Fixing APC SmartUPS 1500

[DyJohnnY]

Hello all,

I managed to get from the company I work for a non-working out of warranty APC Smart UPS 1500 (code su1500i). My hope is to somehow manage to repair it, using a schematic.

the ups itself it basically dead. no lights on display, no relay switching sounds when it starts up,suggesting it is alive somehow.

I'm rather out of reach of any decent service (best offer for repair I received was close to the price for a refurbished unit).
Since I'm good with a soldering iron and do have a background in electronics I'd like to attempt to fix it myself

I've scoured the internet for the past days trying to find a schematic for this unit but I haven't found. i've looked here aswell, where most other UPS models are, just not the one I have. http://www.upsclub.org/schem/APC/

Could anyone share a APC smart ups 1500 schematic?

thanks for any feedback.

[Toasty]

Re: Fixing APC SmartUPS 1500

Check/Replace the batteries first. Dead batteries (shorted or open) on APC units will cause them to be non-functional. Charge them with a standard car charger capable of at least 3 amp. DO NOT use the "Boost" mode when doing this. Just trickle on lowest scale should be fine. iirc, that uses the RBC7 battery pack.

[ EDIT: batterymart.com has the RBC7 for ~$70 + s/h ]

Unless someone has managed to "appropriate" a schematic from APC, there are none to be found. They do in-house service only and all schematics are proprietary. Remember that they provide a $25,000 equipment protection policy with those units...

Toast

[japlytic]

Re: Fixing APC SmartUPS 1500

Make sure that both batteries are evenly charged, and you need to use a special SLA charger (with an indicator of full charge), not a regular car charger, or they will fail prematurely. The voltages of all batteries should be very close to each other.

[DyJohnnY]

Re: Fixing APC SmartUPS 1500

Hhi,

Thanks for all the feedback, i will give that a try and report back.

[Toasty]

Re: Fixing APC SmartUPS 1500

No special charger is required to get the batteries up to see if the UPS will work. APC (as I stated before) will not operate with a no-load (open/dry battery) or zero volts from shorted batteries.

The car charger is fine for getting a charge into them to see if it comes to life at all. It is not intended to be used long-term on these batteries, and as previously stated, do not use the "boost" mode. SLA chargers will not work in most cases with bad batteries. They use a similar "sense" circuitry as the APC UPS's do.

If you connect the charger on the lowest amp rating, and see no increase in current after a few minutes, it is likely that the battery is bad. The RBC7 battery pack is 24v (2-12v/18Ah in series), so you'll have to charge them individually on a 12v charger.

You can also use a standard battery load-checker after they've been juiced up a bit. Just -do not- test across the whole 24v pack, or you risk blowing the 100A connector fuse. Test each 12v battery separately.

Toast

[riotpack]

Re: Fixing APC SmartUPS 1500

Just keep in mind you are working with mains voltage even when the unit is unplugged and that some designs I have seen tied mains neutral to the battery negative.
Could you post some pictures?

[whycomputers]

Re: Fixing APC SmartUPS 1500

I got three non-working SUA1500 units. Two look functional and one is for parts.

Older models need a voltage on the battery side to turn on, in those you will plug them in, see the site wiring fault error if applicable but the rest of the until will stay off. The moment you connect (even for a second) a battery they turn on.

Both units exhibit a strange behavior, they start charging the battery (one at 27.66 the other one at 27.76 but after 10-15 seconds they drop very briefly, almost like an internal short for a second. The voltage on the battery terminal drops to ~21V for one and ~22V for the other. This happens even if I unplug the batteries so it is not them. I can also hear the fan slow down during that second.

What electronic component could cause such symptom? A bad cap or something else?

[tom66]

Re: Fixing APC SmartUPS 1500

Have you considered measuring battery current? This is where the 10A range on a multimeter can come useful. If it goes really high, you may have a short; I suspect it's attempting to load the batteries by powering up the inverter, but the batteries are shot, so no go.

[whycomputers]

Re: Fixing APC SmartUPS 1500

Have you considered measuring battery current? This is where the 10A range on a multimeter can come useful. If it goes really high, you may have a short; I suspect it's attempting to load the batteries by powering up the inverter, but the batteries are shot, so no go.

I thought about it and I will do it when I go home tonight and report back tomorrow. Will it try the inverter even if no batteries are connected?

[tom66]

Re: Fixing APC SmartUPS 1500

How is it going to power the inverter? Is it an online inverter type (inverter is always running?)

[whycomputers]

Re: Fixing APC SmartUPS 1500

It is a live-interactive model so the inverter powers up when needed. I tried to time how often that drop happens and it is about every 15 seconds so it might be the UPS trying to check whether there is a battery or not. A physically damaged electronics element would be more random, no?
The same drops happens if I keep the turn on button pressed, I believe I read somewhere that it forces a battery check.

I connected a DMM in serial and there is almost no current during normal operation (0.01A) but when the drop happens there is a slight current that fluctuates. The max reading is 0.033 and the min is -0.096A.

I tried something new, I have a network card from a SUA750 and I connected it to the SUA1500. It did work and the board is reporting correctly voltage and faults. Current status:

Critical Alarm Battery Disconnected
The battery is not installed properly.
Critical Alarm Site Wiring Fault
A site wiring fault exists.
Critical Alarm Output Power Turned Off
The output power is turned off.

Some info from the logs:
09/26/2012 20:19:24 UPS: A discharged battery condition no longer exists.
09/26/2012 20:15:47 UPS: The output power is now turned on.
09/26/2012 20:15:45 UPS: The battery power is too low to support the load; if power fails, the UPS will be shut down immediately.

The battery setup is a total POS, at rest is about 25V but I connected a 24V fan rated at max 0.14A and the voltage dropped to 22.25V. Current was 0.06A and the resistance of the fan was 1.197MOhm. My rusty physics suggests an internal battery resistance of ~98Ohm about 4-5 times the normal for two 12V batteries.

I think I will order some batteries tomorrow unless someone here suggests otherwise. I will order normal ones and if I decide to expand it with AGM or marine batteries I can always use the back port, this way the unit can benefit from the temperature measurement/adjustment and hopefully not cook the batteries. Maybe a couple of LC-X1220Ps.

[tom66]

Re: Fixing APC SmartUPS 1500

98 ohms is more than 4-5 times normal. It's about 9800 times normal . You would expect resistance in the milliohm range.

[whycomputers]

Re: Fixing APC SmartUPS 1500

True, I missed the scale, the batteries I was looking at were 11-12 mOhm so for two in series I assumed double.