6V battery will not hold a charge

T

TMB

Member
29 TS. Battery purchased in 2009 having trouble holding a charge. Ammeter reads 0 when engine/pop out off. Ammeter reads -6 when attempting to start. It does turn over but not enough to fire it up. Battery was drained down to 60%. Checked the stop light switch and seems to be OK. Lights have not been left on. I noticed driving home the last time a few weeks ago the ammeter read zero while driving at 35 mph. I'm deficient in Model A electrical system knowledge but seems like the cut-out or the generator is the culprit since the generator is not charging at driving speeds. How do I go about identifying the problem?
 
Set the throttle at a fast idle, take a wire and jump across the 2 cutout terminals ---if it charges then it is most likely the cutout.

If the battery is that low you should charge it with a plug in charger first
 
Definitely sounds as if NO charge, when driving, Have you tried to jump start it and then watch amp meter after taking battery charger off? when started it should show a 5 to 10 amp charge and slowly go down a bit as battery is replenished, I know our Alternator replacements sometimes will show a 0 reading after driving , because they can take care of the loads and recharge the battery better than a normal generator does, But normally you will still see a 3-5 maybe charge on your amp meter even after driving quite awhile, you can call or contact me and I can walk you through some simple tests if you would like,
 
Definitely a good way to bypass cutout and yes ALWAYS suggested to charge battery first , No one wants there unit to work harder than normal, as many say that the generator or Alternator will be destroyed if you have it charging a low/dead battery, NOT true but YES will definitely work the unit excessively harder and take LIFE off of the unit.
 
I recharged the battery reviewed the above suggestions and some earlier posts related to the subject. With engine off, voltage at cut off input is 6.1v both grounded to generator case and to engine block. Restarted the car. At fast idle ammeter read +2-3v (charge). I made a 6 ft jumper so I could read the ammeter at same time. When I jumped the cut-out the ammeter jumped to +6-8v momentarily then settled on +2-3v. Before when I was driving I thought the ammeter read 0 but now I'm not sure. Is +2-3v during fast idle normal? If not is there another possible reason (other than battery going bad) the battery is discharging?
 
The ammeter reads amperage , not voltage. Your first really didn't mention whether the lights were on or off when reading the ammeter.
With nothing on the ammeter should read zero.
With low beams on, or stop light on, engine not running, the ammeter should about 8 amp discharge [left needle]
With engine running at fast idle with nothing on the ammeter should read about 3 to 4 amp charge if you run mainly during the day. If you drive quite a bit at night I'd set it so at the ammeter would show 10 to 12 amp charge.
The amount of charge is adjustable if you don't have an aftermarket regulator installed. This is done via the movable third brush under the removable rear generator band.
All that said, if the amount of charge is set at 3 to 4 amps at a fast idle, the ammeter will show a good discharge when the lights are turned on, its normal.
 
Right. Ammeter measures amperage of course. So 3-4A charge at fast idle is normal. My ammeter looked more like 2-3A charge. I assume this rules out my cut-out since the ammeter denotes a charge at fast idle. Well after recharging my battery to 100%, starting the car and keeping it at fast idle (for the cut-out jumper test) for 5 min my battery charger reads 70%. I recharged the battery to 100% once again and now 3 hours later without running the car (I checked all the lights too) the battery now reads 70% again. Is it possible there is a draw someplace or do I have a dying battery? I would think the battery would be good for more than 3-4 years.
 
Easiest to check for a draw is to remove a battery cable. Stick a test light or a volt meter between the battery post and cable end. If the light lights or the meter shows voltage, you have a draw. Start unhooking things until the draw stop and thats the problem.
Plus, it could be that you do have a bad battery. It happens. Best thing to do is have it load tested. A hydrometer may give you a good indication of its condition, but, its best to load test it.
 
If you can't get it charged with a charger, then could be a bad battery like mentioned above. New batteries now days seem to fail often.
 
Thanks guys. If I cannot find a draw I guess I'll purchase a new battery. Thanks for all the advice and education.
 
TMB said:
Thanks guys. If I cannot find a draw I guess I'll purchase a new battery. Thanks for all the advice and education.
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Take a light bulb like the one used in a tail light make a test light out of it with leads and connect it in place of your ammeter. If it lights you have a draw, if not all is ok and its just your battery
 
If I read your post correctly, you said you get a "jump" on the ammeter when you jumper the cutout at a fast idle... Is this correct? If it does that you have a bad cutout and all the new batteries in the world aren't going to help.
 
i got a 1931 model a . and bad as i hated too i had to do away with the generator and go with a 6 volt alternator . only part on mine that aint original .
 
52fordv8 said:
i got a 1931 model a . and bad as i hated too i had to do away with the generator and go with a 6 volt alternator . only part on mine that aint original .
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Sounds like you just needed to repair your generator or your cutout. A properly working generator will work just as fine.
 
52fordv8 said:
i got a 1931 model a . and bad as i hated too i had to do away with the generator and go with a 6 volt alternator . only part on mine that aint original .
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' had to ' .. There really aren't too many reasons why you would have to. A properly set-up generator with an original properly working cut-out is about as bullet-proof as one can get. Its just about perfect with one of Toms EVRs. If you like using the alternator, thats fine, I'm just saying....
 
Have you checked the battery to make sure that none of the cells are low on water and the cables are clean and tight on the posts?
I'd hate to see you purchase a new battery if the old one is still good.

Like others have mentioned though, a four year old battery has probably just outlived it's service time.
 
True about the generator BUT by FAR an alternator provides a MUCH more reliable, trouble less, efficient. improved, charging source for your vehicle,
 
Not sure BULLET proof is an accurate description of a Generator , OTHER than appearance, a Generator fails in every comparison of performance. ESPECIALLY if added accessory's on vehicle
 
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