Smart-UPS 1500 SMT1500 (not SMT1500C) - "Connect Battery" error persists across battery replacement

[BillP]

I have an SMT1500 (not SMT1500C) unit that I bought back in 2011 that started complaining about the need to "Connect Battery".  I had a replacement APC RBC7 battery (real one, not a clone) sitting around (bought it a while ago when it was on sale, had it on the shelf waiting for the day when the original battery died) and finally got around to replacing the seemingly-bad one.  Well, now the same error happens with the replacement. 

How can I figure out if it's the battery or the unit itself?  There's no places like Circuit City (where I used to buy my smaller APC units like Back-UPS) where you could just take it in and say "figure it out".  I don't want to buy a replacement RBC7 only to find out it isn't the battery.  Similarly, I don't want to replace the unit (would probably downgrade to an SMC1500C if so) if it's just that the replacement battery sat on the shelf unused for too long.

What's a mother to do?

[Terry_Kennedy_apc]

How long ago did you purchase the replacement battery? This type of battery needs a "top-up" charge every 6 months at a minimum if not in use. Also, what was the manufacture year (in the serial number, the YY in xxYYdddddddd) of the battery pack?

If you happen to have a DC voltmeter (normally part of a digital multimeter these days), you can check the battery voltage. In your case, the battery pack has 2 12V batteries in series, so I'd expect to see something between 22 and 27 volts depending on the state of charge. You could also check the original battery pack.

[BillP]

On 9/14/2018 6:44 PM, Terry said:

How long ago did you purchase the replacement battery? This type of battery needs a "top-up" charge every 6 months at a minimum if not in use. Also, what was the manufacture year (in the serial number, the YY in xxYYdddddddd) of the battery pack?

If you happen to have a DC voltmeter (normally part of a digital multimeter these days), you can check the battery voltage. In your case, the battery pack has 2 12V batteries in series, so I'd expect to see something between 22 and 27 volts depending on the state of charge. You could also check the original battery pack.

Thanks Terry.  It was a while ago, I don't remember when.  I think I got it from Tech For Less when there was a sale, thinking "Eventually I'll need this when the original goes".  Clearly if they need a "top-up" charge every 6 months I should've waited to buy it until the original "went"!

I went and bought a multimeter.  The voltage across the terminals on the original battery is around ~ 25.91 Volts.  Does that mean it's not really dead, and it's the SMT1500 unit that is actually the problem??

[Terry_Kennedy_apc]

Here is the APC knowledge base article on battery storage (skip to "Bottom Line"): http://www.apc.com/us/en/faqs/index?page=content&id=FA156516

Yes, 25-26 volts seems reasonable. It is possible for the batteries to show a good voltage but then drop to a lower-than-minimum voltage as soon as a load is applied to them, but since both your original and the replacement do the same thing, I'd suspect the UPS itself and not the batteries.

[BillP]

On 9/15/2018 4:21 AM, Terry said:

Here is the APC knowledge base article on battery storage (skip to "Bottom Line"): http://www.apc.com/us/en/faqs/index?page=content&id=FA156516

Yes, 25-26 volts seems reasonable. It is possible for the batteries to show a good voltage but then drop to a lower-than-minimum voltage as soon as a load is applied to them, but since both your original and the replacement do the same thing, I'd suspect the UPS itself and not the batteries.

Thanks Terry. I see the "Bottom Line" says "perform a full recharge cycle". Given that the batteries are provided with the terminals covered by the black plastic plate(s), how is one supposed to "perform a full recharge cycle"? Are we talking using a 2W charger like for a car battery?

I guess the "Bottom Line" is, is there some way to resuscitate either the old battery or the replacement battery via a "full recharge cycle" to eliminate the battery as the cause of the "Connect Battery" problem?

--

Bottom Line:

APC Batteries should be charged to 100% within 6 months of purchase by the end user. If the batteries are to be stored for an extended period of time after that, the following procedures are strongly recommended in order to keep the batteries from discharging beyond the safe limit:

• If the ambient temperature during storage is - 15°C to + 30°C (+ 5°F to + 86°F), perform a full recharge cycle at least every six months.

[Terry_Kennedy_apc]

As I said, I don't think you have a battery problem. If the UPS is properly charging the batteries, you could just swap the battery packs every now and again to keep them charged. This isn't normally a recommended operation, as the Faston connectors (that connect to the 1/4" metal tabs on the battery) aren't really rated for regular disconnect / connect cycles.

I don't think APC has a "recommended" battery charger for their assembled packs. Some sellers of individual batteries offer chargers as an option. In dire situations (like total discharge after a long power failure) I've charged the batteries with a car battery charger (on low power). You'd need to charge each of the individual batteries (2, in your case) separately. This situation normally doesn't arise because people have 1 battery pack for each UPS.

[BillP]

On 9/15/2018 12:54 PM, Terry said:

As I said, I don't think you have a battery problem. If the UPS is properly charging the batteries, you could just swap the battery packs every now and again to keep them charged. This isn't normally a recommended operation, as the Faston connectors (that connect to the 1/4" metal tabs on the battery) aren't really rated for regular disconnect / connect cycles.

I don't think APC has a "recommended" battery charger for their assembled packs. Some sellers of individual batteries offer chargers as an option. In dire situations (like total discharge after a long power failure) I've charged the batteries with a car battery charger (on low power). You'd need to charge each of the individual batteries (2, in your case) separately. This situation normally doesn't arise because people have 1 battery pack for each UPS.

I could try that, I have an automotive charger that's 2W/10W low/high I think.

But is it worth trying?  It seems like (from what you say) it's more likely the unit itself, maybe I should just bite the bullet and get a new one after 7 years ...

[Terry_Kennedy_apc]

You can wait and see if the APC folks have any other ideas about things you could try on your existing UPS.

The general issue with people buying a new UPS is that they often have one good battery (the one they bought to try to fix the problem) and often another good one (the one that was replaced because it was presumed to be bad). 7 years is a good run for a smaller UPS, so a new one will be quite an upgrade. I have an old Matrix 5000 that has been running for 21 years, but those are pretty indestructible. It has gone through quite a few sets of batteries, though.

[BillP · Accepted solution]

On 9/16/2018 3:36 PM, Terry said:

You can wait and see if the APC folks have any other ideas about things you could try on your existing UPS.

Unfortunately they didn't have much else to say, to be honest.  They sort of implied that 7 years was a good run and I should consider their trade-in program on a new one, which is sorta exactly what I expected them to say