[NANOG] Re: Small Capacity UPS

[Gary Sparkes via NANOG <nanog () lists nanog org>]

I'm actually a sizable fan of cheap but decent quality used commercial UPSes, for a lot of scenarios like this.

In my office gear/rack, I have two tripplite SMART1500CRMXL  that I got used when a donation was made to a location 
from an office decommission back in *2011* - so having already long been in service - and the only thing I've had to do 
was batteries.  (the much older model than currently under those part numbers, with just LED indicators instead of the 
LCD - though it does take an SNMP card) - https://tripplite.eaton.com/support/SMART1500CRMXL

And for that, the recent deluge of drop-in LiFePo4 cells has been great. Instead of the design three 12v 9Ah 
internally, it took well to pre-made 12v 10Ah lifepo4 cells. 

Beyond that, it has your standard SB50 for expansion battery pack runtime, which was easy enough to wire up an external 
pack with a "cheap" BMS and a string of LiFePo4 cells, giving me 105Ah at 36V all said and done for the external 
pack....

I've even gone so far for network gear as to taking a small Belkin desk-side UPS and drilling out a hole into its 
casing and running an external battery pack on the side. Instead of the built in 2x 12v 5Ah, it suddenly had 4x 6V 50Ah 
cells. That thing ran a few switches for a very long time, though I never took any measurements, before one of the 
batteries gave out I had a switch going on 5 years uptime in that setup, with multiple extended power outages in that 
timeframe (I'd re-charge it off generator to full at least once a day, and leave it on if I could, but I never got 
anywhere near testing the limits of it from just raw voltage checks) 

Obviously, not solutions for bigger and more enterprisey scenarios, but...... options can be had. And with the battery 
being wired up externally, adding something like a regulated solar output to the battery terminals directly would be 
able to keep the system alive/running longer and re-charge faster too. 


-----Original Message-----
From: Dave Phelps via NANOG <nanog () lists nanog org> 
Sent: Tuesday, April 8, 2025 9:06 AM
To: North American Network Operators Group <nanog () lists nanog org>
Cc: Dave Phelps <tippenring () gmail com>
Subject: [NANOG] Re: Small Capacity UPS

If you don't mind building you own UPS from COTS parts, you may want to look at Xantrex (https://xantrex.com/). I have 
one of their UPS units (the FREEDOM XC PRO 2000) in an RV with 2 100AH LiFePo4 batteries in parallel.

I've considered using them for IT deployments but haven't pulled the trigger just yet.

On Tue, Apr 8, 2025 at 2:30 AM borg--- via NANOG <nanog () lists nanog org>
wrote:

> Oh, im interested with more details about your setup.
> I have 2x APC SmartUPS 1000 units here that I need to replace batts 
> soon. So I slowly think about LFP batts :)
>
> This UPS needs 2x 12V 12Ah batts (RBC4).
> Can you recommend some LPC batts as repleacement?
> There is enough room in UPS to but small BMS on top of batts.
> APC SmartUPC 700 is much worse in that regard. I had one such unit and 
> scrapped it. Batt temps where higher due to cramped space, and so they 
> lifetime..
>
> Regards,
> Borg
>
> PS: You can asnwer off-list w/ attachments :)
>
>
> ---------- Original message ----------
>
> From: Javier J via NANOG <nanog () lists nanog org>
> To: North American Network Operators Group <nanog () lists nanog org>
> Cc: Javier J <javier () advancedmachines us>
> Subject: [NANOG] Re: Small Capacity UPS
> Date: Mon, 7 Apr 2025 12:03:08 -0400
>
> Resending this without pictures because file size rejection.
>
> I'm just catching up on this thread so I have probably missed a bunch 
> but I wanted to share my experience. I originally started to replace 
> old batteries in my UPS's with AGM batteries instead of SLA. More 
> recently I have been going with LiFePo4 (Lithium Iron Phosphate) and 
> with units with 2 batteries (24V) adding in a battery balancer.
>
> examples attached. that white, yellow one is like 28 years old. 
> running strong.
>
> my observations and research reveal that old UPS units sometimes float 
> at a higher voltage, which makes LiFePo4 a perfect upgrade to lead 
> acid based battery technology. Also should last forever. (10+ years 
> and thousands of
> cycles)
>
> I have 5 UPSs, most I got for free. I also have a solar system in the 
> back yard and here in Florida those LiFePo4 batteries (the cheapest I 
> can find on Amazon at the time) are doing just great keeping all the 
> cameras in the backyard running plus I run power tools etc from them 
> as needed. they're not making lithium iron phosphate batteries with 
> high current cranking capacity. next time I have a car battery to 
> change the prices should drop low enough for that I'll be replacing it with that.
>
> On Mon, Apr 7, 2025 at 12:00˙˙PM Mark Tinka via NANOG < 
> nanog () lists nanog org>
> wrote:
>
> > On 4/7/25 12:54, Jared Mauch via NANOG wrote:
> > > And the battery has inbuilt fire suppression system:
> https://eg4electronics.com/backend/wp-content/uploads/2024/03/EG4%C2%A
> E-Indoor-280Ah-Battery-Specifications-Sheet.pdf
> > > Most things can catch on fire, sure.. but not everything lacks any 
> > > safety systems.
> >
> > LFP will experience thermal runaway at about 270°c, while NMC will 
> > experience the same at 210°c.
> >
> > It's quite a lot to subject your batteries to, especially if you 
> > have a reliable BMS.
> >
> > On average, the failure rate of quality LFP cells is about 1 in 10
> million.
> > Mark.
> > _______________________________________________
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