Swapping UPS battery for larger capacity?

[stefanm]

I've seen it on youtube and tutorials also, anyone had experience doing this? I'm talking like quadruple capacity give or take a few AH's, massive batteries may not charge fully (that's my understanding)

 

[bornlibra23]

The bigger problem is the charging current draw of the bigger battery. Assuming that you check for all other variables, native current draw of the larger battery will be larger. You will have to check your charging circuit tolerance for this.

 

[stefanm]

The bigger problem is the charging current draw of the bigger battery. Assuming that you check for all other variables, native current draw of the larger battery will be larger. You will have to check your charging circuit tolerance for this.

As far as I understand charging, the current (Amps) and voltage (charging is done at higher voltage on lead acid, than the batteries output voltage) is decided by the charging circuit and not determined by the battery.

 

[vishal_k]

Do not try this. It will definitely damage the charging circuit of the ups. Inverters are specially designed to charge such high capacity batteries.

 

[stefanm]

Do not try this. It will definitely damage the charging circuit of the ups. Inverters are specially designed to charge such high capacity batteries.

No. nothing would get damaged, worst case scenario is the battery or batteries won't get enough amps or volts to charge. A real world example, I left my interior lights on in my Renault Duster for a couple of days, battery completely dead (9v on my multimeter) a neighbour tried to jump start with his 800 wouldn't get over 11v at the terminals, had to push start it and drive around for an hour, nothing damaged.

I have a small 600VA UPS which I use for my monitor, it's a cheap little unit with a 7ah battery, I will rig it up and test the voltage and amps whilst charging. That will determine if it can charge a larger battery or not.

 

[rsaeon]

Batteries cannot 'pull' more amperage/current than what is available from a charger. Electricity simply does not work that way.

Your phone is a perfect example of this: it'll charge quickly with a 15w charger and charge slower with a 5w charger. It won't burn out the 5w charger by 'pulling' more current, it'll just charge at a slower rate.

If you attach a larger capacity battery than what an UPS is designed for, it will simply take a longer time to charge.

So yes, it's possible they may not charge fully by the time they're needed again (the next power cut) but you'll almost definitely get longer run time.

However there are two things to keep in mind:

1— Smaller UPS's are not designed for prolonged use, they will almost definitely overheat and may burn out. You can consider adding a cooling fan inside the UPS which may help a little. If the UPS already has a fan, then it should be safe to swap in a larger battery.

2 — For safety, an inline fuse is required between the battery and the UPS, do not ignore or skip this step. This fuse is protection from any fault developing inside the UPS (short circuit, water spill) and is necessary because larger batteries have enormous stored energy that can literally melt metal if there's a short circuit.

 

[stefanm]

Batteries cannot 'pull' more amperage/current than what is available from a charger. Electricity simply does not work that way.

Your phone is a perfect example of this: it'll charge quickly with a 15w charger and charge slower with a 5w charger. It won't burn out the 5w charger by 'pulling' more current, it'll just charge at a slower rate.

If you attach a larger capacity battery than what an UPS is designed for, it will simply take a longer time to charge.

So yes, it's possible they may not charge fully by the time they're needed again (the next power cut) but you'll almost definitely get longer run time.

However there are two things to keep in mind:

1— Smaller UPS's are not designed for prolonged use, they will almost definitely overheat and may burn out. You can consider adding a cooling fan inside the UPS which may help a little. If the UPS already has a fan, then it should be safe to swap in a larger battery.

2 — For safety, an inline fuse is required between the battery and the UPS, do not ignore or skip this step. This fuse is protection from any fault developing inside the UPS (short circuit, water spill) and is necessary because larger batteries have enormous stored energy that can literally melt metal if there's a short circuit.

Absolutly correct! One could also swap a larger transformer in and even a separate rectifier board, fan is definitely required for longer charging.

 

[nRiTeCh]

Not at all recommended.
One can install larger capacity batteries in cars and inverters but for ups one shouldn't.
When I had APC I did spoke with the service guy he said larger up to 9v can be carefully accommodated either as external battery pack or internal but during that time even the officially rated 7.5v wasnt available anywhere and had to do with some 7.2v.
So as per his suggestions up to certain level yes and logically higher capacities shouldn't cause any issues but again batteries might take a longer time to charge and circuitry thing comes into place if its actually designed for charging higher capacities and tolerance thing. (not an electric expert though)

 

[gokul.ece22]

Transformer in the UPS board will burn up due to excessive heat.
Increasing the battery capacity will increase the charging time, which in turn puts more load to the transformer.

Normally desktop UPS comes with 12volt 7AH battery.
You can use 12volt 12AH battery as the upgrade. going beyond 12ah will definitely kill the transformer and circuit and result in fire hazard.

Also installing a proper cooling fan for the circuit is must, if you are swapping a larger battery.

 

[lockhrt999]

I've seen it on youtube and tutorials also, anyone had experience doing this? I'm talking like quadruple capacity give or take a few AH's, massive batteries may not charge fully (that's my understanding)

It can be done only if your computer UPS has active cooling. Cheap UPSs don't have active cooling and hence they can't support backup longer than, say, 30 minutes.

Other than that, bigger batteries going to take very long time to charge fully.

Other than other than that, You won't be able to turn on computer with fully depleted batteries because fully depleted batteries going to suck all the DC ups has available inside, leaving nothing to run the computer.

One more thing, good quality UPSs who have active cooling usually have 24v DC circuitry and they use 2x 12v batteries. And tabular or flooded batteries mostly come in 12v. So you are going to need 2 of those.

P.S. Do this only if you already have one such UPS and batteries required on hand.

P.P.S. Don't do this if you don't already own a good quality UPS and big batteries needed. Because it'd a lot cheaper to get a home inverter with required battery. Plus, inverter lets you run cornhub to observe all the corn there is. Because it provides backup to your internet wifi too.

 

[nRiTeCh]

It can be done only if your computer UPS has active cooling. Cheap UPSs don't have active cooling and hence they can't support backup longer than, say, 30 minutes.

Other than that, bigger batteries going to take very long time to charge fully.

Other than other than that, You won't be able to turn on computer with fully depleted batteries because fully depleted batteries going to suck all the DC ups has available inside, leaving nothing to run the computer.

One more thing, good quality UPSs who have active cooling usually have 24v DC circuitry and they use 2x 12v batteries. And tabular or flooded batteries mostly come in 12v. So you are going to need 2 of those.

P.S. Do this only if you already have one such UPS and batteries required on hand.

P.P.S. Don't do this if you don't already own a good quality UPS and big batteries needed. Because it'd a lot cheaper to get a home inverter with required battery. Plus, inverter lets you run cornhub to observe all the corn there is. Because it provides backup to your internet wifi too.

Other than that frequently batteries discharging to 0% will enter into deep sleep mode more often resulting in shorter life spans and premature death!

 

[stefanm]

Other than that frequently batteries discharging to 0% will enter into deep sleep mode more often resulting in shorter life spans and premature death!

Yes you are correct to a degree, batteries fail for the simple reason of sulphication (sp) , this is with lead acid type regardless of deep cycle, such as inverter or marine types.

Now, when we consider the circuit, we would have to increase the va of the transformer and maybe the capacitor bank, as voltage won't change. As for the rectifier diodes they should be in spec anyway, no doubt worth checking the datasheet first.

 

[nRiTeCh]

Yes you are correct to a degree, batteries fail for the simple reason of sulphication (sp) , this is with lead acid type regardless of deep cycle, such as inverter or marine types.

Now, when we consider the circuit, we would have to increase the va of the transformer and maybe the capacitor bank, as voltage won't change. As for the rectifier diodes they should be in spec anyway, no doubt worth checking the datasheet first.

If you fell you got some knowledge on the subject have a keen interest to experiment, you may proceed but cautiously in a controlled environment.

 

[rockyo27]

You can also try lithium ion cells....smaller footprint...obviously costly but more juice and longer lifetime and you will also be needing a separate charger/balancer.
I'm thinking of doing in one of my UPS.

 

[rsaeon]

Because it'd a lot cheaper to get a home inverter with required battery.

This is a far better option. I got my first UPS in 1999 and switched to sine-wave inverters in 2015 and I wish I did it much sooner. They're far more robust and you have a wide range of batteries available. Even a cheap 250va square wave inverter from SuKam with small ish battery (by inverter standards) can power wifi for several days. For short power cuts (1 to 2 hours), you don't even need a new battery. I bought a used 150AH battery from OLX for half price on the original bill (with half the warranty period remaining) and it still provides a decent backup with my APC 850VA home UPS four years later (two years after the warranty expired) when powering wifi and lights. There is maintenance involved, topping up the battery cells with distilled water every now and then.

The downside with using inverters as UPS's is that not all of them switch over quickly enough, but I've found that if you choose a power supply that's about double of what you require (at least 750w) then there's no problem as the high capacity power supplies have larger capacitors which can handle the momentary cut in power as the inverter switches to battery.

 

[stefanm]

If you fell you got some knowledge on the subject have a keen interest to experiment, you may proceed but cautiously in a controlled environment.

I have no issues with experimenting, I'm not concerned about "explosions" either. I would like to expose that industry through (also others) for fooling and ripping off people, but ultimately that's just how commerce works.

 

[Jasku]

Sorry @stefanm for highjacking your thread, but which 600va UPS are you going to experiment with?

Super interested, I am contemplating getting a new UPS/Inverter for my PC (5950x/3080), just need it for 10 mins till the gen kicks in. I have the APC RS 1000 BR-IN, now this is one of the older more robust UPS from APC, the batteries are bust, I would like to replace the batteries, but am not sure since I am unable to take out the existing batteries, they are mostly likely swollen. This does have a external batter pack connection at the back, but I cannot find documentation anywhere if it will support the BR24BPG-IN external battery pack from APC for their pro model.

I am most likely going to go for the BR1500 for a 2 year warranty and should satisfy my need and will upgrade the battery of the existing RS1000 with increases capacity. But if anyone has successfully made the RS1000 work with the external battery pack, would love to hear.

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[blr_p]

I've seen it on youtube and tutorials also, anyone had experience doing this? I'm talking like quadruple capacity give or take a few AH's, massive batteries may not charge fully (that's my understanding)

Can you post these videos here ?

 

[rsaeon]

This is a good example of how it could/should be done:

 

[adder]

Connecting larger batteries will not kill the ups.

I have used a apc sua1000uxi which is equal to a sua1000xli model. It comes with a a 5A charger, the leaflet provided with the ups said one can use a string of 12v+12v 80ah battery with multiple parallel configuration.

You will only take a longer time to charge.

That video above is the method I used, granted all the fuses and wire came with ups.

Even before this in early 2000s, I used a old apc 500va modified sinewave ups with a higher capacity external battery for years.