Dead SUA1500RMI2U

[Anonymous user]

I've had this for a few years, but for at least the last few months it was inadvertently left unpowered so the batteries would have discharged. If I now plug it into a power socket, it is completely dead, even after several days allowing for the batteries to recharge.

I disconnected the batteries and measured the voltage at 7.2V. I'm guessing they should be 24V and hence are in a bad way, but even so, with the unit powered from the mains I think I should be able to turn it on. In fact, shouldn't it run with no battery connected at all?

Anyway, looking around the back I see that the circuit breaker is apparently out indicating it has tripped. But when I push the thin white button back in (against the light spring) it simply comes out again. There's no clicking, not catch on the button, it's just like a spring plunger with no mechanism to hold it in. The response from APC support is that the whole thing needs replacing which they will do for £600, way more than it cost new in the first place and it's going in the bin before I spend that sort of money on it.

Having researched a bit more, I am left unsure of the operation of this little button. Exactly what are its correct positions? It seems there are different views on this to be found. I've no idea what it was like when it was working, but now it is sticking out 4.75mm (that's .182" for those who don't understand metric). I've no idea whether this means it has tripped, or is in fact in its normal position. If the latter, that would explain why it doesn't seem to catch in any further, but if the former, I've no idea why this would be, nor how to get it to reset.

So, I'm left with a conundrum. Do I chance that the trip is OK and splash out on some new batteries, or would that be a waste of money? Has my circuit breaker actually tripped and if it has, why is it not resetting and is there anything I can do to fix this?

Suggestions?

[BillP]

The little white "button" you're referring to is the output circuit breaker. When it is tripped (because the equipment to the outlets is drawing too much amperage), it sticks out really far (maybe an inch or inch and a quarter) so what you're describing indicates it has not tripped. It is normal in this state for you to be able to push it and it pops back out a little bit. This output circuit breaker would also only prevent the UPS from outputting power and not prevent it from turning on. An input circuit breaker would do that which this model does not have.

And yes, this UPS has a 24V battery bus and floats at about 27.5vDC. My understanding that I have confirmed with the global tech support lead on this product is that in most circumstances, SUA models will power on with no battery if there is some juice left in the system or in a capacitor some place. But if it has been in storage for a very long time and to the best of your knowledge used to work, it is likely fresh batteries will re-energize the UPS and it is truly fine.

So, if it was me, I'd try new batteries if you could (or provide it a 24vDC power source somehow) but there is also a remote possibility that of course there is something wrong with the UPS.

[Anonymous user]

Very helpful answer thanks. I'll try and find a 24v DC PSU, I think I have one somewhere and hopefully I'll see the UPS come to life. Then I just need some new batteries. I hope

I'll update this once I've tried the above.

[BillP]

Just be careful of course and also, if it doesn't turn on while connected to good AC input power, then you can also try "coldstarting" it if it he has the good DC voltage. To do this, make sure it is unplugged/removed from AC power and then hold down the "test" AKA the on button on the front panel and see if you hear two beeps. You'd want to let go during the second beep.

[Anonymous user]

I absolutely do not recommend trying a 24 volt DC power supply as a substitute for the real battery in this UPS (or any ups for that matter). Short of having the DC power supply on a 100 % isolation transformer you will have no control over what the ground references are for this source in relation to that of the DC bus in the UPS, and you could end up blowing up the UPS and the power supply too and put your own safety at risk. As Angela suggested the likelihood of the UPS being ok is high so invest in a set of batteries ( with a good store return policy) and see if the UPS comes to life.

Good luck !

[Anonymous user]

Good point, although trying to run it from 24v supply only, i.e. NOT connected to the mains (or anything else), should not present a problem.

However I'm still somewhat confused. I also have an SUA3000i with flat batteries (after long service though) and both UPSs are equally dead. But I thought you could hot swap the batteries. In which case they should be able to run on AC mains power alone, but they do not. Neither give even a flicker of life. So is 'hot swapping' of batteries not a feature of these UPSs?

[BillP]

"Hot swapping" the batteries means to me that if a UPS is running online ("hot") and actively supporting a load, that you can remove and reinstall batteries without doing anything special or affecting the UPS output. So, yes both of these models support this function. I am not sure what definition of hot swapping you're referring to?

[Anonymous user]

Angela N. wrote:

"Hot swapping" the batteries means to me that if a UPS is running online ("hot") and actively supporting a load, that you can remove and reinstall batteries without doing anything special or affecting the UPS output. So, yes both of these models support this function. I am not sure what definition of hot swapping you're referring to?

Yes, that's exactly what I mean, but does the UPS have to be already up and running before disconnecting the batteries? Does it not mean that the unit can be started up without any batteries?

BTW, I've ordered some batteries for the 1500. Fingers crossed.

[BillP]

Yeah hot swapping to me only refers to swapping the batteries when the UPS is online. The situation you're talking about is just referring to replacing or installing new batteries while it is turned off which can also be done. This UPS is supposed to start up without batteries assuming it hasn't been sitting for years where every single capacitor is discharged I think. So, that is why I suggest batteries may still solve the issue and are worth a try.

[Anonymous user · Accepted solution]

OK, received the new batteries, inserted them and left it to fully charge for a couple of days. The unit was humming slightly during this time but otherwise silent. I have just turned it on and it does so perfectly, performs its self-test and is apparently ready to rock 'n' roll. So the batteries do seem to have been causing the problem. A couple of them were actually split which is rather surprising since it had done so little work.

All seems good now, thanks for the support.