I know it works, but never understood how: Batt/Alt/Start
 

The battery feeds power to the starter through the negative cable/post.

When the Alt/Gen takes over, HOW does it recharge the battery:

1. Alt/Gen>Junction Box>Ammeter>Junction Box>Starter>back up the negative cable to the battery?

OR

2. Alt/Gen>Frame/Block Ground>through the frame>positive cable to the battery?

If 1, does the negative cable change direction of flow to let the power back into the battery? How does this work if the battery is still providing a buffer to the whole electrical system, and could be feeding some power from the battery to the system?

If 2, is it the logical idea that electricity flows from positive to negative?

3. It's really just magic and little elves under the hood, so just accept it!

This whole theory is hard for me to grasp having grown up in an era of Negative Ground, but even in 1978 I was puzzling on this as I replaced (X3) the starter on my '73 LeMans!

Re: I know it works, but never understood how: Batt/Alt/Start
 

Generator through the ammeter to the battery

Re: I know it works, but never understood how: Batt/Alt/Start
 

#1. Electrons in a solid metal flow from neg to pos. I heard/read somewhere that early expermenters going back to Ben Franklin and his kite got the flow direction wrong but the labels stuck.
That said, my other hobby is ham radio, and modern physics has complicated that simple theory. BAsically, it really is magic, with the little elves inside the wires making smoke that carries the current. When the smoke gets out, all the electrons go with it and the device doesn't work anymore. You may have noticed this yourself.

Re: I know it works, but never understood how: Batt/Alt/Start
 

Actually it is both paths 1 and 2. In path 2 in the direction that you indicate and in path 1 in the opposite direction of what you indicate.

Current always flows in a closed loop.

Re: I know it works, but never understood how: Batt/Alt/Start
 

View the terminal on the starter switch as an extention of the negative post and not as part of the starter. Other than a common ground the 2 systems are completely seperate until the switch is depressed. No current flows through the starter until the switch is depressed. Some people have a hard time with electricity and refer it all as PFM. Rod

Re: I know it works, but never understood how: Batt/Alt/Start
 

An easy way to think about it, is in a DC circuit when there are two sources of power connected, the source with the higher voltage will assume the load. The battery is at 6.3 volts. The generator (or alternator) puts out a higher voltage and takes over the electrical load. It sees the battery as another load and sends current to it, which charges it up.

it works the same with a positive ground. Current is still flowing in the same direction, only with a different ground reference.

Tom Endy

Re: I know it works, but never understood how: Batt/Alt/Start
 

Even the schematic symbols are drawn "the wrong" way.

Re: I know it works, but never understood how: Batt/Alt/Start
 

As it is with all new discoveries, theory takes much convincing for it to become generally accepted. In the beginning we thought that all things physical must be positive, therefor Franklin labeled Lighting as Pos. and the ground (earth) as Neg. It wasn't until atomic theory was able to isolate the outer most electron on an atom (the valance ring electron) as negative charged and then realized that it was attracted to an atom that need an extra electron that we were able to show that the flow was neg. to pos.

Re: I know it works, but never understood how: Batt/Alt/Start
 

I recall an instructor during the first few weeks of navy electronics school telling the class: "The direction of current flow is a matter of theory since you can't see it. Here in the navy current flows from negative to positive. The air force may tell you it flows in the opposite direction, but you aint in the air force, so if you want learn anything in this school get it through your head current flows from negative to positive."

Tom Endy

Re: I know it works, but never understood how: Batt/Alt/Start
 

I see nothing wrong with the defined direction of current flow. In fact it couldn't have been different.

Current is a transport of electrical charge. In the case of electrons in a wire, the charge being transported is negative. The direction in which they move must therfore be the opposite ( negative direction) of the direction of positive current flow. Two negatives multiplied ( negative charge times negative direction) gives a positive direction of current flow.

If we imagine that the electron had been a positively charged particle, it would have been moving in the same direction as the direction of positive current flow.

On the following I am a litte on thin ice, but I believe that where you have positively charged elements as for example positively charged ions in an electrolyte, they do actually move in the same direction as the positive direction of current flow.

Re: I know it works, but never understood how: Batt/Alt/Start
 

Ignoring the whole positive-negative aspect, if the generator is providing more voltage than the nominal battery voltage, the battery will charge and the generator will be providing all the power for the car as well. I believe the battery will act as a "buffer" if you have an original generator; that's why you have to adjust your generator brushes to prevent too much current from "cooking" the cells. If you have an alternator the electronic regulator will control the voltage even if the battery is missing.

Re: I know it works, but never understood how: Batt/Alt/Start
 

I don't care which way it goes either Sparky.

The best way to deal with it is think plumping. Current is volume. A fire hydrant is a high current device. kids play in the water when they open them open. Voltage is push, the kids play as the volume is not being "pushed so much but raise the push/voltage it will knock the kids over and push them down the street. A squirt gun at it's pressure (voltage) and small volume (current) is harmless. Apply the squirt guns pressure to a fire hydrant and it can be lethal.
The battery is a filter or a condenser if you will. The generator is the pump to the battery, but like filling a tire you need higher pressure than what is in the tire. Like two tanks connected together, the tank with more water will feed the lower level.
This may seem an odd way to look at it but if you are unfamiliar with electricity you'd be surprised what you can do thinking of plumbing.
A bad connections is a clogged pipe. And open connection is I have water here in the pipe but not there so it's between the two points.
I hope I have not confused the issue.

Re: I know it works, but never understood how: Batt/Alt/Start
 

i too use plumbing lingo when im trying to explain something electrical to people. resistance is like lime buildup or corrosion in a pipe, a short is a water leak, an open is a pipe cap, valves are like switches, T's and 4 ways are like nodes or wirenuts.

there are the 2 different ways of looking at electricity and which way it flows: theres electron theory which is neg to pos due to an atom needing an electron.

then there's hole flow which is our usual standard of pos to negative because when an electron leaves one atom it leaves room for another free electron so there is a "hole" there for an electron to go. so if you look at it from the holes point of view thier going pos to neg haha.

Re: I know it works, but never understood how: Batt/Alt/Start
 

Your local community college or tech school will have a course in basic electricity. Well worth the time and money!

Re: I know it works, but never understood how: Batt/Alt/Start
 

Read all the posts and haven't learned a thing, other than add one new electrical term that even Google doesn't have a defination for, so Rowdy what is PFM? I've always wondered if the electricaly gifted that understand the invisable are also more knowledgeable in thing religious? Bob

Re: I know it works, but never understood how: Batt/Alt/Start
 

All I know is opposites attract, but I'm positive that I want a female that isn't negative.:D

Re: I know it works, but never understood how: Batt/Alt/Start
 

Pure f*****g magic :eek:

Re: I know it works, but never understood how: Batt/Alt/Start
 

Mitch nailed it for sure.

Understanding and beleiving in something we can not see sure don't hurt with our religious beleifs. In both we can not see the proccess only the results. Difference is we can normally get things to go our way with electricity and we have to understand that we have no direct control over Gods actions. At times though both require prayer and patience. Rod

Re: I know it works, but never understood how: Batt/Alt/Start
 

The best thing I've seen all day!
Thanks Tom:)

Re: I know it works, but never understood how: Batt/Alt/Start
 

Ok, finally an electrical term I can understand. All the electrical magic left my Dad's Roadster 30 years ago. Bob

Re: I know it works, but never understood how: Batt/Alt/Start
 

haha its usually just F&M for me...

pesky hoses always clogged with copper:cool:

or at work us electricians are refered to by the mechanics as wirebenders, we call the mechanics hammer draggers.

Re: I know it works, but never understood how: Batt/Alt/Start
 

It may help you to think of the circuit as supply and return, in the case of an A supply is the neg. post ( via the wires) and return is the positive post ( via the car frame). In the case of an A the supply is a negative voltage when referenced to the frame of the car (return). The starter is of course bolted to the return side and a switch in the supply side allows you to control the current flow at will (think of it as a valve in a water pipe). The generator is bolted to return side and is wired to the supply side the cutout is just a switch in the supply side that connects the generator to the battery automatically when the generator is generating a voltage that is higher than the battery so that current can flow from the generator to the battery.

For now do not try to understand the electrical theory of electron flow, magnetic flux.... Etc... This type of theory is beyond simple posts here.

Re: I know it works, but never understood how: Batt/Alt/Start
 

Thanks Jon, I know it works some how, I'll just never be a guy than can do it, time to do some body work on the Roadster, that I full understand and enjoy. Bob

Re: I know it works, but never understood how: Batt/Alt/Start
 

Hi Tom,
Were we in the same class LOL???? ATN Ehrenhofer
Naval Aviation Electronics Training Millington TN
Squadron VA727 NAS Glenview 1965/72
Ken:D:D

Re: I know it works, but never understood how: Batt/Alt/Start
 

see body work is something i hate doing. i can do electrical ll day long. how about you fix my cab and sheetmetal and ill fix your electrical leaks:cool:

Re: I know it works, but never understood how: Batt/Alt/Start
 

Working on Electric Forklifts I end up doing a lot of both. Thankfully the body work does not have to be exacting, just good enough to not cause problems. Did some body work on the delivery this last winter. That went alright and most went as planned. Rod

Re: I know it works, but never understood how: Batt/Alt/Start
 

I've worked with more than a dozen guys who can't get their heads right when dealing with positive ground. The most recent event, I took the battery out of the car and asked him, "What's so different now?". The look on his face was suitable for framing, but believe it or not, still a problem. "Because the grounds hook to the hot side!" Hot side? No such thing.

We can surely study electrons, atomic theory, Ben Franklin, et al, but it still doesn't replace good grounds (star washers can be your friend) and clean connections. It still doesn't replace a well set generator that doesn't cook the battery. Terms like "juice" and "hot" can be confusing for many as well. My best advice would be a cup of coffee and the wiring diagram for your car. Start at the battery (forget the + and - signs) and follow the circuits. As to how does it charge the system/battery, well that's easy. Through that extra small wire that shares the battery connection with the starter switch. It's the connection to everything else via the box on the dash panel (firewall), which also loops through the ammeter so you can see if it's charging or draining the system. Using the plumbing reference, the ammeter is like a clear sight glass to observe flow through a tube. Not to dis the topic, some things are best left to the engineers who designed them. Look how long it's lasted.

Re: I know it works, but never understood how: Batt/Alt/Start
 

personally i like cleaning up vehicle grounds (weither pos or neg) and putting a little bit of conductive grease between the cable and frame or whatever part. ensures it wont rust and gives better conductivity.

also you can never have enough grounds!

Re: I know it works, but never understood how: Batt/Alt/Start
 

That's the thing I'll never get my head around, ONE little wire runs EVERYTHING on the car without bursting into flame. Battery cables must carry 50 times the electricit but that little thing is carring the same juice. Don't understand it, then again I can't understand why some people can't block sand a panel dead smooth and apply black paint. I'll just never get it. Bob