Question for the tractor electricians

[RFB]

I have an Kubota L5030HSTC.

It has four 27watt work lights (2 front/2 rear) on a single 15 Amp fused circuit.
(There is only one 15 Amp fuse in the block that is marked as the position for "Work Lights".)

I want to change those lights out for four 50 watt work lights, which will exceed the circuit rating by about 1.6 amps. (16.6 amps on a 15 amp circuit)

If I were to replace the 15amp fuse with a 20 amp fuse, that would solve the first step.

The real question is: Is that extra 1.6amps significant enough to seriously overload the circuit wiring?

 

[bigdad]

That's a good sized Kubota, do those big ones have a big enough alternator to handle the increased load? I would worry about that before the wire size.

 

[kennyd]

No way would I do that! You have no idea what the switch is rated for, or the plugs in the harness's, or the sockets, or even the gauge of all the wiring feeding the light circuits

 

[RFB]

bigdad: The 60 amp alternator will handle the output.

kennyd:

With all due respect since I did ask the question, but I do know what the rating is on all of those components: 14.99 amps. Otherwise it would not be fused at 15 Amps.

My question is, from an electrical engineering standpoint, whether or not an additional 1.6 amps is beyond the capacity of those components, excepting the fuse itself?

Pertinent to the question is also the fact that the additional 1.6 amps is distributed between 2 different switches and circuits, coming into one fuse block location, so each switch/light circuit is only seeing an additional .61 amps beyond rated capacity based up[on a 15 amp fusing.

The original lamps are 27 watt which equals 2.25 watts. (50 watts at 12 volts equals 4.16 amps). Nonetheless, the circuit is fused at 15 amps, so that must mean that amperages below 15 are "safe". Is an additional 1.6 amps pushing the components too far.

 

[kennyd]

If you plug a heater into an outlet in your house-and it pops a circuit breaker, Would you install the next higher rated breaker to solve the problem?

When doing your calculations for current draw, use 13.8 volts instead of 12 volts. That is the approximate voltage the alternator puts out the charge the battery.


Edit: Changed 3.8 volts to 13.8 volts

 

[RFB]

keenyd,

Are you saying that my 60 amp alternator will not (through the voltage regulator) charge the battery at a level higher than 3.8 volts?

 

[SPYDERLK]

keenyd,

Are you saying that my 60 amp alternator will not (through the voltage regulator) charge the battery at a level higher than 3.8 volts?

He meant 13.8. I think you will have no trouble with the slight overload. Where it will show up 1st if it shows at all will be connectors or switches. If resistance develops at a such a contact/connection the higher load will cause heating to be more critical.
larry

 

[RFB]

From the engineering standpoint, I was using 12 as the conservative figure and hoping for the 13.8 for even a little more flexibility.

His 3.8 confused me so I started searching for battery charging capacity and came up empty. (My traditional knowledge was 13.8.)

The switches themselves will realistically see only a about a 1.7 amp increase going from the 27 to the 50 watt lamps. (2 switches/4 lamps)

Thanks

 

[mjncad]

RFB:

What gauge wire is used in your rig's lighting circuit? Are the lights run directly through the switch, or through a relay, which is common practice for automotive lighting circuits such as headlights and work-lights.

My concern in your case is switch rating, existing wire gauge and condition, and length of wire run that could result in excessive voltage drop.

I just tested out my latest wiring and lighting modifications today, and I ran all my lights through relays where 18 gauge wire from the switch activates the relay's coil. The wire from the relay to the lights is 14 gauge. The lights I bought appear to have come with 18 gauge pigtails. It would have been easier, simpler and involved less wire to eliminate the relays; but since relays are accepted practice, who am I to argue with those who went before me.

Although I special ordered my tractor, I can't remember if I ordered the extra capacity alternator or not and my sales paper work doesn't list the options I ordered, just the tractor and implements. I looked at the Denso alternator's rating plate today, and no where to be found was an amp rating, unless it is buried in manufacturer's code; however the voltage rating was readily apparent. I have a hunch an alternator will be on the project list.

 

[mopacman]

I think I would try it on the 15 amp fuse first it might work, then go to the 20 amp fuse. The only time I have had trouble with switches is when I have gone from 2 bulbs to 6 bulbs. I think the switches will be the week link. If you deside to change wiring I would go to a relay system and use the switches and wire you have now to operate the relays and add a new circuit for the lights but I dont think you will need it......Larry