Another charging question

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Model T Ford Forum: Forum 2016: Another charging question
Top of pagePrevious messageNext messageBottom of page Link to this message  By Allen banks on Tuesday, June 07, 2016 - 12:51 pm:

Hello all, bare with me as I'm brand spanking new to the hobby. My 23 is all stock with a 6 volt system. When I start the car in the garage cold, it charges between 6-8. Then when it's out on the road in mag and even sitting warm, it doesn't show a charge at all. Could the temperature really be factoring in here? Where do I start?
Thanks!


Top of pagePrevious messageNext messageBottom of page Link to this message  By G.R.Cheshire on Tuesday, June 07, 2016 - 12:56 pm:

Allen once your battery is charged the charge rate will drop to between 1 and 2 amps. If you are running on magneto in the daytime with no lights there is virtually no drain on the battery. as long as you are not having any other difficulty I wouldn't worry too much about it. T's do not havee the need for electricity like modern cars (Thank Goodness) :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem - SE Michigan on Tuesday, June 07, 2016 - 04:03 pm:

Allen,

It sounds like you may have a voltage regulator on your generator instead of a cutout. They will look the same but are internally very different. The VR will act exactly as you describe, initially charging the battery to make up for the discharge of having just started the engine, plus whatever discharge due to sitting. As the battery approaches full charge, the VR backs down the generator to produce just a small "maintenance" charge, barely noticeable on your ammeter.

Try this. Once the charge has backed down to "zero", turn on your headlights. Does the ammeter go down to and stay at -10A, (approx.), or, does it dip down momentarily and recover to "zero". If it does the latter, you've most likely got a VR. If it does the former, you've got a faulty generator.

BTW, I'll "bear" with you, till we know each other better. :-O)


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Wednesday, June 08, 2016 - 09:53 am:

Just to be clear. If you are idling and turn on the lights the ammeter will NOT come up to zero charge even if you have a VR since the generator does not put out much at idle and the headlights are a significant load. After turning on the lights - increase the motor speed and see if the ammeter recovers to at least near zero. If yes then you do have a VR and it does sound like your car likely has one. If yes then just drive - the VR will take care of the battery.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem - SE Michigan on Wednesday, June 08, 2016 - 10:15 am:

John,

Yes, excellent point, as always.


Allen,

Any progress or updates??


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Whelihan Danbury, WI on Thursday, June 09, 2016 - 06:23 am:

I find that my ammeter reads about 2 amps or so once the battery is charged with a FP regulator...until recently. I rechecked all the connections and even installed another good 6 volt battery: no change, still zero at fast idle. Checked the voltage at the generator output terminal fast idle: 3.27 volts, regulator terminal 6.24 volts. I was ready to pull the generator and then figured I would try to re-polarize it first. Removed the VR, briefly touched the power lead to the generator terminal, then re-installed the VR. Once started and running, the generator was back to normal: around 8-10 immediately after starting, then tapering back to 2 amps once the battery had been recharged. Odd problem I have never experienced before.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Thursday, June 09, 2016 - 11:35 pm:

Kevin:

Check for any presence of oil on the commutator of the generator. I think your generator was not putting out anything there for awhile. It is not likely that repolarizing the generator did in fact change it back from being backwards since having a generator polarized backwards would have damaged the VR and yet it shows no damage. More likely you momentary polarization produced an arc at the brushes and burned off some oil or dirt and got it started again. Check for any debris in there and if oil is there, find out how it is getting into that area.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Thursday, June 09, 2016 - 11:43 pm:

Kevin:

I forgot to mention that since your readings are showing 3 place decimal accuracy I suspect you are using a digital meter to take those readings and those are very suspect since the Model T ignition system interferes with digital type meters and they read strange numbers when the engine is running. This has nothing to do with quality of the digital meter but just that the area surrounding the T engine is an RFI (Radio Frequency Interference) zone big time and digital meters just can't operate in it. Use an analog type meter with the needle on it and take the readings again if you were using a digital type. Never attempt to read the voltage on the generator post when the VR is operating since those readings will seem very low but that is normal. Your meter simply cannot read a complex waveform on any of its scales.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Whelihan Danbury, WI on Friday, June 10, 2016 - 12:17 pm:

John: Thanks, I forgot about the RFI issues with digital meters. After opening the brush cover I checked for oil residue. None present and commutator looked fine. What I did notice was that there was some brush dust on the inside of the cover. So I took a can of Mass Airflow Sensor spray I had laying around and gave it a few shots to clean it out, then followed up with the air hose. After a 20 mile drive this morning, everything seems to be charging fine.


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