SMC1500 "Connect Battery" alarm - what does it mean?

[Anonymous user]

My SMC began throwing this alarm.  It sits very quietly on a shelf, undisturbed, doing its job, and the battery is of course connected.  I note that there are a number of potential alarms for battery degradation and failure, but when I search this error, I see a lot of suggestions about replacing the battery.  Is this alarm typical of a bad battery?  If so, what are the other more specific battery failure alarms for?  And if this alarm indicates some other problem, how do I know?  I don't want to buy a new battery if the alarm really means "your charging circuit is bad" or "your logic board was bad".  I don't want to waste time or money.  So how can I troubleshoot this problem effectively?

Thanks,

J.

[BillP]

Hi J,

You can initiate a self-test from the UPS display to diagnose the battery health. However, in certain cases even degraded batteries are capable of charging up to float voltage and passing the self-test. You may need management software to initiate this self-test (PoweChute Business Edition) as the SMC models don't have a Control menu on their LCD display and would otherwise self test every two weeks or whenever they are turned on.

How old is your SMC? A typical VRLA UPS battery will last between 3 to 5 years, depending on number and depth of discharges, operating temperature, etc.

Another way of troubleshooting a potentially degraded battery is to connect a (non-critical) load with known power rating to the UPS and disconnect the UPS AC input. This chart will help compare the actual UPS run time at that specific load level to the run time expected form a new battery.

[Anonymous user]

Thank you for the detailed reply.

I suspect it's the batteries.  It's over 4 years old and when I pull off the front cover, the battery cases are very hot and there are salts condensed on the top surface at the seams.  

I'm going to just roll the dice and get a new battery for it.

I have another question - how do you get the batteries out?  I can't quite get a grip on them and they don't seem to want to move.  I don't want to shut down the UPS or take it out of its location - that would be a chore and require me to power down the loads.

Thanks,

J.

[BillP]

Hi J - 

You should immediately turn the UPS off and disconnect it from input power. When batteries get too hot or are left charging after they have failed, they can experience a state called "thermal runaway" which can cause them to swell, vent, and sometimes even leak. When a battery is in this state it is importantly to not continue charging it. Once your unit cools, you may find that the batteries are able to be removed from the unit. If they are still firmly lodged at that point you would likely need to replace the UPS. We do not recommend disassembling the case to remove a swollen battery due to potential safety hazards. 

[Anonymous user · Accepted solution]

I discovered while perusing the menus that this is an SMT, not an SMC.  Anyway, yes, it does appear one of the batteries has swelled and is making removal very difficult.  But I have no intention of throwing this expensive device in the trash because of a battery.  The device should be designed so that batteries which fail in this way are easily removable, and it should contain temperature sensors which stop the charging circuit on overheating.

J.