Thread: Overloading Electrical System

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Is it possible to fry the electrical system by plugging too many accessories into the lighter? I have a high-powered 1 million candle spotlight for the bush, but I have been advised that it may blow the alternator. Is there any truth to this? If I turn off all other electrical appliances, will it ease pressure on the system?

It should only blow the fuse. I tried hooking up a generator through a power inverter in my Ranger during the Great Midwest Blackout a couple years ago. The inverter could handle the power draw, but the lighter circuit could not (hey, it was all I could think to do on short notice ). I replaced the fuse and no problem.

Well, it really depends on how much of a load it puts on the system, what the alternator is rated for, and how often you use it.

Now, I agree with Swifster that if there is too much current draw in a given circuit, it should blow the fuse; but, say for example it runs to 95% of the max draw on the circuit and you operate it for a given period of time. The fuse may never blow but it could indeed damage your alternator, by (believe it or not) damaging the electro-mechanical components of the alternator.

Think of it like this, any time you draw current from an alternator, you are creating a larger electro-magnetic resistance to the spin of the alternator's guts (thats a technical term there ). This is why when you kick on the heater and the radio at idle for example, your engine rpms drop a little. The more current you draw from the alternator the more physical resistance you create, and as such the more heat you create inside the alternator. Do it enough and yeah, you can, as you put it "fry it" without ever blowing a fuse.

Hope this helps,
Dutch

no its no truth to that. you bat. is made to carry a certain load for a certain amount of time whether you have an alt hooked to it or not. if you left the light on all the time with the motor running and the alt. couldn't keep the bat up then your bat would go dead but that shouldn't burn the alt. up. you would be taking more amps. out of the bat. than the alt could put back, so you would need to go to a bigger alt. but if you're just use a light every now and then for short period of time then go for it. its not gonna burn up anything just because you pluged it in.and if its a short in the light then it should blow the fuse, if for some reason its to much load for the wiring then it should blow a fuse. if youer gonna do this for long periods of time then you will need a bigger bat and higher amp. alt.

If it is a valid comparison, I have a Million Candle power light that I use in my boat. It also plugs into the cigarette lighter. Been using it for years and it never burned out the alternator in my ourboard motor, nor did it ever run the battery down. It also never blew the fuse. If those things did what you say I don't think they would be as popular as they are. If you are concerned about it, get one of the ones with an internal rechargable battery.

Pat

Originally posted by DennyW
You and Mike are right on this. I just looked up amp rateings. 3-5 amp is no problem at all. Should work fine. I don't know what I was thinking. I think it was like a bush truck with multiple lights, hahaha.

you'er slipping dennyw, You must have had a bad new yrs. Im gonna have to fire you and hire you back for less money.

Originally posted by DennyW
I hear ya. Got a headach today. I may just sit answering out for today, hahaha.

that lady done got you all shook up.

You should only run 80% of the the rated load on the alt to prevent damage. A 60 amp alt should be able to handle a cont 48 amps. At least that is how electrical is rated on everything else. For example a 100 amp transformer can not be loaded more then 80% of its rated load or 80 amps. This is done to prevent overheating and damage. The same thing applies to wire. But generally wire is larger than what the maximum load is. I know this because I am a licensed journeyman electrician. Look it up in the National Electric Code. It does not apply to automotives in the code but electricity is electricity. We use deep cycle marine batteries wired in series to run 277 volt lighting and such.

Originally posted by jramshu
You should only run 80% of the the rated load on the alt to prevent damage. A 60 amp alt should be able to handle a cont 48 amps. At least that is how electrical is rated on everything else. For example a 100 amp transformer can not be loaded more then 80% of its rated load or 80 amps. This is done to prevent overheating and damage. The same thing applies to wire. But generally wire is larger than what the maximum load is. I know this because I am a licensed journeyman electrician. Look it up in the National Electric Code. It does not apply to automotives in the code but electricity is electricity. We use deep cycle marine batteries wired in series to run 277 volt lighting and such.

jramshu, you're not comparing apples with apples. the guy was asking about a light that you plug into the lighter. you don't believe that ford and gm figured in to their charging system a little lead way? i don't believe any one thing that you can buy that's made to run off of the lighter is gonna burn your alt. up. he was told he could do it , now you are telling him don't go over 80%. he don't know what 80% of his system is ,but now he still don't know what to do. Tell him it will be ok to run his light some times and he don't have to worry about burning his alt. up.

I believe a lighter is 20 amps so you can run a max of 16 amps on it. Take the watts and divide them by the volts and that gives you the amperage of the device. For example 200watts divided by 12volts equals 16.6 amps. That is pushing the circuit. Check out this site.
http://www.zena.net/htdocs/alternators/alt_inf2.shtml

It still has wattage. Candlepower just tells you how bright it is. Wattage is actual amount of electricity that is used.

Originally posted by lt1s10
jramshu, you're not comparing apples with apples. the guy was asking about a light that you plug into the lighter. you don't believe that ford and gm figured in to their charging system a little lead way? i don't believe any one thing that you can buy that's made to run off of the lighter is gonna burn your alt. up. he was told he could do it , now you are telling him don't go over 80%. he don't know what 80% of his system is ,but now he still don't know what to do. Tell him it will be ok to run his light some times and he don't have to worry about burning his alt. up.

Electricity is electricity whether ac or dc. So I am comparing apples to apples. And yes they did put some lead way. It is called the wire size and the ampacity of the fuse block. That way you can go to a higher alternator if necessary. I believe most are #4 going to the fuse block which is good for a little over 100amps. Most cars I have run into are like that anyway. But to make it short no a spotlight will not burn up an alternator.
Like I said before the sometimes hostlie enviroment of CHR comes out again.

So what is the formula for candle power?

CandlePower The unit for measuring the quantity or intensity of light energy emitted by a directional lamp (i.e., narrow spot, spot, flood, wide flood, etc.).

CandlePower is expressed in Candelas. Confusion is caused for some when one manufacturer lists a lamps CandlePower as "Center-Beam CandlePower" while another notes it as "Mean CandlePower" while still another uses "Candela" as the heading for the same information in their Lamp Data Chart. Any of these listings refer to the lamp CandlePower and are considered to be the same.

CandlePower is used in the Inverse Square Law calculation.

Some texts indicate that 1 candela = 12.57 lumens; do not try to convert lumens to candelas using this formula. Results will be inaccurate.

Originally posted by DennyW
We are talking candle power

jramshu i have no idea what amps. a 1 million candle spotlight would draw, but i wouldnt worry about pluging it into a lighter to see if it burnes or not. thats the reason they put fuses in the system.