Solved Can two UPS Devices be hooked together to provide longer backup time?

[Mike Lynch]

If possible, I'd like to provide longer Backup time for a PC when the AC power fails.
I'm hoping there is a way to hook two UPS's together to easily do that.
The cost of two 1350VA/810Watts at+-$100 is affordable.
The units are also manageable in weight and size for me to handle.

 

[MisterEd]

No. However, you could buy something like an APC Back-UPS Pro 1500, 1500VA (model BR1500G) UPS which has the option to plug in an optional BR24BPG Supplemental Battery Pack for even longer runtime.

Unfortunately, you may not want to spend the $400 for this UPS and its optional battery pack.

Saving Back-UPS Pro 1500, 1500VA, 120V, LCD, 10 NEMA outlets (5 surge)
APC Power-Saving Back-UPS Pro 1500, 1500VA, 120V, LCD, 10 NEMA outlets (5 surge) - APC USA

APC UPS 1500VA Battery Backup Surge Protector, BR1500G Backup Battery Power Supply with AVR
https://www.amazon.com/APC-Back-UPS...=pc&sprefix=BR1500G,computers,398&sr=1-1&th=1

APC Back-UPS Pro External Battery Pack (for 1500VA Back-UPS Pro models, formerly Back-UPS RS 1500)
APC Back-UPS Pro External Battery Pack (for 1500VA Back-UPS Pro models, formerly Back-UPS RS 1500) - APC USA

PC External Battery Pack, BR24BPG, Supplemental Battery for UPS Model BR1500G (Sold Separately)
https://www.amazon.com/APC-External-Battery-BR1500G-BR24BPG/dp/B0047E5B90?th=1

 

[file3456]

They call these things "generators." They don't generate anything.


https://www.amazon.com/s?k=battery+...efix=battery+generator,aps,155&ref=nb_sb_noss


So, what you do is when your UPS kicks in you'll have X amount of time in minutes to safely power down, right? So what you do is unplug the UPS from mains power (the main power source like the wall) and plug the UPS into one of those battery "generators." Not exactly ideal, but might be a better solution.

If you know anything about electronics and electricity (doubtful based on your inquiry) you could make this setup work automatically with a relay. BUT! If you know nothing about this stuff, DON'T DO IT! You could also buy a couple LiFEPO4 batteries and do the same thing. They're great batteries for many reasons, but expansive.

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Lithium is waaay better than lead acid...

 

[Megahertz07]

Most UPS has a small battery. Measure the voltage. If it's 12 to 13V you can plug an external car battery and it will last much longer (almost 10 times longer)

 

[Mike Lynch]

I'm a novice at most things.

My original thought was:

Two of the same type UPS Devices with a Power Cable having three pronged plugs on each end of an appropriately sized wire(s). The wire(s) would then have the positive wire and the negative wire(s) reversed, "twisted" within the cable. I keep thinking, like Batteries in a flashlight. Positive to Negative providing the same power. Again, I do not know what I'm talking about so you know what my thought are worth.

 

[Megahertz07]

I'm a novice at most things.

My original thought was:

Two of the same type UPS Devices with a Power Cable having three pronged plugs on each end of an appropriately sized wire(s). The wire(s) would then have the positive wire and the negative wire(s) reversed, "twisted" within the cable. I keep thinking, like Batteries in a flashlight. Positive to Negative providing the same power. Again, I do not know what I'm talking about so you know what my thought are worth.

DON'T do it.
The output of a UPS is AC that are not in phase within each other. You probably will damage both.

A UPS has basically 3 stages:
1) An AC input with a rectifier and a battery charger
2) Battery (that you can enlarge the battery)
3) A inverter to convert 12V CC into 120V AC

 

[Mike Lynch]

How would I hookup a Car Battery?

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Friends,

After considering the responses to my Thread, I'm going to throw in the towel!
I appreciate each and every response but I believe I do not have the understanding to continue.
Thanks again for trying to help me.

Best regards,

Mike Lynch

 

[file3456]

Most UPS has a small battery. Measure the voltage. If it's 12 to 13V you can plug an external car battery and it will last much longer (almost 10 times longer)

I just want to point out here for safety sake and educational use that a car battery is not a good idea for two main reasons.

1) They release toxic fumes. I can't remember the exact chemical. I believe it occurs while in a charging state. And if I can remember, is flammable.

2) A car battery is great for cars and other ignition systems since they provide that needed "high cranking Amp" ability for a few seconds. Long term drain is not so great. The cut off voltage is higher than a Lithium Iron Phosphate battery. (There's a type of rating for that. I can't remember it now).

I have a LeFePO battery and can run my scanner ("police scanner") on it for at least 22 hours straight. This battery is 6Ah. Doing the math of Amp consumption of around ~.250 mA from the scanner (that's with constant audio on high) that's around ~ 24 hours of contentious use from the battery. ( 6/.25 = 24).

These Lithium Iron based batteries are great for low current devices or a home brew UPS. For one, they're cut off voltage is a lot better, and the Lithium Iron versions are not prone to explode and catch fire like the Lithium Phosphate counterparts. These do have phosphate, but it's also iron. LiFePO4. Li = Lithium Fe = Iron Po = Phosphate. Again, they are pricey though. I picked up my Kastar 12V 6 Ah battery on eBay for around ~$40 bucks I think it was. The other great thing is that they have at least a 2,000 charge cycle. I think the other Lithium Phosphate batteries have that as well though. I can charge this battery from "dead" to full in about 1 hour and 37 minutes. I have been doing experiments on this thing and recording the data. LOL You have to use a LiFePo charger though. The one I have is a Fuyuang model FY1504000 which is apparently UL listed which is pretty good considering. You want UL listed electronics for safety reasons. I bought the charger on eBay as well.

Believe me when I tell you lots of stuff can be had on eBay cheaper and with free shipping over Amazon. It's just that shipping time may not be there. I really don't care. So long as I get the thing withen a week. LOL Very long time eBay user. First created my account in 2003. Well, I lost my password to that account and created a new one in 2005. I've seen on rare occasions eBay users since eBay first came about circa 1995! :O

And you should NEVER plug in a car battery into a UPS. The UPS charging circuity is ONLY meant for lead acid batteries and at that for a specific type meant by the manufacturer. Same applies with using a LiFePo battery in a UPS meant for lead acid batteries. You'll probably have a fire in no time if you try to charge a LiFePO battery with a lead acid charging circuit. The lesson here is if you're not a qualified electrician, competent amateur radio operator, or don't know a lot about electrical stuff, don't mess with it. If you do and fail, in the end it could be negligence on your part and when the house goes up in flames say goodby to the insurance payout.

 

[Megahertz07]

F22 Simpilot you are completely wrong.
Most UPS like APC, as car batteries, use lead sealed acid batteries. They may release hydrogen gas if overcharged.
Here are APC - UPS batteries. As you can see they are ALL sealed Lead-Acid with suspended electrolyte leak proof battery.
I have successfully installed a 65Ah, 12V car battery on a 1200VA APC - UPS. It's working for years now on a small office.

A 12V 6Ah is 72Wh. On a 810 Watts UPS it will last less than 5 minutes. 810W coming from a 12V battery drains 67A. Your 12V 6Ah battery will melt or explode in less than a minute.

 

[file3456]

What exactly am I wrong about? You need to define a clear definition and not run sentences top to bottom obscuring the charge of being wrong. It's like having a finger pointed "at you" from a distance except you're one of many in a crowd.


I'm assuming the charge of wrongful opinion is the idea of the use of a car battery in a UPS. Literary had to read your post at least four times to make sure. Though, you're not the only one who's post I've had to read top to bottom several times to ascertain with at least 90% confidence that I know what the issue is and can then post a meaningful response about the issue. Whether my response is of opinion or objectionable.


I would like to bring to the "court's" attention Exhibit A for consideration since I presume this is a judgment on my intellect.

So how can hydrogen sulfide occur? It can be produced by the broken battery or by heat production when overcharging it. In such conditions, hydrogen can be released from the sulphuric acid solution which can form the poisonous hydrogen sulfide gas.

Your Car’s Battery Can Be Deadly | Strange Chemistry

The Press Democrat - Wikipedia

If you use flooded batteries the UPS will continue trickle charging after the batteries are actually at 100%, resulting in 'gassing off' distilled water from the cells.

batteries - Extending the backup runtime of a UPS with an external car battery - Electrical Engineering Stack Exchange

User John - Electrical Engineering Stack Exchange


I stated that you should NOT use a car battery in a UPS. I made no inference to AGM or wet batteries once so ever. In your defense however, you also made no distinction between AGM and a wet battery. Leading me to the erroneous conclusion of wet battery types. Never the less, I felt a duty to inform the OP and others that may come across this topic that they shouldn't use a car battery (wet type) for a UPS. Shouldn't even mess with it at all regardless unless they know what they are doing and/or have done lots of research. ( I did make mention of home owners insurance)...

A 12V 6Ah is 72Wh. On a 810 Watts UPS it will last less than 5 minutes. 810W coming from a 12V battery drains 67A. Your 12V 6Ah battery will melt or explode in less than a minute.

This statement doesn't reflect anything I said at all. I never stated I'd use a 6Ah battery for a 810 watt load. Where have I stated that specifically? That's just a dumb assumption on your part or lack of reading comprehension. I simply stated I use my LiFePO 6Ah battery for a scanner that consumes .250 mAs. Nothing more, nothing less. Blanket erroneous statements like that can cause wars or the collapse of a corporation...