Electronic geeks required
#41
Le Mans Master
Thread Starter
Sorry Jeff, too damn cold here the last few daze, and other issues running wild....and having just put the 3rd alt in there, I let it fail first.....be a while, I hope.....I did use a CS144 on a camper I did some dozen years ago...feeding a marine deep cycle for the inverter, as well as the 24 series for starting....
but these daze my spine and other arthritic areas just slo my enthusiasm to nothing anymore...damnit....
but these daze my spine and other arthritic areas just slo my enthusiasm to nothing anymore...damnit....
We just need volunteer #2.
Mike>? Do you have access to a scope?
Last edited by Big2Bird; 01-11-2019 at 02:54 PM.
#42
#43
I have this scope that plugs into my laptop. Ive only used it a few times but it seems to work. Measure the voltage ripple at alternator output and bat neg ?
Last edited by Greengear; 01-11-2019 at 04:44 AM.
#44
Le Mans Master
Thread Starter
#45
Burning Brakes
Here's my weapon of choice lately from EBAY for about $45. It's a DSO168 portable digital storage scope. 20Mhz bandwidth, no laptop required.
Last edited by DblTrbl; 01-13-2019 at 07:26 AM.
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#46
Le Mans Master
Thread Starter
The more data, the better. See what you can measure.
#47
I just got a dc clamp on amp meter. It was cool to see how many amps my c3 starter and headlights draw.
I have done quite a bit of automotive wiring repair over the years but I still dont use a scope much. Maybe making it easier to conmect would help.
#48
Race Director
Ok, you made me curios so I checked my '71. When I converted to electric fans and EFI I swapped out the stock 10SI alt for a 12SI. It's an el cheapo Autozone rebuild, but it's been fine for years. With fans running half speed + stereo on (big Rockford Fosgate amp from the 90's) I got this:
Alternator stud: 0.18V
Battery: 0.016V (notice the extra zero in there)
Btw, no need for a scope to measure ripple. A good 'True RMS' volt meter is all you need. I use a Brymen BM829s.
Alternator stud: 0.18V
Battery: 0.016V (notice the extra zero in there)
Btw, no need for a scope to measure ripple. A good 'True RMS' volt meter is all you need. I use a Brymen BM829s.
#49
Le Mans Master
Thread Starter
Ok, you made me curios so I checked my '71. When I converted to electric fans and EFI I swapped out the stock 10SI alt for a 12SI. It's an el cheapo Autozone rebuild, but it's been fine for years. With fans running half speed + stereo on (big Rockford Fosgate amp from the 90's) I got this:
Alternator stud: 0.18V
Battery: 0.016V (notice the extra zero in there)
Btw, no need for a scope to measure ripple. A good 'True RMS' volt meter is all you need. I use a Brymen BM829s.
Alternator stud: 0.18V
Battery: 0.016V (notice the extra zero in there)
Btw, no need for a scope to measure ripple. A good 'True RMS' volt meter is all you need. I use a Brymen BM829s.
#50
Race Director
Too cold to crawl under the car and don't like doing that with it running. It will be close to the battery readings anyway.
And I don't think I can get to the starter post with my long tube headers without burning most of the skin off my hands. lol
And I don't think I can get to the starter post with my long tube headers without burning most of the skin off my hands. lol
Last edited by zwede; 01-11-2019 at 08:37 PM.
#51
Le Mans Master
Thread Starter
Fair enough. Thank you for your efforts. It starts the baseline.
#53
Le Mans Master
Thread Starter
#54
Totally stock wiring inmy car.
Here is my reading seems like 100hz ripple but I could be wrong.
Pic shows about 10 waves per 100ms division. Last pic shows how ripple stops but baseline voltage remains as soon as I turn off engine.
The thing that seems to potentially invalidate my test os that the scope shows 1.6v not 13-15v as I wouls expect. This could be because my probe has a 10x switch on the side.
Here is my reading seems like 100hz ripple but I could be wrong.
Pic shows about 10 waves per 100ms division. Last pic shows how ripple stops but baseline voltage remains as soon as I turn off engine.
The thing that seems to potentially invalidate my test os that the scope shows 1.6v not 13-15v as I wouls expect. This could be because my probe has a 10x switch on the side.
Last edited by Greengear; 01-11-2019 at 10:33 PM.
#55
Tech Contributor
Member Since: Jun 2004
Location: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
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Been watching this thread, but have been tied up with unexpected family stuff the past few weeks. Finally getting caught up. I've got a couple scopes that have been gathering dust lately, but I oughta be able to play around a little on this topic. The '69 is apart right now to take some more weight out of the car, but my "84 is running. I moved the battery in it to the rear compartment for better weight distribution, so it ends up electrically configured somewhat similar to a C3. I run small batteries in both cars for reduced weight, but I can probably scrounge/install a regular size battery too for a bit of comparison purposes.
#56
Le Mans Master
Member Since: May 2003
Location: Fernandina Beach FL
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2023 Restomod of the Year finalist
2020 C3 of the Year Winner - Modified
Back in the day...30 years ago when I worked for Kenwood- Car Audio- we did a lot of testing trying to solve the infamous "alternator whine."
On a brand new at the time 90 T-Bird SC - The frequency was in the couple hundred range @ 1800RPM. So 100Hz sounds correct at idle.
On a brand new at the time 90 T-Bird SC - The frequency was in the couple hundred range @ 1800RPM. So 100Hz sounds correct at idle.
#58
Melting Slicks
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CI 5 & 8 Veteran
Good read on the subject
The following article is a good reference for this discussion.
https://moretraction.com/2018/08/31/2416/
https://moretraction.com/2018/08/31/2416/
Last edited by Bullshark; 01-12-2019 at 09:34 PM.
#59
Le Mans Master
Thread Starter
The following article is a good reference for this discussion.
https://moretraction.com/2018/08/31/2416/
https://moretraction.com/2018/08/31/2416/
#60
Le Mans Master
Member Since: May 2003
Location: Fernandina Beach FL
Posts: 8,481
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2023 Restomod of the Year finalist
2020 C3 of the Year Winner - Modified
The following article is a good reference for this discussion.
https://moretraction.com/2018/08/31/2416/
https://moretraction.com/2018/08/31/2416/
Sort of confirmed my dirty bus and the clean buss thoughts- AND the often debated large a$$ wire I run-
THANKS for posting it up!!!
BTW- I like this- have only see 1 post versions