[AT] Charging batteries

[Ron Cook]

I have never been around an Allis Chalmers or Ford 6-volt tractor that 
the electrical system performed correctly.  International Harvester and 
John Deere are the only other brands I have any experience with.  I 
currently have both of those I use and have no problems at all.  I do 
not have an IH M, but I remember they were marginal on cranking.  6 volt 
obviously not enough.  Same with John Deere A.  12-volt fixes both of 
them.  6 volt simply was marginal to begin with.  As far as charging,  I 
am of the opinion it has to do with the generator's rpm and in the case 
of the Ford, a cheap low output generator.  10 amp generator would take 
all day at full speed to charge the battery back up and I doubt anything 
other than brand new would put out anywhere close to 10.  Doing chores 
and such just won't do it.

Ron Cook, Salix, IA

On 3/12/2019 8:26 AM, Ken Knierim wrote:
> An old-timer friend explained part of the issue with 6 volt systems. 
> The brushes in the starter will drop about 2 volts out of the 6 volts 
> available just in the brushes IF they're working correctly. That's a 
> large loss that can't really be made up by heavy cables or any of the 
> other tricks used on the 6 volt systems. Adding a couple volts to them 
> really made a difference IF the charging system could develop that 
> much voltage. However, many times it wouldn't because the generator 
> didn't get enough RPM's due to belt losses or slow engine speeds like 
> our old tractors. So while 8 volt systems were sometimes OK, there 
> were fewer battery options and sometimes severe system limitations 
> until 12V was widely adopted.
>
> I use 12V on the starter for my Case D's. The charging circuits are 
> all 6 volt and I've been considering a boost circuit but after Cecil's 
> issues with the Belarus, I've reconsidered it and may just find a 
> small alternator that I can fit in there. It'll only work on belt 
> driven ones (the generator between the drive and magneto might be a 
> tough one to substitute...) but those projects all take "round tuits" 
> that seem to be in short supply...
>
> Ken in AZ
>
> On Mon, Mar 11, 2019 at 9:49 PM <deanvp at att.net 
> <mailto:deanvp at att.net>> wrote:
>
>     I’ve listened to these charging problems but what I haven’t heard
>     is what the charging voltage is at working RPM’s.  Then what the
>     resulting charging current is at the working charge voltage. I’m
>     really interested in trying to understand this problem. If the
>     generator is doing it’s job then the problem either has to be the
>     Regulator or Cut Out Relay.  On the 6V system I am familiar with
>     on the 1940 Slant Dash B’s they also had a 3 position switch that
>     determined how much the charging rate was desired.   But it seems
>     to me that working back from the battery is the only way to figure
>     out why the charging system is unreliable.    It isn’t rocket
>     science and I think most if not all of us can understand the
>     fundamentals.    But something important is being missed. If the 6
>     volt batter charging voltage isn’t approaching 7.5 to 8V “sum ting
>     is wong.” So if that isn’t up to par work back through the relay
>     and then to the generator.  I would honest guess the problem is
>     the generator .  The disadvantage of a generator over a Alternator
>     is the generator output is rpm dependent where it isn’t on the
>     Alternator. But…..usually a tractor is worked at close to full
>     throttle most of the time so a generator should be adequate.   But
>     maybe there is another issue here. Maybe 6V is marginal even if
>     everything is working properly.  Many 6V systems are converted to
>     8V or 12V systems and then work flawlessly. Even with a
>     generator.   So maybe the bottom line is 6V will never work very
>     well because it is under designed. For the job at hand. 6v leaves
>     little to no margin even if charged and grounded properly. Maybe
>     at 6V we are fencing with windmills.  And maybe 8V or 12V provides
>     the margin that was needed even from the beginning of the life of
>     the tractor.  Sometimes the laws of physics are very unforgiving.
>
>     Dean VP
>
>     Apache junction, AZ
>
>
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