Battery Charging

AA Ford Discussion Group relating to the repair and restoration of your AA Ford.
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John Losch
Posts: 14
Joined: May 7th, 2014, 3:58 pm
Body Type: 82b stake bed
Model Year: 1930
Location: Holliston, MA

Battery Charging

Post by John Losch » June 20th, 2014, 6:03 pm

Second Question:

I have only recently owned my 1930 AA (for the second time) after it was restored by a former student of mine. (long story not necessary now). He converted it to a negative ground 12 volt system all in accord with the information in the "Schild book" and in accord with other references on the subject.

Almost from the beginning I frequently found the truck with a dead battery, and after much testing discovered that the alternator had a dead short to ground at the output terminal. I replaced the alternator with a Delco 10 SI, 65 amp, the one most recommended.

At this point all I can say is that the alternator seems to keep the battery charged, but if I turn on the halogen lights the ammeter shifts to a discharge position of seven amps. I have never seen the ammeter show a charging position since I installed the new alternator, even when the battery was low. Right now, I assume that if I were driving with the lights on, I would be running and lighting off the battery, rather than with energy from the alternator.

I am at a loss. Basically, I guess I don't know how to test the charging system. I have a "multitester" with amps, volts and ohms resistance, but I am not sure what I should expect as suitable at any reading of the meter. I was told that if the battery showed a charge of 13.5 volts I and the truck should be happy. It showed 12.5, and I am curious, but not happy.

Any and all advice will be appreciated.

John Losch

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spectria
Posts: 1874
Joined: May 15th, 2008, 9:53 pm
Body Type: Mail Truck, Stakebed
Model Year: 1931
Location: Quincy, Ca.

Re: Battery Charging

Post by spectria » June 20th, 2014, 6:39 pm

12.5/6 volts is battery voltage, not charging...

You would want to test the Alt output at the main terminal of the alt to ground using a suitable VOM, digital is best. Engine speed should be off idle, pulley size matters, many alternators don't light up until 600 rpm or more, sometimes requiring a boost of RPM to excite them, then you are ok... Charging voltage for a 10si should be 13.5 to 14.2 volts. lower or higher leads to poor results.
Run a "ground" from the alternator to the engine and frame...

In practice I have found that bad connections answer most questions about dim lights or slow cranking.

Check every connection by disassembly, cleaning and reassembly. Looking will not reveal minor corrosion at a connection... A .2v voltage drop at any connection is a maximum.

Check this link for a few good answers:

http://www.nastyz28.com/forum/archive/i ... 70409.html
Dave in Quincy, Ca. I love Pics!!!! Post them All!!! :)
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bud valerius
Posts: 356
Joined: May 14th, 2004, 5:24 am
Model Year: 1930
Location: Manhattan , Kansas

Re: Battery Charging

Post by bud valerius » June 21st, 2014, 12:36 pm

I have a 6 volt alternator on one of my AA's I ran a wire from my brake light switch to the da plug on the alternator that excites the alternator to start it charging as the rpm are to low to start the alternator charging . I used the brake light switch as the exciter because you always put your foot on the brake when starting

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spectria
Posts: 1874
Joined: May 15th, 2008, 9:53 pm
Body Type: Mail Truck, Stakebed
Model Year: 1931
Location: Quincy, Ca.

Re: Battery Charging

Post by spectria » June 21st, 2014, 3:05 pm

bud valerius wrote:I have a 6 volt alternator on one of my AA's I ran a wire from my brake light switch to the da plug on the alternator that excites the alternator to start it charging as the rpm are to low to start the alternator charging . I used the brake light switch as the exciter because you always put your foot on the brake when starting
Brilliant!
Dave in Quincy, Ca. I love Pics!!!! Post them All!!! :)
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rsierk
Posts: 93
Joined: February 23rd, 2005, 7:27 pm
Body Type: 185-B
Model Year: 1931
Location: Christiana PA

Re: Battery Charging

Post by rsierk » June 21st, 2014, 7:05 pm

In a Model A, I always use my right foot on the starter button and the gas pedal. I don't have time to put it on the brake, unless you are talking a modern car with automatic trans. - they are a different story.

bud valerius
Posts: 356
Joined: May 14th, 2004, 5:24 am
Model Year: 1930
Location: Manhattan , Kansas

Re: Battery Charging

Post by bud valerius » June 22nd, 2014, 5:26 am

I hope you put your foot on the brake after you start your AA , I have my brakes hooked up and working and have the floor boards installed so I don't have to drag my feet to stop

ModelAkid
Posts: 478
Joined: June 3rd, 2013, 6:15 pm
Body Type: 186-B stake
Model Year: 1931
Location: SoCal
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Re: Battery Charging

Post by ModelAkid » June 25th, 2014, 12:34 pm

While parked, I use the hand brake.
As for the electrical issues, my advice is go back to original. I have had over a dozen A's & AA's and all original 6 volt systems. I really don't understand why people change to 12 v., unless they need to plug in a radar detector or CB radio.
I wanted a music player in another old car I have. I took a boom box that used four size D batteries and added a cord with a cigarette lighter plug so it does not need batteries. Now I can play old music or Amos & Andy tapes in the car, just like what was heard on the radio "back in the day".

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