I think I have too many lights now...HELP [Archive] - JKowners.com : Jeep Wrangler JK Forum

: I think I have too many lights now...HELP

07-17-2008, 02:34 PM
OK here's what's going on. I have a 2002 TJ 4.0

I have four 100watt Lights on my light bar connected to a 30 amp relay, a 30 amp fuse and a heavy duty rocker switch.

I have two 55 wat rock lights connected to the factory fog light wires.

I have four 55watt rock lights connected to a 30 amp relay, a 15 amp fuse and a heavy duty rocker switch

Plus my two 55watt factory headlights.

Total wattage is 840 when I turn all the lights on.

I'm currently running a factory alternator with a Yellowtop battery.

I tested all the lights yesterday while the engine was on idle. Just a few minutes after, the battery voltage meter wen to approx 10 volts. I left it like that for about 10 minutes and it was still around 10 volts. When I rev'd the engine, the battery voltage meter went back up to 14 volts.

I drove the Jeep around the parking lot with all the lights on for 10 minutes and the battery voltage meter stayed at 14 volts (which is normal).

I don't want to have something burn up in the middle of the trail in the middle of the night so my question is, will my alternator coupled with the Yellow tyop battery carry this much wattage or will something fail? Should I upgrade my alternator or install a second yellow top battery? what do you guys think?



07-17-2008, 02:40 PM
All I know is if I need a nightlight I'm taking you with me :laughing:

07-17-2008, 02:47 PM
All I know is if I need a nightlight I'm taking you with me :laughing:


07-17-2008, 02:52 PM
Hey Bash, that guy from delta that just signed up may be able to answer this... :grinpimp:

I have some 55 watt lights I am gonna wire up as rock lights on my jeep too. :beer: I only have two for the front right now, gonna pick up a set of the rear too tho.

07-17-2008, 03:58 PM
sounds normal to me. the alternator doesn't put out 14V until rpm's are raised higher than idle. if you were up around closer to 3000rpm and it still wasn't putting out 14V, then i'd be worried.
adding another battery won't help, since it isn't a voltage shortage problem - the lights won't be using the battery unless the engine is not running.

07-17-2008, 04:22 PM
Thanks for the info. I just won't light everything up at the same time until I get a stronger alternator. Another memeber suggested I use LED's for my rock lights so I won't drain as much power. Once these lights break (some day) I'll switch them to LED's and upgrade my alternator when I get the mula. Thanks for info and all the help.

What's going to happen when I get a winch?

07-17-2008, 08:10 PM
Just don't winch in the dark!!!

07-17-2008, 08:30 PM
Switch out all those rocklights for some LED rocklights that don't draw so much. Then if it still pulls too much, get yourself a high output alternator.


Delta Lights
07-18-2008, 01:33 PM
um... I'd suggest that you either run a bigger alt.

run less lights with a flood lens (for rock lights)

HID run half as much amps...

LED are good too.. but are more like a flash lights (spot)

08-02-2008, 05:10 PM
Well, the stock alternator is 160amps which is a bit over 2 kilowatts @14vdc so I suppose if you had all the lights on, A/C on, FAN on high (20amps there), with your wipers on, you might be pushing the alternator a bit.

OTOH, I wouldn't let the voltage sit at 10 volts for any great length of time. That just means you are discharging the battery and if something happened the engine died, possibly you could have drained the battery enough not to allow a restart. (that's MY paranoia talking. I want a second battery myself.)

So, if the voltage goes back up to the 14v range above 1000 rpms or so, I wouldn't worry too much about the alternator handling it.