Light switch melted - Help!!

KiotiKevin · Jul 28, 2004

Hey guys,
I installed a set of flood lights on my ROPS on my Kioti CK25. 2 double 55w lights. I had a 50 amp toggle switch with a wire feed directly from the battery with an inline fuse (20amp) holder just before the switch. 220 watts of light for about 30 minutes - lights wouldn't shut off. Melted the inside of the switch! Should I reduce the fuse to 10amp ? Do I need a relay ? All and any suggestions welcome. Thanks
Kevin

Darren · Jul 28, 2004

Do I need a relay ? ... Yes!

Junkman · Jul 28, 2004

I would suggest that you use a relay and to put each light on its own fuse. Also, use a 10 or 12 gauge wire for each lamp. I would believe that you were just pulling too much amperage through that switch and that is why it melted. How its rating was determined is hard to say. It might have been rated for intermittent use. If my calculations are correct, you are drawing just a little less than 10 amps per light. I would use a 15 amp fuse for each fixture. How were the connections made at the switch? Many times, these type switches use spade connectors that just don't handle the amperage well enough. Also, the type of wire that you use is also important. A finely stranded wire will carry more current than a solid wire. How you make your connections is also important. I like to do a wire splice and then solder it to make connection such as these. Then I will either use heat shrink or electrical tape to complete the connection. In some instances, I would use both if I thought that water/moisture might be a problem.

BB_TX · Jul 29, 2004

Actually it is a little less than 10 amps (9.16) total for both lamps. (power in watts = volts x amps or amps = watts / volts). Obviously a switch with that rating should not have a problem with less than 10 amps. A lower rated fuse would not reduce the current. It would just blow if you went much below 10 amps. A relay is probably your best bet. But make sure you get a relay with contacts with a DC rating of more than 10 amps, preferably 20 amps. Some general purpose relays are only rated for AC.

Junkman · Jul 29, 2004

watts divided by volts = amps........
one fixtures with two 55 watt bulbs = 110 watts x 2 fixtures = 220 watts. 220 divided by 12 = 18.333 amps total or 9.16 amps per fixture. The tractor has two fixtures, so the total amperage draw on the switch was 18.333.

BB_TX · Jul 29, 2004

Oops!! /forums/images/graemlins/blush.gif I missed "double". You are correct.

boustany · Jul 29, 2004

Does seem unlikely a 50 amp switch would have cooked with that load. You sure of the switch rating? 50 amps is one honkin switch. I've seen 10 amps, but never 50!

Whats the part number/manufacturer of the switch?

Darren · Jul 29, 2004

That's why it's important to buy a relay that's rated for DC amperage. The 50 amp rating by itself is meaningless.

TWINKLE_TOES · Jul 29, 2004

Kevin,

Which ever way you go 'Switch or relay" the contacts need to be rated for the lamp load. A well specified contact is rated for pure resistive, inductive and incandescent lamp. Inductive loads derate the contacts by a factor of ~ 4 from the resistive rating and a factor of 10 for the lamp rating. A lamp will have an inrush current ~ 10 times it's running current. Your switch overheated in the carry only mode from contact heating, so I suspect it was a piece of junk from the get go.

Use 13.8 Volts to 14.2 volts for your current calculations, 12 volts would only occur with engine off and weak battery.

GaryK · Jul 29, 2004

provided the lights were not wired in series

KiotiJohn · Jul 29, 2004

I HATE electrical stuff! /forums/images/graemlins/grin.gif John

BB_TX · Jul 29, 2004

I agree with Brian that 50 amps is one heck of a switch. We use a lot of heavy duty switches here. I looked in some our catalogs and could not find anything approaching 50 amps in a toggle. Especially DC. I expect it was not marked correctly or severely overrated.

nitroxn · Jul 29, 2004

My suggestion it to use small toggle switch to activate a bosch relay. Most relays in automotive stores are rated for 30 amps DC. Looks like your lights 4 bulbs x 55 watts divided by 12 volts gives you just under 20 amps of current. I would stick with the 20 amp fuse BUT put it close to the battery so it can protect the tractor. Example your fuse is 1 foot from your switch the switch is 4 feet away from battery. What keeps the other three feet from shorting and catching the tractor on fire? If you need any diagrams I will be glad to help.

Curtis

MikePA · Jul 29, 2004

<font color="blue"> If you need any diagrams I will be glad to help.</font>
A diagram, including wire size, location of relays, switches, etc., would help me. /forums/images/graemlins/cool.gif I'd like to redo my aux lights and doing it right would be nice. /forums/images/graemlins/grin.gif

I bought 2 automotive kits that came with switches and relays. I'd like to use a switch panel in the dash instead of 2 separate ones near the ROPS.

KiotiKevin · Jul 29, 2004

Thanks Guys,
First of all I want to say thank you for all the responses, I really appreciate it !
I picked up a 40A-12VDC relay & plug with 5 wires today. I found a guy to explain where each wire goes. I am going to try to attach a couple of pics and maybe you guys can let me know if this is the right one. wires - red85 -blue30-white86-yellow87- & green87a. Can someone tell me which wire goes where . Then I will know if that guy gave me the right info. Thanks
Kevin My Tractor Pics

Inspector507 · Jul 29, 2004

Kevin,
Looks like 30 is where your battery feed for your lights go.
87 and 87A are where you connect the wire that goes to the lights.
85 and 86 are where your switched 12V power goes.

That's from looking at the picture you attached.

BB_TX · Jul 30, 2004

You might try the first picture in this attachment. The relay coil would be 86/85 and the contact would be 30/87. You would also need a fuse in the 12v source line of course. DC devices are often polarized (i.e. makes a difference on which side you put the positive wire) but there is no indication on that device that it is polarized.

KiotiKevin · Jul 30, 2004

I apologize for not being up to speed on the electrical jargen like polarized etc. To simplify - could you tell me if I would be right by doing this - I tye the red85 & blue30 together connect it to the inline fuse(feed) then I attach yellow87 to light #1 & green87a to light #2 then I attach white86 to one side of the toggle switch then I run a ground from the other side of the toggle switch ? So actually the only wire going to the toggle switch from the relay is the white86 ? Would it also be safe to say that I would be ok with the 1 toggle switch for the 2 lights ?
Kevin
My Tractor Pics

BB_TX · Jul 30, 2004

Kevin - I modified the sketch a little. You wire from the fuse to 30 on the relay and to your switch. Wire from 87 to your lights. Wire from the other side of the switch to 85. Then wire the grounds as shown. Wiring this way, there is very little current that goes thru the switch (only the relay coil current). The main load goes directly from the fuse to the relay contact to the lights.
Look carefully at the relay module. See if there might be a small + sign at or near either the 85 or 86, or any where for that matter. If there is a + sign, then it is polarity sensitive and we may need to revisit it. If there is no + sign then it should not matter.

KiotiKevin · Jul 30, 2004

Thanks Bill, I hope you don't get frustrated with me but I'm not much for technical diagrams although it looks pretty straight forward for most. I guess I can't see past the 5 colored wires with the relay and toggle switch.
Please correct me where I'm wrong :
1/"You wire from the fuse to 30 on the relay and to your switch." - I hook the Blue#30 to the fuse(what color# goes to the switch?)
2/"Wire from 87 to your lights." - There are 2-#87 wires Yellow#87 & Green#87A (do I hook up one to each light?)
3/"Wire from the other side of the switch to 85." (does that mean I hook up Red#85 to the other side of the switch?)
4/What do I do with White#86 ?
Thanks for tolerating me !
Kevin
My Tractor Pics