Running a UPS under a car battery...
- Thread starter legtu
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DarkLight
Enlightened
I would use a deep cycle ....
turbodog
Flashaholic
2 things
1) a large battery will take longer to charge so the ups's charging circuit might need extra cooling if it doesn't have a fan in there already
2) a ups is designed (usually) for a gel cell battery. these have very slightly different voltages than a wet cell (car) battery. you could possibly over or under charge the car battery as a result of this.
I'd stay with a gel cell.
1) a large battery will take longer to charge so the ups's charging circuit might need extra cooling if it doesn't have a fan in there already
2) a ups is designed (usually) for a gel cell battery. these have very slightly different voltages than a wet cell (car) battery. you could possibly over or under charge the car battery as a result of this.
I'd stay with a gel cell.
Brock
Flashaholic
3rd thing
Most inverters in UPS's are made to run for a given length of time knowing the battery will die. So running them constantly will generally overheat them unless you have a way to keep them cool or aren't loading them much. Even their internal fan is made to keep them cool for only so long.
But yes it can and is done. Charging a larger battery and keeping it charged is generally the issue when doing it.
I have to say though in a case like this you are often better off using a cheap small inverter or go all out and get a big inverter with a built in 3 stage charger and a larger battery bank.
Most inverters in UPS's are made to run for a given length of time knowing the battery will die. So running them constantly will generally overheat them unless you have a way to keep them cool or aren't loading them much. Even their internal fan is made to keep them cool for only so long.
But yes it can and is done. Charging a larger battery and keeping it charged is generally the issue when doing it.
I have to say though in a case like this you are often better off using a cheap small inverter or go all out and get a big inverter with a built in 3 stage charger and a larger battery bank.
James S
Flashlight Enthusiast
I have one of these under my desk right now. It works fine as long as you take into account what Brock brought up. The heat management is very important especially when dealing with cheaper, or smaller UPS units.
The smaller units are never thought to run more then 5 or 10 minutes and if you look inside, the heat sinks are nothing but a metal block attached to the output transistors. They don't radiate worth a darn and the whole thing is supposed to shut down before the thing overheats. Even in fancier brand name units the smaller ones don't appear from my checking to have any thermal protection at all. So they very likely will catch fire or at least melt down if you run them for too long. Forced air cooling is absolutely vital when pushing the smaller units with a bigger battery.
And a deep cycle is vital as well or your usage time will go down with every cycle and in not very many usages at all it will be useless.
The smaller units are never thought to run more then 5 or 10 minutes and if you look inside, the heat sinks are nothing but a metal block attached to the output transistors. They don't radiate worth a darn and the whole thing is supposed to shut down before the thing overheats. Even in fancier brand name units the smaller ones don't appear from my checking to have any thermal protection at all. So they very likely will catch fire or at least melt down if you run them for too long. Forced air cooling is absolutely vital when pushing the smaller units with a bigger battery.
And a deep cycle is vital as well or your usage time will go down with every cycle and in not very many usages at all it will be useless.
BatteryCharger
Flashlight Enthusiast
Charging and draining a car battery inside your house is a very bad idea. Both processes create hydrogen; hydrogen is explosive; when battery acid explodes inside your home it leaves quite a mess. /ubbthreads/images/graemlins/wink.gif If you want to use a big battery make sure it's sealed. A wheel chair or golf cart battery would be a much, much better idea.
LitFuse
Flashlight Enthusiast
[ QUOTE ]
raggie33 said:
charge it out side
[/ QUOTE ]
The problem is that it's charging constantly whenever it's hooked up to the UPS.
Unless your UPS is specifically designed for extended runtime via an external battery, I think this is a bad idea. Most of the consumer grade UPSs you find for sale these days are not up to the task of continous use. In particular the newer APC units you might find at your local retailer are basically just junk, and are nothing like what they were making 10 years ago. APC recently had a recall for units that were prone to catching on fire during the 5-7 minute runs that the stock battery would provide. I don't think the risk of burning down your house it worth it, and if you want to add a non-standard battery to a UPS, at least get one that's set up for external cells, like the APC Smart-Ups models.
Peter
raggie33 said:
charge it out side
[/ QUOTE ]
The problem is that it's charging constantly whenever it's hooked up to the UPS.
Unless your UPS is specifically designed for extended runtime via an external battery, I think this is a bad idea. Most of the consumer grade UPSs you find for sale these days are not up to the task of continous use. In particular the newer APC units you might find at your local retailer are basically just junk, and are nothing like what they were making 10 years ago. APC recently had a recall for units that were prone to catching on fire during the 5-7 minute runs that the stock battery would provide. I don't think the risk of burning down your house it worth it, and if you want to add a non-standard battery to a UPS, at least get one that's set up for external cells, like the APC Smart-Ups models.
Peter
enLIGHTenment
Enlightened
[ QUOTE ]
legtu said:
Is it plausible? Since UPS' run off SLA's, its charging circuit should be compatible with the car battery and give me xxx mins/hours more runtime as compared to its stock batt.
[/ QUOTE ]
Generally a good way to earn a Darwin award.
Car batteries are the wrong type of battery for this application and consumer-grade UPS inverters aren't up to long-term use. If you want or need serious blackout runtime, get a UPS designed for the application, like APC's Smart UPS 3000NET. This unit will source 400 watts for around 3.5 hours, or 1KW for just under an hour. If you need more runtime (or more power), then you're really in the market for either the kind of battery bank found in off-grid houses (huge & expensive) or a generator.
legtu said:
Is it plausible? Since UPS' run off SLA's, its charging circuit should be compatible with the car battery and give me xxx mins/hours more runtime as compared to its stock batt.
[/ QUOTE ]
Generally a good way to earn a Darwin award.
Car batteries are the wrong type of battery for this application and consumer-grade UPS inverters aren't up to long-term use. If you want or need serious blackout runtime, get a UPS designed for the application, like APC's Smart UPS 3000NET. This unit will source 400 watts for around 3.5 hours, or 1KW for just under an hour. If you need more runtime (or more power), then you're really in the market for either the kind of battery bank found in off-grid houses (huge & expensive) or a generator.
bfg9000
Flashlight Enthusiast
- Joined
- Jan 7, 2005
- Messages
- 1,119
You really can make your own: http://www.dansdata.com/diyups.htm
As for me, I bought lots of those $700 APC SU3000 UPSs for just $12.50 apiece after the dot-com implosion in 2000, and about half of them so far have needed 4 new SLA batteries ~$80/set. Lamps, everything is running off of those and I can even keep watching TV when the power goes out--gotta like that sine wave output. Ironic that I have so many flashlights. The NET versions are simply the rack-mount versions.
As for me, I bought lots of those $700 APC SU3000 UPSs for just $12.50 apiece after the dot-com implosion in 2000, and about half of them so far have needed 4 new SLA batteries ~$80/set. Lamps, everything is running off of those and I can even keep watching TV when the power goes out--gotta like that sine wave output. Ironic that I have so many flashlights. The NET versions are simply the rack-mount versions.
prescottrecorder
Newly Enlightened
I'm using the Minuteman XRT series UPS. I bought a refurbished one since they cost a mint new. It'll power 1500 Watts or so for as long as the batteries last and that's just up to the size of your pocketbook since you can add as many batteries as you want. True sine wave output, huge isolation transformer that cleans up the power during non-blackout periods etc. The only problem I have with it is that it has a fan that runs all the time: low speed normally and high during power outages. But I guess that's why it has a potentially unlimited runtime.
turbodog
Flashaholic
Watch out for the larger units. Most of them are 24v or even 48v input. The apc smart ups 1000 is 12v input, and maybe the 1400 also. Some of the 1400s were 12v and some were 24v.
enLIGHTenment
Enlightened
[ QUOTE ]
bfg9000 said:
You really can make your own: http://www.dansdata.com/diyups.htm
[/ QUOTE ]
Cheaper and easier to get an all-in-one unit rather than messing around with a separate charger and inverter. No need to manually top-up charge the batteries to keep them healthy, and capable of sourcing 800VA indefinitely.
bfg9000 said:
You really can make your own: http://www.dansdata.com/diyups.htm
[/ QUOTE ]
Cheaper and easier to get an all-in-one unit rather than messing around with a separate charger and inverter. No need to manually top-up charge the batteries to keep them healthy, and capable of sourcing 800VA indefinitely.
prescottrecorder
Newly Enlightened
[ QUOTE ]
Turbodog said: Watch out for the larger units. Most of them are 24v or even 48v input. The apc smart ups 1000 is 12v input, and maybe the 1400 also. Some of the 1400s were 12v and some were 24v.
[/ QUOTE ]
He's right, the Minuteman XRT UPS runs off of 48V d.c. You'd have to put some batteries in series but you can still use 12V batteries (in multiples of four). I needed to run a whole studio worth of gear for at least two hours so I needed a big one. Anyone out there with a monster UPS powering the whole house?
Turbodog said: Watch out for the larger units. Most of them are 24v or even 48v input. The apc smart ups 1000 is 12v input, and maybe the 1400 also. Some of the 1400s were 12v and some were 24v.
[/ QUOTE ]
He's right, the Minuteman XRT UPS runs off of 48V d.c. You'd have to put some batteries in series but you can still use 12V batteries (in multiples of four). I needed to run a whole studio worth of gear for at least two hours so I needed a big one. Anyone out there with a monster UPS powering the whole house?
i am running a ncr 2kva pure sine with 5 type 27 deep cycle batts.this was built by exide.
i have a bestpower 3kva 36v we run at hamvention with 6 l16
we beat these up with all sorts of odd loads.
one year we ran the roof a/c in the trailer.
this year we grilled steaks on a foreman grill.
beats the overpriced crap hara arena pushes.
in general the older heavy units with metal cases are good for external battery conversion.
most important is a properly sized fuse to prevent disaster if you get a short.
no fuse plus dead short= big ball o fire.
a typical deep cycle battery can deliver enough to totaly melt down 6ga cables in a few seconds.
and you need very heavy cables to limit drop from resistance.
if you are carefull these extended run ups's are quite safe.
i have a bestpower 3kva 36v we run at hamvention with 6 l16
we beat these up with all sorts of odd loads.
one year we ran the roof a/c in the trailer.
this year we grilled steaks on a foreman grill.
beats the overpriced crap hara arena pushes.
in general the older heavy units with metal cases are good for external battery conversion.
most important is a properly sized fuse to prevent disaster if you get a short.
no fuse plus dead short= big ball o fire.
a typical deep cycle battery can deliver enough to totaly melt down 6ga cables in a few seconds.
and you need very heavy cables to limit drop from resistance.
if you are carefull these extended run ups's are quite safe.
I was shopping for a 24 volt inverter for my wheelchair so I can run it right off the batteries than a 12 volt one to run off of my 24-12 volt converter so I would loose less in conversion and wouldnt be limited to 23 amps on the 12 volt side, but 70 of the wheelchair battery boxes. Anyhoo, I found a few 24 volt inverters that double as a charger. In fact i think home power had an article on how to make your own back up supply using a cart multiple deep cycle batteries and a larger inverter taht doubles as a charger and it automatically flipped between charging and running.
I do agree with the heat thing. I have a small inverter, 30 watts max, no fan and man, it gets too hot to touch after 15 minutes powering my 19 inch tv. I have a 450 watt unit with a fan and man, it works well and cool.
I do agree with the heat thing. I have a small inverter, 30 watts max, no fan and man, it gets too hot to touch after 15 minutes powering my 19 inch tv. I have a 450 watt unit with a fan and man, it works well and cool.
Brock
Flashaholic
[ QUOTE ]
Anyone out there with a monster UPS powering the whole house?
[/ QUOTE ]
Well I have stacked SW2512's. That is Trace (now Xantrex) 2500w each and they are stacked for 120vac/240vac use so I can run 5kw loads. It will start and run our 3 ton AC if it has to, but more importantly it can run the well pump. I have 1000amps at 12v (12kw) worth of batteries and 230w of solar (plan to add more again this summer). I run about 1/3 of our house regularly (fridge, freezer, computers fire alarm) off the inverter setup, but I can run the whole house in a pinch. I also have a 5kw and a 1kw genset to back up the batteries and a line run to the garage to charge the battery bank from a car or my third smaller 550w 12vdc charger if all else fails.
We live at the end of a long dead end road and our power goes out regularly, although not as often since we bought all this /ubbthreads/images/graemlins/wink.gif My dad always jokes that if the power goes out I will know because some light will go on. I have a 12v 10w lights at the bottom and top of each flight of stairs that come on if the grid goes out. I just added a switch to shut them off because last summer the power was out for 2 days and I was sick of them being on all the time /ubbthreads/images/graemlins/smile.gif
Anyone out there with a monster UPS powering the whole house?
[/ QUOTE ]
Well I have stacked SW2512's. That is Trace (now Xantrex) 2500w each and they are stacked for 120vac/240vac use so I can run 5kw loads. It will start and run our 3 ton AC if it has to, but more importantly it can run the well pump. I have 1000amps at 12v (12kw) worth of batteries and 230w of solar (plan to add more again this summer). I run about 1/3 of our house regularly (fridge, freezer, computers fire alarm) off the inverter setup, but I can run the whole house in a pinch. I also have a 5kw and a 1kw genset to back up the batteries and a line run to the garage to charge the battery bank from a car or my third smaller 550w 12vdc charger if all else fails.
We live at the end of a long dead end road and our power goes out regularly, although not as often since we bought all this /ubbthreads/images/graemlins/wink.gif My dad always jokes that if the power goes out I will know because some light will go on. I have a 12v 10w lights at the bottom and top of each flight of stairs that come on if the grid goes out. I just added a switch to shut them off because last summer the power was out for 2 days and I was sick of them being on all the time /ubbthreads/images/graemlins/smile.gif
prescottrecorder
Newly Enlightened
Way cool /ubbthreads/images/graemlins/tongue.gif I almost wish my power were less reliable so I could get neat stuff.
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