Hi guys,It's been a while since I've posted here. Feeling slightly contemplative tonight. So I've passed my degree in electrical and electronic engineering recently graduated. Even got a 1st, but there's still something I don't completely understand. I've moved into a well known firm that manufacturers large mining vehicles. I can do my job no problem but I've this constant bug. I often understand the complex missing the very basic.
Here's my problem I get the engine's doing most of the heavy lifting.
But it's still a 12v battery doing everything else. Like wth I mean wth it takes two 9v batteries to power my remote.
Is it just cause its bigger. Like a whole lot of 12v channel adding the current? There's something fundamental that I haven't understood correctly about this, or I feel there's something more

 

If the 9V batteries you're referring to are the "transistor radio" type, they don't have much capacity. How are the batteries wired in your remote? Series or parallel?

Like a whole lot of 12v channel adding the current? There's something fundamental that I haven't understood correctly about this, or I feel there's something more

I don't understand your question. What channel? Adding current from what?

 

Oh yes right the batteries in a tv remote I mean they're in parrell so they're basically just one. Where as the ones in series link together to form a chain

 

I don’t know your mining devices obviously, but I imagine the battery is only used to start the vehicle then an alternator charges the battery after it’s up and running.

The startup current for vehicles is quite large 100s of amps. When you turn the ignition key power is sent to the starter. The starter turns the flywheel and engages the crankshaft and gets the motor turning. Once the motor is running the driver releases the ignition and the starter disengages the flywheel. The motor is connected to the alternator thru a pulley system to charge the battery for the next start of the motor. The alternator also provides the power for the vehicle once it’s running - not the battery. This entire process takes a few seconds to complete.

Big car batteries provide a lot of current and you need a large battery for that. Your TV remote takes milliamperes at most and are very low energy so the battery is much smaller.

The battery technology in the two systems is also different for the very same reasons.

There’s probably a YouTube that explains all this in better detail.

 

Battery cells in series or parallel a still a single battery pack.

 

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Right Tindel so it's the alternator supplying the continuous power. Happy days so what about this large initial delivery of current. As our not so subtle friend up here has pointed out the current is a property of the voltage and the resistance so where's the small resistance coming from?

 

Here's my problem I get the engine's doing most of the heavy lifting.

After the motor in a car, truck or tank is started, it no longer counts on the battery to power anything. After the motor/engine is started, everything is powered by the alternator/generator. Most vehicles will actually run, after being started, without a battery in them.

 

The low resistance is the resistance of the winding on the starter motor.

Les.

 

Right Tindel so it's the alternator supplying the continuous power. Happy days so what about this large initial delivery of current. As our not so subtle friend up here has pointed out the current is a property of the voltage and the resistance so where's the small resistance coming from?

So I've passed my degree in electrical and electronic engineering recently graduated.

Not to be crude or mean, but if your second quote is true, maybe you should see if you can get a refund on your tuition.

 

Right Tindel so it's the alternator supplying the continuous power.

You neglected to mention in your OP that you were discussing a gas/diesel/non-electric vehicle. That makes a big difference.

In non-electric vehicles, the alternator is sized to provide power for most of the "accessory" drain. The battery is mainly used to start the internal combustion engine; so it isn't working hard most of the time.

 

Not to be crude or mean, but if your second quote is true, maybe you should see if you can get a refund on your tuition.

This is incredibly rude, crude, and mean. It's easy to get through engineering school and understand how to design a motor, but not understand what a motor does. Why do you think most first jobs are either test or systems? It's so that greenhorns can get the larger picture before they get their first design role.

 

Here's my problem I get the engine's doing most of the heavy lifting.
But it's still a 12v battery doing everything else.

Your post rambles around a bit, but doesn't actually ask a coherent question.

What engine?

What battery?

What "else"?

ak

 

This is incredibly rude, crude, and mean. It's easy to get through engineering school and understand how to design a motor, but not understand what a motor does. Why do you think most first jobs are either test or systems? It's so that greenhorns can get the larger picture before they get their first design role.

But if you get through school/college and don't understand even basic things? Maybe if you studied something other than what the question is about I can see it, but he claims to be a graduate and doesn't even have a clue.

 

But if you get through school/college and don't understand even basic things? Maybe if you studied something other than what the question is about I can see it, but he claims to be a graduate and doesn't even have a clue.

I was an EE and I knew nothing of ME things when I graduated. I learned how a car worked by fixing the car when it broke! Hell, my school didn't discuss alternators or batteries either - at least not in undergrad, maybe some of the graduate courses discussed them, but I didn't go to grad school. We learned the basics of magnetics and coupling of transformers and battery impedance. Never once discussed an alternator, electric motor, or the differences in battery cells, capacities, and chemistries.

We can't possibly expect schools to educate engineers on every single topic. Just EE has power, embedded systems, controls, RF, lasers, integrated circuits, etc... and each of these have their own subdisciplines (and I didn't include computer science which IEEE also supports). How many people you know can do all of these things with any amount of talent? I'm a rare breed and have experience in four of the six fields mentioned, but only consider myself an expert at one of them. 1! 15 years of literal blood, sweat, and tears... and expert at only 1, and am really only an expert at a small subset of the topics of that 1! God forbid this poor new grad (I'm assuming an EE) doesn't know how vehicles (Mostly ME type stuff) work at the system level after going to engineering school!

Give this kid a break and answer his questions instead of telling him how dumb he is. He's not! He's doing EXACTLY what he should do... research and find the information to plug holes in his knowledge... that's really what undergrad is about! Who better to learn it from than somebody with years of experience like yourself!

@KevinEamon - keep asking these kinds of good questions and find your answers. You'll be a better engineer because of it.

 

@KevinEamon P.S. Find a good mentor at your work that you can speak freely with; They will be a great sounding board to answer these kind of questions, and provide other benefits as far as career guidance, helping navigate difficult situations at work, etc.

 

I have always considered a degree a qualification gained after a university course. Not something when leaving school. I think we were taught enough in O level physics at school to know basic electrical theory.

Les.

 

I was an EE and I knew nothing of ME things when I graduated. I learned how a car worked by fixing the car when it broke!

I'm not either of those things. But I have a strong desire to learn, and learn about many things. Doing so makes you multi faceted and smart in practical ways. To say that a graduated EE can't be expected to unders stand how a large car battery is more powerfull than a small 9V radio battery just defies common logic. And doesn't say much for todays education or students for that matter. I'm sorry if it offends your senses but....

 

I'm not offended... You're being an ass and wanted to call you out on it. No way you would treat this person this way if you weren't behind the veil of secrecy.

Way too much being an ass on this forum. Probably drives more people away than brings them in.

 

Oh yes right the batteries in a tv remote I mean they're in parrell so they're basically just one.

No, they are not.

And, it is spelled 'parallel'. Where are you located?

ak