, you can also use an IUoU charging profile which most of the renewable energy industry uses. In fact some forklift chargers will also use the IU charging profile (Bulk and absorb, no float): but they take longer to charge the batt, so aren't as popular.

    From the battery technology handbook:
    Attachment not found.
    Attachment not found.
    So, if I were in your shoes, I'd just use an absorb of 2.35 and a looooong absorb phase then monitor the charging current. When it drops to 1mA for every Ah, note the time it took since the start of absorb to get there, that's your new absorb time.
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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #10
    Re: EXIDE - EPZV charging

    Hi,

    If you do a google search for "charger assignments for traction batteries" the first link is a paper explaining the charging profiles. From that paper they do take PzV batteries up to 2.65V during the final stage of charging, so I wouldn't be too surprised if your manufacturer says to take them up to 2.8V.
    As I said before, in my opinion, the IUIa curve that the manufacturer gave you is just one of many ways to charge your batteries, you don't have to follow it. None of the RE chargers support that curve, and from the literature the purpose of that curve is to give the fastest charge possible.
    You can charge using the normal bulk, absorb at 2.35V and float curve. And then confirm with your manufacturer how often (and if) you should do an EQ charge at higher voltage.

    Have sent you a PM about the book.
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  • fca1
    fca1 Solar Expert Posts: 124 ✭✭
    #11
    Re: EXIDE - EPZV charging

    thanks for the PM :)

    Now i always read that gel don't need equalizing but these are more traction batteries in gel, so and all i read point to voltages up to 2,65 or even 2.8...So maybe they can go up to that voltages...
    I don't want to fry them they are brand new and should last at least 5 years..
    my tristar in gel option don't even allow equalizing..

    stephendv wrote: »
    You can charge using the normal bulk, absorb at 2.35V and float curve. And then confirm with your manufacturer how often (and if) you should do an EQ charge at higher voltage.

    Have sent you a PM about the book.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #12
    Re: EXIDE - EPZV charging

    It appears there are two major classes of GEL batteries... One is the type that has been used for years in UPS type applications. Very capable of high output current (like AGM), but if you charge over C/20 (5%) rate of charge (or equalize), gas pockets can form in the GEL and permanently damage the battery (gas pockets isolate plate area from electrolyte GEL).

    And, there is another GEL battery type that appears to have charging specifications very similar to AGM (can take very high charging currents--actual limits not listed). No mention of gas pockets forming. I have no idea what makes this type of GEL battery different than the traditional GEL battery that we have been warning RE folks away from.

    For AGM and GEL, it is not that they don't need equalization, but that if you equalize, that generates gas (hydrogen and oxygen). There is usually a catalyst inside the battery to recombine the gases back into water, but if equalized too much, they will vent and permanently lose the water (and reduce battery life).

    So, some mfg. have been recommending a "soft" equalization for AGM--Basically just holding the charging voltage for a few hours longer instead of dropping immediately back to float (a couple times a year). I guess that AGM (and GEL?) batteries do not need as much equalization as flooded cell batteries (cells do not drift apart as quickly as flooded cell from self discharge/variations in construction).

    You need to read the recommendations for your GEL batteries and see what the mfg. recommendations for charging are.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #13
    Re: EXIDE - EPZV charging
    BB. wrote: »
    It appears there are two major classes of GEL batteries... One is the type that has been used for years in UPS type applications. Very capable of high output current (like AGM), but if you charge over C/20 (5%) rate of charge (or equalize), gas pockets can form in the GEL and permanently damage the battery (gas pockets isolate plate area from electrolyte GEL).

    And, there is another GEL battery type that appears to have charging specifications very similar to AGM (can take very high charging currents--actual limits not listed). No mention of gas pockets forming. I have know idea what makes this type of GEL battery different than the traditional GEL battery that we have been warning RE folks away from.

    For AGM and GEL, it is not that they don't need equalization, but that if you equalize, that generates gas (hydrogen and oxygen). There is usually a catalyst inside the battery to recombine the gases back into water, but if equalized too much, they will vent and permanently lose the water (and reduce battery life).

    So, some mfg. have been recommending a "soft" equalization for AGM--Basically just holding the charging voltage for a few hours longer instead of dropping immediately back to float (a couple times a year). I guess that AGM (and GEL?) batteries do not need as much equalization as flooded cell batteries (cells do not drift apart as quickly as flooded cell from self discharge/variations in construction).

    You need to read the recommendations for your GEL batteries and see what the mfg. recommendations for charging are.

    -Bill
    All true Bill, I still think using them in a stationary mode for RE creates issues that is not a problem in a Forklift bouncing along all day shaking the gel to get the bubbles to the top. I tried 2 sets of D8 size for a friend that he insisted on and both set's died within a year of install.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #14
    Re: EXIDE - EPZV charging

    BC04,

    That may be the reason. From the little I read, I did not see a difference in the makeup of the GEL between the two battery types.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #15
    Re: EXIDE - EPZV charging

    I think there's a difference in the plate construction. All the *Pz* batteries use "armoured" tubular plates (Pz = PanzerPlatten) whereas in the US most of the batteries are flat plate designs.
    Attached a more detailed description.
    Attachment not found.

    Can't remember where I read that this was a strange cultural thing: the japanese hardly use flooded batteries, preferring AGM and gel for almost everything. In Europe we use the tubular plate designs because of their supposed longer life- very little use of the flat plate trojan/rolls type designs. And in the US, I think you guys prefer the flat plate designs because they work out much cheaper than the others :)
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  • fca1
    fca1 Solar Expert Posts: 124 ✭✭
    #16
    Re: EXIDE - EPZV charging

    Hi there, just to update all on this ,
    So i was looking for a charger, and the decision was almost done for the victron skyla, meanwhile with this doubts on the specs of charging and having the sp2100 60 amps version from exide at good price i bought the the exide.
    It was setup by exide for the charging curve for the these batts, and yesterday i tried a charging cycle and here its the result:

    i-scbMFzX-L.jpg

    you can't see it in graph because i started at 23:15 and the graph is only from today starting at 0:00, but they where in bulk charging at almost 1h (60amps) the rest you can see in the pic...

    The batts are supposed to be charged all days like this in their real life usage (forklift), how should i configure the mppt60 to simulate this curve ?

    i was thinking on putt all settings in custom mode and put i like this:

    absorption 28.2V for 4h
    equalise 31.46v for 2h *all days ? this simulate that last part that make the batts up to 31.46v bur will it use what current to do it Huh Huh Sad

    Do you think that i can use the equalize function to simulate that last stage ?

    But if i remember the mppt60 goes from bulk to equalize ..


    these are real strange batts gel that go up to 2,65v
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #17
    Re: EXIDE - EPZV charging

    28.2 volts is a fairly low absorb set paint (14.1 volts at 12 volt bank)--assuming ~77F/25C battery bank temperature. That low of absorb voltage is typically seen with automotive alternators and AGM storage battery systems.

    For a standard flooded cell system, we would be looking more towards 29 volts (14.5 volts) for charging. You will get the batteries full, quicker and would (usually) "waste" less available current from your solar array.

    31.46 volts (~15.25 volts) would be an "equalization" charge from my point of few (I am not a battery expert). I see that it took another ~1.5 hours for the battery voltage to rise to the 31.46 volt set point--To me, that would appear to indicate that your battery bank was not "full" and you where able to stuff quite a bit more AH into the bank before it "stabilized" at the 31.46 volt set point). Or, your cells needed a lot of equalization current because cells were way out of balance.

    And you carried the 31.46 volts for 2+ hours after the voltage stabilized--Normally, at that point, I would suggest that you check the cells' specific gravity every 30 minutes and when the readings (for all cells) stop rising--That is when your battery is 100% full and you stop charging/return to float charging.

    I believe that equalization (>29 volts @ 77F) for a full battery (which generates lots of gassing) is hard on a battery and should only be done when needed. I understand forklift battery chargers appear to charge batteries very quickly (so they are ready for the next shift)--But if it can be avoided, I would not suggest lots of high voltage charging/gassing if possible. It can shed material and drive oxygen gas into the positive plate and cause "excessive" grid corrosion.

    Again, I am not battery expert--Just from my various readings on the subject.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #18
    Re: EXIDE - EPZV charging
    BB. wrote: »
    For a standard flooded cell system, we would be looking more towards 29 volts (14.5 volts) for charging.

    These are gel batts.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #19
    Re: EXIDE - EPZV charging

    Stephen,

    What are your thoughts about charging to 31+ volts for these batteries?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #20
    Re: EXIDE - EPZV charging
    BB. wrote: »
    Stephen,

    What are your thoughts about charging to 31+ volts for these batteries?

    -Bill

    Lol, I was staying silent, because I have no idea! I replied to the OP on another forum, in a nutshell: you can't replicate the IUI charging curve of their charger using an IU (bulk-absorb) charger like any MPPT controller. That final constant current stage must be current limited, which none of the controllers can do properly. So trying to substitute it with a current-unlimited EQ is asking for trouble IMO. But I don't know much about gels, so: 31V EQ + Gel = "does not compute" to me.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #21
    Re: EXIDE - EPZV charging

    Here is an Exide document on charging these cells (I think):

    http://www.sonnenschein.org/PDF%20files/IUIa_GiV_engl.pdf
    Equalisation charge
    Total voltage £48V: Equalisation
    charge is not necessary.
    Total voltage > 48V: Equalisation
    charge every 4 weeks.
    Ip = 2 * I2
    I = 0A

    Trying to figure out the Ip value (15 min of Ip, and 15 min of zero; x24 times). Don't see any definition of Veq other than >2.8v per cell is a fault.

    I2 appears to be 1.1% to 1.35% of C(5 hour?) capacity? So--equalize current would appear to be pretty low... And with 15 min on/15 min off, then it may give time for gas to reabsorb before creating a gas pocket/damage?

    I agree, I don't see any way of doing this "automatically" with a standard MPPT charge controller.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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