Apc batteries backup reduced

I have apc 3000xl with 4 x 100ah sacred sun batteries in use for 2-3 months.now backup time of system is reduced I checked voltage when fully charged in different times which are 14.56,12.50,13.0,14.30 14.12,12.75,13.44,14.15 14.60,12.53,13.22,14.12 This reading I got after putting load on batteries for 15 minutes > 12.65,11.97,12.45,12.65 Please give your valuable suggestions what to do now. Can it be corrected by setting apc constant again or by charging batteries with external charger.

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Proper battery voltage can only be checked when batteries are resting for 2--3 hours , i.e no load on battery and no charger is connected

@yousaf465 I will check voltage as you told and write here

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The 2nd battery which has less voltage with it pc fan was connected to keep apc cool now fan is connected to 3rd battery which has less voltage then 1st&4th

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[quote=“Feras, post:4, topic:21374”]

The 2nd battery which has less voltage with it pc fan was connected to keep apc cool now fan is connected to 3rd battery which has less voltage then 1st&4th Sent from my Z10 using Tapatalk

[/quote]

batteries are connected in series ?

Batteries are connected like this

Again readings of fully charged > 14.61,12.49,12.96,14.36 Below are readings after batteries resting for 2 hours& 50 minutes without any load with apc off 13.27,12.44,12.94,13.30 (I disconnected pc fan too when putting batteries on rest)

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[quote=“Feras, post:7, topic:21374”]

Again readings of fully charged > 14.61,12.49,12.96,14.36 Below are readings after batteries resting for 2 hours& 50 minutes without any load with apc off 13.27,12.44,12.94,13.30 (I disconnected pc fan too when putting batteries on rest) Sent from my Z10 using Tapatalk

[/quote]

read the VRLA table in this excel file http://jgdarden.com/batteryfaq/SoC.xls

IMHO, In series voltages should within +0.3V of each. :)

Ok I saw that table.mine value are different by big margins.i don't know if the voltage of 2nd&3rd battery are lower then 1st&4th from beginning or after attaching pc fan.

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[quote=“Feras, post:9, topic:21374”]

Ok I saw that table.mine value are different by big margins.i don’t know if the voltage of 2nd&3rd battery are lower then 1st&4th from beginning or after attaching pc fan. Sent from my Z10 using Tapatalk

[/quote]Have you checked the datasheet ? One of these http://www.sacredsun.com/product_show_240.html ?

@yousaf465 So what is important for me in that datasheet? Is 100ah battery capable to provide 5amps for 20 hours? Please tell rough estimate of backup time for my system

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[quote=“Feras, post:11, topic:21374”]

@yousaf465 So what is important for me in that datasheet? Is 100ah battery capable to provide 5amps for 20 hours? Please tell rough estimate of backup time for my system Sent from my Z10 using Tapatalk

[/quote]

Manufacturer usually give voltage setting for their batteries e.g http://www.trojanbattery.com/BatteryMaintenance/Charging.aspx

See VRLA

Is it Sp12-100 ?

For cooling use a 48V fan, which are easily available from hall road or yateem khana in Lahore.

Backup depends on the load.

Yes sp12-100

This is the fan connected to apc with a single battery

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[quote=“Feras, post:13, topic:21374”]

Yes sp12-100

This is the fan connected to apc with a single battery Sent from my Z10 using Tapatalk

[/quote]

Yes, same fan is easily available in 48V version @ hall road.

were you able to download the datasheet ? It doesn't download for me.

Your batteries should be able to provide 2.4 KWh of energy @50% DOD, that is without considering the losses.

Which means you can run 1000W load for approx 2 hours and 20 mins with batteries at 50%DOD.

I downloaded datasheet the page didn't open but I clicked again&it downloaded.but I didn't get what you told to look at trojan batteries page.

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At 50%DOD = 2 hours 20 min Means from fully charged to discharged it should give backup of 1000watts for more then 4 hours? Som1 wrote 100ah battery should give 5amps for 20 hours.is it ac or dc amps?

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[quote=“Feras, post:16, topic:21374”]

I downloaded datasheet the page didn't open but I clicked again&it downloaded.but I didn't get what you told to look at trojan batteries page. Sent from my Z10 using Tapatalk

[/quote]

It does mention these values

Charging Voltage = 14.7V (-25mv/C)

Float voltage: 13.62

Max charging current 30A

[quote="Feras, post:17, topic:21374"]

At 50%DOD = 2 hours 20 min Means from fully charged to discharged it should give backup of 1000watts for more then 4 hours? Som1 wrote 100ah battery should give 5amps for 20 hours.is it ac or dc amps? Sent from my Z10 using Tapatalk

[/quote]

you will damage your batteries if you go below 85% on regular basis.

that 2 hours 20min is estimation actual value may vary.

Also see discharge table on second page in datasheet.

5Amps @ 20hr is DC amps.

Just checked volts today batteries not used & apc not charging anymore 14.67,12.47,12.95,14.40 Battery no 2&3 have almost same volts like yesterday after on resting state for 2 hours&50 min. Isn't apc not charging them at all or very little only? Yesterday I disconnected pc fan from battery but values show no difference on charging volts

Found 2 readings from May 2014 some days after installing apc&batteries.

13.63,14.06,13.15,13.68 ( on 21/05/14 )
13.72,13.96,13,07,13.73 ( on 24/05/14)

I see that volts of 2nd battery were good then but decreased now but volts of 3rd battery are somewhat less from the start.

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