APC UPS Charge Percentage Not Updating

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APC UPS Charge Percentage Not Updating

Just bought a new APC UPS (SMT750) and it's up and running. I've connected a USB cable from the UPS to my iMac. Snow Leopard recognizes the UPS, and shows the current charge percentage.

Now when the power is disconnected, and the iMac is running on battery power the charge percentage does not change on the Mac, while it does change on the front of the UPS. I have the iMac setup to shutdown when the remaining power is 20%, however this won't do much good if it thinks it's always at 100%.

Windows 7 running in Fusion calculates the charge percentage correctly.

Any ideas?

24" iMac 2.8GHz, Mac OS X (10.6.2), APC (SMT750) UPS

Posted on Dec 8, 2009 8:16 AM

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Answer 1

Dec 9, 2009 4:45 AM in response to jjxc90

Is the unit Mac compatible?

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Answer 2

The hatter

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Dec 9, 2009 8:18 AM in response to DaddyPaycheck

No, they are "agnostic" and lack Mac OS version or native support. PowerChute ended with 10.4.4 and can cause panics.

The unit is fine, the front LCD panel works, so have you tried letting it run down to 10-15%?

How much run time does it offer? and do you need? (I have a number of APC RS/XS and others but have switched to CyberPower 1350VAs recently.)

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Answer 3

jjxc90 Author

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Dec 9, 2009 8:26 AM in response to The hatter

It seems to have enough power to let the iMac run for about 35-40 minutes which is plenty.

I've let it run down to about 50% (as displayed on the front LCD panel) but the UPS status on the Mac still says 100%. Funny thing is, when I disconnect the USB cable and reconnect it, the status will update to the correct percentage on the Mac but then remain unchanged from that point onward.

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Answer 4

sgarnett

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Dec 29, 2009 6:04 PM in response to jjxc90

The new APC Smart-UPS series uses a new protocol called "Microlink" instead of their old standard "UPSLink". I don't know if 10.6.2 can support it or not. The APC faq does not answer that question, but does mention an adaptor card (AP9620, goes in the UPS) to support the old protocol. However, that will not be available until Q2 2010 (again, per the faq).

What I don't know is whether Snow Leopard supports the new protocol and you just have a minor, correctable problem, or if you are out of luck.

I was just about to order an SMT750 myself. Have you been able to get the iMac to shut down when the battery is low?

The older model SUA750 is significantly less efficient under light load, but is probably more compatible.

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