Sealed leadacid UPS battery testing/conditioning
Sealed leadacid UPS battery testing/conditioning
(OP)
Hi All -
I have several UPS's here that use the typical 12V 18AH sealed lead-acid batteries. A couple of these have died, in that they light up the "replace battery" LED or similar means.
I've pulled the batteries out, but I'm sure that they're not ALL bad - there's about 10 of them. I hope not - they run around $35.00 each :( How can I test them, and is it possible to recondition them ?
I know one is definitely bad - it only shows 1.8V total. It doesn't seem to take a charge from my bench power supply - 14.5V and it only pulls 2mA.
Two that came out of a single UPS both show 13.1V, yet the UPS claims they're bad. They appear to have taken a charge, since they'll only accept about 300mA or less from my bench power supply set to 14.5V. But *something* must be wrong with one or both of them.
Help ?
Dean.
I have several UPS's here that use the typical 12V 18AH sealed lead-acid batteries. A couple of these have died, in that they light up the "replace battery" LED or similar means.
I've pulled the batteries out, but I'm sure that they're not ALL bad - there's about 10 of them. I hope not - they run around $35.00 each :( How can I test them, and is it possible to recondition them ?
I know one is definitely bad - it only shows 1.8V total. It doesn't seem to take a charge from my bench power supply - 14.5V and it only pulls 2mA.
Two that came out of a single UPS both show 13.1V, yet the UPS claims they're bad. They appear to have taken a charge, since they'll only accept about 300mA or less from my bench power supply set to 14.5V. But *something* must be wrong with one or both of them.
Help ?
Dean.






RE: Sealed leadacid UPS battery testing/conditioning
http://www.thomasregister.com
and type Batteries: Lead Acid under Product or Service that will return 108 companies to potentially contact for tech support.
Do this likewise for UPS
RE: Sealed leadacid UPS battery testing/conditioning
There aren't many things that can go wrong with a sealed battery if it's properly managed. But a modern charging circuit actually puts transient (sub millisecond) shorts on the battery, and looks at the response, then makes a complex decision as to the likely life left in it. If it fails this test the circuit marks it bad. So a battery marked 'bad' might still 'work' but it IS definitely on the way out. So change it as soon as funds permit.
RE: Sealed leadacid UPS battery testing/conditioning
The others should be more or less OK though, and I just want to identify them.
Thanks for the replies people -
Dean.
RE: Sealed leadacid UPS battery testing/conditioning
How old are the batteries? Expect a 5-year max. life out of most sealed-cells.
RE: Sealed leadacid UPS battery testing/conditioning
1. CHARGE BY BENCH DC POWER SUPPLY AT 15 V CURRENT 10-15 % OF AH CAPACITY UNDER CVCC MODE.KEEP FOR SIX HOURS, WHEN IT STOPS TAKING CURRENT.
NOW DISCHARGE IT USING 12 OHM / 20 WATT WIRE WOUND RESISTANCE, UP TO THE VOLTAGE LEVEL GOES 7.5V
REPEAT THE PROCESS AGAIN. IF YOU BATTERY CHAGING CURRENT IMPROVES MEANS IT TAKES 10-12 % OF AH CAPACITY IN CVCC MODE OF POWER SUPPLY, CHANCES ARE YOUR BATTERY 50 - 60 % CHANCES ARE YOUR BATTERY IS RECOVERED. IF SITUATION IS SAME. GO FOR ANOTHER TECHNIQUE.
2. THE REASON FOR GOING THE BATTERY IN HIGH IMPEDENCE, THAT
BATTERY HAS DEVELOPED HIGH IMPEDENCE, WHEN WE APPLY POWER SUPPLY IT TERMINAL DEVELOP VOLTAGE OF 20-30 V , A FICTIOUS VOLTAGE, THAT BATTERY NEED TO BE CHARGED USING PULSE CHARGER BASED CIRCUIT,OR GIVING TRICLE CHARGING, LIKE IN AUTOMOBILE
OR USING 555 TIMER DEVELOP THE CIRCUIT.
THIS CIRCUIT CAN BE DEVELOPED BY YOUR OWN BY USING FOLLOWING PRINCIPLE
PULSE VOLTAGE[ RMS][KEEPING PULSE FREQUENCY UPTO 1-2 KHZ
FIXED]= CURRENT[FIXED=2-5 % OF AH CAPACITY ]*BATTERY RESISTANCE.
MEANS WHEN BATTERY IMPEDENCE IS MORE VOLTAGE WILL BE MORE ACROSS IT [ AFTER FEW SECONDS BATTERY START REDUCING IS HIGH IMPEDENCE AND CIRCUIT SHOULD STOP REDUING PULSE VOLTAGE.]
THIS IS THE ONLY AND LAST METHOD YOU CAN APPLY, TO RECOVER DEAD BATTERIES.
THE BATTERY NOT RECOVERED BY SUCH TECHNIQUES IS DEAD FOR EVER.
RECOMMANDED GUIDE LINE TO KEEP YOU BATTERY HEALTHY.
1. YOU BATTERY NEED TO BE DISCHARGE, ONE IN A WEEK FOR LET
SAY ONE HOUR UPS BACKUP, GET MIN 15 MIN DISCHARGE ONCE IN WEEK.
NOTE CHARGING CURRENT IT SHOULD BE 10 -15 % OF AH CAPACITY. CHARGER SHOULD BE CVCC TYPE.
IN CASE THE CURRENT IS LESS AFTER DISCHARGE, ASK YOUR UPS VENDOR TO FIND SINGLE FAULTY BATTERY IN TOTAL BANK OR PROBLEM WITH HIS CHARGER.
ALL CHARGER SHOULD BE CVCC TYPE. WITH GOOD FILTER CAPACITOR.
ANY QUESTION
FROM
EX- AIRCRAFT ENGINEER
MUKESH CHAUHAN
RE: Sealed leadacid UPS battery testing/conditioning
Mark in Utah
RE: Sealed leadacid UPS battery testing/conditioning
RE: Sealed leadacid UPS battery testing/conditioning
Dean.
RE: Sealed leadacid UPS battery testing/conditioning
From another thread referencing this one :
dumbo (Nuclear) Jan 19, 2003
Discharge down to 30 mA and repeat until the sulfur deposit disolves this could take a while you got a good start. I have read that some have had success in reversing the deadness. Each time should show some improvement. Be patient, could take weeks, use only trickle current.
What exactly is meant by discharge down to 30mA ?
Dean.