Batteries inflated now i cannot replace them

[Anonymous user]

i got 2 SMART UPS 2200XL and i was going to replace the batteries for some new ones until i notice that the old ones have inflated and now they cannot be removed, anyone got any tips on how to remove the batteries. the only idea i got is to remove the frame around the batteries and see if i can remove it then

[Anonymous user · Accepted solution]

I had this battery inflating issue on two of the 4 batteries in a DLA1500RM2U battery pack which i was suprised at since this is a later unit with a temperature sensor... also due to the design of the UPS i had to practically destroy it to get the batteries out (and it was an APC battery pack too)

[Anonymous user]

I get units in from field locations all the time with swelled batteries. Generally these units are 6 to 8 years old and never had a battery replacement. Some come back with batteries so swollen they cannot be pulled out. I take the top of the unit off, use my hands and open up the frame a bit to get more clearance, then use a very thick screwdriver and work the tray out...whole process may take me 10 minutes to get the tray out...I take my time. When the batteries come out, you can bend the frame back and you wouldn't notice a difference.

That is good info to have on the battery voltages. I track the battery voltages in my monitoring software and will have to go back and look at my units.

Message was edited by: cernst

[BillP]

first thing i'd make sure of is that the unit isnt turned on and charging the batteries still. so either, unplug the batteries if you can get to the connector or turn the UPS off.

you may need to open the chassis, if this isnt under warranty (opening the unit will void the warranty), and then remove them. only problem is, you would need to be certain that the swollen batteries haven't damaged the actual UPS electronics.

and for the future, are these in a hotter than usual environment? if you replace them, you want to make sure that this wont happen again by making sure they are in a cool and ventilated environment.

[TheNotoriousKMP_apc]

Thanks, just wanted to know how someone who already refurbed our UPS's handles that situation. Obviously I cannot go and tell a customer to do that, but having read what you wrote it enlightens me a little more as to how to approach the situation with customers explaining what the possibilities are when achieving "thermal runaway"

[Anonymous user]

The UPS applies constant voltage to battery packs, so when one of the dozen cells in series fails, each cell gets excessive voltage, which causes excessive evolution of gases, and bulging of case. It happens sometimes. Though unlikely, a failure in charging regulation circuit can cause this too.

Get the chassis apart, and you might need to spread the case apart a little with some tools to free the battery. Be careful to avoid injuries.

[TheNotoriousKMP_apc]

KVar,

Just trying to get your understanding on this. Since most of the time we've seen a failing or failed battery charger, causing the swelling of the battery. Would you still recommend that the customer crack the case to remove the battery and eventually replace it? We've seen that the same charging circuit could cause the new battery to do the exact same thing, just in less time.

[Anonymous user]

The Notorious K.M.P. wrote:
KVar,

Just trying to get your understanding on this. Since most of the time we've seen a failing or failed battery charger, causing the swelling of the battery. Would you still recommend that the customer crack the case to remove the battery and eventually replace it? We've seen that the same charging circuit could cause the new battery to do the exact same thing, just in less time.

It takes know how to test the charging circuit, however without testing it, I can't recommend what to do.

for 48v units, battery voltage shouldn't exceed 55.3 or for 24v units 27.7v. Since the UPS won't allow the charging circuit to activate without verifying the existence of voltage across battery terminals, you'd have to use an external source fed through a accumulate enough charge in the unit to jump start it then, use a bleeder resistor to clamp the voltage and see what the charging circuit will hold it at... or you could use a already fully charged battery if you're quick.

So, when you install an already fully charged battery and allow the UPS to charge, the voltage should climb up to 55.3(48v nom) or 27.7v, but if it keeps going past it, the charging circuit is broken.

For a 48v unit, you'd connect the battery, plug the UPS in to activate the charging circuit, remove the battery and connect a 10W 470 to 500 ohm bleeder resistor and check the voltage across the resistor. WIth a properly fuctioning regulator, this voltage would not exceed the aforementioned values.

[TheNotoriousKMP_apc]

Oh absolutely not. We don't make that recommendation anyways. However, there are some customers who for peace of mind, would like to know what caused this. Now I have a beefier response to their question.

Thanks again.

[Anonymous user]

The Notorious K.M.P. wrote:
Thanks, just wanted to know how someone who already refurbed our UPS's handles that situation. Obviously I cannot go and tell a customer to do that, but having read what you wrote it enlightens me a little more as to how to approach the situation with customers explaining what the possibilities are when achieving "thermal runaway"

If I was in your position, I wouldn't even tell them to open the chassis and pound out the old battery is not a good idea for liability reasons. There are six cell in each battery module and each cell has a pressure relief valve. Usually the hydrogen and oxygen are combined and condensed back to water, but sometimes the gas production becomes excessive and the valves can clog. In combination with softening caused by heating, this is what causes ballooning.