Last Man Posting

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Re: Last Man Posting

#14731 Post by Technic[Bot] »

Loaded switch as mosfet based switch or as spring loaded switch?
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Re: Last Man Posting

#14732 Post by Bellhead »

As in, the switch bares the full brunt of every electrical load it controls. No relay, no solenoid, no transistor. The full amperage of every load on the circuit goes through that one switch, whichever one it may be. Wiper motors, heater blower, lights, starter solenoid.. Everything but the horn and the starter itself.

Modern engineering did away with loaded switch wiring decades ago because it puts immense stress on the switch, but mine are all still working quite well.
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Re: Last Man Posting

#14733 Post by Technic[Bot] »

I know that at startup most cars current can climb up to a couple hundred amps on start up. And mechanical switches may or may not spark on such conditions. Probably not a bad idea we went solid-state.
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Re: Last Man Posting

#14734 Post by Bellhead »

A few things: "solid state" just means there are no moving parts, such as relays, or points/breakers, or distributors.

Next, the starter motor is a ridiculously powerful electric motor that uses a crapload and a half of amperage, which is why the starter solenoid is so necessary. But even smaller loads, like 15 amperes, would easily be enough to damage a simple toggle switch. To put that into perspective, a 15A load at 14V, normal running voltage, is 210 watts, which is quite a lot of energy. Running all that power through a little switch on the dashboard involves a lot of stress, and should it fail, risk of a major electrical short. Literally deadly in the wrong situation.

Also, switches don't spark when turned on, nor while on. The spark occurs when the switch is opened (turned off) under load, because the amperage through that circuit has nowhere to go in that moment, and a sudden burst of voltage occurs in that instant, which creates the spark you see. Imagine dropping a wall in the middle of the highway: hit one car and it stops, then gets hit by the car behind them. The wall feels each and every impact, and even if only for a moment, has to deal with an insane amount of force just due to the combined momentum of everything it has to stop. Same basic principle, on a much smaller scale.
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Re: Last Man Posting

#14735 Post by Technic[Bot] »

Yes solid states means you change everything to transistors without moving parts.

200 watts is indeed significant power. And I wouldn't want to get 210 W across my body. Yet the average toaster is 700-1000 watts. Do not get me wrong it is definitely a lot specially for a tiny switch rated for 3-5 amps but is not really out of the park.

Also besides starting the gas engine the alternator is also more of a generator than a motor and as I think your standards alternator is rated at values like 100 amps @ 6000 Rpms
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Re: Last Man Posting

#14736 Post by Bellhead »

Okay. In case you were unaware, if your house uses natural gas for the stove, the toaster is almost certainly the single largest electrical load in the house. Not kidding. And the formula for watts is W=V*A, so in a 12v system running at 14v, 210 watts is 15A. For a switch rated for 3A, that's a death sentence for the switch; it would melt internally. On the other hand, in a 110v AC household line, 210 watts is less than 2A, which is far safer for contact.

On another note, my CJ has a redline around 4500, maybe less, and the original 125A alternator hit peak at about 1500 rpm. Most alternators are designed like that, so they can handle loads under normal driving conditions. It only has an 85A now, but even then, the line from the alternator to charge the battery is a gauge thick enough to tie up a small horse, and has no fuses in it. That line doesn't go through the dash, and has no switches to worry about. The only power that would go to the alternator would power the coil, and that doesn't need much power at all.

Sorry. At work, had rough day. Needed to rant about cars and stuff.
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Re: Last Man Posting

#14737 Post by Technic[Bot] »

I am sorry?

The toasters is indeed a high power consumption artifact but I do not think it is the highest rated element in the typical home, my microwave is rated at 1.2 Kw which is slightly higher than my toaster, coffe makers are also high power devices from 800 to 1200 kW similarly rated to toasters. Fridges are surprisingly low power, at around 500 W but even then washing machines can go up to 1.5 kW and tumble dryers can go up to 2kW, not to mention water pumps which even small pumps (1/3 hp) are around 1000 W these are a bit more problematic than the toaster in my opinion since these are inductive loads but anything reasonable modern should be power factor corrected, besides most power companies won't charge for reactive power, but i digress. Finally non-linear loads, electronics, are also surprisingly high powers a laptop can be around 100 w and a full gaming desktop can go up to 500 W. In any case depending on your local building code most house wiring are rated at around 30 Amps (mine is) which at 120 Vrms is around 3.6 kW.

So your car wiring should be around 1-2 AWG correct?

Also do not sweat it! I also enjoy to talk about this stuff I like to thing I am somewhat knowledgeable about these things
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Re: Last Man Posting

#14738 Post by Bellhead »

I don't know what gauge it is, but the main cables from battery to frame, starter and alternator are pretty beefy. And the rest of them are pretty thick for being regular harness connections. I wouldn't doubt that they would handle the load no problem, but the issues in this case are not only that the circuit is built with a certain fuse, and I would risk overloading it, but also that this system is old enough that it uses a mechanical flasher, so if I load up that circuit, it will invariably affect the turn signals, probably for the worse.

The electrical system of a vintage CJ-5 is basically like a pole jammed in the top of a cliff. It'll be perfectly fine, forever, and will serve its purpose perfectly, until somebody messes with it. The issue is, I don't know how they wired this stuff 50 years ago, so I have to Jerry-rig it using custom wiring and hardware, without interfering with it, and I refuse to use computerized -or even transistorized- aftermarket hardware of any kind if at all possible, given how much of this thing is period. "There's no such thing as a numbers-matching CJ", but it's still possible to use the same hardware they would have back then, or at least use the same components. Maybe improve on the methods a little, but I want as much of the tech to be of the same era as possible.

For instance, I'll be using solder and shrink-wrap tubing underneath the electrical tape, and I'll probably wire the relay coil grounds to a toggle switch, which I know full well would not have been done back then.
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Re: Last Man Posting

#14739 Post by Neutral Smith »

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If it moves but shouldn't: Duct tape. If it doesn't move but should: WD-40. With a hammer everything fits, and if it still doesn't fit: bigger hammer. If it can't be fixed with a hammer it's an electrical problem.

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Re: Last Man Posting

#14740 Post by Kellard »

That's so nobody can sue them
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Re: Last Man Posting

#14741 Post by Bellhead »

It should not be possible to sue somebody for your own stupidity. It's like Silica Gel having a "do not eat" warning. It shouldn't be there. If you eat something you find in an electronics package as an adult, you deserve to be yeeted out of the gene pool. Natural selection at work.

Children are a different story, but any responsible parent would teach their kid not to eat random things, or at least keep them away.
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Re: Last Man Posting

#14742 Post by Technic[Bot] »

The problem is stupid people are not stupid all the time. Once I almost get run over because for whatever reason my brain refused to look down the street for incoming :maeve: cars. Fortunately the kind lady decided not to run me over.

Besides even if we let "stupid" people die i don't think we would expert enough evolutionary pressure to actually see any effect.

Also the more modern the car the less service he end user is meant to do. Have you ever heard that modern tractors cannot be serviced by te end users? Not because they are too stupid to do so but only authorized technicians are allowed to do it. Unauthorized tinkering is detected by the tractor and may refuse to start later.

Long term i think we won't even have manuals since we won't own the cars. You will simply hail a taxi, from your phone and will take you wherever you want to go. Taxi company will own and maintain its fleet.

Considering the total cost of ownership for modern cars that may not be so bad.
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Re: Last Man Posting

#14743 Post by Bellhead »

And this is why I don't rent or lease vehicles. I want my car to be my car, and I want to drive it. Call me crazy if you want.

That said, way back when, it was far more common for people to be smart enough to do their own maintenance most of the time. I'll also call into account the difference in attitude of the populous over the last 50 years or so. People weren't taught to obey rules and be safe instead of stupid, they were trained. Difference being, somebody trained a certain way will instinctively think that way. I was trained not to swear by my mother as a child, and up until I became a tech where I work now, I never swore. I'd sworn maybe 10 times in my entire life up to that point. Now, as a mechanic, I'm more than fluent, and couldn't stop if I tried.

I was also trained to be part of society, not at odds with it, so it's second nature to be to keep an eye over my shoulder when walking, and to turn down my radio in the company of others, ask for help and give when necessary.. all that fun stuff. Nobody ever really told me to always pay attention (that I remember, anyway), it's just that's the way it was, and it's how I was raised. On the other hand, political correctness and social justice warriors and the like have determined that the government should have a say in how kids should be raised, which results in much softer forms of parenting, and in turn, looser conditioning for social and infrastructural situations. (I think that's a word.) If people these days were raised with the discipline of those born, say, 70 years ago, warnings such as "don't drink the stuff in the battery" wouldn't be necessary.

But no, society must protect the idiots, and in doing so, will create dumber and dumber people. Relevant:

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Re: Last Man Posting

#14744 Post by Technic[Bot] »

That is why I do not own a car. For me it makes no economic sense. In any case selling you rides is more profitable than selling cars. That is why there is so much interest in companies like Uber and Tesla. Also those John Deere tractor i mentioned were bought not leased.

On the other hand I think vehicles have become more complex over relatively little time. What can be realistically fixed by yourself in your own garage is less and less every year. And that is by design.

Next parenting methods have high variance meaning results vary a lot. A lot of people raised on the more strict means turned to be great some other rejected all what they were taught the second the left their parents home. Raising kids is hard we have not figured a perfect catch all method that always work.

I do believe we must protect the "idiots" not because some paternalistic vision but because depending on the metric we are all idiots. You do not fix idiocy by purging people as you may end up purging yourself if you are not carefull. But with education.
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Re: Last Man Posting

#14745 Post by Hayate »

Cars aren't real
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