Hey all,
Sorry if this is an incongruous solution but:
I converted my car (1275) to a modern (although Lucas) alternator and
haven't looked back since.
(1=A2)
ctp
At 4:15 PM -0800 1/9/98, DANMAS wrote:
>In a message dated 1/9/98 5:01:56 PM Eastern Standard Time,
>Matt.Kulka@hboc.com writes:
>
>> Okay, I can visualize getting a cheap ammeter and connecting it between
>> a battery post and cable to find out how much various things load my
>> charging system. But you can't very well measure the draw of your
>> coil's primary and secondary circuits (because the alternator never runs
>> without that load.) As a point of curiousity, does anyone know how much
>> juice it takes just to create the sparks?
>>
>> Also, what the heck is the formula for watts, voltage and amperes again?
>> I haven't used it since high school.
>
>Matt,
>
>Let's start with the last part first:
>
>1) Watts =3D Volts X Amps
>
>2) Amps =3D Watts/Volts
>
>3) Volts =3D Amps X Resistance
>
>4) Amps =3D Volts/Resistance
>
>Substituting 3 into 1, we have
>
>5) Watts =3D Amps X Amps X Resistance
>
>I wouldn't suggest that you try to measure the current drain. I would
>recommend that you sit down with a pencil, a calculator, and your schematic=
,
>and calculate the loads, using the formulas above. The wattage ratings for =
the
>lights are readily available, but you might have to do a little guess work
>with other things, such as the heater fan. Based on my own experience, I ca=
n
>give you some rough approximations, though (very rough).
>
>Heater fan - 5 amps or less
>WS Wiper motor - 1.5 amps
>WS Washer motor - 1 amp
>Horns - 5 amps
>Electric gauges - 0.1 amp each
>Fuel pump - 3 amps (racing pumps might draw up to 15)
>ignition coil (primary only - the secondary doesn't draw from the alternato=
r)
>- 4 amps or less
>Radio - Depends on the volume, but a good average is to calculate the amps
>based on the rated output wattage
>
>Just the other day, on the Triumph list, a question was raised as to the
>correct ratings for fuses. I calculated the loads on my TR6 on a fuse by fu=
se
>basis, and I reprint it here. The results should be very similar for any of
>the LBCs of the same era.
>***********************************************************************
>"RED" fuse - This fuse feeds all the tail, parking, marker, and dash lights=
,
>and pulls less than 6 amps.
>
>"PURPLE" fuse. - This fuse feeds the glovebox lamp, courtesy lamps, trunk
>light, the horns, and the hi-beam flasher. With the exception of the horns =
and
>the flasher, the load is less than 3 amps on this fuse. For a stock headlig=
ht,
>flashing the hi-beams pulls about 9 amps, and the horns draw around 5 amps.=
If
>you have quartz-halogen lights, the current will be more, but you really
>should have them on a separate, un-fused, power source anyway (yes, I said
>"un-fused" - that is not a typo!), and they should be relay operated. It is
>very unlikely that you will have the doors, trunk, and the glovebox open wh=
ile
>blowing the horn and flashing the lights. Even if you should do this and bl=
ow
>the fuse, the headlights, both hi and low beams, will still work, as they a=
re
>fed from another circuit. The flasher merely bypasses the headlight switch.
>
>"GREEN" fuse - This one is a little harder to determine, as you will seldom
>have all loads on at the same time, but the maximum load, with everything o=
n,
>is about 20 amps. This fuse supplies power to almost all of the loads that =
are
>switched on with the key, the most notable exception being the ignition
>circuit, which is fed directly from the key with no fuse.
>**********************************************************
>As you can see, you will have to consider the likely load combinations when
>figuring the maximum draw, rather than just adding everything up. For examp=
le,
>no need to include both the high beams and the low beams, unless you have
>rewired your car so they can both be on at the same time. Also, no real nee=
d
>to figure the horns, as they are only used momentarily, and the battery can
>supply any over draw they might create for that short length of time with n=
o
>problem.
>
>If anyone is interested, I would be glad to post my entire response to the
>Triumph list here as well. It had to do with replacing the 35 amp Lucas fus=
es
>with 35 amp fuses from the auto parts store (don't do it!).
>
>Equation 5) should be looked at with interest. All wires have resistance.
>Current through any wire produces wattage, or heat. From 5), you can see t=
hat
>if you double the current, the wattage, or heat, is quadrupled! Interesting=
,
>eh?
>
>Dan Masters,
>Alcoa, TN
>
>'71 TR6---------3000mile/year driver, fully restored
>'71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion - see=
:
> http://www.sky.net/~boballen/mg/Masters/
>'74 MGBGT---3000mile/year driver, original condition, slated for a V8 soon!
>'68 MGBGT---organ donor for the '74
|