Battery Charging? New to that!

[dduelin]

I agree that there is resistance etc. But the discussion of "regulation" was less theoretical and more about the belief on the part of some that the alternator on a car is designed to regulate the charging rate of a motorcycle battery connected by jumper cables. Surely you don't believe that too?

Clearly you don't understand this. If you connect two batteries together in parallel with jumper cables the regulator still regulates the output of the alternator to the "battery". The two batteries have become one and the regulator on the alternator acts accordingly. The good battery in this situation acts kind of like a capacitor - it is fully charged and damps the amount of charge current the regulator allows. The battery will only accept the amount of charge current it can take. In cruising sailboats, RVs, diesel electric submarines, emergency electrical back-up systems, etc. the battery "bank" is made up of two to hundreds of batteries connected in parallel, ie., positive to positive and negative to negative.

If the opposite cables touch together without being connected to the flat battery that is a different matter because you created a dead short across the car battery. Connecting them properly in parallel does not create the massive inrush of current that you can weld with.

I think you believe that when you connect the cables to the flat battery it is the same as touching them together and creating a dead short, at least you project that in your last response.

 

[dduelin]

*guffaw*

Boolean Logic or Chaos Theory evincing itself?

Dunning-Kruger Effect is more like it.

 

[Johnny D]

Clearly you don't understand this.

I have restrained myself so far and tried to remain respectful and kind. But what is going on here is that a guy with no understanding of basic electronics is attempting to give a lesson to someone who does.

I am not an electrical engineer but my Father was, and I have had this stuff drilled into me since I was a kid. I was playing with capacitors and transistors and building FM radios from scratch when I was 8 years old. So let me explain this one last time:

1) Higher voltage will overcome lower voltage. An alternator that is regulated with a voltage regulator at 14 volts will always have a higher voltage than a 12 volt battery. This is the reason why electrons flow through the battery and charge it. Once the battery reaches a voltage level close to say 13 or 14 volts, the resistance increases enough that current slows down and theoretically ceases. There is no magic intelligence built into an alternator that knows what is connected to it, whether jumper cables are being used or anything else. There is only a voltage regulator. The alternator also has a maximum Amperage output which is dependent on the design and to some extent the engine RPM.

Ok? No magic goes on so far. What you seem to believe is an intelligence built into an alternator is actually Ohms law in effect. It has to do with load and resistance. There is a short explanation of Ohms law here if you need a refresher course.

2) If you connect two batteries with jumper cables (in parallel I hope), current will immediately begin flowing, whether there is an alternator running or not. Just as before, the battery with the higher voltage will transfer some of its stored power through electron flow into the battery with lower resistance. Again, this is only regulated by Ohms law. There is no magical amperage regulator built into the alternator.

3) Now many battery chargers DO have some intelligence built-in. The more expensive they are, the more intelligent they can become. They can provide power at different amperage levels, which is DIFFERENT than an alternator which is always capable of outputting its maximum amperage and has no control of its own.

I hope this helps you to understand. If it does not, do not feel bad, as electricity can be a difficult thing to grasp. There is tons of information available on the web.

The fact is that with both cars and motorcycles becoming more and more computerized, it is becoming more risky than ever to jump start anything with ignition switched on. I have heard of people who fried the ECU in their car by jump starting another car, even when the engine was not running. They had the ignition switch on which opened the circuits to the ECU computer, and whatever spikes they created with the jumper cables made its way into some very expensive electronics.

It is very important to know the charging rate of the battery when hooking up a charger or another alternator to the battery to charge it. You should never exceed this rate. And if you are using a car to jump start a Motorcycle, NEVER start the car engine.

And finally, even if you do not agree with any of this, I am not wanting to continue arguing about it. I'd rather go back to the oil thread and argue there

 

[L.B.S.]

Dunning-Kruger Effect is more like it.

I had to look that up...

lol

 

[670cc]

I have restrained myself so far and tried to remain respectful and kind. But what is going on here is that a guy with no understanding of basic electronics is attempting to give a lesson to someone who does.

I am not an electrical engineer but my Father was, and I have had this stuff drilled into me since I was a kid. I was playing with capacitors and transistors and building FM radios from scratch when I was 8 years old. So let me explain this one last time:

1) Higher voltage will overcome lower voltage. An alternator that is regulated with a voltage regulator at 14 volts will always have a higher voltage than a 12 volt battery. This is the reason why electrons flow through the battery and charge it. Once the battery reaches a voltage level close to say 13 or 14 volts, the resistance increases enough that current slows down and theoretically ceases. There is no magic intelligence built into an alternator that knows what is connected to it, whether jumper cables are being used or anything else. There is only a voltage regulator. The alternator also has a maximum Amperage output which is dependent on the design and to some extent the engine RPM.

Ok? No magic goes on so far. What you seem to believe is an intelligence built into an alternator is actually Ohms law in effect. It has to do with load and resistance. There is a short explanation of Ohms law here if you need a refresher course.

2) If you connect two batteries with jumper cables (in parallel I hope), current will immediately begin flowing, whether there is an alternator running or not. Just as before, the battery with the higher voltage will transfer some of its stored power through electron flow into the battery with lower resistance. Again, this is only regulated by Ohms law. There is no magical amperage regulator built into the alternator.

3) Now many battery chargers DO have some intelligence built-in. The more expensive they are, the more intelligent they can become. They can provide power at different amperage levels, which is DIFFERENT than an alternator which is always capable of outputting its maximum amperage and has no control of its own.

I hope this helps you to understand. If it does not, do not feel bad, as electricity can be a difficult thing to grasp. There is tons of information available on the web.

The fact is that with both cars and motorcycles becoming more and more computerized, it is becoming more risky than ever to jump start anything with ignition switched on. I have heard of people who fried the ECU in their car by jump starting another car, even when the engine was not running. They had the ignition switch on which opened the circuits to the ECU computer, and whatever spikes they created with the jumper cables made its way into some very expensive electronics.

It is very important to know the charging rate of the battery when hooking up a charger or another alternator to the battery to charge it. You should never exceed this rate. And if you are using a car to jump start a Motorcycle, NEVER start the car engine.

And finally, even if you do not agree with any of this, I am not wanting to continue arguing about it. I'd rather go back to the oil thread and argue there

I'm pretty much with you on this one. Good explanation.

What I have had to do at times to get a BT Jr, or my larger 2,6,12 amp smart charger to acknowledge a severely discharged battery, is what you basically said. I hook the battery (removed from the bike) to a jump start battery pack or a non running car battery for a few minutes to get a brief quick charge and get the voltage bumped up, then switch to the small "intelligent" charger, where the logic circuit will now see there is a battery connected and take it from there.

Greg

 

[Jay Fridays]

Should have just jumped the battery... bottom line....lol

 

[Johnny D]

WRONG== would not have worked soon as it started and you disconnect the good battery the bike would kill

Someone else earlier in the thread had posted a similar statement, except they had said it would not "bump start" unless the battery had 10+ volts for the fuel injector.

What is being overlooked there is that once the bike was running, the alternator would continue to supply electricity to keep things running as well as to charge the battery.

The NC700 is my first fuel injected bike, so I cannot speak from experience here, but common sense tells me that the ECU and fuel injectors do not care where the voltage comes from. It uses power from the alternator while running.

 

[Bug Dr.]

If you don't hear the fuel pump prime when you turn the key don't even bother with trying to bump start the bike. Just sit down and have a cold drink and hope help comes soon.
Mike

 

[dduelin]

Someone else earlier in the thread had posted a similar statement, except they had said it would not "bump start" unless the battery had 10+ volts for the fuel injector.

What is being overlooked there is that once the bike was running, the alternator would continue to supply electricity to keep things running as well as to charge the battery.

The NC700 is my first fuel injected bike, so I cannot speak from experience here, but common sense tells me that the ECU and fuel injectors do not care where the voltage comes from. It uses power from the alternator while running.

I can speak from experience with Honda's PGM-FI system. If the system voltage is below the threshold to close the relay there is no fuel pump pressurizing the injector rail and no fuel injectors injecting. You can push the bike all you want and never change that. If you turn the bike on and don't hear the whirr of the fuel pump pressurizing the injectors then save your energy on pushing and start working on getting sufficient voltage in the MC battery.

When the battery died on one of mine while riding due to an electrical failure the bike started acting up. First thing I noticed the instruments starting blanking out intermittently then went off and a few minutes later the engine acted like it was running out of gas. It only ran a couple more miles like that then quit completely. On the side of the road the battery was dead and could only click the main relay when the start button was pressed. I got a tow home and checked the system voltage and it was 10 something. I charged the battery for a while and got the bike to start but it was obvious that the charge system was toast as the system voltage remained under 11 with the bike running. Long story short the alternator had failed due to an open circuit rotor and had to be replaced.

 

[Johnny D]

If you don't hear the fuel pump prime when you turn the key don't even bother with trying to bump start the bike. Just sit down and have a cold drink and hope help comes soon.
Mike

So it will not prime once it gets power? Are you sure of this?

Ok I will edit this. I went to that infinite source of all wisdom and knowledge (Google)

It is for certain that the fuel pump requires a certain voltage before it will work, and it is certain that the engine is not going to start without the fuel pump.

... If the system voltage is below the threshold ...

Correct Dave, but I assume that "system voltage" does not equate to just battery voltage.

Google says Dead battery: forget it. Low Battery: maybe.

I would say, If the battery is completely dead, it might pull the output from the alternator down too low to fire it up.

I would say, ST-1100 or 1300, too heavy, forget it anyway unless its parked at the top of a hill.

NC700X Low battery, go for it. Dead battery, charge it

I am actually hoping that it someone else, and not myself that gets to try it first

 

[JDE]

So it will not prime once it gets power? Are you sure of this?

Ok I will edit this. I went to that infinite source of all wisdom and knowledge (Google)

It is for certain that the fuel pump requires a certain voltage before it will work, and it is certain that the engine is not going to start without the fuel pump.



Correct Dave, but I assume that "system voltage" does not equate to just battery voltage.

Google says Dead battery: forget it. Low Battery: maybe.

I would say, If the battery is completely dead, it might pull the output from the alternator down too low to fire it up.

I would say, ST-1100 or 1300, too heavy, forget it anyway unless its parked at the top of a hill.

NC700X Low battery, go for it. Dead battery, charge it

I am actually hoping that it someone else, and not myself that gets to try it first

I think I've read on here where some already have tried this and were successful in push starting their NC. With a LOW battery mind you, not a completely dead battery.

 

[showkey]

Someone else earlier in the thread had posted a similar statement, except they had said it would not "bump start" unless the battery had 10+ volts for the fuel injector.

What is being overlooked there is that once the bike was running, the alternator would continue to supply electricity to keep things running as well as to charge the battery.

The NC700 is my first fuel injected bike, so I cannot speak from experience here, but common sense tells me that the ECU and fuel injectors do not care where the voltage comes from. It uses power from the alternator while running.

^^^^^^^^^^^^^^^^
The above is right on..........if the battery is not super dead, the bike will most likely will continue to run after the jump start. I recall others saying they were successful in push starting a number of bikes.

So it will not prime once it gets power? Are you sure of this?

Ok I will edit this. I went to that infinite source of all wisdom and knowledge (Google)

It is for certain that the fuel pump requires a certain voltage before it will work, and it is certain that the engine is not going to start without the fuel pump.



Correct Dave, but I assume that "system voltage" does not equate to just battery voltage.

Google says Dead battery: forget it. Low Battery: maybe.

I would say, If the battery is completely dead, it might pull the output from the alternator down too low to fire it up.

I would say, ST-1100 or 1300, too heavy, forget it anyway unless its parked at the top of a hill.

NC700X Low battery, go for it. Dead battery, charge it

I am actually hoping that it someone else, and not myself that gets to try it first

We maybe back to just the words used.................The pump prime is not the problem, low battery will cause the pump not to pump. (The pump is self priming) . We are back the permanent magnet alternator........the alternator in this bike does not need battery power to make power........but the bike does need some battery power to close critical relays to run........that power can come from the alternator or the battery.

The alternator in the ST and Goldwing needs some battery power to the alternator to allow the alternator to make power.
As JD stated might depend on how dead the battery really is..........pushing a ST up the slightest hill is not happening

One other trick if this happens to anyone (on any bike)........unplug the headlight.........key on head light draws a lot of power.......unplugging saves that power for starting and running the bike during the push start, kick start or jump process or what ever emergency methods are being tried.

Back in the day before fuel injection.........running low on battery power caused the vehicle to stop because it lost spark, with fuel injection the low battery will cause the vehicle to stop because the fuel pumps stops. The reason pumping fuel to 40-60 psi taking a lot of power.........more power demand mean first to stop working. (Depending in the vehicle normal fuel pressure is 40-80 psi).

 

[dduelin]

^^^^^^^^^^^^^^^^
The above is right on..........if the battery is not super dead, the bike will most likely will continue to run after the jump start. I recall others saying they were successful in push starting a number of bikes.






We maybe back to just the words used.................The pump prime is not the problem, low battery will cause the pump not to pump. (The pump is self priming) . We are back the permanent magnet alternator........the alternator in this bike does not need battery power to make power........but the bike does need some battery power to close critical relays to run........that power can come from the alternator or the battery.

The alternator in the ST and Goldwing needs some battery power to the alternator to allow the alternator to make power.
As JD stated might depend on how dead the battery really is..........pushing a ST up the slightest hill is not happening

One other trick if this happens to anyone (on any bike)........unplug the headlight.........key on head light draws a lot of power.......unplugging saves that power for starting and running the bike during the push start, kick start or jump process or what ever emergency methods are being tried.

Back in the day before fuel injection.........running low on battery power caused the vehicle to stop because it lost spark, with fuel injection the low battery will cause the vehicle to stop because the fuel pumps stops. The reason pumping fuel to 40-60 psi taking a lot of power.........more power demand mean first to stop working. (Depending in the vehicle normal fuel pressure is 40-80 psi).

I once rode my airhead BMW about 300 miles like that. A bad rotor killed the charge system and drained the battery. I disconnected every light but the running/stop light and got home with a battery that had less than 8 volts in it at the end but it was a very simple bike. If you recall the circumstances of my ST1300 breakdown when I figured out the acute problem of a dead or dying battery I disconnected the headlights and the bike did start and run a few moments but FI and ECU's need a good supply of clean electricity and that was used up before I could get my gear back on. The alternator did not come on line so the day was done.