Help. Electrical system/lights pulsing?

[hot_rod_hooligans]

For starters, electrical is not my strong suit, I have taken a class in Electrical and Electronics, but my brain did a bit of a data dump when I finished the class. I can do the "mechanical" part of wiring, running wire, wiring up lights, electrical fans, switched, etc., but trouble shooting is not my strong suit.

I installed a new battery and alternator in 2019 after watching the voltometer drop significantly when electric fan, AC compressor, lights, etc. would turn on, but car never did die on 1 1/2 hour drive. Installed 34/78 Optima Red top dual post and 130A alternator and 2 guage battery and alternator cables, voltometer would still drop(electric fan does draw a lot of power) so I went big to eliminate any doubt, and swapped 250A alternator. Still dropped voltage, both idling and at speed. I believe it's also causing problems with the HEI performance. I'm almost positivive the alternetor isn't the source of he problem, but attached to it, but I'm not sure exactly where to start looking.

 

[Don Jacks]

If,when it drops it doesn';t drop below battery voltage[12.5v] I wouldn't worry about it.Try spinning the alt.faster[smaller alt.pulley and or larger crank pulley.]The 130 or the 250 amp rating isn't what it puts out at an idle.

 

[La Hot Rods]

Where are you getting the power for the fans?
I would have the power feed from the battery to a relay that powers the fans.

 

[hot_rod_hooligans]

If,when it drops it doesn';t drop below battery voltage[12.5v] I wouldn't worry about it.Try spinning the alt.faster[smaller alt.pulley and or larger crank pulley.]The 130 or the 250 amp rating isn't what it puts out at an idle.

It's been several months since I've really gotten out to drive it, but with multiple items running it would drop below 12V, but I can't say by how much, I do remember it was by a concerning amount. I'm not positive there is truly a charging issue, we did the entire 2019 Hot Rod Power Tour without breaking down(well, there was a tank of bad gas in Indy, but not related), just a continuous pulsing in the power system.

Where are you getting the power for the fans?
I would have the power feed from the battery to a relay that powers the fans.

It's a 2 speed Volvo van and dual speed relay set up, and it appears that the guy my Dad had wire the dash, even put a relay on the back side of the Autometer water temp guage with Pro-Control to kick on the high speed fan, so I guess it has a relay to turn on the fan relay. Super redundant I know, I'm working on it.

 

[Jim Sullivan]

You may want to hook up a second volt gauge to double check the first gauge's reading.

 

[blkblk63ss]

Read reviews on that battery and several five or six said battery didn't last a year . My son even had a optima and did not last very long . So you may want to check since it's three years old if I understand your post. Charging system should be 14.3 area everything off at idle. You probably know that.

 

[La Hot Rods]

I have a Optima red top dated 1/14 that is still working great.

 

[blkblk63ss]

I have a Optima red top dated 1/14 that is still working great.

One of these days you will say,,,,,Really!!!!!!!!!!

 

[64ss409]

Is the pulsing easily visible while driving with headlights on at night?

 

[DonSSDD]

I have a Optima red top dated 1/14 that is still working great.

I have a 2003 Kirkland lead acid in my 63.

 

[hot_rod_hooligans]

Is the pulsing easily visible while driving with headlights on at night?

Yes, all of the lighting does it when it’s running, some more obvious than others though.

 

[hot_rod_hooligans]

I finally got it out for a drive last night and got video of the voltage. Idk how well this will work, but here it goes

 

[hot_rod_hooligans]

You may want to hook up a second volt gauge to double check the first gauge's reading.

What the gauge is showing is reinforced by what the lighting is doing. The gauge spikes are pretty damn close in time with the lights pulsing and inconsistent idle.

Read reviews on that battery and several five or six said battery didn't last a year . My son even had an optima and did not last very long . So you may want to check since it's three years old if I understand your post. Charging system should be 14.3 area everything off at idle. You probably know that.

I’ve had good luck so far with it, but I also keep it on a Battery Tender and have a cut off switch. Though, I’ll probably end up with an Odyssey next go around.

 

[blkblk63ss]

Does the charging system fluctuate like that with headlights off??? If not then check lighting system like headlight switch and wiring. What headlights do you have stock or otherwise????

 

[64ss409]

Has your alternator been changed to a newer internally regulated unit?

 

[hot_rod_hooligans]

Does the charging system fluctuate like that with headlights off??? If not then check lighting system like headlight switch and wiring. What headlights do you have stock or otherwise????

Yes, both dash and interior lights will do it as well. Headlights are glass housings with H3 bulbs and a relay fed harness straight off the battery.

I'm going to try and dig through the rats nest of wiring under the dash and chase the power wire feeding the fuse block, maybe I'll find something there.

 

[hot_rod_hooligans]

Has your alternator been changed to a newer internally regulated unit?

Yes, it is a 200A internally regulated alternator

 

[409newby]

I know on Chrysler alternators a bad diode would act this way ???

 

[64ss409]

It acts somewhat like a breaker kicking in and out. Has one been added somewhere in the charging system?

 

[hot_rod_hooligans]

It acts somewhat like a breaker kicking in and out. Has one been added somewhere in the charging system?

No, just a battery cut out switch.