Ammeter reading +30 above 1000 RPM

[moose]

Thank you Greg and Curtis. This verifies my new harness is correct. Darn, was hoping I missed a wire location. So now back to the brain scratching.

First where should I add the protective 30 amp inline fuse? Alternator white wire?

Then I will try swapping batteries since it's the low hanging fruit.

Thanks again all

[Curtis]

Easiest thing to do is put a fuse or circuit breaker between the alternator and white wire.

[cbez]

I have mine right off the alternator.



Check AC and DC voltage at the battery while running/revving.

I think it must be the regulator..even though you replaced it. It is the regulator's job to keep amps/voltage down. The fact that it increases with RPMs to me says regulator as opposed to a short. 30 amps to me seems VERY high for a charging circuit especially on a freshly charged batery so I don't think it's just post-cranking amp draw.

The fact that it starts and runs fine, seems to say you don't have a major battery problem either.

Try Duralast VR728..you can always return it if that's not the issue.

[moose]

Cbez, nice clean installation. Is that a circuit breaker of sorts or fuse? Anyway, looks nice.

I'll shop for the VR728 here but probably have to order it. Not sure you noticed, I'm in Kea'au/ Pahoa Hawaii.

So I'm off to the parts store.

Thanks all

[redroadster]

Loose the alt belt a bit if it is charging 30 amps it won't be then , A maxed out alt pulls a heavy load and sounds different than lite charged
Have you slow charged the batt. to see if it still maxed out just unplugging a old style VR can change its current flow hooked back up ,
It in the day, techs wouldn't touch it because then it was worse , most customers didn't want to pay for wiring replacement , / repair
You can be putting only 13.0 v out that will pull high amps
But low charging

[moose]

Have the 30 amp circuit breaker installed following cbez design.

Ordered the Duralast VA738 regulator that will arrive February 14th. $31 including shipping.

I'll let you all know on the 15th if that solved the problem. Thanks all.

So do you all think I can give the voltage regulator to my wife for valentines day since it arrives on the 14th? Just asking the question lol

[Gregs672000]

So do you all think I can give the voltage regulator to my wife for valentines day since it arrives on the 14th? Just asking the question lol

Um, wanna stayed married...?
My wife likes a show called "90 Day Fiancé" or some spin off of that. In a recent episode, a guy on the show meets the supposed "love of his life" face to face for the first time. Looks wise she is waaaaaay out of his league. His Christmas gift to her when they meet is an electric toothbrush. Now, I'm not a very good gift giver, but even I could do better than that! So no Moose, no...

Then again, IF your wife LOVES your regulator gift, then maybe you have truly scored beyond expectation!

[redroadster]

Greg , you know the significance of a electric oscillating tooth brush and young single women ....right
Just tell the wife you got her , her own keys to the Roadster

[RBMann]

Moose-

I just bumped into an old thread about this same issue.

viewtopic.php?t=1878

Toward the bottom was this easy cheap gem that I am going to check on my roadster.

"Had this happen last week. Out for a quick run and noticed the amp gauge was almost at 30a. Got home and the battery was sizzling. Checked the connections at the alternator and on one of the plastic plugs (goes to the harness under the master cyl) was badly corroded. It is a three prong (I think) male/female connector. Used a cleaner (CRC contact cleaner) , cleaned the other connections and the grounds. Cranked it back up a revved the engine. The meter behaved normally, slight movement to +. Easy to check it out. Phil Herring SRL311 07036"

[Curtis]

Also note that the plastic insulator on the alternator for the large white wire can crack or break completely leading to shorting. I've seen this destroy the harness.

[moose]

Thanks Curtis and BBMann. I inspected the harness and connections. All look good. Also paid close attention to the positive and negative side of the alternator. All looks good.

My new voltage regulator arrives Monday and will update this thread. Hoping for success.

[cbez]

Were you able to check your voltage DC and AC at the battery with it running and revving?

Generally, a short will rapidly destroy the wire it's on, as you've seen. A bad connection will increase the resistance in the circuit, and actually lower the amperage.

I still think it must be the regulator, but I am not an expert on every possible fault condition on the charging system either.

the other thing I could imagine is an internal problem in the battery causing the alternator to overcharge it. keep in mind amp meter is showing flow INTO the battery not load on the system. you could hook up a big ass 30 amp light and the meter would show 0.

if the field windings were shorted that could also bypass the regulator.

[david premo]

FYI the alternator is an AC generator rectified to DC, however there is no place to measure AC voltage in the system. I’ll try to keep this simple, on 12 volt automotive electrical system the battery voltage is about 12.5 to 13 volts at rest and with a property operating charging system it should read around 13.7 to 14 volts when the car is running. Sometimes it’s slightly less until you rev up the engine. AMP’s is a measurement or flow, and with current flow as high as 30 AMPS at idle on a 30 AMP system tell me the alternator is over charging the system.

[DAC21]

The Linda module JT sells / rents probably would have helped.

viewtopic.php?p=327213&hilit=Linda#p327213

[redroadster]

Some testers check / show for alternating current leakage
that's what you look at scoping it and most of the 60-70s alts leaked he needs to get a good tester on it with amp clamp and the battery instead of guessing
I'd check the neg / ground to the charging coil ,try a redundant ground wire & the multi plug off the stock regulator should be taken out wires soldered and heat shrink at this age brass connector to copper wire just doesn't last with good connection over 10 yrs ( of course I'm in the jungle here in Midwest)
Usually the VR issue is wiring or brushes alt issue back when they were around , we got it after they hung a new VR on it