[Glavas]

Okay, so I run 2 x 130W spotties
2 x 90W headlight globes

P = VI
I = P/V

Spots

I = 130/12
I = 10.8

Headlights
I = 90/12
I = 7.5

Total current drawn by all lights; 2(7.5) + 2(10. = 36.6amps

Zook has a 20amp alternator? How does my car continue running with such a huge current draw?

[atari4x4]

20 amp alt? are you sure, they'd have to be 45 or 55 amps

[Glavas]

atari4x4 wrote:

20 amp alt? are you sure, they'd have to be 45 or 55 amps

I could have sworn I read 20 somewhere.

Even with a 45, stereo + dash lights + ignition + these 36.6 should surely be more than 45?

[ellis]

i think the stock sierra alternator puts out 45 amps

[Glavas]

Seems it is 45;

However, shouldn't my car still be struggling?

[atari4x4]

got a volt gauge/mulit meter?

[Glavas]

atari4x4 wrote:

got a volt gauge/mulit meter?

Of course.

Measure I across battery and I at back of Alt?

[atari4x4]

i don't know, your the mechanic, i work on computers.... don't they teach that shit anymore or is it just oil changes & R/R parts now days?

[Glavas]

atari4x4 wrote:

i don't know, your the mechanic, i work on computers.... don't they teach that shit anymore or is it just oil changes & R/R parts now days?

They teach me the theory and repairs, not how to modify unfortunately lol.

I can diagnose alternators and batteries, chase electric faults etc.

This has got me confused though. Am kind of concerned as I'm fitting 4 x 55W HID's and 2 work lights.

[Ben_Sierra]

Remember, the alt, and all the electrics run at more like 14.4 Volts when the car is running, not 12...

[Glavas]

Ben_Sierra wrote:

Remember, the alt, and all the electrics run at more like 14.4 Volts when the car is running, not 12...

This is true. but do the electronics actually get the 14.4V? I didn't think they did.

Even at 14V, powering that many lights should be a concern, yet people are doing it presumably without alternator upgrades.

I'm thinking it's more likely my maths fails up there...

[Ben_Sierra]

Remember that when the engineers at suzuki designed the electrical system, they didn't design it for 130W spotties or any other form of upgrade, so if you start loading up the electrical system, sooner or later your alt is gonna reach the limit of what it can power...

[Glavas]

Ben_Sierra wrote:

Remember that when the engineers at suzuki designed the electrical system, they didn't design it for 130W spotties or any other form of upgrade, so if you start loading up the electrical system, sooner or later your alt is gonna reach the limit of what it can power...

Exactly what I'm worried about

Seems as if other people are doing it? I mean nearly everyones got spots, many have got 4!

Basically I'll have 2 x 130 on the bullbar, 4 x 55 HID on the roof. 2 x 91 LED work lights only drawing .3amps

And some rock lights while I'm doing all the wiring.

HIDs will be covered in town and only used wheeling/country driving. Worries me whether the alt will max out and die or not.

Currently, it shows no signs of struggling, and I recently did a 4 hour block of driving with 2 x 130 2 x 100 on :S

[atari4x4]

have you looked into doing the 110amp falcoon alt upgrade?

[Glavas]

atari4x4 wrote:

have you looked into doing the 110amp falcoon alt upgrade?

Looks like I'm going to have to lol.

[31zook]

it's a dead easy upgrade btw

[Glavas]

31zook wrote:

it's a dead easy upgrade btw

Exactly the same on the 1.6 as the 1.3?

[Teracis]

Remember you've got your battery in there as well and you don't run at full load all the time.

I.E. you go for a drive at night and are running under full electrical load. so you take your 37 amps for the lights (i'm lazy) and then your other load (ignition + stereo e.t.c)

Now, if this is over the 45A produced by your alt (at the 14.4 it produces) then instead of being able to power your car and charge your battery, it will be unable to supply enough current and without doing any calculations I think the voltage drops to battery voltage and the battery starts supplying current as well.

So you can think of it like a water tank. You put the hose in for an hour in the morning and an hour in the afternoon (driving in the day with bugger all load so you're charging your battery at a high rate) then, you go for a drive at night under full load which is like turning the tap on at the bottom of the tank.

Now, as long as the amount of energy you're putting into the battery (daylight driving) exceeds the amount you're taking out (nighttime driving + starting e.t.c) then your battery will stay charged and you won't notice. Until you go on a long trip at night and you're using energy from the battery (because you're well over the alternator output) and you're out long enough to drain the battery.
Now, if you did have this happen and things started to dim, Ideally you'd turn the lights off immediately and this would stop the car from stalling, I don't think you'd get much warning though.

I'm only a normal sparky not an auto sparky and I just woke up, but that's the basic theory of it.
SHORT VERSION You have a system with a storage device and a fixed input. If you take more out than the input then you are removing energy from the storage device, if the output drops below the input, you start topping up the storage. If the output stays higher than the input long enough, you will empty the storage device.

If I've confused you let me know, options are increasing the input (upgrading the alternator) which is the best fix.
Increasing the storage capacity (running a dual battery, which is a bandaid fix to give you a longer overload time).
Decrease the output (turn off the lights :p).

Ideally you would change alt's and run dual batteries but that's more expense! If you're super worried you've overloaded it, find someone with a dc current clamp meter and run everything while measuring the current draw on your alt + battery.

Good luck with it.

[coneykid]

Hope you have a spare head lamp switch running 90w head light bulbs. Run 35w hid kits or relay your head lamps and change that alt.

[zuk_244]

Glavas wrote:

This is true. but do the electronics actually get the 14.4V? I didn't think they did.

Even at 14V, powering that many lights should be a concern, yet people are doing it presumably without alternator upgrades.

I'm thinking it's more likely my maths fails up there...

From what i can see the math looks good. The 14.4 volts will get to the electronics and then gets regulated down inside the headunit etc as needed.

People do run lots of lights and overload there alternators, but they are the same people always chasing new alternators when they burn them out.

Im no expert on it but id say that when the alternator gets near max current it should just drop the voltage back when it cant keep up, eg put out 13.2V or something instead of the full 14.4V. Thats what alot of generators will do.

[stocker]

Ben_Sierra wrote:

Remember, the alt, and all the electrics run at more like 14.4 Volts when the car is running, not 12...

This is a lie and we all know it . Most of the time an Alternator will only punch out around between 13.7 and 14.1... you have to allow for internal losses in the Generator. not only that. when it goes through the rectifier and converts from singlephase AC to single Phase DC You get a loss purely from the conversion of the Sinewave and heat Dissipated. 8D

As for your power problem... either don't turn all your lights on at the same time or upgrade the altenator PS: its more like 30A Draw from ur lights

[31zook]

Glavas wrote:

31zook wrote:

it's a dead easy upgrade btw

Exactly the same on the 1.6 as the 1.3?

i believe so....

[Glavas]

Teracis wrote:

Remember you've got your battery in there as well and you don't run at full load all the time.

I.E. you go for a drive at night and are running under full electrical load. so you take your 37 amps for the lights (i'm lazy) and then your other load (ignition + stereo e.t.c)

Now, if this is over the 45A produced by your alt (at the 14.4 it produces) then instead of being able to power your car and charge your battery, it will be unable to supply enough current and without doing any calculations I think the voltage drops to battery voltage and the battery starts supplying current as well.

So you can think of it like a water tank. You put the hose in for an hour in the morning and an hour in the afternoon (driving in the day with bugger all load so you're charging your battery at a high rate) then, you go for a drive at night under full load which is like turning the tap on at the bottom of the tank.

Now, as long as the amount of energy you're putting into the battery (daylight driving) exceeds the amount you're taking out (nighttime driving + starting e.t.c) then your battery will stay charged and you won't notice. Until you go on a long trip at night and you're using energy from the battery (because you're well over the alternator output) and you're out long enough to drain the battery.
Now, if you did have this happen and things started to dim, Ideally you'd turn the lights off immediately and this would stop the car from stalling, I don't think you'd get much warning though.

I'm only a normal sparky not an auto sparky and I just woke up, but that's the basic theory of it.
SHORT VERSION You have a system with a storage device and a fixed input. If you take more out than the input then you are removing energy from the storage device, if the output drops below the input, you start topping up the storage. If the output stays higher than the input long enough, you will empty the storage device.

If I've confused you let me know, options are increasing the input (upgrading the alternator) which is the best fix.
Increasing the storage capacity (running a dual battery, which is a bandaid fix to give you a longer overload time).
Decrease the output (turn off the lights :p).

Ideally you would change alt's and run dual batteries but that's more expense! If you're super worried you've overloaded it, find someone with a dc current clamp meter and run everything while measuring the current draw on your alt + battery.

Good luck with it.

Thanks, a great help boys.

Headlights are being rewired for the globes with relays.

I have a current clamp I didn't think the battery would be able to supply the current!

I guess I'll order in an EL alternator and do the conversion.