Using a regular Car Battery with an APC...???

Whitedog

Diamond Member
Dec 22, 1999
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Mt battery just died on my Smart UPS 1400 Net. After pulling it out, I thought of something. I wonder if I could rig it up using a big Car battery instead of buying a new battery made for the unit? I don't even know if I can even get a bettery for it or not. It's kind of old.

Has anyone ever done anything like this before? I'm just curious if it makes a difference what kind of battery you use... as long as it's 12 volts.

?:confused:
 
 

ai42

Diamond Member
Jun 5, 2001
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Yes I saw some short article like a year ago. Some guy ripped apart his UPS and found like 2x 12v batteries (in series). So he swapped them for 2 car batteries. He got insane battery life, like he ran his whole computer for something like 9 hours with the power meter only falling to 1/2 level.
 

McCarthy

Platinum Member
Oct 9, 1999
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I'd be interested in the success stories like above, especially a year or so afterwards. But that said...here's the opposing view.

From here

Warning and caution: Some units will generate lethal amounts of AC power whenever the input power cord is unplugged-after all, this is their primary function. There may be a certain sequence of events you must follow to shut the unit off and turn it back on when working on or near the battery, or with the unit open. Also, be careful to neutralize any leaking battery electrolyte if necessary.

Having said that, you need to be careful, the diode and fuse are a good safety measure, but everything depends on the voltage that the UPS expects to be supplied by the battery. Not all of them work at a nominal 12 VDC. I've got an old SOLA unit that uses a 72-V battery to generate about 750 W of sinusoidal AC power; it weighs more than 75 lbs and is larger than a small microwave oven. One of my other units, a Best Fortress 600, has a LED display on the front that tells me, among other things, the battery voltage, and it reports a nominal 26 VDC when the unit is operating.

Depending on the make and model, some UPS units can sense their own internal temperature, and when that gets too high, they shut down. So even if you provide additional run time with external batteries, if the load is high enough, the UPS may not stay running long enough to make use of it. The better units have microprocessors inside that check operating parameters and rate of discharge, and they can decide when they've provided enough battery operation regardless of how much battery capacity you may have. Companies such as American Power Conversion, and probably all the other major UPS manufacturers, make units that utilize external power packs to extend their run time, but they are designed for this application.

If the required voltage is compatible with the external battery you want to use, the UPS may provide enough charging current to charge the external battery itself; it just may take longer to fully recover after a power failure. How dead is the internal battery? Is it just low on charge? Are any cells shorted or open? I presume the unit is not under any sort of warranty. Plug it in, turn it on, and let it charge without an external load for 24 hours, then measure the battery voltage and see if it has reached the proper level. If it has, you can probably connect your (fully charged and equal in voltage) external battery directly in parallel with the internal one. If not, remove the internal battery and try connecting the wires to the external one. Many use some sort of push-on spade lug connector.

Most car batteries are lead-acid and can emit hydrogen gas while being charged. This is usually not a problem in an automobile since it tends to sit outside most of its life instead of under your computer desk. UPS batteries are usually sealed and of the gel-cell type, in which the electrolyte is not easily spilled. They still have vents on top, but these are for emergency use only. They also are rated to operate near 120 VAC circuitry, which isn't usually present in the average car.

Another thing you should consider is the age of the unit. If the battery is dead, it's either been left off and uncharged for a long time, or it's past its useful life of five years. Go out and check on some new units of similar or higher capacity. You might find it's easier and cheaper to throw the old unit out and buy a newer, better one for less money than you might spend buying a battery and a charger, and connecting everything together. The modern units have hot-swappable, user-replaceable batteries, and some companies will even give you the option of returning the dead battery for proper disposal. APC even has a trade-up program that means it will accept your old UPS as a trade-in towards one of the new units. One thing's for sure, a new unit will definitely be lighter than any car battery!

There are some items to consider when purchasing or even using an UPS. Think about maximum capacity in watts and volt-amperes (VA); total run-time at full load; output waveform: square wave, sine wave or modified sine wave; switching time (AC to battery); recharge time; upgrade opportunity and replacement; control signals from the UPS to the computer system (this can be either a relay closure or full ASCII messaging).
 

Whitedog

Diamond Member
Dec 22, 1999
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The main part that caught my attention was this;
Most car batteries are lead-acid and can emit hydrogen gas while being charged.
I would have to rig it up in my garage or something and run a special circuit to my den before I would consider doing this. hmmmm...
I'll have to look into this more before considering this.

Interesting though. A couple of "Marine" batteries could produce some significant battery time huh? :D
 

MichaelD

Lifer
Jan 16, 2001
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Originally posted by: Whitedog
The main part that caught my attention was this;
Most car batteries are lead-acid and can emit hydrogen gas while being charged.
I would have to rig it up in my garage or something and run a special circuit to my den before I would consider doing this. hmmmm...
I'll have to look into this more before considering this.

Interesting though. A couple of "Marine" batteries could produce some significant battery time huh? :D

I'm glad to see you realize this. Standard Automotive/Marine batteries are nothing to fool with. The Hinderberg didn't explode all on it's own you know; Hydrogen had a bit to do with it! :Q

OTOH, you could purchase a sealed gel-cell like an Optima yellow-top (deep cycle battery...the red top is a "starting battery.") and that should work being that the sealed gel-cells exude no gasses.

I have looked at how the batteries are for my UPS. It's ridiculous!!! It would only cost a few dollars more to buy a whole new UPS! It's usury, I say!! *stomps foot*
 

Whitedog

Diamond Member
Dec 22, 1999
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Yes, I priced a battery replacement... $169. Yuk!

Where could I go to find these sealed Gel batteries? I'd be interested in this. The thought of rigging my backup power in the garage isn't appealing at this time. ;)
 

wtfiwwm

Member
Apr 23, 2003
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there is a thing that you could try, i have done this with varoius results, most of the time it worked as intended but once the battery exploded! so be warned.

if you have a powersorce of about 12V and max 6A, connect it to your battery backwards( plus to minus and minus to plus) for a sec or so, keep doing this for about 10-20 times and then se if you can sharge your battery.

i have had about 80-90% success with this metod
 

sharkeeper

Lifer
Jan 13, 2001
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Definitely not recommended!

First of all, wet acid batteries MUST be vented! H gas WILL explode if allowed to build up in confinement around electrical devices.

Next, car batteries have thin plates and are not designed for deep discharge. This will destroy the batteries after a few cycles.

Finally, the inverters in the cheap UPS' mentioned are designed for intermittent use ONLY! Extending the run times (or attempting to do so) by using a much higher capacity battery is an invitation to destroy the inverter transistors! You have been warned!

-DAK-
 

Whitedog

Diamond Member
Dec 22, 1999
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Finally, the inverters in the cheap UPS' mentioned are designed for intermittent use ONLY!
Is a Smart UPS 1400 Net considered a "cheap" UPS? Serious question.
Also, I'm not interested in running the system on battery power for any exteneded time.
 

Whitedog

Diamond Member
Dec 22, 1999
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Those Optima Batteries don't appear to be sealed Gel batteries, but they do appear to be "non-venting" (under normal circumstances). Do you think these batteries would safe to use indoors hooked up to an APC UPS? They look to be Good batteries.
 

Jeff7181

Lifer
Aug 21, 2002
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Little lesson on car batteries...

Lead-Acid batteries produce hydrogen (not may produce, they DO produce) while being discharged, and while charging. The amount of hydrogen produced COULD possibly be enough to cause problems in an enclosed space.

The optima batteries mentioned are non-venting under normal circumstances, however, they can, and will produce and vent hydrogen if they're deep cycled (discharged completely and charged back up again)

Deep cycling batteries will dramatically shorten their life... unless you get deep cycle batteries, such as the ones meant for marine and offroad use.

Is it possible to use them to power a UPS for computers? Probably... is it recommended? I wouldn't recommend it. Is it a cheaper solution than getting a UPS with the correct capacity for your needs? AT $125 a piece for the cheap ones... I doubt it.
 

NTB

Diamond Member
Mar 26, 2001
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Originally posted by: shuttleteam
Definitely not recommended!

First of all, wet acid batteries MUST be vented! H gas WILL explode if allowed to build up in confinement around electrical devices.

Next, car batteries have thin plates and are not designed for deep discharge. This will destroy the batteries after a few cycles.

Finally, the inverters in the cheap UPS' mentioned are designed for intermittent use ONLY! Extending the run times (or attempting to do so) by using a much higher capacity battery is an invitation to destroy the inverter transistors! You have been warned!

-DAK-

Your last point kills this idea I think, but wouldn't a deep cycle marine battery cure the second problem? You'd still have to keep it vented, of course...it's still a wet acid battery.

Nate
 

sharkeeper

Lifer
Jan 13, 2001
10,886
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Is a Smart UPS 1400 Net considered a "cheap" UPS? Serious question.
Also, I'm not interested in running the system on battery power for any exteneded time.

Yes it's considered an inexpensive UPS. UPS' that have extended runtime capabilities including but not limited to UBS systems typically cost tens to hundreds of thousands of dollars.

If long runtime is your goal, purchase a desktop UPS with enough runtime so that you can plug the UPS into a gasoline generator! It's far cheaper and safer. (providing the generator is outdoors!)

-DAK-
 

ScrapSilicon

Lifer
Apr 14, 2001
13,625
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Originally posted by: Whitedog
Those Optima Batteries don't appear to be sealed Gel batteries, but they do appear to be "non-venting" (under normal circumstances). Do you think these batteries would safe to use indoors hooked up to an APC UPS? They look to be Good batteries.

they are good..but most newly-built homes..are too tight to have gases of any sort being vented in them..you would want to do the remote install(outbuilding or a fire/shock-resistant locker that has dedicated venting to outside)Gel Cell
A technique for sealed lead-acid batteries. The electrolyte solution is in a gel form, usually silica gel, instead of plain liquid.Notice the chemical makeup...hydrogen can be vented.
and that should work being that the sealed gel-cells exude no gasses.
you did not read McCarthy's post..
UPS batteries are usually sealed and of the gel-cell type, in which the electrolyte is not easily spilled. They still have vents on top, but these are for emergency use only.
..I've replaced UPS batteries..they do have vents..they would not be there unless needed..even small like they are...
Originally posted by: shuttleteam
Is a Smart UPS 1400 Net considered a "cheap" UPS? Serious question.
Also, I'm not interested in running the system on battery power for any exteneded time.

Yes it's considered an inexpensive UPS. UPS' that have extended runtime capabilities including but not limited to UBS systems typically cost tens to hundreds of thousands of dollars.

If long runtime is your goal, purchase a desktop UPS with enough runtime so that you can plug the UPS into a gasoline generator! It's far cheaper and safer. (providing the generator is outdoors!)

-DAK-

very good ideaI linked the Optima line due to...OPTIMA Yellow Top and Blue Top products are the battery of choice for deep-cycle power needs. Compared to conventional batteries, voltage output is more uniform across the discharge curve, more deep cycles are tolerated, and they can be mounted in any position with zero corrosion and zero leaks. They recharge faster than conventional batteries, and typically deliver 1.5 - 2x the service life.Common Deep Cycle Applications:
Performance audio
Trolling motors
Portable lighting
Winches Inverter power
Security system backup
Sump pump backup
RV/Camping power
..did know a fellow who had a forklift battery pack assy for...nm
rolleye.gif
 

Whitedog

Diamond Member
Dec 22, 1999
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The optima batteries mentioned are non-venting under normal circumstances, however, they can, and will produce and vent hydrogen if they're deep cycled (discharged completely and charged back up again)
I think it should be considered that a battery such as one of those would not likely be discharged under circumstances we're discussing.

The one fellow posted someone ran their make-shift setup for 9 hours and only drained half the capacity. I'm only talking about 15 or so minutes of drain time, in which case would NOT drain hardly any juice from the cells.
In a case like this, I would "think" it would be Highly unlikely the battery would do any "venting" due to recharging.

Thoughts on that?

Plus, as I mentioned before, I'm considering setting the system up out in the garage, so I would feel it as being safe there as well.

I DO like the idea of the generator too.
I could rig it up to automatically startup and switch power over to it whenever power went out. That would be Cool. :) Though that would be an extremely expensive setup! :(
 

Whitedog

Diamond Member
Dec 22, 1999
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Uhmmm... Big question here. The batteries in my UPS seem to be 2-12VDC batteries running in Series. If I choose to use some type of Car Batteries or something am I going to have to run a PAIR of them in Series to get 24Volts??????

:frown:
 

McCarthy

Platinum Member
Oct 9, 1999
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Just remember even in the garage to make sure it's in a ventilated area. Not a closet, or in an enclosure so the wife doesn't yell at you for 'that ugly contraption'.

Unlike most of our mods, tweaks and other morally questionable abuse of electronics around here this one can cause a nasty explosion. Not to mention the fumes aren't so hot for your lungs.

However, I do have some questions about the reasons cited for wet cells not being appropriate for this application aside from the safety issue. I'll use my own power company as an example. Only one in the past five years has the power been off for more than four hours, only two other instances I know of where it was off for more than an hour. It's quite reliable. But during storms and high winds there are common quick outages lasting from a single second to a minute. These would be my application.

Normal UPS battery is up to this task of course, except some of my UPS units are getting old and I'm at that "pay as much for a battery" or "buy a new unit" crossroad. Using a $10 garden tractor battery is a very attractive alternative as ventilation is not a problem in my situation.

So given an application like this, where it wouldn't be draining the battery more than a few percent at a time, would it's life still be vastly shortened?

As for unit run time destroying the inverter transistors, that doesn't seem to be a large risk in my application either - units are rated for 10-20 minutes with original batteries, well above the outage 99% of the time. Though if I did this I would run them for a full cycle as a test to make sure the units either shut down or didn't overheat to the point of fire hazard. Damage to the UPS itself isn't the concern for me, back to overall household safety.

That's the perspective I ask all of you to approach this from. Even though I'm tempted myself and curious on the effectiveness even once safety is achieved, I can't emphasize it enough in this instance.
 

AgaBoogaBoo

Lifer
Feb 16, 2003
26,108
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Originally posted by: Whitedog
Uhmmm... Big question here. The batteries in my UPS seem to be 2-12VDC batteries running in Series. If I choose to use some type of Car Batteries or something am I going to have to run a PAIR of them in Series to get 24Volts??????

:frown:

*Aga runs and takes the batteries out of his parents' cars without telling them* ;)
 

Whitedog

Diamond Member
Dec 22, 1999
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OK, I'm making way too many posts in this tread... I should have had this all straightened out by now...

The question still stands. Is the DC input voltage 24 Volts on these things? I can't find any papers on APC.com that has any of these details. I don't know if these batteries are 6Volts each to "make 12 volts" or if they are 12 volts each and are putting out 24 volts. There kinda glued together with a sticker on one that says 12 volts... I suppose it means 12 volts each battery. I guess I deserve it for not having a meter huh. :eek:

I'll just have to take this as my answer...
Some guy ripped apart his UPS and found like 2x 12v batteries (in series). So he swapped them for 2 car batteries
Which means I'll have to go any buy "another" battery tomorrow. LOL.

Yes, I picked up one of those red top Optima's. That is a damn nice battery. :D