Overview

Model: Back-UPS ES 750

Battery Details

Lithium Iron Phosphate Battery Replacement

I ordered this LiFePO4 battery off amazon which is the exact same size as the original.

Cost: $63 CA plus Taxes.

NASTIMA 12V 8Ah Rechargeable Lithium Iron Phosphate Battery,Built-in BMS, 4000+ Cycles LiFePO4 Battery Pack, 10A Max Output.

https://www.amazon.ca/dp/B0B5WBHDDN?smid=A32QMQUDJWY3FO&ref_=chk_typ_imgToDp&th=1

Tested this battery's capacity pulling 2A. Capacity came up as 8.8Ah.

Note: Battery voltage stays at 0v once discharged until voltage is applied. Does not bounce back on it's own.

I performed a capacity test on the old lead acid battery. The battery had a 3 Ah capacity when drained to 10.5v at 2A.

Shutdown Problem

I ended up having some quick shutdowns after replacing the battery.  

On this UPS I have the following items connected:

Ok, so battery has a 10A max output, which is 1A at 120V.

Lets figure out what are real power usage is....

It looks like this will work if we don't have the Dell PowerEdge on the UPS.

So, 10A is beyond the 1C, so ideally we should aim for a max of 8A discharge.

Based on this information, this battery is insufficient for our load.

Testing the battery with a 10A load, the battery quickly dropped to 11.6V which the UPS would consider to be 0% left!

Configuring the UPS

List Commands

> upscmd -l  ups@localhost

Instant commands supported on UPS [ups]:

beeper.disable - Disable the UPS beeper
beeper.enable - Enable the UPS beeper
beeper.mute - Temporarily mute the UPS beeper
beeper.off - Obsolete (use beeper.disable or beeper.mute)
beeper.on - Obsolete (use beeper.enable)
load.off - Turn off the load immediately
load.off.delay - Turn off the load with a delay (seconds)
shutdown.reboot - Shut down the load briefly while rebooting the UPS
shutdown.stop - Stop a shutdown in progress
test.battery.start.deep - Start a deep battery test
test.battery.start.quick - Start a quick battery test
test.battery.stop - Stop the battery test
test.panel.start - Start testing the UPS panel
test.panel.stop - Stop a UPS panel test

Issue Command

>upscmd ups@localhost beeper.disable
Username (root): admin
Password: 123456
OK

Test

>upscmd ups@localhost test.battery.start.quick

>upscmd ups@localhost ups.test.result

References