Mines a cyberpower model, I use it only for my monitor as I'm currently using a laptop, need something cheaper than expensive inverter batteries which are 12k plus here.
Swapping UPS battery for larger capacity?
- Thread starter stefanm
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The cheapest option would be buy the same battery that UPS is already using and connect it parallely to the battery in the UPS. It'd more than double the backup.
There's another cheaper option than above cheapest option. If your monitor uses external power brick then you just need to get a DC to DC converter. It shouldn't cost more than Rs. 150 online and it'll give you a few times the default backup and that too without upgrading your battery. Lemmeno if your monitor has external power brick and you want to use this option.
It's mains voltage in only.
My main concern is that I'm going to a desktop from a laptop and here in Goa power cuts are frequent, I need at least 30 mins backup for the pc, I'm already getting that on the monitor. Also it'll be just for the pc, so an inverter battery won't be practical, as a wild guess I'd need around 40ah.
You can get more than 30 minutes of backup from any good quality UPS having dual batteries. I have APC RS 1100 and it gives like 60 minutes of backup. Such UPS cost upwards of 4-6k for sure.
I know the power cuts and voltage fluctuations of Goa. I'd, instead of spending 5-6k on another UPS, would get a cheap inverter+small battery combo off the OLX for almost the same money. You don't have to run whole house off inverter. You can simply connect your current UPS to inverter just like that. And it shouldn't take hella more space than the this battery mod you are thinking.
And I have considered the idea of connecting bigger batteries to my UPS many times before in the past but for some reason it never seemed economical. I'd suggest you try it only if you already have own such battery. But buying brand new battery seems risky economically. You don't know that your UPS will accept big battery.
I know my current APC runs fine with other batteries because I charged batteries from my vehicles during the covid lockdown and this UPS didn't complain. Although I have owned many brands of UPS, I have done this experiment with only one more brand called PowerSafe and it didn't accept non-lead acid battery. It was extremely finicky of the battery voltage. Lead acid batteries have very slightly different voltage than other batteries.
So, if you invest some money to get 40Ah battery, there's no guarantee that UPS will accept that battery.
Then wouldn't it just run on battery all the time? Or is that what they do anyway?
Yes. Your computer is always running off the battery no matter mains is on or off.
Essentially inside UPS,
Step 1: 240v AC -> 12v DC (used for battery charging and for step 2)
step 2: 12v DC -> 240v AC (used to run your computer)
There's no 240v AC -> 240v AC passthrough in UPS.
There's one across the road, but I doubt he'll have as only opened a few months ago and he told me business was slow.
This will cause the battery to have a shorter life. Since the external charger is going to keep cyling it each time, depending on the external charger design and amp rating.
Remember the UPS itself needs to consume some power from the battery to run itself about 1A or so and top on that the battery will need to be in float voltage and current( around 0.3A to 0.4A for a typical 150A battery).
So if you need to run a pc you need a beefy external lead acid battery charger.
If you just put a dumb laptop charger or powersupply like the one in the above videos, you will cook the batteries soon, since the voltage is above float voltage and the float voltage varies from gel/ to flooded to tall tubular batteries.
You maybe right, I'm personally not going to use a laptop charger if I do something like this, I'm thinking more on the lines of an actual battery charger that has an manual mode. The reason why is, apparently by fast charging you can reverse the sulphication that occurs, which is what kills batteries. It's not something that you'll daily, but every few months. I also have my 7 years old 200ah inverter battery, which gives 1.5 hours backup just running a router, modem and a 16 watt pump on my aquarium. I'm going to attempt to rejuvenate it to a degree, I'll post the concept and practice after I've done that, I bought 2 litres of H2S04 to make new electrolyte (very expensive from a lab supplier) as battery electrolyte isn't sold here in Goa (available across the border in MH).
Dinesh6252
Contributor
Have personally done that with an APC 1500VA model. Used A 24v 100AH battery pack with a 20A DALY BMS . The BMS was also modded
for higher discharge current (100A) since it was purchased without calculating the peak discharge current. A seperate Li-ion charger is being used to charge the battery pack to 29.4. Haven't checked full backup though.I am looking for a UPS to power my monitor during the power cuts. Other areas of my house is already covered by an inverter. I am using a ROG strix asus laptop connected to a LG 27 inch 4k Monitor. How much backup time can we expect from your APC RS 1100 UPS a) if I only connect the monitor b) if connect both together?
I haven't tried your use case but if it can power a non-gaming full computer for an hour then I'll say it may power your monitor for 1:45 hr and with laptop maybe for 1:15 hr.
Surprised by lower estimates? Did you expect it to run for several hours on monitor alone? UPS are highly inefficient at 12v DC -> 240v AC conversion. So, even with 0 load, it may last for 2 hours.
And please for the love of god, don't buy my piece of crap APC. Get something else.
blr_p
Oracle
I still have that piece of crap. Bought in 2006. The batteries could be better.
Actually my expectation is only to cover about 1 hour. Usually in our area the power comes back within an hour. Oly on shutdown days, power will be absent from 9 to 5. Any other brand you recommend? I have not used a UPS for almost 10 years now. Before that...surprise....APC UPS 1000Va... but forgot the backup times it used to give
You can buy any UPS and it'll be good for an hour for your monitor.
This german spectacular engineering failure has batteries mounted on their sides. My brand new exide batteries are leaking even though they are called sealed.
Sealed batteries aren't actually sealed, if you pop the cover off you can access the electrolyte.
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