PSU does not function on battery power

[Anonymous user]

Hello, I have a Rosewill RBR-1000MS PSU plugged into battery backup socket on APC BR1500MS, but when BR1500MS is disconnected from AC input power, the Rosewill PSU turns off (although the fan/led of it continue to function), and will not turn on again, until BR1500MS has AC input power again.

This was tested with ONLY the Rosewill PSU plugged into UPS.

I am assuming that this PSU is not compatible with this UPS. Do I need to adhere to rigid specifications of some sort when choosing a replacement PSU?

Thanks in advance for any feedback!

[BillP]

Hi Neil

I don't know the specs of that power supply but it may be that it isn't compatible with a step approximated sine wave, which is what the Back UPS range of UPS output is when it's on battery.

Regards

Matt

[Anonymous user]

On 11/20/2018 2:09 AM, Matt said:

Hi Neil

I don't know the specs of that power supply but it may be that it isn't compatible with a step approximated sine wave, which is what the Back UPS range of UPS output is when it's on battery.

Regards

Matt

Thanks Matt for your quick reply! I haven't seen 'stepped approximated sine wave support' in any specifications for when shopping for PSU, can you offer any guidance as to how I might go about finding a PSU that functions correctly on battery power?

UPDATE: Well according to my vendor, and also someone who answered another owner of BR1500MS on this support forum, my BR1500MS is in fact something called "PURE SINE WAVE", although Ben suggests that even so this should not be the compatibility issue I am experiencing. Ben indicated this in the following thread: https://forums.apc.com/spaces/4/back-ups-surge-protectors/forums/general/85041/what-s-the-difference...

Any ideas? I am uncertain how to proceed.

[BillP]

My apologies, that range of Back Ups haven't been released in to the European market yet, where I am, so I didn't recognise it as a pure sine wave Back UPS.

The BR1500MS has only a capacity of 900W so it is under powered if your PSU is working to full capacity (You would get an overload alarm if that was the case).

Other things that come to mind is it has an 8-10ms transfer time both transferring to battery and from battery to online, usually servers are more sensitive to that.  You can minimise the transfer time by changing the Back UPS sensitivity to high. 

If you connect the Back UPS to your computer with and use the Powerchute Personal Edition software, it might highlight the issue to us.

Regards

Matt

[Anonymous user · Accepted solution]

SOLVED: The Rosewill PSU would not function on UPS battery power because it requires a ground connection, and so by unplugging the APC unit from wall socket, there was no path to ground. The Rosewill PSU does function correctly on UPS battery when circuit breaker it opened, because ground connection is maintained. WOOHOO!