electrical charging

[79403ta]

Hi all i have a 1997 Z71 with the 5.7 vortec and i have a question the other day i added some driving lights(got from Walmart) on my bumper and last night while driving down the road my regular head lights were on , my new driving lights, and my a/c was on high the system seemed fine but when i come to a stoplight my volt guage goes down to about 11-12 volts am i putting too much strain on the alternator/battery ?? the new lights are the only add on..on my truck they were $20 at Walmart and god do they work great !! thanks for any info Jason

[locknkey]

The Alt is perhaps usually am 32 to 38 amp stock, if you need more power to run more amp driven devices, you'll need a alt that will produce the necessary output to run those extra add ons, the driving lights you added, is perhaps an extra 55 amps, so if you add everything that you had going at the same time, then your lowest charge to your amp will be lower, since you're useing a stock alt.
If you had a 100 amp alt (with a voltage reg to match it) you'll be able to run everything up to the max output of the alt....you can order these special alt at most any auto parts outlets or right here on the internet....

[Fireplug]

no driving lights from wal-mart are 55 amps you meant 55watts. 55amps would fry most of the wires in that truck.
Check and make sure that the ground for the driving lights is good and clean and tight. Also check the battery termanals clean them and make sure that they are tight. How old is the battery??? it might be weak.

[locknkey]

Yep...its supposed to be wattage, a new battery would not carry the wattage he needs to light up the road, an 100 to 130 amp alt, with matching built-in regulator would carry the load even at idle... anything else above that will heat up his wires and possibly melt them, 12 volt current only goes one way to a circuit (direct current). A 12 volt battery with an 38 amp alt will not carry 55 watts on idle, and really if you think about it, the battery is only there to keep the ignition from dieing (if there is no charge coming from the Alt.) and to start the engine, everything is powered by the Alt during engine running...on another note, try disconnecting the battery neg post while engine is running to check if the Alt is charging...if it dies then you know the Alt isn't charging the battery and the engine is only running from the battery when its connected to the circuit.

[roadrunner_70]

Disconnecting your negative cable while the engine is running is old school, and it a surefire way to fry the diodes in your alternator. There are other, safer ways to check your charging system.

[Fireplug]

disconnecting the neg cable on that truck will cause you a ton of problems like fried alt, smoked pcm from a voltage spike , melted wires at the starter and ign switch. NEVER PULL THE NEG BATTERY CABLE ON A RUNNING ENGINE WITH A COMPUTER