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Author Topic: Exide EPZV-BS255 charging specs  (Read 10504 times)
fc
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« on: June 28, 2012, 07:54:41 PM »

Hi there
I'm almost finishing a deal where i will buy 24 of these for forklift... unfortunately the place where i can do the best deal don't have many know how... and i can't find anywhere the specs charge voltage float voltage etc...
the only doc i found is this
 http://www.gnb.com/Media/files/Downloads/IndustEuro/Operating%20Instruction%20Sonnenschein_EPzV_56025017_MXSVDOEPDF00212.pdf

but very little information ...
any knows where can i get a decent user guide /tech specs for these ones ?

regards.
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Eleanor
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« Reply #1 on: June 29, 2012, 09:41:44 PM »

fc, this document covers flooded and gel cells. The document you posted is a generic manual for this type of cell and hopefully this will help  :

www.zvei.org/Verband/Fachverbaende/Batterien/Documents/Merkblaetter/11%20e%20Charger%20Assignments%20for%20Traction%20Batteries%202004-04.pdf
« Last Edit: June 29, 2012, 09:44:47 PM by Eleanor » Logged

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fc
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« Reply #2 on: September 28, 2012, 09:11:41 PM »

hi there
finally the batteries arrived and still i have doubts what should be the charging voltage, i always heard that gel batts are very sensitive to overvoltage...

For a gneric epzv gel batts what will be a safe charging voltage ?

eleanor, thanks for the doc but still not clear to me this setting ... i found on exide site manuals for other batts where they clear state charge voltage and float voltage...
but the traction epzv i can't find the charging voltage....  2.30 2.35 2.40   wackoold
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Eleanor
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« Reply #3 on: September 29, 2012, 12:28:20 AM »

Hi fc, my understanding is that the method of charging for the EPzV cells is similar to that for the flooded EPzS cells but the absorption voltage is lower at 2.35V instead of 2.4V. This voltage applies at 30C and the charger should be temperature compensated.

Our charger is IU so charges at a constant current (I) up to 2.4V and then constant voltage (U) with decreasing current. A forklift charger would then go on to raise the voltage to 2.65V/cell for both EPzS and EPzV cells but as our charger doesn't do this we have to get around this by regular equalisation charges. The document you posted earlier suggests a float voltage of 2.30V/cell at 30C.

The graph below shows the "official" way of charging EPzV cells and if your charger doesn't do this I think you will need to ensure that the cells reach 2.65V regularly by equalising. I would measure SG to determine the state of charge for our flooded cells but as you can't do this I suppose you could measure the voltage across each cell when they are absorbing and this should give you a good indication of the individual SOCs and how well balanced they are.

Others here know more about charging gel batteries and if you can get information from the Manufacturer or Supplier this would be best  Roll Eyes


* PzV.jpg (12.27 KB, 340x242 - viewed 2383 times.)
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fc
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« Reply #4 on: September 29, 2012, 02:13:19 PM »

The reseller / exide contact only says I need to use a sp2100 charger..
But no more details ..
Can I put a gel epzv upto 2.65v Huh
All my cells are at 2.07v except  2 of them that are at 2.17v
I will charge each upto 2.35v to put all leveled and later connect them to the tristar mppt60.

I will try to find the manual of the recommend charger to see how it works..

Thanks
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clockmanFR
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« Reply #5 on: September 29, 2012, 04:34:45 PM »

Hi Fc,

With all my gel lot, i charge with the Tristar MPPT 60 at the No2 on their list of charge settings, (being Absorb at 14.15 or 2.35v per 2v cell. My Wind turbines use Tristar PWM 45's set at 0.0083v higher for each 2v Cell.

Once charged all my gel batts will hold at 2.17 per 2v cell.
 So for my 48v 1100ah system, that's 52v holding and i use the batts down to 49.5v.


* P9290270a.JPG (102.21 KB, 492x655 - viewed 631 times.)
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fc
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« Reply #6 on: October 01, 2012, 02:58:58 AM »

Thanks and do you "equalize" ?
Following the doc Eleanor posted these bats would go up to 2.65v ..
Today I manually charge them one by one up to 2.35v
After few hours rest all are between 2.18 and 2.19

Next week I will connect them to the solar system
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Eleanor
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« Reply #7 on: October 01, 2012, 11:22:46 AM »

There's a brochure for the charger here www.exide.com/Media/files/Downloads/IndustEuro/2100_net_chargers_accessories_en.pdf. Above the table on Page 4 there is a list of charging profiles for different types of Exide cell. Which solar charger are you using?  Huh
PS You could try asking the Supplier what the end of charge voltage is  fingers crossed!
« Last Edit: October 01, 2012, 11:30:55 AM by Eleanor » Logged

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clockmanFR
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« Reply #8 on: October 02, 2012, 08:41:44 PM »

Hi fc,

My MPPT 60 is set for manual Equalization.

And most of the time the heat sensors seem to take the voltage up anyway.  Roll Eyes
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fc
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« Reply #9 on: October 08, 2012, 10:05:26 PM »

hi there, i got this from exide, the charging profile for the sp2100 charger for these batts.




So i must put my mppt60 to go up to 2.35v in mppt and 2 hours in absortion...
any comments..
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Eleanor
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« Reply #10 on: October 09, 2012, 12:14:58 PM »

End of charge voltage 2.8V/cell, or 67.2V for a 48V battery bank, higher than I thought. I suppose to ensure that every cell reaches 2.65V a slighty higher voltage is required. I can't see anything in the Morningstar MPPT manual that suggests it will supply more than 64V, maybe someone who has one can confirm? Do you have another charger? I run quite a long absorption for our flooded cells using the Outback to cover the V= constante and I = constante phases and then equalisation around once a week for the second I = constante phase. It's not perfect and a more time consuming way which would be more like the recommended charging profile would be to manually step up the voltage after absorption which I keep meaning to try  Roll Eyes
 
If the Morningstar won't go past 64V I think you probably need a charger that can charge at a higher voltage and use it regularly to do the final stage of charging. If it's running from a generator then it will need to be sized so that it won't stall it. Maybe Forum members should get in touch with Morningstar to ask if they can increase the charger voltage if it isn't high enough as running a generator for the sake of a few volts seems a bit silly stir

I don't really have any experience of gel cells though ......  surrender
« Last Edit: October 09, 2012, 12:20:38 PM by Eleanor » Logged

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fc
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« Reply #11 on: October 09, 2012, 12:27:08 PM »

That strange because they people at exide told me that after 2,35v i should only left in constant voltage for 3h maximum ...
didn't get the 2.8v also.... im running my system at 24v


regards
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Eleanor
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« Reply #12 on: October 09, 2012, 12:47:51 PM »

I don't know fc, the graph looks like the one I posted earlier with constant current to 2.35V, constant voltage at 2.35V during absorption and then constant current again as the voltage rises to 2.8V so IUI. I'd forgotten you have 24 cells because are running two 24V banks in parallel so will the Morningstar charge at more than 32V for a 24V bank?
I wouldn't want to be the one who causes you to overcharge your batteries. Maybe someone else can comment?  Huh
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fc
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« Reply #13 on: November 03, 2012, 11:41:00 AM »

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 her its the result:


you can't see it in graph becaus 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 equalise function to simulate that last stage ?



these are real strange batts gel that go up to 2,65v  banghead


« Last Edit: November 03, 2012, 11:42:56 AM by fc » Logged
stephendv
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« Reply #14 on: November 03, 2012, 06:04:16 PM »

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 equalise function to simulate that last stage ?

Not quite.  Firstly, that last constant current stage that the exide charger does is current limited (for PzS it's 5A/100Ah, for your gels perhaps something different), this is to ensure that the battery doesn't gas too much during that stage.  None of the renewable energy charge controllers will let you specify a current limit for EQ.  So if you just program the FM to EQ at that voltage you might overcharge and overgas because of too much current.
Secondly, I believe the FM's don't first do an absorb before doing an EQ, they just go straight from bulk and attempt to reach the EQ voltage so you would end up spending much more time above the gassing voltage than is spent during the IUI curve of the exide charger.  Also not good.

Honestly, I don't understand why gel batts would use the IUI curve.  As I thought I understood it, that final "I" phase was there to mix the electrolyte and ensure the batt reaches 100% SoC.  So why you would want to do that with gelled electrolyte is beyond me.  Perhaps I have the wrong end of the stick with this curve  wackoold

I've also been trying to replicate the IUI curve with the midnite classic and have come to the conclusion that it's not necessary.  It's just a convenient curve for forklift batts because you can charge fast and get nicely mixed electrolyte at the end of the charge.  It's also easier to determine when end of charge is reached, because you can just watch the voltage, and when it stops rising you're done.  But it's not the only way to charge a forklift batt, and I think it would be detrimental to the health of the batt to follow that curve every day in an RE system when the battery is not actually discharged much at all.  Unnecessary stress and voltages when the batt could very well be quite full already (> 80%).

The trusty "Battery Technology Handbook" compares IUI charging with IU (bulk-absorb.  In forklift land there's no time for float) charging and just says that if you choose to use IU charging then you need to do a periodic EQ to mix electrolyte because the mixing isn't as good as with IUI charging.  It also says that an advantage of IU charging is that you can parallel charge a bunch of different batteries at the same time.  So I take some solace that IU is a charing method used by industry and not just peculiar to the renewable energy world.

In my opinion, you could do a normal bulk-absorb-float daily and then do an EQ at a lower voltage monthly.  The reason for doing a lower voltage EQ is to try and limit the current.  You're at a disadvantage because you can't measure the SG, so won't know for sure how your charging works out.  So you're going to have to rely on the current going into the batt to determine when to finish absorb and EQ.  Clear as mud  reindeer
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