Back-UPS Pro 1500 (BR1500G) won't power on without battery attached

[Anonymous user]

I have a BR1500G that stopped functioning properly after a battery replacement (genuine APC replacement battery).  I made a post a while back about the primary symptom (battery will charge, but not stay charged), but I've realized that a major symptom is that the unit will not power on without a battery attached.  All other 1500G units will turn on without the battery attached and this one no longer will.

Any idea what internal failure might have caused this?  I'm interested in trying to repair it if possible.

[robmir_apc]

Have you tried to Brain Dead it ?     Unplugged, no battery and pushing, without releasing it,  the power button for 30 sec ? 

[Anonymous user]

Thank you for the suggestion.  I had tried a bunch of "resets" when this first happened (battery out, unplugged, hold down power button for 10 seconds and then insert battery), but not a "braid dead" reset of 30 seconds.  I just tried that and there was no change.  I really think that this is a hardware issue where the 24VDC power supply is dead, but the DC battery charging circuit works.  The unit will still charge the batteries, but won't keep them charged and won't work without a battery plugged in.  It's as if the batteries are being used for the DC internal DC supply voltage since the one inside the unit is dead.

[robmir_apc · Accepted solution]

Unfortunately I have mixed feelings with this series, I have 3  ( all with the external battery pack) and 2 of them have problems where one of them started when brand  new , requiring a brain dead reset every time it was plugged ( I forwarded this UPS  to a relative in South America so I couldn't send it back to honor the  warranty ) and since then every time there is a blackout and it exhaust it's battery and turn itself off, when the power return it has to be reset through the brain dead procedure so a unattended installation is out of question.    The second one after a couple of years started to show always a maximum of 330 remaining minutes without any load. Batteries were replaced ( both internal and on the external battery pack) and followed the APC recommended procedure to reset the remaining time allowing it to discharge with a 50% load without any success.  By the way opening the external battery pack to replace it's 4 internal batteries is a nightmare when the housing of this batteries got deformed and inflated which jammed  the external battery pack sliding side panel and had to broke part of it. 

Our newer UPS  are the  SMT and SMX  series, all equipped with network cards and managed remotely