Confused about lights...B7800

[idaguide]

I'm really feeling stupid that I can't figure this out. I've searched and read all kinds of posts here about adding lights to tractors, but I'm still not sure what to do.

I own a B7800Kubota with about 70 hours on it. First tractor. Love it. Can't believe what I'm gettin' done. You folks here have been a great help, particularly in making we work SAFER!

I need to add lights, like everyone else, to plow snow at night. After reading all these posts I'm worried about burning out my alternator, so have come to a standstill.

There is a spare wire ('stubbed'?) off the rear lights. Was told it's where to add the lights. Question is, can I add three 50 Watt Halogens (two forward, one backward) on here without burning something out? Do you string them in a series (like Christmas tree lights), or all from the same point? Do have to put fuses in line? Is it better to have switches right on the lights?

I'm good at wiring houses, but don't understand it on vehicles. I'm hoping that someone with the same tractor--or similar--can cut to the chase for me. Most of what I've been able to find here has been, frankly, over my head.

Thanks in advance for any help you can give me.
grae

 

[6sunset6]

I am sure others will pitch in but I will give you my 2 cents. The stub at the back if it came from the factory should be fused someplace. Hang a meter on it or a 12 v light bulb and pull fuses till you find it. DC is really simple, Volts times amps = watts. So if the fuse you find is 10A times 12 v you can power 120watts on that wire like 2 55w lamps. If it's a 15 A fuse then you can power 180w 3 55w lamps would fit right in. Most likely it will be one or the other. In reality alternators put out more like 14 v but stick with 12 for counting. I am guessing but I think if you stick with those number your alternator will be fine. If there is no fuse ( hard to believe but could be) then it gets a little harder. You need to find out what the alternator is putting out, just to be safe. what ever it is use an in line fuse for what ever you need or can get out of it. To the switch You can mount a switch and use it for all of them but if the stub is in the back might be easier to get a light with a switch on it. or lights. This should get you started.

 

[idaguide]

Thanks, Bob.
g

 

[6sunset6]

oh yeah forgot wire size #14 is good for 15 A AC DC probably a little more than that # 16 would probably run one light ok. but small for more than that. They will just be dimmer than they should be and the wires will arm up a little.

 

[idaguide]

Bob,
From your example, does that mean that if I find a 10amp fuse, but want to put three lights on, I can replace it with a 15a fuse?

Or does it not work that way?
grae

 

[6sunset6]

not usually it depends on the wire size and other demands on the system. If it is a factory fuse I would not replace it with anything bigger. If it's 10 amps use one light front and one light back. For plowing I think there is so much reflection off the snow it would work fine. If it's for mowing point them both to the front . On my machine the front lights are built in . I had a stub on the back and I added a light with a switch on it. But my stub powers up with the ignition switch also. I have a second stub on the other side I use for a 12 volt demand pump on my sprayer. It comes on with ignition but the pump only runs when I spray i.e. on demand. Little off your track but I was on a roll.

 

[number two]

Not to forget the Kubota B7800 comes standard with the dynamo,not an alternator. The dynamo only puts out something like 12-14 amps. You can't run many lights on that! An alternator kit is available for a little less than $200from Kubota. There have been some threads in the Kubota Owning/Operating section dealing with adding lights,dynamos,and adding alternators. Perhaps a search will find you some more help. Good Luck.

 

[Soundguy]

If it were me, I'd grab a 12v 'fog' lamp relay ( they are usually rated for 30a ), and hook that stubbed power line to it's 'coil' connector, and the other 'coil' connector to chassie ground. then run some 10ga wire from the battery, immediatly thru a fuse, and then up to the NO contact on the relay. From the other NO contact on the relay, run to your lamps.. wire the lamps in parallel.

Keep inmind that most tractor 12v lamps are 55w.. though i have seen lower like 35w.. etc.

Each 55w lamp will consume about 4.6a

Your 10ga wire will handle 3 of them. Size the fuse for the next highest amp rating exceeding your planned consumption. IE.. 1 lamp=5a, 2 lamp=10a, 3 lamp= 15a These can be SB fuses. Or you can add 5a across the board and go for FA fuse and still not worry about your 10ga wiring.. etc.

If your chargeing system cannot keep up with your power requirements, keep in mind that your storage battery will be in discharge and making up the supply load difference. A good battery will do this for a decent amount of time.. make sure you turn your lamps off an allow the battery to replenish before you switch the tractor off, or at least drop it on a trickle charger when you park her.. etc. depending on your charging system, you may not want to exceed 80 to 100% of max draw for extended times. It all depends on how the regulator is setup.. some systems are fine running at 100% availability to meet needs of demand.. etc.

You could always add a seperate 'zip cord' style lamp switch at each lamp so you had the option of running all, any, or none, depending on the needs

Soundguy

 

[meatwad]

Hello,
There is a factory circuit for work lights, it does come out a the rear of the tractor wiring harness near the back turn signals. On my B7800, the circuit has a 20 Amp fuse. At 12 volts, that is 240 watts of power. I run four 50 watt lamps, 2 in the front, 2 in the back. I have a simple toggle switch I added in so I can turn the lights on and off. I have used the lights a lot and have had no problems at all.

Bob

 

[Soundguy]

The 20a rating is for the fuse protection.. I wouldn't want to be running that? 14awg? wire at 17a continously. but that's just my opinion..

soundguy