APC Smart-UPS 1500VA with LiFePO4 Batteries

[Braingears]

I currently run a server rack in my garage that constantly consumes 900W-1100W continuously 24/7. My HP Servers are VERY SENSITIVE requiring Pure Sine-Wave, or the redundant power supplies will instantly shut down.
For over 10 years I've used APC Smart-UPS 1500. I very quickly replaced the built in batteries with:

• (2) Series 49 (aka H8) Lead Acid & AGM batteries.
• (4) 6V 175Ah Flooded Deep Cell batteries
• (2) 4D Flooded batteries.
• (2) 8D Flooded & AGM batteries.

They typically didn't last long, because they got cooked by the built-in charging voltages. The larger batteries would do much better over time. So far, I haven't been able to figure out how to change the charge voltage, and don't know how many amps it charges at. Since the original batteries are only 14Ah AGM, I can't imagine it being too high.

Has anyone already done this swap?
Did you have to make any modifications to the UPS?
Can I have two identical APC 1500's connected to a single 24V 200A LiFePO4 battery?

I'm also considering Victron EasySolar-II to replace this setup. It would also give me the ability to feed solar power into the charger / inverter / controller thus allowing solar energy to supply power to the equipment and offset my grid electric costs. I haven't found very much information on how clean the Sine-Wave is on these units, and still need to do more research. For now, I already own multiple APC Smart-UPS' and would like to start there.

 

[DJSmiley]

What about a MPP Solar or Growatt 24V grid/solar inverter? LFP charging profiles included, much more efficient (The old APC's arent the most efficient onest) and the ability to add PV (and configure it to use PV when available)
And a lot cheaper than a Victron Easysolar...


With these kind of servers I expect they are running on 240V and not on 120V (power supplies have lower output on 120V) so a PIP 3024 would be a great competitor to the Victron imho

PIP 3024GK European Model Voltage Only 230V NO 120V! – Watts247.com

watts247.com

 

[Braingears]

The servers are running multiple redundant power supplies at 120V each.
I really like the Victron Bluetooth interface, and complete trust their product line. PowerContol & PowerAssist are a plus too (I ran off a generator for over a week the last time a hurricane came through Tampa Bay).

I haven't researched the other manufacturers yet, although don't want to be cross referencing codes back and forth with a book. I prefer an easy-to-use phone or computer interface to manage it. Even my APC Smart-UPS' have a management card that can be accessed from my computers.

 

[Braingears]

@DJSmiley - I would recommend looking at these. It explains why I like PowerAssist and was staying away from the GroWatt. In my case, I really need a clean and reliable pure sine-wave.

Will generator work with Growatt?

Has anyone successfully used a generator as backup with a Growatt inverter/charger? The user manual for the Growatt 3000 TL 24v says, Note: When connecting generator, the generator should be no less than 10KVA and (Only diesel generators allowed) So, can it be that only 10000 watt diesel...

diysolarforum.com

 

[danpass]

Any more input on the straight swap from SLA/AGM to LiFePo4 ?

Any worries on the charging circuit and algorithm?

Can it really be a drop-in replacement to use a LiFePo4 of the same physical dimensions?

-

 

[Braingears]

@danpass - I've drilled a hole out the side for the Anderson 50A plug on my APC Smart-UPS 1500. I don't care about fitting into the same physical dimensions.

 

[120vjohn]

For most 36v UPS`s final charge voltage is 42v for lead acid is 2.33v/cell. if you use 10 NMC cell in series is 4.2v/cell, hi not last long.
To use 12 LFPcell in series you need 40v for 3.35v/cell, at 40 v you can also fit 10 NMC cells in series.
You can adjust charging voltage, by modifing divider that reads that voltage, but you must identify it first.
What about LTO cells at 42v 17 LTO cells in series fit well, in given conditions these LTO cells are expected to last about 10 years, and are suitable for fast discharging and charging without damage.
I run LTO offgrid, for 7 years without any degradation, with common appliances and welding.

 

[timselectric]

@danpass - I've drilled a hole out the side for the Anderson 50A plug on my APC Smart-UPS 1500. I don't care about fitting into the same physical dimensions.

That's what I am doing also.
280ah cells.

 

[timselectric]

Has anyone already done this swap?

Doing it soon, myself.

Did you have to make any modifications to the UPS?

Only making physical modifications, due to 280ah cells. LiFePo4 and AGM charging profiles are very similar. It's a good swap.

Can I have two identical APC 1500's connected to a single 24V 200A LiFePO4 battery?

Probably, as long as the chargers are isolation type.
My two will have their own cells.

 

[OffGridInTheCity]

Has anyone already done this swap?
Did you have to make any modifications to the UPS?
Can I have two identical APC 1500's connected to a single 24V 200A LiFePO4 battery?

I have about 10 APC 1500s and 3 APC 3000s. I've been using 7s7p lithium-ion packs as replacements for the lead acid in the 1500s and one of the 3000s and a 14s12p in a 2nd 3000. Nearly 4 years now with twice daily cycles between off-grid and grid with no problems.

The APC 1500 maintaing about 27.6v and cut-off at about 21v. For lithium-ion 7s this is 3.95v hi and 3.0v low - well within operating specs.


The APC 3000 is the same except has 2 x 24v lead acids so I used 2 x 7s7ps... BUT the batteries gradually drift over 6-9months so I have to manually rebalance...

and built a 14s12p....


AND as I write this... I'm building a 14s @ 130ah Frankenstein battery to mount externally and power my 3 APC 3000s from the same battery. The APCs have limited knowledge of their internal batteries other than self-test and you can do calibrations - but that's under your control.
The charging rates are small - will not hurt 18650 or LifePo4.


I don't see why you can't do the same AND I think LifePo4 8s work just fine as the hi voltage will be ~3.45v/cell and 2.64v low - perfectly OK for most LifePo4 specs.

 

[120vjohn]

3.45 in float is too hi for LFP, expected life is about 3 years.
LTO last longer in hi float voltage, but is expansive.
Large lead acid are also good, E.G. NSB100FT agm, or larger, or tubular plate gel, or OPZv, you can also use individual lead acid OPZv cells

 

[Delmar]

I also have multiple APC UPS’s.

Yes they are inefficient, especially compared to the modern high-frequency inverters. However the UPS does many nice things to keep your sensitive servers happy:
* Switching between grid and battery within ¼ hz.
* Bucking & boosting the line voltage (without using the battery).

I have a 1000XL with internal 18AH’s and external 35AH’s AGM. Has only been running a couple of years so don’t know the battery longevity.

I have an ancient 5U 3000XL for emergency home backup that is connected to my golf cart Trojan FLA. I don’t charge from the UPS. Note the UPS was not happy with elevated battery voltage when the golf cart was charging on solar.

 

[timselectric]

I have two 1500's. One is 9 years old. It's just now ready for a battery swap. This is why I am switching over.

 

[byteharmony]

I have about 10 APC 1500s and 3 APC 3000s. I've been using 7s7p lithium-ion packs as replacements for the lead acid in the 1500s and one of the 3000s and a 14s12p in a 2nd 3000. Nearly 4 years now with twice daily cycles between off-grid and grid with no problems.

What did the 7s7p setup run you?

Any experience with this kind of thing or recommendation on what to use? 18650

7S 29.4V BMS Battery Box Battery Power Pack Wall Li-ion 18650 Battery Holder | eBay

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7s7p 23.1 Ah @ 60 AMP BMS (guessing, not sure what the 60 AMP is other than perhaps max draw?, also have an option for bluetooth, interesting, IF it had a PC app to watch bluetooth... super cool)

$352.74 ($15.27 / Ah)


I think the increase to 23 Amp hours from 15 with SLA is smart to overcome the charge discharge LIPO issues.

Lifepo4 idea 50Ah : (cells recommended by Will on his site): $500 ($10 / Ah)

Narada 50Ah | 3.2v LiFePO4 Cells | Grade A+ ~ Current Connected

Price is PER CELL, minimum quantity 4 cells, and only sold in groups of 4 Brand new cells. No signs of swelling and QR codes are in-tact. Guaranteed to pull over 50ah capacity. Covered for 1 year under our warranty policy. Stocked in USA - Ships immediately. Strong M6 threaded terminals...

www.currentconnected.com

Cells alone: $400

Will battery control: $100

Lastly the one I think may be ordering tomorrow if I don't hear from anyone
Lifepo4 idea 25Ah: $335.20 ($13.41 / Ah)

Affordable Electric Vehicle Batteries & Components from Electric Car Parts Company

Electric Car Parts Company is your one-stop-shop for affordable electric vehicle parts and components including batteries. Shop our selection and order now!

www.electriccarpartscompany.com

25Ah
Cells alone: $235.20

Will battery control: $100


Given that the SLA batteries will run $200 for 15Ah the Suggestions for improvement please.

 

[OffGridInTheCity]

What did the 7s7p setup run you?

- 49cells * 1.00 = $49 (I used second hand cells )
- I used Chargery 8T BMS = $150? (not sure). But a DALY of similar BMS would work = $45 - https://www.amazon.com/DALY-Bluetooth-- Resetting-Program-Lithium/dp/B08PTW9BQV
- 4 x 5 cells spacers - $5
- Solder/wire/Anderson plugs - $30?
- Labor = Free

Total of $150. More of a smaller project to learn than saving big $. You might be able to find some 12v LifePo4 on amazon in the 15-17ah range and put 2 in series as direct replacement for 2 x lead acids - a lot less work

Any experience with this kind of thing or recommendation on what to use? 18650

7S 29.4V BMS Battery Box Battery Power Pack Wall Li-ion 18650 Battery Holder | eBay

Find many great new & used options and get the best deals for 7S 29.4V BMS Battery Box Battery Power Pack Wall Li-ion 18650 Battery Holder at the best online prices at eBay! Free shipping for many products!

www.ebay.com

7s7p 23.1 Ah @ 60 AMP BMS (guessing, not sure what the 60 AMP is other than perhaps max draw?, also have an option for bluetooth, interesting, IF it had a PC app to watch bluetooth... super cool)

$352.74 ($15.27 / Ah)

Holders are expensive and the $ add up fast. I just soldered my 18650 cells with 8awg bare copper wire as the bus

I think the increase to 23 Amp hours from 15 with SLA is smart to overcome the charge discharge LIPO issues.

Lifepo4 idea: (cells recommended by Will on his site): $480 ($9.60 / Ah

Narada 50Ah | 3.2v LiFePO4 Cells | Grade A+ ~ Current Connected

Price is PER CELL, minimum quantity 4 cells, and only sold in groups of 4 Brand new cells. No signs of swelling and QR codes are in-tact. Guaranteed to pull over 50ah capacity. Covered for 1 year under our warranty policy. Stocked in USA - Ships immediately. Strong M6 threaded terminals...

www.currentconnected.com

Cells alone: $400

https://www.amazon.com/Equalizer-Balancer-Transfer-Equalization-Capacitor/dp/B09MS9JPDZ/ref=sr_1_1?crid=2Y8P1WPA3QWDR&keywords=8s%2Bbalancer%2Bcapacitor&qid=1659571560&sprefix=8s%2Bbalancer%2Bcapacitor%2Caps%2C81&sr=8-1&th=1

cheap balancer: 40

https://www.amazon.com/gp/product/B07797N9BG/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

Monitor: $40

I see people chatting about Batrium all the time, adding that would allow remote monitoring via a computer but it looks like that's about $500?

Batrium is WAY OVERKILL for 7s7p
I use Batrium but I have 14s800p worth of cells in operation at the moment totaling 2080ah @ 48v.

I appreciate your enthusiasm - perhaps you could view this 1st battery as an experiment. My 2 favorite (reliable) places to view a wide variety of 2nd hand cells are
Battery Hookup - https://batteryhookup.com/ *Also has reliable BMS and cell holders.
Battery Clearing House - https://www.batteryclearinghouse.com/

You could think about....
- 18650 7s7p or 7s pouches that will fit
OR
- 8sXp LifePo4 cells or small bricks? and see what fits

and start learning about building a battery + BMS'ing it + operating it and get hands-on about how it all works

 

[byteharmony]

Wow, amazing, absolutely amazing!

I was so excited to get the first UPS moving I purchased one set of the 25Ah batteries yesterday. They arrive Wednesday. I have the same 8S balancer from my RC toys shown in your picture. I hoped they’d come close to the same voltage and then I’d wire that up to start since I was really jumping the gun with ordering right away.

I have lots of APC 1500 units in production so I’m excited to get a test unit online and then evolve it as I learn.

This would be my first 18650 project as well, thank you for opening my eyes to that world.



From battery clearing house (thanks for the link): 7s2p for $17.5 (2x units @$35)

So to go 7s8p that would cost $70

Of course we know nothing about the BMS, size, quality, discharge and charge rates….

A almost educated guess is that I could recycle the original power wires and fuses reconfiguring them to all be parallel.

Wow, progression

23.1 Ah $352 $15.27 / Ah

50 Ah $500 $10 / Ah



To your system:

15 Ah $150 $9.74 / Ah



To your deal:

16 Ah $70 $4.37 / Ah



That may just be half the price of the replacement new SLA batteries!!



I’m thinking of ordering 6 hoping I get one that works? Test them in a lipo testing bag outside my house to see what they do?

I’ve never done this, any suggestions?

Thank you so much for your help! Could I send you a gift? @OffGridInTheCity

 

[OffGridInTheCity]

Thank you so much for your help! Could I send you a gift? @OffGridInTheCity

No way - the point of this forum is to share info, and if it helps then that's the reward. Good luck.

 

[timselectric]

I'm going to use 280ah cells, with mine.
Should last all night. lol

 

[byteharmony]

I'm going to use 280ah cells, with mine.
Should last all night. lol

It's like a whole new world and I have most if not all of what I need to get started right now!!

I have a 1500 unit charging sad Miady 16Ah batteries now. Current meter shows 1.27 Amps while at 26.7Volts.
(Will review):

I hooked them up in series (not recommended) with a balancer and lots of meters to make sure nothing blows up in my first test. So far, SUCCESS

I ordered that 16Ah set i wrote about above, they are also scheduled to arrive Wednesday.

With just this small success I'm already seeing your setup @timselectric replacing my little 1500Watt DC inverter in my honda Pilot. On party weekends it was killing my truck battery when the sun went down (I have a solar panel on the roof rack). I was thinking of getting a charger and some big Lipo batteries to keep her going at night. Skip that, I'll just put the charge controller right on the Lipo's and use the inverter in the APC all the time. When / if power get's low I can fire up a generator and use the charge controller in the APC while not skipping a beat at the part. Tim If I use your 208Ah I may not need to have the boys run the generator at all!! I should also be able to get the software for the UPS on a laptop to be able to monitor the whole thing while I DJ and Karaoke the party!

 

[timselectric]

I have an APC UPS with dying batteries. So, it's the perfect time for an upgrade. As I build the batteries for my solar system. Any that don't test well enough for the big system, will be put towards this project.