Scored some free UPS batteries.. suitable for my EG4 3000EHV-48?

[Hardware99]

I was able to pick up 16 of these batteries from a UPS system when we closed out our data center.

I plan on doing a 4x 4 series/parallel battery bank.

I’m not sure how they will perform since these are high capacity batteries but they are designed more for higher current for shorter time. They are AGM so they should do ok though.

Any thoughts?

 

[v_green57]

As you said, datacenter / cell phone site AGM's are designed for long periods of being at float, and the occasional outage. They sometimes don't do well in daily cycle applications such as solar.

That being said, you got 'em, and they were free. Go ahead and try them but do careful and periodic monitoring of each battery and the performance of the array overall. Can't hurt anything as long as you are aware that you may need to "retire" them at any point. Be sure to set the charge params per the specs on the battery and use the AIO external battery temp sensor.

Have they got a date code on them?

 

[Hardware99]

They are about 5 years old. Since I was the data center engineer, I do know that that didnt get any real heavy use. The UPS was backed up by a 200kW generator so any outage lasting more than 20 seconds wiuld trigger the ATS, gen would start then switch over after about 20 seconds.

The UPS wss rated at 160kVA but it ran at about 25% or capacity for the last 3-5 years. String of 40 batteries were used.

 

[v_green57]

Yep, that's the kind of use they're designed for.

I have a couple remote wireless sites using ex-cell phone backup batteries bought used. Many years in service and they still perform well.

BUT:

The load there is a constant apx. 25W. Not the usual "household" load. The daily DOD is probably <20%.

 

[Hardware99]

This will mainly be for blackout-busting. I will be putting about 2.2kW of solar on the garage (I have the panels already)

Since max draw of the 3000 is about 65A, and I will in no way draw that much, a 4-parallel string shouldn’t draw more than maybe 10A in each string. I plan on keeping charging current relatively low to keep stress off the batteries

Since the 3000 can supplement from the grid (the display implies double-conversion; AC-DC-AC), I plan on feeding a critical loads panel, so solar will help supplememt grid power and keep the batts topped of

 

[v_green57]

Roger that. Not the usual day-to-day. More like the situation they were retired from.

Just remember to check individual battery voltage every now and then whilst running a 1850W blow dryer or equivalent. Would be a drag if your "blackout buster" left you in the "black" (hah) when you need it.