Alternator question

[mathews xt 600]

For some reason I can't do a search. Do I need the 40amp alternator to run two small work lights. Thanks

 

[Daren Todd]

If you go with LED's, you can add as many as you want with out worrying about taxing the current alternator

 

[mathews xt 600]

OK good to know thanks

 

[North Idaho Wolfman]

To give you a complete answer, need to know what tractor your dealing with!

 

[85Hokie]

For some reason I can't do a search. Do I need the 40amp alternator to run two small work lights. Thanks

Like NIW said, need to know that tractor model to know how many amps your alternator is rated. But the LED lights that Daren pointed out - you can run those with the tractor OFF for hours at a time!!

Even a small output alternator will light up those 4" round or square lights. They typically use < 2 amps each. I have 4 of these LED lights and there is no sign of high amp draw across the single circuit.

I would NOT get typical lights with filaments = the LED will last a good long while the prices have dropped down to nothing and they provide a lot of light.

http://www.amazon.com/TMS®-1260LM-C...TF8&qid=1433271454&sr=8-2&keywords=LED+lights

http://www.amazon.com/TMS®-18w-1260...TF8&qid=1433271454&sr=8-9&keywords=LED+lights

less than 10 bucks a light, were closer to 25 bucks a light a few months ago!

 

[Bulldog]

How does a 18w light compare to standard lights? I have never used any of the work lights before. I had a chance to buy a 300w light bar but wasn't sure if it would cause problems or not.

 

[ShaunBlake]

How does a 18w light compare to standard lights? I have never used any of the work lights before. I had a chance to buy a 300w light bar but wasn't sure if it would cause problems or not.

18 wats is a lot of LED light... or sometimes a nice glow. It depends on the circuitry that drives the little buggers. Development of the LED has improved/evolved to the point that almost everything offered is of excellent quality, so you don't need to pick Cree (as my ignorance led me to do) over Phillips; Edison over Nichia; etc.

However... the circuitry is all over the map, and there is no yardstick like name brands for identifying good quality. And worse, very fee vendors provide the light output data -- they all seem determined to camouflage that by bragging on their wattage. BS!

Safest route is to demand the Kelvin color of the light, and view high-resolution pictures of their lights illuminating something you're accustomed to seeing (empty field; trees; ditches; rocks; whatever). The K color will help you see better, according to your environment and your tasks. Harsh white might be better for you to pick up detail, or warm white might let you look for longer periods without eyestrain (and I don't mean that hard white will cause eyestrain -- warm white might be a bigger culprit if you have to strain to pick up detail).

I've gone on and on, and haven't covered much. Best choice #1 is buy an inexpensive light and try it out. Use its specs to evaluate other lights whose specs come closer to your preferences/needs. Best choice #2 is buy from a vendor who will accept no-question returns try-and-return until you hit the pleasing arrangement.

HTH,

 

[Stubbyie]

Having the power available to operate lights has virtually nothing to do with the tractor itself.

Concentrate on the alternator output measured in amps.

Original poster mentions a possible 300-watt light bar.

Use this conversion, next below, and you can go back and forth in calculating the required power.

"Watts = Volts times Amps"
or saying exactly the same thing but just rearranged a little bit
"Amps = Watts divided by Volts"

For the 300-watt lightbar...

Amps = 300-Watts divided by 12 Volts
Amps = 25-Amps

Another part of the puzzle is the battery. Lights are going to run off the battery while the battery is being recharged by the alternator. A large draw on a small or weak battery will discharge the battery because for whatever reason the alternator won't keep up. The alternator does not "force" the battery to accept a charge---the battery governs how much charge it will accept from the alternator.

If both the battery and alternator are in optimum condition the power genereated by the alternator should 'pass through' the battery and power the lights while the battery remains static in its storage capacity or perhaps even loses some storage, depending on the power draw.

For a huge power draw (parade float pulled by tractor) have had to use two batteries wired in parallel to have enough power no matter what the alternator was producing. Same thing in emergency vehicles (lights, 200-watt siren) or for winches on trucks.

Best today is to spring for LEDs and forget about them after properly installing: plenty of power, plenty of alternator output, plenty of light, plenty of reserve battery capacity.

Please post back your continuing experiences so we may all learn.

 

[Bulldog]

Stubbyie, the light bar that boy is wanting to sell he said according to the paperwork that it only draws 8.2 amps. That just doesn't seem right for a 300w light. What do you think?

ShaunBlake, he said it's 6000K on the color. Like I said before, I haven't had any of these yet and know nothing about them.

Thanks for the info from both of you.

 

[85Hokie]

Stubbyie, the light bar that boy is wanting to sell he said according to the paperwork that it only draws 8.2 amps. That just doesn't seem right for a 300w light. What do you think?

ShaunBlake, he said it's 6000K on the color. Like I said before, I haven't had any of these yet and know nothing about them.

Thanks for the info from both of you.

In the old days - and many of us still get hung up on WATTS and light......my mom will not listen will I tell her that WATTS aint got shyte to do with the light that is being produced - OTHER than higher in watts = more light, which is true. BUT.....

Watts is a term of electrical usage, or HOW much power is being used to make "light"

these days - LED lights are making a hellva lot more light per unit of watt!!!
We are creating ways to make the same amount of light with far less energy - or watts.

The real way to determine the "light" is to see how much light we are talking about - LIGHT amount is measured in LUMENS - this is how much light you are going to see. Most LED lights put out not too many lumens, but you pack them little buggers in tight, and you get a huge amount of light in a very small package. Here is a good article on Lumens and watts :

http://lumennow.org/lumens-vs-watts/

I bought a "shop" light for my new shed that I park my BX-25D in, I debated over and over to get the ol' fashion 4' tubes......by the time I buy the unit and 2 bulbs (25 + 8 + 8 bucks) I would be cussing in the cold when that ballast cant get the lights to burn, and then i will replace the bulbs. So I went to Lowes and found a LED 4' bulbless light.......looks sorta like a 4' tube type, except there are no tubes, no ballast.....and for about 50 bucks, it make a shyte load of light, almost blinding light!!!! The total watts is about 1/4 of the tube types too and the light is instant, no flicker no nuttin but light.

When buying for a 12 volt system - you DO have to pay attention to the WATTS still, because it will boil down to the amps being used by the lights.
We all determine watts = volts x amps. And this is true - a 100w will draw about 8.3 amps when the battery is being used.....however, once the alternator is on the volts will increase to about 13.4 or higher... which in turn will lower the amps a bit to closer to 7.5.

Moral of the story - look at Lumens - and then look at amp draw to determine the load on the alternator/battery!

 

[ShaunBlake]

...

... Lights are going to run off the battery while the battery is being recharged by the alternator. A large draw on a small or weak battery will discharge the battery because ...

both battery and alternator in optimum condition [current] should 'pass through' the battery and power lights ...

Best today is to spring for LEDs and forget about them after properly installing ...

My goodness! What a great treatise! About the only thing you didn't mention is the effect of the 'pass-through' on the battery. This ought to be added to the OTT Articles!

Kudos, my man!

 

[ShaunBlake]

... WATTS aint got shyte to do with the light that is being produced - OTHER than higher in watts = more light, which is true. BUT.....

Moral of the story - look at Lumens - and then look at amp draw to determine the load on the alternator/battery!

Another great explanation, covering another aspect of the issue. Not so simple an issue as it would seem!

I would add to your comments about watts that higher watts ***8800; more light. As you alluded to, current is lost on the way to the little Light-Emitting Diode buggers, but the biggest problem is that MUCH current is lost in the circuitry of the "pump" that powers the little buggers. Some designs are great, and some suck.

And the thing that REALLY sucks is that the folks who put out crappy stuff boast about how much WATTS they consume, and keep secret how many LUMENS they produce.

Think of that as if Kubota boasted about how much fuel your tractor consumed, and kept secret how much horsepower it had. Pretty stupid, eh? Yet that's the kind of marketing we are being asked to accept.

 

[Stubbyie]

I posted a response concerning primarily how to use a simple formula to determine volts, amps, and watts and how they all relate one to the other.

Mr. BullDog then responded with additional information concerning the current draw of the lightbar in question.

What I think is happening is also under discussion by Mr. ShaunBlake in his posting(s): confusion over terms.

The lightbar was probably advertised as producing light "equivalent to" 300-watts while "only consuming" some smaller number of "real electrical watts".

For instance, look at the curly-cue CFL in your home: says it produces 100-watts of light but uses only xxx-watts (varies slightly by brand and marketing hype).

We need to uncouple the conversation and consider lumens (actual light output) or candelas (I forget which is more technically accurate these days as isn't my field and besides, things change (hertz or cyles-per-second: too-may-toe or too-may-tah)).

Go for maximum light output per electrical watt to maximize system efficiency. Just divide lumens (or whatever) by 'real actual' electrical watts consumed. Go for the higher value of a group. Just be certain all the terms being compared are the same 'name'.

My memory is that conversation between 'lumen' and 'candela' isn't simple or generally accomplished without a lot more data than we have to work with. Try calling up a major flashlight manufacturer (as used in fire rescue or industrial explosive atmpospheres) and asking what their numbers mean and provide a comparison. They know precisely, but won't tell you. This allows the marketing types to play games with consumers. You can also toss in 'luminosity' as another term used to intimidate and confuse consumers. Seems like 'candelas' have a certain fluidity in how the value is determined and can be somewhat jiggled to suit the need.

Another topic is light color in degrees Kelvin ("K"). I like a warmer (subjective) yellowish light; that bright blue-white-desert-glare just kills my old eyes at night when working up close on something and seems to produce more shadows and reflections and stark black-white areas. Best bet is to refer to that manufacturer's color chart.

Get an LED that looks good on your machine and that lies within your budget, install it properly (sufficient wire size, grounding, fusing, and switching) and forget about it. If you need more light add another fixture.

On fusing: LED is an "electronic" device, just like a radio. To prevent (or at least limit) possible 'electrical backfeeding', I fuse radios, anything electronic, and LEDs on both positive and negative lines, close to the battery, and always connect both sides directly to the battery.

I've seen some horrendously expensive LED light bars (again, emergency service-type stuff or high-level contractor) that I just can't see as being cost effective for the average consumer. Lots of kids running LED lightbars on pickups around here that the LEDs cost more than it would to replace the truck.

Thanks for continuing the conversation and my apologies for the delay responding. Had to actually do something for a few days.

Please post back comments and observations and to the original poster, how you proceed so we may all learn.