55W bulb VS 100W bulb: Need to upgrade OEM harness?

Dave Bennett

Dave Bennett

Adventurist
I have my IPF 968's on my ARB wired into the Toyota OEM driving light harness and am using the 55W bulbs they came with. No problems so far.

But, the IPF's also came with a set of 100W bulbs :)

Can I get away with using the 100W bulbs without smoking the OEM driving light harness etc?

Experts please advise!

I would like to keep my wiring simple and want to avoid laying wire over the existing OEM stuff if I can.
 
Last edited:
TJVach

TJVach

Observer
Well I wouldn't call myself an expert by any means, but I'll give you my opinion. I wouldn't chance it. I think it's pretty easy to make up an auxillary harness to power the lights. I don't know what the existing harness was rated at, but if it were me I would make one.
 
S

slooowr6

Explorer
Which light is the driving light on Taco?

I've 80/85W bulb in my headlight and it's not a problem. I did the volt drop test I don't remember the number but is has very little volt drop. 100W is less than 10amp on the wire if each light has it's only wire going to the battery it should be ok but if the same line feeds both light then with 20amp it's safer to run another line.
 
G

Grim Reaper

Expedition Leader
RobinP said:
Wow, I had no idea how sensitive bulb brightness is to voltage. The graph in the above link really shows this. Those of us with older wiring harnesses should be doing a voltage test to see.
Click to expand...

Mine is miserable. Almost a full volt on low beams at idle. I will build the harness myself just have not got around to it.

There is a LOT of connections and wire between the battery and the lights.

Actually I should spend the afternoon changing out Battery cables and rewiring my starter relay on my truck from a simular start problem I am having but I think I am going to go bike riding instead LOL.
 
M

madizell

Explorer
Difficult to say whether your harness can carry the larger load without knowing what the harness is made of. If the wiring is all 14 gauge or smaller, it would be well, if not entirely necessary, to replace the wiring with heavier wire. For 100W lamps, 12 is probably sufficient. But, to provide optimum voltage at the lamp without overload, buy a pair of relays which are readily available and not expensive, use the harness wiring as the trigger side wiring, and provide 10 gauge wiring on the hot side running from a fuse block or direct off the battery. That way, you don't need to completely rewire the harness, and the original wires will not be overloaded, as all they will be doing is providing voltage to close the relay. All switches remain the same, and no switch needs to carry a high amperage load.
 
Dave Bennett

Dave Bennett

Adventurist
madizell said:
Difficult to say whether your harness can carry the larger load without knowing what the harness is made of. If the wiring is all 14 gauge or smaller, it would be well, if not entirely necessary, to replace the wiring with heavier wire. For 100W lamps, 12 is probably sufficient. But, to provide optimum voltage at the lamp without overload, buy a pair of relays which are readily available and not expensive, use the harness wiring as the trigger side wiring, and provide 10 gauge wiring on the hot side running from a fuse block or direct off the battery. That way, you don't need to completely rewire the harness, and the original wires will not be overloaded, as all they will be doing is providing voltage to close the relay. All switches remain the same, and no switch needs to carry a high amperage load.
Click to expand...

Great input madizell, thank you!

Anyone have any pics or diagrams of this?
 
Overland Hadley

Overland Hadley

on a journey
Tacodoc,

Sorry for the hijack.

Are you not using the wiring and relay that came with your IPF's? And does that mean that you are not using the IPF on-off switch?

Thanks.
 
MoGas

MoGas

Central Scrutinizer
So you are looking to run >16.5 amps through a system designed for 9 amps. not a good idea. I would use the power from the OE harness to run a relay wired directly between the battery and the lights, fused at the battery of course. That way you don't have an aftermarket switch in your cab either.
 
Dave Bennett

Dave Bennett

Adventurist
Overland Hadley said:
Tacodoc,

Sorry for the hijack.

Are you not using the wiring and relay that came with your IPF's? And does that mean that you are not using the IPF on-off switch?

Thanks.
Click to expand...

No, I'm not using the IPF harness/switch. The 968's on my ARB are hooked up to the OEM harness that once powered the driving lights that come in the OEM bumper. That has allowed me to use the factory switch.
 
cruiseroutfit

cruiseroutfit

Well-known member
Did you get the IPF harness?

We use them all the time in combination with the factory switches, use the factory 12V supply to switch the relay, makes for a really clean install and if done cleanly should look OE. In fact depending on where you mount the relay, you shouldn't even have to drill a single hole.

I've installed dozens of IPF lights w/relayed harnesses, and only in a few instances have I used the IPF switch, I use the OE Toyota switches whenever possible.
 
Robthebrit

Robthebrit

Explorer
I can't tell you if you need to upgrade because I have no idea what size cable Toyota use. If you are running 15-20 amps over 15 feet of cable then you need 10 guage cable.

In an ideal world 3% is considered to be the maximum voltage drop for a 12v system (0.36 volts). For a 15 foot run, here is what I worked out for wire sizes that will give less than 3% volt drop. The currents involved are significantly below the limits of the cable sizes so there is lots of safety built in but make sure to use a fuse of some kind.

amps gauge (AWG)
5 16
10 12
15 10
20 10
25 8
30 8
40 6
50 6


Rob
 
You must log in or register to reply here.

Forum statistics

Threads
188,456
Messages
2,905,229
Members
230,428
Latest member
jacob_lashell

Members online

Total: 916 (members: 48, guests: 868)
Top