John :
There's a good deal of sense in what you say, but I'd like to offer my
reasons for altering the calibration of my ammeter when upgrading from
the stock 19 amp dynamo to a 60+ amp alternator :
1) IMO the ammeter should electrically be where the factory put it :
between the battery and all other loads (except the starter and horns).
This means that, when the engine is not running or the alternator is not
'keeping up' with the load, the ammeter will be carrying the current
required for all the loads. If you try to solve this problem by
connecting the loads to the battery side of the ammeter, then the load
current shows up as a charge when the alternator is operating, and you
no longer have an accurate picture of whether the battery is being
charged or not.
2) Although as you suggest, the ammeter will peg only briefly after
startup, and will not actually be harmed, I find it distasteful to have
a meter peg. Simply a sign of poor engineering. Plus, I get real tired
of explaining to passengers that it's normal.
3) Although I haven't yet reached that point, my eventual plans include
more than 30 amps of load:
16 amps high power (100w) headlights
8 amps radiator fan
8 amps (roughly) MSD 6A ignition
5 amps rewound heater fan
5 amps tail/marker lights
15 amps (roughly) stereo (35w rms output X 4 channels X 75% efficiency)
4) I definitely do not want the meter to peg to the negative side under
any normal conditions, since that is frequently the first indication of
an electrical short. Since much of my electrical system is still stock
(hence unfused), the ammeter has more than once been a sign to shut
things off until a problem can be solved.
Of course, YMMV <g>
Randall
59 TR3A TS39781LO
John Dowson wrote:
>
> Hi,
>
> Hope this does not prove to contentious but I would like to make this
> suggestion about ammeters.
>
> IMHO the principle function of an ammeter is to show wether the
> dynamo/alternator is functioning, if it is meeting the electrical
> load requirements, and if the battery is accepting charge.
>
> To satisfy the above the ammeter should be in the battery line
> (but not including the starter motor) which will allow the ammeter to
> indicate battery charge/discharge. All loads other than the battery
> such as head lamps do not feed through the ammeter but you
> still know if the alternator/dynamo is working by the ammeter indication.
>
> Therefor if you provide a higher current supply by changing a dynamo for
> an alternator then there is no reason to change the ammeter range. If you
> have a good battery it will still only take as much charge as it needs which
> will probably be around 10A (very variable number) so the standard 30A meter
> range is what is required. Even if the needle is on the stop no damage will be
> done as it should only be there for a short time and then drop back to a
> reasonable charge rate.
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