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A couple questions Answered

Hey guys, I want to bug you's again. Instead of trying to ask about different things in one of my other topics, I wanted to start a new one. I went to the local dump today, and one of the first things I spotted was Three, not just one, booster packs. You know, the ones you can charge up and boost a car with, and some of them have inverters built into them so you can run small appliances. Well I snapped all three of them up, thinking that at the very least, the lead acid batteries inside them would be OODLES of help towards making a full scale wind generator (I plan to build one or two full size wind generators with car alternators, whenever the good weather comes and I can work outside). Well, I got them home and cracked them all open. Turns out that only one battery is good to me (pictures below). The two identical units have 350 watt inverters built into them (I've removed one so far), but the batteries were bulging and the sides were split open, although not leaking, which was good, less mess to clean up. The third booster pack I opened appeared to have been already attempted at being opened. 4 of the 6 screws had been drilled out (which is beyond me as far as why they would do it? They were only phillips screws), but maybe they weren't successful? It had a couple wounds of electrical tape around it to hold it together. Needless to say, whatever cutting tool they used, cut into the battery itself (they cut too far in, dumbasses...), and so my main question here is, is the battery safe to charge, and use? I took some macro's of the damage and some of the cut marks seemed to have gone far enough in to cut into what appears to be a white plastic lining inside, as the white crud on the sides of the battery feels more like burnt on plastic from a cutting disc than it does acid that oozed out and dried up, so the damage doesn't appear to be that bad. What's the worst that could happen anyways? Also, the battery has about almost 8v left in it, and another question is, is that too low for a 12v battery? Like has it been discharged too far? Also, aside from the battery. I found this plate with a transformer, giant capacitor, and a pcb that looks like it was some kind of voltage converter board (I would take a picture but I've since cut a few things off of it and I won't even bother now) The transformer puts out 25v and you can see in the pictures what the capacitor is rated for (I would like to know what I can use this capacitor for, or if I should save it and wait till I can make a bank of capacitors for a tesla coil project or something) What I can't figure out, is what is this square device I found that was plugged into one of the output leads of the transformer? It only had two leads coming off of it, one is marked + and one -, the other two terminals don't have marking on it. No model numbers or anything. Does anyone know what this is? Also, last in my pictures is one of the inverter boards I pulled out of one of the power-packs. I cut the second outlet off and wrapped the first one in tape just to make sure I dont' shock the hell out of myself. I have my truck battery sitting inside over the winter, and with a good 12.71v, I thought it would be the perfect battery to try the inverter on. I brushed the wires onto the top terminals of the battery and although I could hear a bit of sparking, I saw nothing and the indicator light on the power switch didn't light. The volt meter also showed nothing from the 120v outlet. So I tried shoving the wires into the bolt sockets that the truck's wires bolt into, and I quite literally startled myself as it emitted a really loud BEEEEEEEEEEP, I nearly jumped through the roof. The indicator light turns on when I flick the switch to I and I can hear the transformer making a little buzzing sound. However, when I measured the AC voltage from the outlet, I didn't write down the voltage, but it was around 3v? Not even quite that much. I'm not sure if the inverter is screwed or if it has something to do with the switching nature of power inverters causing my multi-meter to not read it right? One other thing I will note is that I had to cut the power switch leads to remove it from the case, then re-solder the switch. The switch has 2 black wires and one red, I tried my best to make sure that each black wire went to the terminal on the switch it came from, and I assume if I didn't hook the switch up right, it wouldn't have lighted up or anything right?? I don't want to try plugging something into it for fear that it will blow up in my face, at least not until I know it's functioning like it should be, however I doubt these power packs were throwing out for failure of the inverter... *On the side note* I apologize for these (sometimes) rediculously long posts or just mundane questions. However, I like to be thoughrough with my questions so that there are very little questions asked, about my question, in the first place. As it seems to waste a lot of time asking for details about this or that problem, when you could just throughly explain it all in one go. This is what I try to do, so there are no blank spaces for you guys to try and "assume" where you don't know the proper information. Secondly, I've really appreciated the help, and sometimes just the helpful and creative ideas I hear from others, makes me feel good, like there's actually some people on here that know what they're doing and I can trust their answers (Nacho, kiteman, caitlyn's dad, 1010100100, all of you regulars, have been great help to me) *End of girlish requiem*

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12V

9 years ago

DANGER! Never charge a damaged battery. the acid has leaked out and evaporated it way be damaged because starting a car is very hard work it may gas,leak or explode if charged in that condition! if you do have a good one you should use 13.8v to charge if the battery is not often used but constantly charged. you should use 14.8v to charge if you discharge often and below 11v don't constantly charge at this if it is charged. 8v is very low for a 12v sla the maxi recommended is 10v if charged @14.4+v immediately after otherwise it will sulfate and lose capacity but it is usually recoverable at 8v but it might need to be connected to a desulfator.

I won't charge it, Ironically I still have it sitting on my floor, and haven't disposed of it yet.

. Not sure about your battery. I'd be inclined to trash it. . > square device ... one is marked + and one -, the other two terminals don't have marking on it. . Bridge rectifier. If you look close, you may find sine wave symbols near the unmarked terminals.

Hmm, I'm not sure nacho. I looked and there's just a + and a -, although I just noticed a number on the side: ""MDA2501"" and ""M 8186"" If it's a bridge rectifier, could I use it to use a AC motor for a wind generator, and hook this up in line with it to get DC?

. MDA 2501 is the part number and M 8186 may be a date code. . It should work as long as you don't exceed the voltage and current limits.

Ok, so there isn't really any minimum voltage required then?

Okay! I thought that unless you had diodes for low voltage purposes, using low voltages would leak through a diode where-as it should be stopping the voltage. I have no idea where I got that idea from though.

Typically, silicon rectifying diodes have a "forward voltage drop" of about 0.6-0.7 volts. So you'll loose a small amount of any voltage you "plug in."

Oh...well apart from my wind mill's motor support breaking away from my window this morning (thankfully just shortly after I woke up), it only produces like 0.5v in wind that's just strong enough to start it spinning. I'm sure in a storm or something it would probably pull in the motor's full current rating as it got spinning pretty fast last night (probably why my super glue job broke apart), and it wasn't even that windy outside. So really, will I only get like 0.1v out of it after? I suppose I'll have to try it. Also, how should I hook this diode up? Do I want to just provide it's input to the labeled + and - terminals? And the other two unmarked terminals are the output? Makes sense now that I think of it, as far as why they're un-marked. As nacho pointed out in the wiki link he sent me, bridge rectifiers also provide polarity protection, I think that's awesome and was just what I was looking for. I need to find where to buy these puppies.

It's possible to build a bridge rectifier from four germanium diodes, which only have ~0.3V voltage drop. IF the current supplied and drawn isn't too much, and the voltage within limits. The bridge schematic on NachoM's link is all you need to know to build it. Unfortunately, there's always a "cost." RE: the hookup-- the + and - terminals are the output, not the input. Are you absolutely certain you need a rectifier? Sure, if the rotor spins backwards the polarity will reverse, and a rectifier will correct that. But a DC motor should still provide a DC output... I hooked up a 12V DC brushless CPU fan and got negligible AC, but more than 1V DC when I blew on it... I guess the polarity issue is one reason most wind generators mechanically compensate for wind direction (if they use DC generators.)

>It's possible to build a bridge rectifier from four germanium diodes, which only have ~0.3V voltage drop. IF the current supplied and drawn isn't too much, and the voltage within limits. The bridge schematic on NachoM's link is all you need to know to build it. . I know this, I read the whole wiki page (why the hell is wikipedia so god damn handy these days???) I don't have anywhere around here to buy raw electronic componants, like strips/rolls of resistors and diodes, or capacitors and stuff like that, I need to go make a trip down to the city and make a huge list of stuff to buy.. Also, I was thinking if I could buy these square rectifiers like they are, it lets me heatsink the rectifier (diodes are supposed to have lower forward voltage drop at lower temps? oh wait nvm, it's the hotter they get, the lower the forward voltage, my bad) But at least the terminals on the rectifier let me easily connect it without soldering. >Unfortunately, there's always a "cost." RE: the hookup-- the + and - terminals are the output, not the input. . I figured as much, but I think on a VCR motor if I made one into a windmill (they're supposed to produce like 6-8v dc easily?), then the 0.2v forward drop would be nothing to me. >Are you absolutely certain you need a rectifier? Sure, if the rotor spins backwards the polarity will reverse, and a rectifier will correct that. But a DC motor should still provide a DC output... I hooked up a 12V DC brushless CPU fan and got negligible AC, but more than 1V DC when I blew on it... . Yes I'm sure I'd like to use one. I know a DC motor makes DC regardless, but the polarity reverses, and then how do you charge a battery it's hooked up to when it's firing through the negative, and then spinning the proper way around and firing through the positive. I've wanted to try mounting some old computer fans up in my trees or something, but I need to figure out how to modify the built in PCB to tap into the coils. >I guess the polarity issue is one reason most wind generators mechanically compensate for wind direction (if they use DC generators.) . Yupperoo, however, I don't want to do this, as that's one more thing you have to worry about, is the wire getting all wrapped up. So I figured with some diode steering, I could hook enough mini turbines up to one battery charger and always have a little something trickling into it, as at least one windmill outside would be picking up power from the wind at a time. (if I mount them all random directions).

Sounds like you're headed in just the right direction (no pun intended.) Good luck with finding components. I keep a "running list," and try to order as much at one time, to minimize the shipping (doesn't matter--I always forget something...)

Haha ya joker.. What's a running list? It makes sense to order as much at a time as some manufacturers will probably give you a deal too with the more quantity you buy. I went to a chinese electronic shop in Toronto that had drawers of parts from floor to ceiling all over, of course I never brought any kind of list with me and didn't end up buying much other than alligator clips (I should buy a good handful next time), some serial connectors (whom one I gutted for the pins inside to fix a broken vga cable). Aye, perhaps you could help me figure out a useful list of parts that are commonly used for different projects (for example, the 7805 regulator?)

. Some 555s, in different flavors. . General purpose diodes. . A few op-amps (741, &c;) . LEDs . Resistors in various values and wattage ratings. . 7812 VR. Might want to get a few 79xx (negative) VRs. A variable VR would be nice to have handy. . Capacitors for ripple filters.

Awesome! I can remember some of those parts from different projects on here (and hackaday.com and others).

Is that it though? Like what about common parts for building speaker crossovers and parts for OH yes now I remember, I want to start getting into microcontroller programming...SOOO bad. I know I could learn quick but I just really don't know where to start and what to buy vs. what's the best thing I should start with or get as far as programmer boards, and those micropic things that people are always building robots and using to speed control DC motors with PWM (is that spelt right?). I sound so vague right now but I think you have the idea. Basically, what parts do you think would be required to even make a programmer board?

LED's, I've been interested about using bi-color leds or even those tri-color led's that can make like 64k different colors. But of course, those require some kind of micro-controller to blend the colors together.

I'll just stop talking and show you a couple links to some instructables I'd like to try building so I can modify them into other things, just for a general idea of what I'd like to get for parts:

AC LEDS

Oh and I want to try building one of these

. Unless you have an unlimited budget, you're gonna have to make some decisions about what's really worthwhile to have on hand. Since you have an interest in speakers, then you may want to get some coil bobbins and magnet wire, instead of op-amps. Probably want to add some higher-wattage resistors and maybe some caps for crossovers to your collection. . You may be better off investing some of your funds in tools.

>Unless you have an unlimited budget, you're gonna have to make some decisions about what's really worthwhile to have on hand. . Well I wish it were unlimited, but I assume $50 would buy a LOT of resistors, capacitors, and diodes (and other project parts like that), although I know it depends on the values of said resistors, capacitors, and diodes. >Since you have an interest in speakers, then you may want to get some coil bobbins and magnet wire, instead of op-amps. Probably want to add some higher-wattage resistors and maybe some caps for crossovers to your collection. . Coil bobbins! Excellent idea Nacho, if they sell em, I'll buy a good handful. I also already needed some magnet wire (I want to make some of my own motors ;-P) I'll figure out the gauge of enamel/magnet wire that's on a crossover coil I already have, and buy that size (I think it's 16-18awg) As far as op-amps. I used to have some experiance in using them, but it's been so long that I really don't know as far as designing circuits with them. I know I've always wanted to build my own active Opamp crossover (for in line with my stereo rca's?) And it's actually like #2 on my project building list. Is it possible to build an opamp circuit that I can change the crossover setting with jumpers (or modified jumpers with resistors built into the tops of them? I know some crossover designs use what's called a K-net, basically a micro-controller shaped board with resistor holders in the top of it) If you can reccommend a good schematic for building a opamp crossover, I'll print out the parts list and keep that handy for when I go to a shop with those parts I need... I also plan to look and see if the shop sells any audio-quality film capacitors for that purpose. >You may be better off investing some of your funds in tools. . I think you're 99% correct. I need new wire strippers especially, and some kind of de-soldering tool, maybe some braid too. But at the same time, you need parts to use the tools with :P Again, thanks Nacho for being so helpful! I'd be sitting here twiddling my thumbs if it weren't for some of your handy suggestions.

I'll a couple things to NachoM's list: A few 2N2222 NPN transistors--they can switch about 1/2 watt, and are great for small motors and such. These should be about 10 cents per. 7805 regulator or two, if you have any interest in TTL logic chips or microcontrollers. Mylar caps for audio coupling. LM386 1/2 watt audio amps--they can even be used as motor or LED drivers.

Great suggestion! The 7805 puts out USB level voltage @ 5V right? Transistors could also come in hand a couple project I want to build. And small audio amplifiers can be handy for some things. I should also open up my dsl modem and record all the capacitor values, and replace them all with heftier capacitors. Also, where would one buy ferrite cores that they use to put around wires to supposedly block out interference, do they actually work?

Yep, 5V is the same as USB bus levels (and the voltage source pin on the USB connector.)

I'm not certain it's wise to replace all the caps in a modem unless it's not functioning. Capacitors may be interchangeable at the same values, but there are differences between the types--differences in linearity, temp limits, etc. that the engineers were aware of, and "designed-in."

For ferrite cores, try Goldmine, BGMicro or any of the other discount electronic houses. I'm sure they'll block some RF noise. You can probably reclaim some from discarded equip, too.

>Yep, 5V is the same as USB bus levels (and the voltage source pin on the USB connector.) . Thought so, thanks for re-confirming. >I'm not certain it's wise to replace all the caps in a modem unless it's not functioning. Capacitors may be interchangeable at the same values, but there are differences between the types--differences in linearity, temp limits, etc. that the engineers were aware of, and "designed-in." Put it this way, I'm on my 5'th modem, maybe 6th, I've kinda lost count. One blew two caps and I replaced them from some off some old power supply or something and it continued to work until something else just completely failed. I find that the connection is not that reliable, and the high tx levels could be saturating the capacitors or something past what they were meant to do. My internet is fast sure, and I like it. But when I'm on msn and type some messages and then 15 minutes later it informs me that I am logged out and these messages cannot be sent (uber frustration mate). I was thinking of replacing them all with same value capacitors, but higher performance or those rated for slightly higher voltage?

Those problems could be caused by faulty caps. I've had several devices fail due to bad caps (a DVD player (filter), a PC (decoupling), and a Digitech rackmounted signal processor (decoupling).)

They also might be the result of a noisy line. Our broadband performance degraded and eventually failed; the culprit was squirrels!

The audio frequency signal chain is probably what you're thinking of. But those components are the most carefully chosen. Replacing the caps wouldn't necessarily improve performance. In fact, it might make matters worse, if the design accommodates the known limitations (non-linear response) of a particular type of cap, and is replaced with a better, more linear cap. Compare the response of a low-voltage ceramic cap vs. most others...

Others, such as decoupling caps, are probably very cheap and can be replaced. Tantalum caps, for instance, seem to be worthless for another use--and damn-near worthless, period.

(BTW, decoupling caps are those placed all over digital circuitry to act as a shunt for unwanted high-frequencies in the power grid between V+ and ground. Generally they are 0.1uF, and there might be dozens on a computer motherboard. They are the electronic equivalent of preventative medicine. I.E., the designers would say: let's stick a decoupling cap by this IC, and one by this IC, just in case... But they can short out like any cap.)

Also, it's likely that the modems are SMD technology--those aren't easy to replace. The non-smd caps (filter, mostly) are probably the most likely to fail--and the easiest to replace.

>Those problems could be caused by faulty caps. I've had several devices fail due to bad caps (a DVD player (filter), a PC (decoupling), and a Digitech rackmounted signal processor (decoupling).) . This is what drives me nuts, there's tonnes of stuff that gets chucked because of simple to replace parts going bad. >They also might be the result of a noisy line. Our broadband performance degraded and eventually failed; the culprit was squirrels . You would think, but my telephone line sounds clear and with no crackle or popping when you listen to the line on the other end unless their telephone has something going on. >The audio frequency signal chain is probably what you're thinking of. But those components are the most carefully chosen. Replacing the caps wouldn't necessarily improve performance. In fact, it might make matters worse, if the design accommodates the known limitations (non-linear response) of a particular type of cap, and is replaced with a better, more linear cap. Compare the response of a low-voltage ceramic cap vs. most others... . It's hard to say which ones are decoupling caps and which are part of the audio signal, but I think at any rate, replacing at least the largest ones would do something I'd think. >Others, such as decoupling caps, are probably very cheap and can be replaced. Tantalum caps, for instance, seem to be worthless for another use--and damn-near worthless, period. .This is probably what I replaced on mine, as it was having problems attaining a dsl connection and fixed itself after I replaced 2 large tin capped capacitors (standard poly cap's) What if you replaced them all though? They are obviously cheap chinese caps, so putting something with higher tolerance, better build quality might do something? >(BTW, decoupling caps are those placed all over digital circuitry to act as a shunt for unwanted high-frequencies in the power grid between V+ and ground. Generally they are 0.1uF, and there might be dozens on a computer motherboard. They are the electronic equivalent of preventative medicine. I.E., the designers would say: let's stick a decoupling cap by this IC, and one by this IC, just in case... But they can short out like any cap.) .When you look at the circuitry like that yes, but in my modem, the big capacitors are used to couple the signal with my telephone line so I don't hear it while I'm on my phone (although I know it runs in a higher freq than our hearing can hear anyways I think...). >Also, it's likely that the modems are SMD technology--those aren't easy to replace. The non-smd caps (filter, mostly) are probably the most likely to fail--and the easiest to replace. .I suppose some of them probably are SMD, but I doubt there's even enough current going through the capacitor at that level. I've owned 5 of these modems, I've seen their weak point is their decoupling area, as they are always hot, although I've seen others, at my neighbors, that are lukewarm to the touch. Hard to say what the case is.

I can't give a concrete, yes/no answer about replacing all the caps, but if the modems are going bad, they are the prime suspect.

.When you look at the circuitry like that yes, but in my modem, the big capacitors are used to couple the signal with my telephone line so I don't hear it while I'm on my phone (although I know it runs in a higher freq than our hearing can hear anyways I think...)

Yes, that's even termed a coupling capacitor. Coupling serves multiple purposes, the main one is to eliminate any DC offset on the output. Basic types of audio signal coupling:

1) impedance (inductive) coupling (rare, non-linear, more for RF)
2) transformer coupling (uncommon, 'cause transformers aren't cheap)
3) capacitive coupling
4) DC coupling (carries the bias from the preceding stage)

Capacitive coupling is the most common when there's an unwanted voltage offset.

The load determines the size of the output coupling cap. A very low impedance load might require a larger cap than can be installed with SMD tech, so instead the cap is a separate discrete component. This is one place to look for defects. Understand that most of the signal path caps are within the ICs themselves, and unreachable.

All capacitive coupling has a filtering effect as a byproduct. Note how the load changes the frequency response in a simple RC filter. A larger load (smaller resistance) raises the cutoff frequency. (LARGER load = LESS resistance.) The line load itself (or a speaker, for instance) can serve as the R (resistive) component...

An audio phone line has a fairly limited audio bandwidth, and you can probably hear all the tones, if only as pulses.

oh yeah >For ferrite cores, try Goldmine, BGMicro or any of the other discount electronic houses. I'm sure they'll block some RF noise. You can probably reclaim some from discarded equip, too. . I'll check those out, but I know they're good to reclaim from equipment, but I haven't came across too many while in my adventures. I suppose I should be checking old computer cases at the dump for the ferrite rings they used to bring all the wires together for the I/O panel at the front of the case. Where else though will you really find that? What about cables? My dad's friends with the guy that runs the dump, and he's got a big crate now he uses just for cables primarily. Is it worth it cutting open those cores they put around wires, keyboard cables, power cables, etc,?

. It's been so long since I worked with that stuff that I can't make any recommendations. Try to find some "audiophile" sites with circuits. . You should be able to build rather sophisticated crossover networks with some op-amps and a handful of caps and pots. I suggest using the op-amps ahead of the amps, so you don't have to worry about handling all the power (you seem to be pretty good at frying stuff heehee). If you want them in-the-box, I'd stick with passive crossovers. YMMV - like I said, it's been a while.

. Oh! I think a lot of bi-amp'd systems use the scheme I'm talking about.

The Scheme for the crossover? And yes i did want to have it wired ahead of the amp, but I want an active crossover so I can add a switch like those found on car stereos for 3, 6, 8, and 12 db of boost. Aswell as other bass boost circuits that are found in those. I suppose I need to brush up on my schematic reading skills again. Passive crossovers do the trick, but I think if you were to op-amp and bi-wire all your speakers, and provided done properly, would probably sound better.

Think of a running list like a shopping list: You are going to the store on Friday so Monday you find you need Pasta, and Tuesday you see you will run out of cereal, etc. Then, when you order, you get it all for a postage and handling charge that doesn't include that monster starting rate 5 times.

Ohhh, that makes sense now, thanks goodhart!

A "running list," is like a running faucet--it just keeps going. You add new stuff when you think of it...

. A search for "MDA 2501 +datasheet" should tell you what you need to know about your bridge. For your purposes, just about any bridge that will handle the voltage/current should work. Ie, don't worry too much about the other params.

Hmm, I pretty much figured, I was just worried about the diode consuming like all of the small amount of current produced, but read my post to gmoon to see what im getting at. As far as the datasheet, I will look it up, but i'm neglecting any more files landing on my mac's desktop right now, it's kinda full, and umm...so is all the other places I shove these files when my desktop gets too cluttered (just too much random crap to find what you're after, not so much an actual space issue) Hopefully there is a datasheet, as this unit is pretty old, oh jeeze, I just googled it in another tab real quick, nothing man... But you said that a 4 diode bridge is just diodes, I guess diodes are really the only thing you don't have to worry about much but the maximum voltage passible through it, depending on the project. Oh well, it's a simple device, I'll figure it out, I thinks maybe I should save it for this spring tho when I got to make a full size wind turbine (I personally want to get your msn or some kind of IM, so I can show you what Im working on as I go along, without having to post up a big topic and explain myself out what I'm building, just to get a quick answer to something) Hope I don't sound like I'm asking you to be my encyclopedia either ha ha, but you're awesome nacho, you always have some kind of answer other than "I don't know what you're talking about" or something like that, you know..

I am no battery expert, but I'd have to say, If you charge it, and theres a cut. You shouldn't charge it.zap

Good point, I still have the damn thing sitting here, but I haven't tried charging it yet no. 101011010 told me I should cut it open and remove the good cells (providing that it was assembled like I've seen other lead acid batteries). Usually all they are, are a big plastic black box with 6-8 cells wired in series internally, and if you can get the top off, you should be able to remove them?

I'll find out when mr.Dremel meets melted plastic

soon afterward, Mr. Punkguyta meets sulfiruc acid

So you think they aren't self-contained cells? Well damn

don't risk it your dremel is worth more then the battery

throw it out.. if you try to charge it, you might destroy a couple cells, and since the casing is compromised, it isn't safe

Ok OK, I won't charge the battery. I'll have to put them out in my shed until I go to the dump again.

fan should turn on when the inverter heats up

That's what i thought! I just tried it a couple days ago with a desk lamp and the lamp lit up as bright as when it was plugged into the wall. I assume this inverter is OK

>plug a load (preferred resistor load like incandescent lamp) into the outlets and see if inverter works i think unless the inverter is made to be ultra silent the fan should run all the time. see to where it goes on the circuit board and test it directly if the fan itself is ok . That makes sense, I'll try the light bulb whenever I pull it out again (probably tommorow). I don't think the inverter was made to be quite so much as it didn't run off that big of a battery, so perhaps the fan is only supposed to come on when there's a heavy load? The 450 watt inverter I borrowed from a friend before only turned it's fan on when I put a heavy load on it, but even my laptop's power supply would make the fan run

i dont think they try to save battey if inverter is 350 W and 90 % efficient (which is high for inverters like this) it still wastes up to 35 W power and atleast few watts with low load. a fan from computer power supply at full speed is only about 1.5 W - not much compared to the inverter itself