Battery Replacement - APC Back- UPS 900

[Johnd651]

So the UPS seemed to be lasting less and less every time. Finally yesterday I got the dead battery alarm. Seems like the battery melted on the inside, so I will be replacing the battery when a new one comes in. 5 screws and 2 battery terminals.

 

[Sean Clark]

Why did you go with AGM (excelent choice) and not LiPo?

 

[Johnd651]

Why did you go with AGM (excelent choice) and not LiPo?

I did not buy the battery yet, so I can. The Amazon Pic is of a direct replacement. How would I find a physical size lipo that matches?

 

[Johnd651]

Also, will it charge correctly? I don't know what protection is built into the UPS? This one is at least 5 years + old.

 

[Johnd651]

So why pay so much more for just 1 extra AH?

 

[Baylott224]

Or they have some of the battery back up systems from ecoflow have a automatic ups mode on those 30 ms Switch over. it's a lipo battery also way bigger than that for cheaper

 

[Johnd651]

Or they have some of the battery back up systems from ecoflow have a automatic ups mode on those 30 ms Switch over. it's a lipo battery also way bigger than that for cheaper

I like the UPS since I use Sicce pumps and will also run some other minor equipment on the battery

 

[Reefering1]

I like the UPS since I use Sicce pumps and will also run some other minor equipment on the battery

The ups will not properly charge a lipo battery. I suggest using agm car batteries. A single 94r or 49 series agm battery is about 10x the capacity and can easily be installed anywhere- just extend the 2 wires..
I use 4 100ah car batteries wired to my apc 1500va ups. It will provide 500-800w for 18 hours+. It charges/ maintains it just fine

 

[Reefering1]

Why did you go with AGM (excelent choice) and not LiPo?

The ups will not charge it properly and agm battery is much, much more stable(safe). Especially if water is involved. People don't realize a lipo fire is almost impossible to put out. A few years ago, around here, a Tesla got in a accident and caught fire. The firefighters couldn't put it out so they had to use the firetruck to push it into a retention pond to let it burn itself out.

 

[Johnd651]

The ups will not properly charge a lipo battery. I suggest using agm car batteries. A single 94r or 49 series agm battery is about 10x the capacity and can easily be installed anywhere- just extend the 2 wires..
I use 4 100ah car batteries wired to my apc 1500va ups. It will provide 500-800w for 18 hours+. It charges/ maintains it just fine

I was wondering if the built in lipo bms would do the trick.

It is funny you posted the car batteries. I was actually thinking about the big trays of old server UPS batteries I have that I reconditioned for my kids ride on jeep, and extending the wires out of the housing.

 

[Reefering1]

I was wondering if the built in lipo bms would do the trick.

It is funny you posted the car batteries. I was actually thinking about the big trays of old server UPS batteries I have that I reconditioned for my kids ride on jeep, and extending the wires out of the housing.

Not sure how the bms would integrate with the ups as they don't simply put out voltage to charge. They are sensing the battery condition and adjusting as it goes(much like the lipo bms). It might work though...

 

[Reefering1]

It is funny you posted the car batteries. I was actually thinking about the big trays of old server UPS batteries I have that I reconditioned for my kids ride on jeep, and extending the wires out of the housing.

If you do, might be a good idea to add a 12v 4" pc fan, in the ups, to keep it cool during extended use. Alternatively I bought my apc smart ups1500 for $100 with bad batteries(vs. 400-700 new).
I also have a battery source.. I fix cars and when these bmw and Mercedes come with battery messages on dash but still start fine- I save and reconditioned those batteries.
I've replaced the batteries once in the 8 years since hurricane irma.
Lipo batteries like(need) to be exercised(discharged and charged), agm or any other lead acid batteries do very well when maintained at full charge.

 

[Johnd651]

If you do, might be a good idea to add a 12v 4" pc fan, in the ups, to keep it cool during extended use. Alternatively I bought my apc smart ups1500 for $100 with bad batteries(vs. 400-700 new).
I also have a battery source.. I fix cars and when these bmw and Mercedes come with battery messages on dash but still start fine- I save and reconditioned those batteries.
I've replaced the batteries once in the 8 years since hurricane irma.
Lipo batteries like(need) to be exercised(discharged and charged), agm or any other lead acid batteries do very well when maintained at full charge.

Its funny cause the big server ups cabinet batteries are actually just a ton of 12v in series/parallel. So I just take them apart, find the bad one, and recondition the rest for other uses.

 

[Malcontent]

I replaced the batteries in two of my UPSes a few weeks ago. They had the same exact Leoch batteries. The UPSes were purchased in late 2019 so long overdue for a battery replacement. It was only $66 after tax and shipping for four batteries from batterysharks.

LiFePO4 apparently can't provide the same amount of current so I opted to continue with lead acid batteries.

 

[Brian_68]

The ups will not properly charge a lipo battery. I suggest using agm car batteries. A single 94r or 49 series agm battery is about 10x the capacity and can easily be installed anywhere- just extend the 2 wires..
I use 4 100ah car batteries wired to my apc 1500va ups. It will provide 500-800w for 18 hours+. It charges/ maintains it just fine

Having different branded batteries in parallel is not the best for performance or safety, especially in one's house:

Yes, you can put car batteries in parallel for backup power, which increases the total amp-hour (Ah) capacity for longer runtimes, but it is critical to use identical batteries of the same voltage, age, and type. Connecting batteries that are not identical can lead to imbalances, reduced lifespan, and potential damage to one or both batteries. For a safer and more reliable setup, especially for deep cycling, it's best to also use a battery isolator or a DC-DC charger.

 

[BeanAnimal]

The ups will not properly charge a lipo battery. I suggest using agm car batteries. A single 94r or 49 series agm battery is about 10x the capacity and can easily be installed anywhere- just extend the 2 wires..
I use 4 100ah car batteries wired to my apc 1500va ups. It will provide 500-800w for 18 hours+. It charges/ maintains it just fine

We should have a battery safety talk some day soon

 

[BeanAnimal]

It’s funny cause the big server ups cabinet batteries are actually just a ton of 12v in series/parallel. So I just take them apart, find the bad one, and recondition the rest for other uses.

With properly sized DC rated fuses and circuit breakers to protect the series parallel chains.

 

[Johnd651]

With properly sized DC rated fuses and circuit breakers to protect the series parallel chains.

No actually. I think I still have one whole APC UPS 48V server tray in the garage untouched. None of the other ones had anything except the batteries in a metal tray, and the plug. Unless the actual UPS has something, the battery trays did not.

 

[BeanAnimal]

No actually. I think I still have one whole APC UPS 48V server tray in the garage untouched. None of the other ones had anything except the batteries in a metal tray, and the plug. Unless the actual UPS has something, the battery trays did not.

It depends on the configuration of the string and its individual series and parallel segments and cell capacities. So cell capacity, total current capability, and output voltage of each segment and the combined segments. Without getting into a lot of math or failure modes, protection must be used if the potential fault current exceeds wire gauge or plate capacity. Smaller arrays like your example APC cabinet rely on internal resistance of wire and the cells to limit fault current. In theory a shorted cell can’t drive enough current through the small array to create a cascading failure. As such, they often omit individual fuses, while larger or parallel systems require them to prevent backfeed and overcurrent damage or cascading catastrophic failures.