What Size Fuse for Lights?

[tntatro 174]

Hello, I have a 1968 Raider 9 repowered with a K301. I'm fixing the lights and tail light and I might put a new cigarette lighter in if the original doesn't work. The lights I have are the LED that fit in the original light sockets. I don't know what the watts are but they are 1650 lumens. Anyone know what size fuse should be used if I add a lighter and what size if I decide not to add the lighter? I have an accessory tab on the key switch so I was planning to use that and put the fuse between the key switch and lighter or if I don't add the lighter I'll put it between the key switch and light switch. The original wiring diagram doesn't have a fuse and looks like it was wired to the battery tab on the key switch. Or should the lighter and lights have their own fuse for each or do I even need a fuse? Or would it be better to wire the lighter to the battery? This is not my tractor so I'm trying to make it reliable.

Thanks, Tim

[Maxwell-8 4,306]

1650 lumens is about 16.5W 

so 33Watt in the front, In the back? 

33w/12v= 2.75A so 5A or 7.5A would be plenty

 

Lighters are often fused to 25-30A, But the electrical system on a Wheel Horse can't deliver that amperage so I would fuse it to 15-20A.

 

I would wire the lights and lighter separate.

Edited Friday at 11:01 PM by Maxwell-8

[ri702bill 8,507]

16 minutes ago, Maxwell-8 said:

I would wire the lights and lighter separate.

 

That way it make diagnosing issues easier...

[tntatro 174]

Thanks for the replies. So would it be better to wire the lighter to the battery terminal on the key switch or wire both from the accessory terminal with a different fuse for each?

[squonk 41,350]

Any circuit on a tractor can deliver what ever amperage is inside the battery for a second. If there is 100 amps in the battery, a short to ground in any circuit will try to deliver the whole hundred amps until whatever wire or device in the circuit burns up. A lighter Is capable of drawing over 20 amps. Wire a lighter with 12 ga. wire and install a 20 amp fuse. If possible check the amp draw of the lighter. You can go up to 30 amps with 12 gauge. The fuse would still protect the tractor in case of a short.

Edited Friday at 11:33 PM by squonk

[953 nut 55,827]

Fuses in a wiring harness are there to protect the rest of the wiring from a short circuit. Keep your fuses as close as reasonably possible to the battery or ignition switch. Buy good quality 30 Amp fuse holders and install your first fuse (30 Amp) between the battery and your ignition switch. Most lighters draw 7 to 15 amps so I would suggest a 20 amp fuse for it. The lighting could be a 15 or 20 amp fuse even though it will not draw much amperage with LEDs.

40 minutes ago, tntatro said:

Thanks for the replies. So would it be better to wire the lighter to the battery terminal on the key switch or wire both from the accessory terminal with a different fuse for each?

I wouldn't run the lighter through the ignition switch, depending on how often it is used the lighter could shorten the life expectancy of the ignition switch. Connect it through a fuse directly from the battery.

[Handy Don 12,467]

24 minutes ago, 953 nut said:

I wouldn't run the lighter through the ignition switch, depending on how often it is used the lighter could shorten the life expectancy of the ignition switch. Connect it through a fuse directly from the battery.

This method has other advantages -- the lighter socket makes a convenient place to plug in a trickle charger. You can also use if for powering something with the engine not running -- like of those small compressors for filling tires or a phone charger.

Just be sure the lighter isn’t pushed in and sticking when you leave the tractor.

[tntatro 174]

Thanks for all the replies, they're very helpful. So I'll use 12 gauge wire for the lighter directly from the battery with a 20 amp fuse. I guess I'll have to get a better fuse holder because the ones I have are for the smaller sized fuses. The lights sound more forgiving. I'll probably use 14 gauge wire and a 15 or 20 amp fuse with my small size fuse holder.

The owner of the tractor is not a smoker but since it has the lighter he may find it handy to use it for other things. Now I want a lighter on my Wheel Horse.

[953 nut 55,827]

10 hours ago, tntatro said:

I guess I'll have to get a better fuse holder because the ones I have are for the smaller sized fuses.

These are for the smaller fuses also but have heavy duty contacts.

https://www.google.com/search?q=30+amp+weathertight+use+holder&rlz=1C1JZAP_enUS981US981&oq=30+amp+weathertight+use+holder&gs_lcrp=EgZjaHJvbWUyBggAEEUYOTIKCAEQABiiBBiJBTIKCAIQABiABBiiBDIKCAMQABiiBBiJBTIKCAQQABiABBiiBDIKCAUQABiABBiiBNIBCTU2NTgzajBqN6gCALACAA&sourceid=chrome&ie=UTF-8

[Kenneth R Cluley 535]

Also, be sure to check ground on hood to eliminate issues with headlights! May have to add ground wire from hood to frame or engine block.

[Handy Don 12,467]

16 hours ago, tntatro said:

So I'll use 12 gauge wire for the lighter directly from the battery with a 20 amp fuse. 

The owner of the tractor is not a smoker but since it has the lighter he may find it handy to use it for other things. Now I want a lighter on my Wheel Horse.

12 is A LOT more than you need. Stranded 16 is plenty, even for the lighter, and much easier to work with. 12ga in house wiring can handle a 20 amp fuse at 120 volts, TEN TIMES the voltage of your horse!

 

The jungle site has lots of panel-mount 12 volt sockets with weather tight lids for marine use. I’ve installed them on two tractors already.

[tntatro 174]

I was only able to wire up the tail light today. I bought a fuse holder with 12 gauge wire and some 12 and 14 gauge wire. The fuse holders I already had have 16 gauge wire. The tail light didn't work with the key in the on position so I'm guessing it needs a better ground but I had the negative battery ground cable unhooked and just set it on top of the negative terminal so that could have been the problem.

 

5 hours ago, Handy Don said:

12 is A LOT more than you need. Stranded 16 is plenty, even for the lighter, and much easier to work with. 12ga in house wiring can handle a 20 amp fuse at 120 volts, TEN TIMES the voltage of your horse!

 

I'll keep that in mind for future projects. I really don't know much about wiring stuff up so I just try what people tell me or what I see in videos. I already bought the wire. The old wire was still there, just cut and unhooked. It appears to be 12 or 14 gauge. I see how 16 gauge would be easier, especially in 30 degree weather.

Edited Saturday at 10:58 PM by tntatro

[Handy Don 12,467]

2 hours ago, tntatro said:

I was only able to wire up the tail light today. I bought a fuse holder with 12 gauge wire and some 12 and 14 gauge wire. The fuse holders I already had have 16 gauge wire. The tail light didn't work with the key in the on position so I'm guessing it needs a better ground but I had the negative battery ground cable unhooked and just set it on top of the negative terminal so that could have been the problem.

 

 

I'll keep that in mind for future projects. I really don't know much about wiring stuff up so I just try what people tell me or what I see in videos. I already bought the wire. The old wire was still there, just cut and unhooked. It appears to be 12 or 14 gauge. I see how 16 gauge would be easier, especially in 30 degree weather.

The original wiring for most horses was 16ga except for the 6 ga battery cables (there were some other exceptions--like with the electric lift actuator.)

[kpinnc 12,539]

Back during my early days in the Army, I (and a couple others) was working on replacing the TADS turret on an AH-64 during a 500 hour phase inspection. As with most military equipment, we had break out boxes to duplicate many functions. On this particular day we were using a little box that supplied low DC voltage to the turret so it could be manually rotated in azimuth. All it did was release the mag brake. 
 

Anyway, it used a 10-amp barrel fuse, and it was blown when we opened it up. Of course we didn’t have a fuse. So my buddy stuck a Phillips screwdriver in the barrel and it worked. When the shop supervisor saw it, he scolded us for such a stupid decision. Without missing a beat, my buddy disagreed and said  “Boss, it would take a couple hundred amps to burn that screwdriver out”… The supervisor shook his head and walked away. You could hear him grinding his teeth from the opposite side of the hangar… 
 

Point being? Never use a fuse that can handle more amps than the wiring it is attached to. It’s meant to be the weak point in the circuit for a reason!  

Edited Sunday at 06:43 AM by kpinnc

[Handy Don 12,467]

9 hours ago, kpinnc said:

 “Boss, it would take a couple hundred amps to burn that screwdriver out”…

So did anyone ever tell the pilots?

 

When I was young I could not understand why so many of my classmates had trouble with math and science and technical concepts. I assumed (yes, pun intended) that they were just not putting in the effort to learn.

Only much later did I realize how significant it was that different people: a) learn in different ways, 2) have different aptitudes, and 3) were not exposed, as I was, to math, mechanics, construction, literature, and technology at home. The revelation has influenced my relationships ever since. I am not smarter than others, I probably do know different things.

[tntatro 174]

10 hours ago, kpinnc said:

Point being? Never use a fuse that can handle more amps than the wiring it is attached to. It’s meant to be the weak point in the circuit for a reason!  

That makes sense, thanks for that and the story. 

I really appreciate everybody's comments. Now I can approach this and future projects with a little more understanding and common sense. 

[squonk 41,350]

I was working on a heating actuator. Low voltage 24 volts AC with these tiny 20 ga. wires. The wires touched and the arc they threw scared the crap out of me. Just because the voltage is low and the wires are small, don't ASSume the amperage will be limited. 

[adsm08 2,183]

3 hours ago, Handy Don said:

So did anyone ever tell the pilots?

 

When I was young I could not understand why so many of my classmates had trouble with math and science and technical concepts. I assumed (yes, pun intended) that they were just not putting in the effort to learn.

Only much later did I realize how significant it was that different people: a) learn in different ways, 2) have different aptitudes, and 3) were not exposed, as I was, to math, mechanics, construction, literature, and technology at home. The revelation has influenced my relationships ever since. I am not smarter than others, I probably do know different things.

 

 

Amen.  Over the years I've been in auto repair I've worked with a lot of guys who thought I was a genius. I tell them all the same thing: "My only special skill is reading the book".

 

I do find electrical is very common for people to struggle with because so much of it is concept and so little is concrete. I've found that if you can explain it with analogies to other more accessible ideas most people get it. I like to use plumbing/water flow, especially when talking about resistance and open-circuit voltages.

[kpinnc 12,539]

4 hours ago, Handy Don said:

So did anyone ever tell the pilots?

 
Oh no, the fuse could have only damaged the test box. We never played games with the mechanics of the helicopters themselves. 
 

…of which I was most thankful for many years later. 

[kpinnc 12,539]

1 hour ago, adsm08 said:

I've worked with a lot of guys who thought I was a genius. I tell them all the same thing: "My only special skill is reading the book".

These days my friend, that makes you a genius! 

 

And all joking aside, it is always a good idea to read the bleeping directions! RTFD!!!! 

[adsm08 2,183]

3 hours ago, kpinnc said:

These days my friend, that makes you a genius! 

 

And all joking aside, it is always a good idea to read the bleeping directions! RTFD!!!! 

 

 

Yeah, the irony is that many times the way the instructions say to do something is so awful and inefficent (in a business that rewards little except for efficiency) that one of my catch-phrases at work is "under no circumstances should the instructions be read, followed, or understood".

 

The incident that coined that one was the removal of a fan blower motor from an Ecosport. The instructions have you tearing the front seats,  the wiper motor, and the dash out. Job is supposed to pay 3 hours, but dash removal pays 6. I figured out how to remove and reinstall it in about 1, removing only 3 other pieces, two of which the instructions tell you to leave in place.

[kpinnc 12,539]

6 hours ago, adsm08 said:

Yeah, the irony is that many times the way the instructions say to do something is so awful and inefficent (in a business that rewards little except for efficiency) that one of my catch-phrases at work is "under no circumstances should the instructions be read, followed, or understood".

Almost nothing more dangerous than an engineer…

 

Except maybe someone trying to transcribe something an engineer says? 

[adsm08 2,183]

On 12/23/2024 at 2:58 AM, kpinnc said:

Almost nothing more dangerous than an engineer…

 

Except maybe someone trying to transcribe something an engineer says? 

 Earlier this year my sister, who lives 1500 miles away, was complaining that everything started breaking right when her handy-man decided to go to Ireland for two weeks, and so she was begging me to come fix things for her.

 

I just responded "You married an engineer, I imagine there are many things in your life that don't work right."

[953 nut 55,827]

On 12/22/2024 at 3:28 PM, adsm08 said:

"My only special skill is reading the book"

Kids today don't want to read and learn, they just want to watch a video.         

[SylvanLakeWH 25,965]

16 minutes ago, 953 nut said:

Kids today don't want to read and learn, they just want to watch a video.         

While true, there are many advantages to having a video to watch as you work on these little 's...

 

I for one found enormous value in having a C-105 sitting next to my two black hood rebuilds... seeing it live is often as beneficial as reading about it... which I also did...

 

There's a reason pics are worth a thousand words...