>
>
> Well,
>
> To answer your questions, it depends on how much you really want to
> understand about it. In real layman's terms, the voltmeter can be summed
> up as follows: (assuming the car is running)
>
> < 12 volts -- something is broken somewhere
> 12-13 volts -- a marginal electrical system
> 13+ volts -- basic electrical system is ok
>
> something on, (such as the starter, lights, radio, spark plugs, etc.)
> Unfortunately, the "water behind the dam" metaphor starts to get real
> complicated when that happens, as various electrical components will punch
> holes of various sizes at various heights in the dam, and require varying
> amounts of current (amperage) to do anything useful, so I'll try to stop
> whilst we may still be ahead, unless somebody really wants me to try to
> continue... (or pick it up themselves at this point...)
>
> --ken
> An amateur Triumph mechanic who took a few EE classes...
>
> Kenneth B. Streeter | EMAIL: streeter@sanders.com
> Sanders, PTP2-A001 |
> PO Box 868 | Voice: (603) 885-9604
> Nashua, NH 03061 | Fax: (603) 885-0631
>
Lawrence,
I think both of these guy were doing a pretty good job, but I would like to
give
you another perspective.
The analogy of voltage to water pressure and current (amperage) to water flow
is
a good one. Higher water pressure means that more water will flow through a
given
size pipe. Similarly, higher voltage means a higher flow of electrons (current,
measured in amperes or "amps" as they are affectionately known) through a given
resistance
What you are probably interested in is what your car's voltmeter or ammeter says
regarding the proper functioning of the electrical system. Either meter will
tell
you if your charging system is generally functioning properly when you
understand
what they mean.
As Ken said, if your voltmeter reads above 13 V. when the engine is at running
speeds your generator/alternator is probably OK. The voltage measured is
(someone
correct me here, if I am wrong) at the generator/alternator output. If the
voltage there is HIGHER than the battery voltage, the battery is being
charged.:-)
If the voltage is lower than the battery voltage, your gen/alt. or voltage
regulator is not working properly and the battery will be discharged. :-(
An Ammeter measures the current flow INTO the battery. Thus, positive flow
implies that all is well, the battery is being charged. Negative flow means
that
your gen/alt. is not supplying enough current and your battery is discharging.
Summation:
Voltage higher than 13 V :)
Voltage lower than 13 V :(
Current positive :)
Current negative :(
This is at driving speeds. At idle, it is normal for voltage to be slightly low
and
current slightly negative.
Hope this helps to clear things up.
Jim Snyder
|