a question of Battery Backup or UPS

[thegayhare]

hello all.

I'll admit I'm rather ignorant of both types of system
but I'm hopping to use one of them for a rather unusual use and I wanted to know if anyone had any suggestions as to which would be better suited for my  purpose.

My time at ac in what was a rather light death of rats costume brought home the need for a cooling system in a suit.  Since my next suit is a cyborg I felt I could get away with something fairly bulky.  I was thinking of maybe a shop blower fan something fairly powerful. 

To run this I was thinking of maybe using either a UPS or battery back up.  I know they are used mianly for computers but I didn't know which would be better for my purposes

Which would you folks suggest? 
Which would have the longest battery life with atleast one fan hooked into them.

[Reese Tora]

Most setups I've seen people post about online use a simple battery pack, usually rechargable batteries, and it's wired to a case fan from a PC(or whatever they have that lights up or requires power). A single 9 volt battery can power a single case fan for a pretty long time, though I forget how long in general(I think 4 or 5 hours, I could be wrong).

Honestly, I'm not entierly sure what you're asking about when you say shop blower and UPS vs. Battery backup.

[llearch n'n'daCorna]

A whole UPS is going to be set up for 110V AC output, whereas a battery is going to be set up for DC output.

Your average UPS is fairly hefty, though - even a small one, like the one I have lying about here (450VA) is heavy enough that I wouldn't want to carry it around on my back all day. The one I'm actually using (1500VA) is about twice as heavy as a standard PC...


Also a shop blower is going to make a _lot_ of noise. And then there's the safety issue - if you get hit by the broken wiring from a 9/12V battery, you can pretty much ignore it. 110V AC is a much much more dangerous issue.

Remember, you're not trying to cool a large area - just enough to make the inside of the suit bearable. And then there's the "covering the outside of the fan" thing, where you have to stop mad buggers from wandering around and pokign their fingers into it and getting hurt. Generally speaking, you're better off with a 120cm fan, since a slower speed will shift more air volume...


I'd suggest a battery pack, myself, for all these reasons, and a nice big PC fan, since then if someone pokes their finger through the grill and into the fan, it's going to hurt, but not remove a finger - the shop blower is likely to remove a finger...

[Tapewolf]

Llearch has pretty much written off a UPS, but in any case you may have problems running a synchronous motor off a UPS inverter since they generally output something more akin to a squarewave than the sinusoidal waveform that an AC motor is expecting.
Either way, your best bet is a small DC fan of the kind used in PCs.  This, as I understand it, is a widely-used technique for cooling the suits.

**EDIT**
Should make sense now.  Damn interrupted posting.

[RobbieThe1st]

As Llearch said, your going to be best off with a normal computer 120mm fan. I suggest spending a dollar or two on a metal fan grill for each side - You can pick them up wherever you get the fan. This will prevent people sticking their fingers into it, and makes it much safer - At least with the one I have, it is impossible for me to stick even my little finger into it enough to touch the fan.

Power wise, either a 9V battery, or a set of 8 AA, C, or D cell batteries will power it.
With the 9V battery, it is going to be very very light, but I doubt it will last very long, especially powering a 120MM fan. For reference, I have a 120MM computer fan I use for personal cooling, and it is rated 12V at 0.6A. Now, I haven't tested the how much less power it takes at lower voltage, and therefor lower speeds, but still, I would estimate that a 9v battery wouldn't last for more than an hour or two - Well, it may keep the fan spinning beyond that, but it will just get slower and slower.

Another suggestion, and I would do this, is to use a set of 8 AA, C or D cells. Note that these will run your fan faster, and longer, but they do weigh a bit more. D cells are going to last the longest, but they weigh more.

If you do decide to go this option, it is actually just as simple as using a 9v, but with one extra step. All you need to do is get two of These. You simply stick the batteries in them, twist the black lead of battery holder #1 and the red lead of battery holder #2 together, and take the two remaining leads and hook them up to your fan the same way you would the two leads of a 9V connector. (I suggest also sticking a piece of tape over the twisted leads to prevent them touching any conductive surfaces)

If you wanted a smaller pack, like the AA or C, you do the same thing, only get two 4-battery AA or C holders instead of the D ones.


Another thing you could do if you wanted with this is to have multiple speeds - with the two 4-battery holders, you have full-speed or half-speed, depending on if you hook them up in series(as I explained above) or in parallel(or if you hook up only one).
You could also hook four two-battery holders together instead, and then have quarter-speed, half-speed, three-quarter-speed and full-speed.

Obviously, you could make this as complex as you want, or as simple as you want, depending on your level of knowledge and comfort.


Hm... Perhaps I rambled on a bit.. Sorry.


-RobbieThe1st

[thegayhare]

you folks don't seem to get the Idea I'm going for here.

the small Pc fans are mainly something you'd have in the head of a suit and I'm planning something like that already.  But what I was thinking with the blower fan (similer to those used in inflatable lawn decorations or advertisements) was to have something I could use to vent air to the rest of my body through a series of hoses.  I was even thinking that since for the cyborg look these hoses could be external I could operate as a walking suit cooler by detaching my own hose and running it down another suits muzzle to give them a quick burst of fresh air.

I can't think of any way to uses a normal fan like that.

how ever I have come up with a new Idea.
that should be quieter and less expensive then the blower fan.
Battery powered air mattress pumps,  2 or 3 should provide me with enough airflow to stay cool.  the only problem I can think of is again power.  The best model I've dound runs on 4 d cell batteries and I'm not sure how long this thing could run on that single charge.

[VSMIT]

That would be a good idea.  The problem I can see with the UPS idea is that it beeps when it's not connected to a wall outlet (unless there's a switch you can flip to turn that off).  Or it'll beep when you turn the series of fans on.  And most are heavy as hell, what with the batteries being about 5 pounds, and a normal UPS will have 2 or three of them.  While the batteries will definitely last longer, I would recommend going with the regular batteries.  Less of a hastle, unless you plan on standing next to a wall the whole Con.

[RobbieThe1st]

you folks don't seem to get the Idea I'm going for here.

the small Pc fans are mainly something you'd have in the head of a suit and I'm planning something like that already.  But what I was thinking with the blower fan (similer to those used in inflatable lawn decorations or advertisements) was to have something I could use to vent air to the rest of my body through a series of hoses.  I was even thinking that since for the cyborg look these hoses could be external I could operate as a walking suit cooler by detaching my own hose and running it down another suits muzzle to give them a quick burst of fresh air.

I can't think of any way to uses a normal fan like that.

how ever I have come up with a new Idea.
that should be quieter and less expensive then the blower fan.
Battery powered air mattress pumps,  2 or 3 should provide me with enough airflow to stay cool.  the only problem I can think of is again power.  The best model I've dound runs on 4 d cell batteries and I'm not sure how long this thing could run on that single charge.

Well, sorry.

I was thinking smaller-scale - Although, have you actually seen a 120MM fan on full-speed? You can definately feel it several feet away. If you need more than that, you could always put say... 4 of them in a square, instead of a larger fan - I know that you could get quite a lot of air with four of them on full-speed.

Air mattress pumps are just that - Pumps. This means that they will produce higher pressure, but, if these are anything like the ones I have seen, don't put out much volume, heat up pretty quickly, and aren't going to have much of a battery life.

Now, you may be talking about something different, and it may be basically a high-speed fan, but still, that is going to cost a lot more, and will definitely be heavier.

I suggest you get ahold of a 120MM fan, hook it to 12V(not 9V, its going to be much faster from 12V), and see if it will work.

The blower fans that I have seen, have a largish, 120V AC motor, which, while it will provide more pressure and volume, is going to be much heavier, and you are going to have to carry enough batteries and a inverter to power it.

If you *need* 120V for your device, and it doesn't take too much power, I would look at those small cigarette-lighter inverters designed for powering little stuff from the car - You should be able to run one of those off 8 D-cells, but you may have to see about alternate types of battery packs, like perhaps a NIMH cordless 12V drill battery pack(a very cheap and simple way to get ahold of a decent pack and a charger). Note that, as Llearch said, the output of these little inverters is *not* true AC and may or may not run the motor, depending on the type. Note that a UPS probably won't be any better or worse than one of these little inverters - I know my decent APC UPS(XS series, 800) provides nowhere near proper AC.

A better idea would be looking for a blower or something designed to run directly from a car cigarette-lighter socket - this means that it will run directly from your battery pack with no problem at all.

I still say however that the absolute lightest and simplest solution would be using a set of computer fans - they are fast starting, very cheap, and extremely light, and work on an extremely wide range of voltages, for different speeds.


-RobbieThe1st

[thegayhare]

I'm not sure what you mean by a 12 volt power supply other then small time 12 volt batteries I was able to find something bigger basically a 12 volt battery used to run those power wheels riding vehicles.

I've got a 120 mm case fan and I can barely feel it while sitting in front of my computer

pluss I'm not sure how I'd hook any of this stuff up I can wire some basic switches but I'm not sure how to do this.  thats why I was looking into into battery back ups and ups systems. 

pluss I'm not sure how I'd use these small fans to funnel air threw the suit

Edit :
I did find computer blower fans
Hmm that might work

[VSMIT]

For a basic switch, thus:

Code Select Expand

|-------------[Fan]----------|
|                            |
|                            |
|                        [Battery]
|                            |
|                            |
|----------[SPST]------------|

For one fan only.  I could draw you up a better schematic if you want (with more fans?).

SPST stands for Single Pole Single Throw, if you didn't understand, and is a type of switch, and basically just a light switch.

[thegayhare]

sorry I ment to say I can wire a basic switch

I know how to do that but what I don't know is how I'd wire a series of fans to a 12 volt power supply 

[VSMIT]

Just wire them in series with each other?

If you're looking for a way to do a parallel circuit, just connect all of the fans to the same terminal on the switch.  And to the same terminal on the power supply.

Like I said, I can do a quick schematic for you, I just need to know exactly what you have/need.

[Reese Tora]

I've got a 120 mm case fan and I can barely feel it while sitting in front of my computer

About that, two things:
1) Is the fan installed in your computer, or are you running it off of a battery?
Unless it's a case fan wired directly to a 12 volt rail(without a connection to a throttle), it's probably throttled down to a lower RPM to reduce noise if it's in your computer. (some fans even have temperature sensors and self throttle even when only conencted to 12v power)
2) Do you know what the fan is rated in terms of air movement? depending on the design of blades, motor, etc, different fans of the same size will move different volumes of air.(IIRC, they are rated in CFM or cubic feet per minute).  Unless you're going to be forcing the air through something tight, the CFM and noise in dB should be the only important factors. (well, they are the most important in computers, and noise can come down to personal preference...)

As I said, most fans I've seen are only powered by a single 9v battery, but these are face and head cooling fans installed int he head, and the reduction in power (and, thus, RPM) is as much for the purpose ot reducing noise as it is for ease of maintainance.

You'll probably have to experiment to see what combination is the right compromise of noise and power for your taste.  I'd suggest going 12 volt and including a variable resistor into the curcuit so you can reduce power to the fan if it's a bit too noisy without having to make any major changes to the battery pack.
(better yet, if you have a fan with a control wire, you could work out a circuit that uses that to adjust the speed, but that's significantly more effort for little immediate gain)

One final note, most of the people I've talked with agree that the important part of cooling is to keep the head cool, and, to that end, have suggested to me that the places to focus cooling on are the face and neck(especially cooling where your artery near the surface of the neck, as that cools the blood that will circulate through your head.)

[RobbieThe1st]

I've got a 120 mm case fan and I can barely feel it while sitting in front of my computer

About that, two things:
1) Is the fan installed in your computer, or are you running it off of a battery?
Unless it's a case fan wired directly to a 12 volt rail(without a connection to a throttle), it's probably throttled down to a lower RPM to reduce noise if it's in your computer. (some fans even have temperature sensors and self throttle even when only conencted to 12v power)
2) Do you know what the fan is rated in terms of air movement? depending on the design of blades, motor, etc, different fans of the same size will move different volumes of air.(IIRC, they are rated in CFM or cubic feet per minute).  Unless you're going to be forcing the air through something tight, the CFM and noise in dB should be the only important factors. (well, they are the most important in computers, and noise can come down to personal preference...)

As I said, most fans I've seen are only powered by a single 9v battery, but these are face and head cooling fans installed int he head, and the reduction in power (and, thus, RPM) is as much for the purpose ot reducing noise as it is for ease of maintainance.
You'll probably have to experiment to see what combination is the right compromise of noise and power for your taste.  I'd suggest going 12 volt and including a variable resistor into the curcuit so you can reduce power to the fan if it's a bit too noisy without having to make any major changes to the battery pack.
(better yet, if you have a fan with a control wire, you could work out a circuit that uses that to adjust the speed, but that's significantly more effort for little immediate gain)

One final note, most of the people I've talked with agree that the important part of cooling is to keep the head cool, and, to that end, have suggested to me that the places to focus cooling on are the face and neck(especially cooling where your artery near the surface of the neck, as that cools the blood that will circulate through your head.)

First off, you are completely right about multiple designs, and how most fans are throttled down.
Second, with regards to those fans with a speed-controller built in... I have never seen one. I don't question that they exist, but I have never actually seen one.
Third, generally the third yellow/white wire is not a speed-control wire, it is simply a data interface. The controller on your computer motherboard or fan-controller then takes that data and, using a variable(either PWM or linear) voltage controller, produces a lower voltage to drive the fan slower.
That being said, this makes varying speed control easy - all you need is a different voltage on the red and black wires. As I said, the absolute simplest way to do that is simply using less cells in series, but that will only vary in large steps, and would be impossible(or very hard) with real battery pack.

for variable speed, note that a variable resistor won't work too well - I have tried. It is horribly hard to adjust, and the speed does not increase in a linear fashion.
A better option would be basicly a LM317 with a variable resistor for adjustment. Now, being as TGH probably isn't going to know how to, or want to, solder up this circuit, I see a much much simpler option: a Zalman Fan Mate 2 fan controller. This is *exactly* the circuit I am talking about(I have two, took one apart). One only costs what... $4, and they are pretty much indestructible.  All you do is plug the fan into one end, and the battery into the other, and you are good to go.

The only downside to these is they are not efficient - If you are running the fan at anything less than minimum speed, you are wasting some power, and, at minimum speed, not a small portion either. This probably won't be too big of a problem, but I had to say it to make sure you are aware of it.

TGH, I happen to know exactly what you are talking about - I happen to have a few of those batteries myself. Those are sealed lead-acid batteries, and as you know, they are heavy.

I was suggesting, instead of using one of those, you use a cordless drill battery pack - something like the one shown here. They have terminals on the top you can just connect the fan directly to, and when it runs out of power, just put it on the charger like you would if it ran out of power if you were using the device it was designed for. If you already have a cordless drill/other power tool, so much the better - Let us know.

Note that, once you figure out what you are going to do, we(well, I don't know about anyone else, but I certainly can and will!) can walk you through anything you have trouble with, step by step.

Also, here is the most powerful 120MM fan I could find on newegg: http://www.newegg.com/Product/Product.aspx?Item=N82E16835185054 130CFM.


-RobbieThe1st

[llearch n'n'daCorna]

Ooo.

The other thing to look into would be remote controlled vehicles; Tamiya and the like. They have rechargable battery packs, and plugs, etc, and would likely provide you with a suitable interface for wiring things to.

[VSMIT]

Yeah, but you'd have to rip apart the vehicle to get to it, and you'd still need to wire a switch into it.

[thegayhare]

Yeah, but you'd have to rip apart the vehicle to get to it, and you'd still need to wire a switch into it.

Yes you'd need to wire a switch but you wouldn't need to tear a vehical apart you can but the battery packs  infact this is wwhat most suiters use how ever from a quick search these units are only rated a 7.2 volts

[llearch n'n'daCorna]

Yeah, but you'd have to rip apart the vehicle to get to it, and you'd still need to wire a switch into it.

You _do_ realise they sell spares, right? I wasn't suggesting TGH buy an entire vehicle...

And yes, I realise they are rated for 7.2V; I was suggesting that 7 or 12 isn't a big deal; worst case, you can plug two of them in series to get 14V, which is close enough to 12 to work.

The advantage of them is that they come with a quick-release plug/socket, and you can get holders for them to glue to your suit on the inside. And if 14V is too much, you can always wire up a quick plug to remove one of the battery packs from the circuit. And they come with a wall quick-charger; 5m charging time, or something (it's been a good few years since I last looked at these, I haven't had a car for over 10 years, and I expect that things have changed, and battery tech has moved on...) per pack; if you've got two on there, you'll probably have a reasonable run time.

And if run time is bad, you can put four of them on there, and run them in series-parallel - two strings of two packs, giving you twice the amps and 14v current. It's the quick-release plugs that you're seriously wanting; that and the solder-free connections.


If all this doesn't make sense, come back and ask. ;-]

[thegayhare]

actualy while looking threw I foiund they also have models rated to 11.1 volts

thats close enough to 12 for me


I figure with this I can get a 3 or four of these batteries, hooked up one to each of the blower style case fans to make the system work.

[shadowterm]

I'm entering this discussion late, But I thought that I'd mention you could rig individual fans to the hoses, and thus keep the original idea while reducing weight. It would be kind of like putting smaller lighter motors on each wheel of a car instead of having a huge heavy central one.