Stationary batteries are almost exclusively lead acid and some maintenance is required, one of which is equalizing charge. Applying a periodic equalizing charge brings all cells to similar levels by increasing the voltage to 2.50V/cell, or 10 percent higher than the recommended charge voltage.
An equalizing charge is nothing more than a deliberate overcharge to remove sulfate crystals that build up on the plates over time. Left unchecked, sulfation can reduce the overall capacity of the battery and render the battery unserviceable in extreme cases. An equalizing charge also reverses acid stratification, a condition where acid concentration is greater at the bottom of the battery than at the top.
Experts recommend equalizing services once a month to once or twice a year. A better method is to apply a fully saturated charge and then compare the specific gravity readings (SG) on the individual cells of a flooded lead acid battery with a hydrometer. Only apply equalization if the SG difference between the cells is 0.030.
During equalizing charge, check the changes in the SG reading every hour and disconnect the charge when the gravity no longer rises. This is the time when no further improvement is possible and a continued charge would have a negative effect on the battery.
The battery must be kept cool and under close observation for unusual heat rise and excessive venting. Some venting is normal and the hydrogen emitted is highly flammable. The battery room must have good ventilation as the hydrogen gas becomes explosive at a concentration of 4 percent.
Equalizing VRLA and other sealed batteries involves guesswork. Observing the differences in cell voltage does not give a conclusive solution and good judgment plays a pivotal role when estimating the frequency and duration of the service. Some manufacturers recommend monthly equalizations for 2–16 hours. Most VRLAs vent at 34kPa (5psi), and repeated venting leads to the depletion of the electrolyte, which can lead to a dry-out condition.
Not all chargers feature equalizing charge. If not available, the service should be performed with a dedicated device.
Comments
Good day all.
I’m trying to find a good charger that is designed to equalize the cells of my 6V batteries. I fully understand the the Rory of it all but can’t find a good charger. I bought an obviously poor quality fully adjustable power supply but it only lasted an hour before failing. Any suggestions would be greatly appreciated.
Mick.
Sirs,
I had 2 x 12v x 200 Ah batteries was used on a UPS for 7 or 8 months, they were giving me 8 hours of load @ 220 AC& 3 A . I installed solar panels (6) with controller (48v) now I'm using the 2 old batteries with 2 new batteries in series (48v).
I noticed that the new batteries charging up to 15v & the 2 old batteries charging only at 13.4 v. Is there's a way to equalize the batteries & bring the 7 month old batteries to the voltage level of the new ones? & how? Please advice.
Sirs,
I had 2 x 12v x 200 Ah batteries was used on a UPS for 7 or 8 months, they were giving me 8 hours of load @ 220 AC& 3 A . I installed solar panels (6) with controller (48v) now I'm using the 2 old batteries with 2 new batteries in series (48v).
I noticed that the new batteries charging up to 15v & the 2 old batteries charging only at 13.4 v. Is there's a way to equalize the batteries & bring the 7 month old batteries to the voltage level of the new ones? & how? Please advice.
I'm no expert, but as I understand it the battery gets fully charged first - so the final trickle at high voltage is what equalizing does. My Noco smart charger does it at 1500mA - 1.5 amps. Basically it cooks he sulfate off the lead plates for 2-4 hours. I've heard of people equalizing for a couple of days - I don't know if I would do that. Maybe 8 hours, then I would give up and get new batteries. LOL
Hi, Could you tell me how many amps I should equalize a pair of Trojan 6V T105 flooded batteries at? I understand the equalize voltage to be 8.10v for one 6v battery and 16.2v for two batteries in series (12v) (according to the Trojan datasheet) not sure what amps is preferable though? some sources are saying 10/15% of battery 225AH rating, others are saying at least 25% of the 225AH Many thanks!
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Hello everyone,
A year ago I have installed 5.2KW UPS with 4 lead acid batteries. I have 3.5KW load. In start it gives me 3 hour backup but later it only gives 45 minutes. I checked the voltage of the batteries and only the last battery in series have low voltage.
then someone told me to replace the batteries with Tall Tublar Batteries(225A) . 2 months ago I changed them and it gives me upto 5 hr backup.
Now I am facing same issue as the last battery have low voltage after 1 hr.