El-Cheapo UPS Battery replacement: Can I use Lithium (LiPo)?

It is very likely that you will find a warning in your UPS manual that states that you should only replace the batteries with the same kind of battery.

50% of my customers have got away with it, the other 50% ended up with damaged batteries - as a result we do not recommend this as a solution.

Best solution is to replace with the same type of battery, and ensure that the load/demand does not discharge the battery below 50% over the period of use, before it is recharged again.

Very simply : It is likely that your UPS will not shut off current draw from the battery while the battery voltage is higher than 10.5V , A LifePO4 battery will likely be fully discharged around 11V. Depending on the charging system you have and the BMS deployed with the battery, there is a potential for the device to continue drawing power from a fully discharged battery, with ugly consequences.

You may get away with it, and you may not! If you understand the charging regime of your device and battery and are able to adjust the system within compatible parameters - good luck!
In a nutshell, well said.
 
Actually we are suppliers, so it's in our interest to sell batteries, not discourage their use.

Its online information like this that leads to customers experiencing problems that lead to expensive losses. We will continue to advise our customers to follow the instructions in their devices user manuals.View attachment 1612315
If you understand what you are looking at, you will identify multiple issues with using these batteries in chargers designed for lead acid batteries. Many devices can operate within these parameters, many can't. 60% of gate motors work just fine, 60% of alarm systems work just fine, 60% of ups work just fine. (Mostly in circumstances where the applied load does not discharge the battery more than around 90%)

It's your gamble. Since most commentators here cannot determine the discharge rate of your particular usage scenario. The rate of discharge will impact the above. Additionally - you will note many of the usage advocates add mechanical intervention strategies that are simply beyond the scope of most everyday users and or require additional charging equipment which shifts the ROI factor in favour of the SLA battery. Additionally it is significant whether the battery is rated at 1C/2C etc - as those specific ratings will further complicate the issue. Additionally you need a function or feature to monitor the SOC of the battery.

Most of these commentators won't tell you that operating your LifePO4 battery beyond 80% state of discharge will harm the health and lifespan of the battery, referencing the above, note that your devices cutoff is likely going to be 10.5V where your LifePO4 battery is well beyond 90% Discharged.
Even abusing a lifepo4 you will get 2000 cycles ie 100% discharge and way more than that if only doing 80%

Rate of discharge does not damage a lifepo4 naturally you have to be in the 1c-3c a lithium can handle and within what the bms can handle

I. Your previous post you said 11v most likely completely discharged so it seems you did not get the graph

.i love it how that appeal to authority gets slipped in

That cutoff voltage
Of 10.5
Is very close to the fully discharged state of a lithium but thanks to sag you won't be able to actually 100% discharge a lithium and even if you did so what the lithium will still function 100%

But arguably if you are using that much capacity from a lithium you would be well below the 50%, of a lead acid too

In fact you are more likely to damage a lead acid battery on a lead acid device than you would damage a lithium on a lead acid device , the irony

Lead acid resellers will always use scare tactics yo keep you on lead acid

While with our use case load shedding ,using lead acid is the silly option and anyone promoting it il,may be the one eyed leading the blind
 
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In a nutshell, well said.
No that appeal to authority means nothing, they wanted to school someone that knows the discharge curve of a lifepo4

When in fact they made several false statements while trying
 
Yes if selecting a lithium for a small ups or gate motor

You have to consider a few things you can't just buy a lithium

Ie the bms current draw tends to always be the weakest link, so you have to buy an item that has the correct abilities for your device

Any charger will charge a lithium
Agreed using a CC/CV charger will charge it quicker

But this notion that only a lithium charger can charge a lithium is just propaganda , especially with lifepo4

With other forms of lithium ie the nmc types with 3.7v nominal or LTO with 2.3v nominal it gets more difficult not that you can't charge them with any but being able to rest assured that if the bms fails the voltage range will be within safe limits and to be able to extract all the capacity of the lithium is where the problem comes in


arguably even a lithium charger that won't exceed the recommended voltages will have bad consequences if a bms fails with some bad luck

if they want to claim they have the know how , they can try and point out why

on this easy question
 
A lithium used within its specs does not care about discharge rate , ie it does not affect a lithium as it does lead acid

ie you can use 1-3c discharge if a bms can handle it (naturally 3c for short stints like gate motors etc not constant)

While with a lead acid anything over 0.05c will see losses meaning you need an even bigger bank

200 -500 cycles dependant on how nice you treat it

While an abused lifepo4 will give you 2000 treated nicely likely 5000 , why are people trying to sell a lead acid with our use case

When a lithium will give you 10x+ the lifetime

And that is just for 80% capacity left cycles , it can still power your devices after you got that 2-5k cycles

So if the price is 2-3x it is a bargain to go lithium
 
Actually we are suppliers, so it's in our interest to sell batteries, not discourage their use.

Its online information like this that leads to customers experiencing problems that lead to expensive losses. We will continue to advise our customers to follow the instructions in their devices user manuals.View attachment 1612315
If you understand what you are looking at, you will identify multiple issues with using these batteries in chargers designed for lead acid batteries. Many devices can operate within these parameters, many can't. 60% of gate motors work just fine, 60% of alarm systems work just fine, 60% of ups work just fine. (Mostly in circumstances where the applied load does not discharge the battery more than around 90%)

It's your gamble. Since most commentators here cannot determine the discharge rate of your particular usage scenario. The rate of discharge will impact the above. Additionally - you will note many of the usage advocates add mechanical intervention strategies that are simply beyond the scope of most everyday users and or require additional charging equipment which shifts the ROI factor in favour of the SLA battery. Additionally it is significant whether the battery is rated at 1C/2C etc - as those specific ratings will further complicate the issue. Additionally you need a function or feature to monitor the SOC of the battery.

Most of these commentators won't tell you that operating your LifePO4 battery beyond 80% state of discharge will harm the health and lifespan of the battery, referencing the above, note that your devices cutoff is likely going to be 10.5V where your LifePO4 battery is well beyond 90% Discharged.
Why not post the charge curve too so people can see to what voltage a lifepo4 will go

Meaning it fits a lead acid profile with ease

The flat curve only affects estimating SOC nothing else

The manufacturers voltage range of a lifepo4 cell is 2.5 to 3.75v

ie 10v to 15v though 14.4v will see it fully charged

Lead acid devices falls within that window that is the beauty of the nominal voltage of lifepo4 and what makes it a drop in replacement

You are spewing propaganda

Bar substandard charging circuits which should just be your incentive to change the crap device

ie one device replacement to prevent multiple battery replacements
 
When using a lithium lifepo4 you have to change no voltage settings on a lead acid device

The only problem you could encounter is that the device has a substandard charging circuit and pops , ie some mecers/rct have this problem

ie they aren't designed to sustain that 10/20A charge rate whatever its max is

And hence why they work fine if set on a lower charge rate with lithium

Some users remedy that by adding extra fan

Lithium will soak up charge while a lead acid is different ie as the amount of salts on the plates becomes less the charge rate actually drops

Meaning that with lead acid it only charges on that 10/20A for a short period

And the lithium will keep it there throughout the charge cycle until it hits the CV phase then the charge rate drops naturally

Lots of people that have not used or understand how a lithium behaves want to educate people on them
 
Why not post the charge curve too so people can see to what voltage a lifepo4 will go

Meaning it fits a lead acid profile with ease

The flat curve only affects estimating SOC nothing else

The manufacturers voltage range of a lifepo4 cell is 2.5 to 3.75v

ie 10v to 15v though 14.4v will see it fully charged

Lead acid devices falls within that window that is the beauty of the nominal voltage of lifepo4 and what makes it a drop in replacement

You are spewing propaganda

Bar substandard charging circuits which should just be your incentive to change the crap device

ie one device replacement to prevent multiple battery replacements

Yeah, some UPSs (I tried a few old ones), and say Magneto lanterns, cannot charge LiFePOs with it's chargers, but my Eaton UPS and Nemtec Energizer can and has handled all this loadshedding over the past year like a charm.
 
What does sunsynk sellers tell its lithium users to do if they can't get coms to work

Change your settings to one of the lead battery profiles normally gel

(Which is also stupid imo)

You have to check if the user has a 48v battery or a 51.2v battery

ie if you have a 16S battery you can do so , if you have a 15S 48v battery not a good idea

Just to show that most specialists have no clue either

I have never encountered any other users questioning people if they are using a 48v or a 51.2v ie 15s or 16s when giving advice on charge voltages for a 48v system

All talk colloquially of a 48v battery when the market is flooded with 2 different configs for 48v systems

And they require different settings

"Specialists" what can you do
 
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Even abusing a lifepo4 you will get 2000 cycles ie 100% discharge and way more than that if only doing 80%

Rate of discharge does not damage a lifepo4 naturally you have to be in the 1c-3c a lithium can handle and within what the bms can handle

I. Your previous post you said 11v most likely completely discharged so it seems you did not get the graph

.i love it how that appeal to authority gets slipped in

That cutoff voltage
Of 10.5
Is very close to the fully discharged state of a lithium but thanks to sag you won't be able to actually 100% discharge a lithium and even if you did so what the lithium will still function 100%

But arguably if you are using that much capacity from a lithium you would be well below the 50%, of a lead acid too

In fact you are more likely to damage a lead acid battery on a lead acid device than you would damage a lithium on a lead acid device , the irony

Lead acid resellers will always use scare tactics yo keep you on lead acid

While with our use case load shedding ,using lead acid is the silly option and anyone promoting it il,may be the one eyed leading the blind
Unfortunately, we have practical experience of our assertions across hundreds of different customer use cases.

As such we aren't changing our recommendations to our customers, and neither getting into hypothetical debates.

Our customers are free to follow online forum expert advice, to their hearts content.
 
Unfortunately, we have practical experience of our assertions across hundreds of different customer use cases.

As such we aren't changing our recommendations to our customers, and neither getting into hypothetical debates.

Our customers are free to follow online forum expert advice, to their hearts content.
That is an awesome shield if you make bullshit assertions
 
What is a bms ?
It seems many don't know

Boiled down to basics a bms prevents a battery from overcharge over discharge by preventing
voltage range that would be detrimental to cells or
amps pulled outside of specified range

With normal operation it is almost impossible to damage a lithium's cells, as long as the bms doesn't pop

Many don't know that what you read on a batteries terminals (voltage) does not always equate to what the cells experience

Yes you get crappy bms's that abuse cells

But that is just it if you have a bad experience with lithium it most likely comes down to the quality of components or the quality if the workmanship during assembly

ie if the manufacturer did not care to properly match cells you will experience odd voltages at the bottom and if they did not care to properly balance odd voltages at the top causing sub par capacity, though the odd top voltages are hidden and many are non the wiser that it even occurs

Anybody that believes a lead acid charger can damage a lithium battery has no clue how a bms works

Suppliers/retailers love scape goats
 
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What is a bms ?
It seems many don't know

Boiled down to basics a bms prevents a battery from overcharge over discharge amps and prevents voltage range that would be detrimental yo cells

With normal operation it is almost impossible to damage a lithium's cells, as long as the bms doesn't pop

Many don't know that what you read on a batteries terminals (voltage) does not always equate to what the cells experience

Yes you get crappy bms's that abuse cells

But that is just it if you have a bad experience with lithium it most likely comes down to the quality of components or the quality if the workmanship during assembly

ie if the manufacturer did not care to properly match cells you will experience odd voltages at the bottom and if they did not care to properly balance odd voltages at the top causing sub par capacity, though the odd top voltages are hidden and many are non the wiser that it even occurs

Anybody that believes a lead acid charger can damage a lithium battery has no clue how a bms works

Suppliers/retailers love scape goats
You sound like a pretty confident guy. Any backup people or folks that can vouch for what you say here?
 
You sound like a pretty confident guy. Any backup people or folks that can vouch for what you say here?
I built my own diy battery three years ago and have expanded said battery twice ie i started with a 12v config then changed it to 24v and later 48v

naturally i don't want to have anybody trust me blindly

And naturally we don't know what we don't know, so i don't assume to know everything about the topic

Don't trust me implicitly, but do the same for the "specialists"


Here is a picture with voltage measured on terminals via charger (buck converter) of a diy lifepo4 battery and voltage on the cells on the multimeter
 

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You sound like a pretty confident guy. Any backup people or folks that can vouch for what you say here?
The advice he gives is valid, it's just a much wider scope than this thread which is about el-cheapo ups's like this:
1699043313035.png
Take a 500W UPS which has a dead 12V battery. 500W divide 12.8V = 40A

Trying to find a little 9Ah LFP battery that can do 40A is a challenge. Also, running them flat can brick it as the BMS shuts down, and the only way to wake it up again is to jump it with another 12V battery. That's how I understand it.
 
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The advice he gives is valid, it's just a much wider scope than this thread which is about el-cheapo ups's like this:
View attachment 1612707
Take a 600W UPS which has a dead 12V battery. 500W divide 12.8V = 40A

Trying to find a little 9Ah LFP battery that can do 40A is a challenge. Also, running them flat can brick it as the BMS shuts down, and the only way to wake it up again is to jump it with another 12V battery. That's how I understand it.
I ran a 100ah lithium on a small ups like that three years ago (well june was 3years ago)

It popped the reason is lithium related

ie it could run for way longer than its design intended

I installed a fan with a switch
That i would switch on during load shedding to help with the heat

The one day i forgot to switch on the fan it overheated and popped

It naturally took forever to charge the battery full (but back then we had one shedding a day so did not care and if i deemed it necessary i just popped the car charger on it too ie 3 chargers charging car charger plus two ups's :)

So i just connected another ups in parralel on the same battery and left it off it still charges when off

So two ups's was charging

And one was used to power tv+media pc

When it popped i discovered the others do a auto shutdown after 15 min so it would only run 15min at a time so i just chucked them started using the 24v mecer 1440w, already had it just had not bought the extra cells yet, so ordered them then
 
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I built my own diy battery three years ago and have expanded said battery twice ie i started with a 12v config then changed it to 24v and later 48v

naturally i don't want to have anybody trust me blindly

And naturally we don't know what we don't know, so i don't assume to know everything about the topic

Don't trust me implicitly, but do the same for the "specialists"


Here is a picture with voltage measured on terminals via charger (buck converter) of a diy lifepo4 battery and voltage on the cells on the multimeter

Your recommendations are contrary to that of most battery manufacturers, apart from voltages and discharge curves there is desulfation and float charges, along with turning on/off equalization modes of chargers- all of which you suggest is BS. All on the back of building a single DIY battery from youtube tutorials?

Fortunately you may have no financial obligations or liability for the recommendations you make on forums - however we do when we sell batteries to consumers, and our observations are based on real life application in a couple of hundred use cases.

As previously stated - in 60% of cases there are no issues deploying these batteries, but in certain instances there are. And a small minority of consumers have the know-how to identify the specific scenarios or employ technical adjustments.

While most lead acid battery chargers will charge a LifePO4 battery there is enough risk of error, including incorrect charge rate to warrant discouraging such application for the majority of consumers.
 
I ran a 100ah lithium on a small ups like that three years ago

It popped the reason is lithium related

ie it could run for way longer than design intended

I installed a fan with a switch
That i would switch on during load shedding to help with the heat

The ine day i forgot to switch on the fan it overheated and popped

It naturally took forever to charge the battery full

So i just connected another ups in parralel on the same battery and left it off it still charges when off

So two ups's was charging

And one was used to power tv+media pc

When it popped i discovered the others do a auto shutdown after 15 min so it would only run 15min at a time so i just chucked them started using the 24v mecer 1440w, already had it just had not bought the extra cells yet, so ordered them then
I think people are trying to avoid the big battery on the side and just replacing the dead acid internal ones with LFPs.
 
Your recommendations are contrary to that of most battery manufacturers, apart from voltages and discharge curves there is desulfation and float charges, along with turning on/off equalization modes of chargers- all of which you suggest is BS. All on the back of building a single DIY battery from youtube tutorials?

Fortunately you may have no financial obligations or liability for the recommendations you make on forums - however we do when we sell batteries to consumers, and our observations are based on real life application in a couple of hundred use cases.

As previously stated - in 60% of cases there are no issues deploying these batteries, but in certain instances there are. And a small minority of consumers have the know-how to identify the specific scenarios or employ technical adjustments.

While most lead acid battery chargers will charge a LifePO4 battery there is enough risk of error, including incorrect charge rate to warrant discouraging such application for the majority of consumers.
A lithium can charge at upto 1c

Which lead acid charger can charge a lithium in an hour?
Lead acid charger are designed to do like 0.2c to not boil batteries

And desulfation cycles won't lift the cell voltage the lithium would just soak up that charge


And if you can find a cheap device that can push more amps than the bms allows

It disconnects the cells so worst case it just doesn't 't charge

If you had crappy lithium with crappy bms sure you might have problems but like i said , before it makes better sense to do one device change than a battery change every 18mnths, any seller keeping people in the lead acid cycle should be avoided
 
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