Ammeter bypass
- Thread starter bronze turbine
- Start date
I like the diagrams you whipped up, also a great refresher on electrical basics. Completely forgot about Ohm's law and parallel circuits. This one in particular shows how the bulkhead connector bypass should be done, as well as where to place additional loads within the circuit.
The only issue I can see is if the engine is off and you for whatever reason, need to have the headlights on. Or maybe you're just listening to music at a moderately loud volume. Would the ammeter have problems with that?
The only issue I can see is if the engine is off and you for whatever reason, need to have the headlights on. Or maybe you're just listening to music at a moderately loud volume. Would the ammeter have problems with that?
72RoadRunnerGTX
New Member
That is correct, the only circumstance where the ammeter is exposed to full vehicle loads is when the engine is off, or engine is running, and the charging system is inoperative for whatever reason. These passenger car ammeters from this time are robustly constructed and can handle quite a bit of current assuming the connections/insulators at the ammeter are in good shape and have not been abused/neglected previously. Most are scaled at about 40 amps one way or the other. The internal bus dimensions enable a much higher tolerance. The stud head to bus connection would be the limiting factor. Verry important to maintain tight ammeter stud nuts but not so tight that the fiberboard insulators are crushed/damaged.
In one of the videos linked, it shows one of my cars running 400 watts if Hella lighting with engine off. Drawing about 25amps, have no concerns with this current through the upsized wiring and ammeter at all. Would have more concern with how long I could run those lights before I couldn’t get the car started.
There was a time when I spent a great deal of time sitting listening to the radio/sound system with the engine off, don’t do much of that these days. There was another time when I ran around with a trunk full of audio amplifiers and/or designed such systems professionally. Would design a separate isolated battery system to power these systems and have no impact to the stock charging/starting system.
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That sounds interesting (to me at least LOL) and I'd like to see an example of how you did the isolated battery system.
72RoadRunnerGTX
New Member
Basically. the same as the “House” or auxiliary 12-volt systems in R/Vs or marine applications. A separate electrical system based around a trunk mounted battery (typically deep cycle), having all audio components connected separately and isolated completely from the car’s electrical system. Using a battery isolator installed at the alternator output to charge both systems as needed but prevent any current draw from either system to/from the other. Effectively isolates the stock/starting system from any impact from the sound system and its battery state. I'll work on a diagram when I get a minute.
Might be similar to some light-duty truck applications where there is an extra battery for the attached travel trailer to run off of? Factory "isolation" battery and harness, charged by the vehicles charging system. I know GM had such an option a while back. Might be more common in the travel trailer world?
CBODY67
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