Watt amps am I drawing?

[raqmup]

Unfortunatley, I don't know how to convert watts to amps...
My load is 600w of driving lights+stereo & 450w amp, winch on the second battery. I'm running two optima blue tops on a solonoid (soonish', not just yet though) What amperage does my alternator need to be to keep up and run the lights, accessories and engine without too much drama? Keep in mind, this is a suzuki sierra running an efi 1600 vit motor

[christover1]

Unfortunatley, I don't know how to convert watts to amps...
My load is 600w of driving lights+stereo & 450w amp, winch on the second battery. I'm running two optima blue tops on a solonoid (soonish', not just yet though) What amperage does my alternator need to be to keep up and run the lights, accessories and engine without too much drama? Keep in mind, this is a suzuki sierra running an efi 1600 vit motor

Volts x Amps = Watts > .. Amps = Watts/Volts christover

[raqmup]

soooo... 12v x say a 65 amp alternator= 780watts. Is this what I could run safley of the alternator without drawing off the batteries. And how much does the computer etc, draw on a 1600 efi to add into the equation?

[christover1]

soooo... 12v x say a 65 amp alternator= 780watts. Is this what I could run safley of the alternator without drawing off the batteries. And how much does the computer etc, draw on a 1600 efi to add into the equation?

I doubt computer would draw too much, but if you go close to max then pooter may play up...You need to allow for power losses thru imperfect things..losses in system would mean less than the 780 watts, even tho the maths is right...but I not sure what the loss would be.
If ya headlights flash in time with the music, then you need more power.
Most alternators charge round 13.5 volts to allow for losses I guess.
christover

[raqmup]

Thanks guys, um, if it means upgrading the alternator, I'm prepared to do that without question, my build up is not one to cut corners of any magnitude, sooo, perhaps a bigger one, say a Holden VS alternator (100amps I think someone said ) I'm also told that it'll fit with not too much of an issue, is this true or is my theory a bit blurry?

[DamTriton]

Let me see...1050 watts = 85 amps, plus what it takes to run the EFI (another 10 amps or so), plus whatever it takes to run the ignition (another 10 amps) plus another 5 amps for bits and pieces, plus the heater fan and A/C clutch (12 amps) seems to equal about 120 amps at full load, and that is with out putting anything back into the batteries to recharge them from self discharge/starting.....

Assuming not all of them are on all the time, but needing to recharge the batteries after cruising your local lap area about a 90 amp would be enough allowing for various losses through the system (usually about 10-20%).

Thought of installing a "Christies" 90 amp genset in the back of the Zook, because you won't have much engine power left if you don't. You also wont get these charge rates unless you have the engine screaming its tits off.

Take two or four of the lights off, halve the amp power (believe it or not, undetectable volume difference, only really WANKER value), and stick with the alternator you have.

Solved..........

[raqmup]

What's the Christie's genset doodah? Sound interesting!
Um, I've chosen to run rooflights for practicality when night driving (bush trax that is) not for tosser value. I don't have money to burn on un-necessary bling, if I wanted w@nker lights I woulda saved my bickies and put bull lamps on the rig... However, that's not the path we're travelling down, soooo- what's a feasable solution to running say 4x 100w XGT's on the roof, I don't have a/c in the sierra (it'd be nice though!), + the rest of the normal load you mentioned previously?

[DamTriton]

What's the Christie's genset doodah? Sound interesting!
Um, I've chosen to run rooflights for practicality when night driving (bush trax that is) not for tosser value. I don't have money to burn on un-necessary bling, if I wanted w@nker lights I woulda saved my bickies and put bull lamps on the rig... However, that's not the path we're travelling down, soooo- what's a feasable solution to running say 4x 100w XGT's on the roof, I don't have a/c in the sierra (it'd be nice though!), + the rest of the normal load you mentioned previously?

Google is your friend..

Christie Engineering
Business type: Manufacturer of high powered DC battery chargers
Product types: DC High current output generators for battery charging, Remote area backup chargers, portable camping chargers, marine chargers, recreational vehicle chargers, Outback Battery Chargers 12 volt-55 amp, 80 amp or 120 amp, 24 volt 45 amp 55 amp or 80 amp. We manufacture petrol or diesel powered chargers to suit your needs..
Service types: Supplier of remote area battery charging
Address: 123 Delaware Rd Horsley Park, Sydney, NSW Australia 2164
Telephone: 02 9620 1208

[Guy]

What's the Christie's genset doodah? Sound interesting!
Um, I've chosen to run rooflights for practicality when night driving (bush trax that is) not for tosser value. I don't have money to burn on un-necessary bling, if I wanted w@nker lights I woulda saved my bickies and put bull lamps on the rig... However, that's not the path we're travelling down, soooo- what's a feasable solution to running say 4x 100w XGT's on the roof, I don't have a/c in the sierra (it'd be nice though!), + the rest of the normal load you mentioned previously?

I call BS .. 4 XGT's on the roof of a Zuk and you claim no wanker value ?

Spend a few $$ on good wireing to your headlights using quality relays etc as well as 1 set of XGT's .. With that kinda setup in a Zuk you will not outdrive your lights.
if your really need that much light that high up I would assume its for river crossings etc so an expensive boom box with a big amp will soon be an expensive lump of aluminum

That said .. have a look at most late model efi vehciles, I am pretty sure that most hyundias etc will have an Alt the 100 or so amp range (to cope with EFi power windows etc . should also have the right type of pulley for your system)

Carry spare belts and be prepared to change alts on a semi regular basis as you will be working it pretty hard. The addidtional load of pulling the alt will have some impact on engine performance .. power dont come free ..

[dumbdunce]

also your winch should be run off your first (starting) battery, not the second one. roof lights are gay, they just through big reflections of your bonnet and bullbar in your eyes, ig you want a lot of light invest in HID's headlights and chuck the rest out. lots of light, no dumb olverhead lights to get whacked on trees, and very low operating currents.

what Gary said about the amplifier. you're a deadset wanker if you need more than about a true 100W (true RMS, which is where you can estimate consumption from not peak or PMPO bulltits) sound system in any car, any louder than that is just stupid dumb.

summary: stock alternator, HID lights, more real-world approach to stereo and you won't need to spend a cent on upgrading the alternator or a second battery. of course, it's your money and your poseur value.

cheers

Brian

[V8 Middy]

Its interesting that some of you quote losses of 10 to 20% as power not being used. Its been correctly stated that Watts = Volts x Amps. Don't forget that Watts = Amps^2 x resistance.

Therefore, if you have big losses in your wiring, multiply that loss by the current squared to find out how many watts are going to waste.

Also keep in mind that a 450W amp will rarely, if ever draw 30A, if it does, only at the peaks (ie. each "doof" of your doof doof music) and you can always turn it down while the lights are on

[carts]

also your winch should be run off your first (starting) battery, not the second one.

Why is this?

[dumbdunce]

also your winch should be run off your first (starting) battery, not the second one.

Why is this?

several reasons: 1. because unless your dual battery management system is capable of supplying 400+ amps, running the winch from a second battery will fry the dual battery manager*, leaving you without a winch and without a second battery - even most big solenoid controllers** are only good for 100 - 200 amps.
2. the main starting battery is usually a starting type (High CCA at the expense of a slight loss of Ah/joule capacity) battery, which is good for high current, short duty cycle applications, like winching. Second batteries are usually a deep-cycle type battery (for low current, long duration use like camp lights, fridge etc), which are destroyed very rapidly by high current drain.
3. The alternator output is wired directly across the main (startring) battery, so to minimise losses/maximise the assistance from the alternator during winching and to accellerate battery charge recovery immediately after winching, you want the alternator as close to the winch (and winch battery) in the circuit as possible.


* In solid state battery controllers, there is usually over-current thermal shutoff which in a winching situation allows the unassisted battery to die very quickly - as if the engine wasn't running. Note solid state means there is necessarily some voltage loss to start with.

**There are voltage losses in all dual battery management systems, even with solenoid switching, and the I^2R losses at those points in a 12V system are considerable at high currents.


cheers

Brian

[raqmup]

guys, I've asked for advice, not to be insulted- hence why I haven't posted on here for ages... I'm sorry if my rig setup doesn't fit into your shoe box values of what a 'real 4wd' is... It;s a daily friver as well, so gimmie some slack and I'll take constructive criticism- not outright insults... Thanks to those who have nad can help, I'm open to listen, just don't like the BS that comes with some of the recommendations. Thanks

[murcod]

Someone mentioned Hyundai alternators were even around 100 Amps earlier- the wife's '96 Excel has got a Mando 75 Amp one. Still not a bad size considering some late model Commodore ones were only 80 Amps!!

[DamTriton]

guys, I've asked for advice, not to be insulted- hence why I haven't posted on here for ages... I'm sorry if my rig setup doesn't fit into your shoe box values of what a 'real 4wd' is... It;s a daily friver as well, so gimmie some slack and I'll take constructive criticism- not outright insults... Thanks to those who have nad can help, I'm open to listen, just don't like the BS that comes with some of the recommendations. Thanks

No disrespect, but you came onto a hardcore 4WD site asking ricer questions. There are plenty of more appropriate forums for those sort of Q's, with ppl that have more expertise in that area.

My answer was a reasonable attempt at adding the power requirements, an education in basic acoustics/electronics (FYI you have to go 10 x the power to achieve double the SPL, a doubling of the power actually makes a barely perceptable difference in SPL, hence the wanker value reference), with a description of possible problems, and a reasonable (and more legal) solution to some of the issues.

If you have questions about offroad wheels/tyres, suspension, driveline, or other true 4WD reated questions, there are ppl here that would be more than happy to help.

"Horses for courses"

[hienuf]

Posted: Tue Jan 11, 2005 8:49 am

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No disrespect, but you came onto a hardcore 4WD site asking ricer questions. There are plenty of more appropriate forums for those sort of Q's, with ppl that have more expertise in that area


he is asking general questions ...........Garyinoz this is a hardcore site yea
Y U DRIVE A KIA....THATS NOT HARDCORE...LOL

[dumbdunce]

Posted: Tue Jan 11, 2005 8:49 am


he is asking general questions ...........Garyinoz this is a hardcore site yea
Y U DRIVE A KIA....THATS NOT HARDCORE...LOL

have you SEEN Gary's Kia? or seen him Drive It?

[DamTriton]

Posted: Tue Jan 11, 2005 8:49 am


he is asking general questions ...........Garyinoz this is a hardcore site yea
Y U DRIVE A KIA....THATS NOT HARDCORE...LOL

have you SEEN Gary's Kia? or seen him Drive It?

What he said...

[hienuf]

not the point im making.........dont insult other ppl just cause you know more or you dont agree with mods they have/dont have.


i am the strongest beliver that most 4bys are as capable as there drivers.

and im not bagging him for owning a kia but whats wif the king dick attitude.

[hienuf]

when ppl ask questions wether u think smart or stupid u have a choice to reply.but dont reply if ur gunna put em down/bagging

[dumbdunce]

I think you're inferring some malice into Gary's or my posts that just isn't there. The questions are "ricer" and this is a "hardcore" forum; we have answered in the spirit of the board, with a view to keeping costs down and modifcations legal and sensible. If you or others choose to interpret that as some kind of vilification of the original poster, the inference is all yours. Advice has been asked for, and duly given - and like any free advice, it's possibly worth what you pay for it. That said, Gary is one of the most down to earth and realistic blokes on this forum, and my advice would be to listen to his advice, as he is usually right on the money. I don't always agree with him (after all, he drives a POS Kia ), but he always has intelligent and well thought out reasons behind his advice and opinions which encourage others to think a little more about the modifications they are proposing. If after hearing what others have to say, the advice is ignored - like I've already said - it's your money - but when it all starts to break because you ignored good advice, you can't say you weren't warned.

[Sixty]

raqmup -mate, look for an alternator of at least 80 amps. That will be able to handle the load your looking at. I'm running 600w just in lights (4x h/lights & 2x spots) as well as a average stereo, radio's, fridge etc, along with a winch off of the second battery. My batteries are NZZ's (overlander??), with a diode type isolater. Havent had a hassle with this setup for eight years. Standard cruiser alternator on a diesel.


Al

[hienuf]

i think i have met gary yrs ago suz4wdclub angelsea trip.at that time i think his kia was pretty std and yes if i remember correctly nice guy.


Take two or four of the lights off, halve the amp power (believe it or not, undetectable volume difference, only really WANKER value), and stick with the alternator you have.

Solved.

i agree

[DamTriton]

not the point im making.........dont insult other ppl just cause you know more or you dont agree with mods they have/dont have.


i am the strongest beliver that most 4bys are as capable as there drivers.

and im not bagging him for owning a kia but whats wif the king dick attitude.

In all honesty, I don't think you will find too many ppl on this forum with 450 Watt amps/Doof-Doof setups. That is not what this forum, or the ppl on it, are about. (Equipment way too expensive to drown).

If you aren't prepared for you rig (whatever it is) to get dirty, damp (very!), damaged (not intentionally), or dented then maybe you are in the wrong place. If I had thousands of dollars worth of all the top bling stuff installed in a vehicle, I don't think I would be taking it through many bogs/rivers, or over rocks.

My post was also an attempt to get the original poster to see that what you want, and what you need, are two things seperated by the laws of physics, with a splash of common sense. Sometimes it just aint worth the hassle.



Yes, I do own AND use my Kia to the best of its abilities, and most ppl who have seen it, (particularly recently) would agree that it is a reasonably capable vehicle for what it is. I have fun, and enjoy my chosen sport.

[hienuf]

gary 4 what its worth i know most ppls have good intensions wif there replys.....................hope to see the kia out and about

[benjamin78au]

well a few things is that 450 watt amp the rms value or just what is on the out side, cause if it is rms then it will chew a bit of power, but then yoiu would also know it not good for the cd player to be in use as u go bouncing. there is nothing wrong with having a very loud stereo in a car , jus attach the amp to the sub box and if doing some deep tracks , just take the box out. You having the lights on the roof i assume it is a hard top why not put the head unit in like a roof console.

You might find the current vitara alternator lacking if you run everything flat out. plus loud noise 4wding kinda is distracting , but that my 2 cents

[robbie]

moved to autoelec forum.

[raqmup]

Sheesh fella's, I like some of the advice and yes, 450w amp is what is printed on the amp, and that's what I used to run when it was more of an 'about' town' zook, all sound shiate is now mounted in custom roof consoles way out the way of the murky h2o... I've actually thought about these things... 2nd to that, I drive my rig long distances AND I have a passion for ace tunes and good sound- I DJ on weekends, so I love music guys- really, it's not a big deal All unnessecary BS has been yanked/turfed in place of functionality, the zook is set up to tackle hardcore terrain and even though I will treat it with respect, I'm overly sure mother nature will not...
That in mind, your advice is listened to- I'm not a dumbarse twinkletoes who knows SFA about wheelin' , so advice that is sought is not because I don't know where my bonnet catch is- I actually have more than good reason to ask- I don't want to go ahead and f@rk things up just because I was unsure...
I'm sure people have opinions about roof lights, I've made mine for distance night driving and pitch black night drives in Victoria, poser value or whatever- my choice at the end of the day, I'm sorry if they seem a silly idea to some...



Now, instead of worrying about who's treading on who's toes, I just wanted to know about some alternators that will fit on the zook, without going to extremes in the way of mods or fabrication around the 80-100amp range, the rig has enough power to run a bigger one without feeling like a ball and chain effect. The hyundai ones are reativley cheap and I'm not overly sure on how they'd go on a fourby, are there any others worth consideration?

[dumbdunce]

ok, ignoring for a moment all the reasons wny you do not need a higher rated alternator, take your alternator out, take it to an auto electrician, and tell him what amps you want it to supply. he will replace the stator winding and diode pack with the gear required to make the current you require. hand over the cash and fit your alternator back where it fits. It's probably not the cheapest solution but its the only one that does not involve cutting corners or hacking alternator brackets or the alternator mountings or splicing wiring harnesses etc etc etc.

couple of final questions - why are you so intent on the blue top optimas? aren't they the same as the ellow tops but with pointless double terminals? Also, since you don't appear to be planning any deep-cycle type accessories (fridge, camp lights etc) then maybe red tops with the slightly higher CCA would be more applicable to the high current loads you are talking about (or do you plan on parking for hours with the stereo running loud and the roof lights on?)

is the 450 watts of the amplifier a true 450 watts (average maximum power) or is this the advertised, 'PMPO' figure? you need the true average maximum rated power to start with the calculations, and as this is the lion's share of the load you are talking about, so it makes sense to get it right.

as for the rest of your load, instead of guessing, put an ammeter in series with the battery and the fusible links and load it up - ignition, lights, whatever else you want to run, and MEASURE the current required, so you have an accurate idea of what the requirements are.

cheers

Brian

cheers

Brian