SMX1500RM2U minimum load for self test?

[JohnsIsland_apc]

What is the minimum load for a self test to properly occur?

As I recall, if the load is below 20-30 percent, when the battery is old, during a self test the UPS will drop the load.  If I use a SMX750, the load is about 50%, so the self test should function properly, however the run time is a bit lower than I would like.  If I use a SMX1500RM2U, the load is about 25%, the run time is probably acceptable to the company, and the UPS is the same as most of the other UPS's at the company.  However, if the self test won't function correctly, I would rather not use the 1500.  I understand the best solution would be the 750 with an external battery, however that would add significantly to the cost.

I appreciate the help on the forums.  I did read several pages of posts and tried searching, but the search returned an error message.

Thanks,

Jeff

[BillP · Accepted solution]

Jeff,

We recommend having a load of at least 20% for a self test as this will give a more accurate reading into the runtime and lifespan of the battery.  There is no set amount of load that would cause a drop during the self test.  If your batteries are in a poor state, and your load is large enough where the poor state of your batteries can not sustain the load the length of a self test, then you would encounter issues.