24v battery questions

[greenhouseparos]

I have a 24v battery bank using 12 x 2v opz 1000ah batteries. It is being charged with an 80amp outback charger connected to a 2660w array.
The batteries have been charging for about a month now without any load being connected to them.
Water levels are good.

I have read on other posts that a 100% charge voltage is 25.4v yet I have only ever measured 25.2v.

Questions:
Should they be 25.4v?
If they should how can I get them to this voltage? i.e. what is the charging procedure?
What would a good equalization charge voltage and duration be? 

 paul
 

[billi]

Hi Paul

temperature  will also  have an influence .....how cold  are your batteries , this time  of the year ?

I  do not think   , that anything is wrong, but do you use a temp sensor with the outback controller  ? And did  you adjust the charging Volts in the controller to match your batteries ?

My  outbacks  are charging until 29.6 Volts are reached and at this Volt the batteries  boil  /simmer the voltage is hold and only the amps decrease ,  but this is  for normal rated temperature  of the battery (i think it is 20°) , now in winter cause my battery is cold , the temp sensor  connected to the charge-controller  lifts this 29.6 V setpoint  up  to 30.5  and over , depending on battery temp

Billi

[greenhouseparos]

Billi

yes i got the temp sensor wired up and i checked the menu of the charger and it has agjusted the charge voltage.
i am in Greece not far from Roger and we are experiancing some low temps about 5-6. the batteries are inside a basement but there is no door so it does get cold inside.

what is the adjustment in the charging voltage to match the batteries?

Paul 

[Justme]

Are you using more energy than you are collecting?

If so then the bats wont ever get fully charged.

Your array is also under sized for the bank size.
(assuming the bank has been sized for a sensible load size)

[guydewdney]

"month now without any load being connected to them. "

[billi]

Paul you can adjust voltage setpoints ....see page23  in the manual ,but  sure you should   do this   according to the battery manufacturer recommendation

If the batteries   are not new , surely a equalizing charge is a good idea   at 31 Volt

[Justme]

"month now without any load being connected to them. "

Ok Ok so I missed it lol

[greenhouseparos]

definetly no loads connected. i did a 4 hr 30v equalising charge yesterday just to give them a stir.

i have been trying to contact the manufactures for a couple of days now to get their view but no answer.

will try again monday

 

[Eleanor]

Paul, are they OPzS cells? The Manufacturer should be able to provide brief Operating Instructions which include information regarding rest voltages and SGs for fully charged cells. I’d get a hydrometer as soon as possible and become familiar with using it. Measure the SG of each cell when you think they are fully charged and reference the values (at 20°C) to what the manufacturer says they should be when they are fully charged. I’d probably start to get concerned if the cells aren’t receiving a full charge at least once a week. Undercharging is something that can easily creep up on you without you realising. Hopefully you have a secondary means of charging if the PV isn’t enough?

Again, the recommendations for the voltages and time intervals for Equalisation will be in the Operating Instructions which the Manufacturer or Supplier should be able to provide. Once you’ve used them for a while you’ll get a feel for when they need equalising or you may just decide to do it monthly or whatever the recommended interval is. At the moment I’d focus on getting to know the bank and making sure it gets a good regular charge  

PS The above was written before your last reply

[billi]

Hi Paul

I have read on other posts that a 100% charge voltage is 25.4v yet I have only ever measured 25.2v.

I just had a look in a OPzS   brochure and the voltage of a fully charged cell at 20°  should be 2.08  Volt  so 24.98  Volt for a 24 V Bank

In the same brochure  they say other Batteries like AGM or Gel type  cells  have  2.12 Volt   so  25.44Volt

Sorry in German only http://www.google.ie/url?sa=t&rct=j&q=opzs%20ruhe%20spannung&source=web&cd=13&ved=0CCYQFjACOAo&url=http%3A%2F%2Fwww.batterie-discount.com%2FInstalation_Instructions_56029019_de.pdf&ei=yAEcT6ztDofOswaT18xH&usg=AFQjCNHSyrQmGBTO3Smxs8JpZ8wi6g6JdQ&cad=rja

Billi

[Eleanor]

I've had a sleep and realised that they could be OPzV gel cells so no use for a hydrometer. Best to get the Instructions for Use from the actual Manufacturer but they tend to be generic and there's both below for one particular Manufacturer :

OPzV : http://www.enersys-emea.com/reserve/pdf/EN-zV-OM-002_0506.pdf

OPzS : http://www.enersys-emea.com/reserve/pdf/EN-Flooded-IOM-001-DCS-1002M_0310.pdf

Hopefully one of these is right 

[greenhouseparos]

they are from Sunlight which is a Greek company. and they are water filled.
adjusted the charger voltage set points this morning (increasing both abso and float charge) and we had a full cloudless day of brilliant sunshine. voltage after sunset 25.2v.
will look for hydrometer and hope tomorrow i can find somebody at their desk 

[rogeriko]

After charging 25.2 volts is full. Only during charging will you see any higher voltages. What were the volts at 2 o'clock this afternoon?

[eabadger]

I always thought 25.4v was normal on forklift batteries, our 1000aphr set rests at that.
I have found this brilliant link for forklift batteries charging, chemistry etc. answered a lot of my questions.
Make sure you read all the pages.


http://evbatterymonitoring.com/WebHelp/Battery_Book.htm#Section_3.htm

Steve

[billi]

Again ,  i am not sure  about the resting Voltage of traction batteries ......  perhaps its higher than for the OPzS Paul  is having

http://www.hoppecke.com/content/download/302/1943/file/Installation_Instructions_for_stationary_batteries_en1008.pdf


Perhaps the Voltage is lower for the OPzS    cause  much more electrolyte  in the cells than in the PzS  traction ones ?

Billi