TOPIC:

I run honda spree batterys on all my race bike/hillclimbers that require a battery. any small 12 volt will work but , you aint gonna electric start much on a spree battery. at least i wouldnt think so. minimal wiring like the diagram above is just about all i use( even less we dont run lights) and keeps battery chargede and ignition happy, even with hipo coils and elec. ignitions. just my two cents worth . jonnybiker

thanx guys!! that is what Im looking for, im not worried about electric start I can kick a jumbo jet to life. lol, I 1 kick cr500's all the time at deadman starts at harescrambles so im sure I can kick this 400 to life

I didn't read this thread carefully enough to absorb all that was said... lots of good info, but I did pick up on: "The battery is the filter componenet of the electrical system that smooths the output from the alternator which is pulsing DC voltage."

The battery doesn't smooth out from the alternator. In fact the battery doesn't connect to the alternator. It connects to the regulator/rectifier. The alternator produces AC which the reg/rec converts to DC and also controls the voltage level output TO the battery. Nominal at idle should be around 12 VDC and at full voltage, about 14.5 VDC (3K rpm or so). The battery requires a voltage above 12VDC to maintain charging.

wiredgeorge wrote:

I didn't read this thread carefully enough to absorb all that was said... lots of good info, but I did pick up on: "The battery is the filter componenet of the electrical system that smooths the output from the alternator which is pulsing DC voltage."

The battery doesn't smooth out from the alternator. In fact the battery doesn't connect to the alternator. It connects to the regulator/rectifier. The alternator produces AC which the reg/rec converts to DC and also controls the voltage level output TO the battery. Nominal at idle should be around 12 VDC and at full voltage, about 14.5 VDC (3K rpm or so). The battery requires a voltage above 12VDC to maintain charging.

The alternator puts out AC pulses. The rectifier converts the AC pulses to DC pulses. The battery smooths out the DC pulses (which is probably what Bountyhunter meant). Without the battery, it's possible to have 20v or higher peak pulses.

The regulator regulates the AVERAGE voltage, but doesn't control peak voltages. So it is important to have a battery or capacitor to smooth out the pulses into a steady, useable DC voltage. Even with a battery or capacitor the DC will have a ripple to it. The ripple may be as large as 2v Peak-to-Peak. But without a battery, the pulses may be 20v Peak-to-Peak or even much higher when the regulator starts to interfere. Then you have a problem. I posted a discussion about the problems associated with pulsed DC and how it can do harm:
kzrider.com/component/option,com_joomlab...,4/id,184674/#184674

wiredgeorge wrote:

I didn't read this thread carefully enough to absorb all that was said... lots of good info, but I did pick up on: "The battery is the filter componenet of the electrical system that smooths the output from the alternator which is pulsing DC voltage."

The battery doesn't smooth out from the alternator. In fact the battery doesn't connect to the alternator. It connects to the regulator/rectifier. The alternator produces AC which the reg/rec converts to DC and also controls the voltage level output TO the battery. Nominal at idle should be around 12 VDC and at full voltage, about 14.5 VDC (3K rpm or so). The battery requires a voltage above 12VDC to maintain charging.

Since most modern alternator's have the rectifier assembly in them, I was simplifying it by giving the big picture: the alternator assembly supplies pulsing DC voltage to the system, and the battery does indeed act as a giant filter capacitor to keep the system voltage smooth.

There are a number of other factors which conspire to cause voltage spikes in an auto-MC electrical system without a battery or some type of storage element, the worst of which is that the secondary main charging current is controlled by the smaller current in the primary winding. The voltage regulator assembly usually controls the alternator's output by modulating the current. The bad news is, current flowing in an inductor can never change instantaneously so there is inherent lag time to the command's of the regulatro circuitry and that allows overshoot. The system relies on the battery or capacitor to limit the voltage as the thing overshoots.

The other design topology used in the past was to use silicon controlled rectifiers whose gates are controlled by the voltage regulation circuitry.

The upshoot of this all is that I know it's dangerous to run without a battery.... I learned the hard way. My battery failed and burned a cell open which then effectively disconnected it from the elctrical system. I got the bike running with the kickstarter and made it about one mile. In that distnce, the foillowing items were fried by overvoltage spikes:

Brake light bulb
All small instrument panel bulbs
Ignition Igniter Module

I coasted to s top when the last one fried.

loudhvx wrote:

wiredgeorge wrote:

I didn't read this thread carefully enough to absorb all that was said... lots of good info, but I did pick up on: "The battery is the filter componenet of the electrical system that smooths the output from the alternator which is pulsing DC voltage."

The battery doesn't smooth out from the alternator. In fact the battery doesn't connect to the alternator. It connects to the regulator/rectifier. The alternator produces AC which the reg/rec converts to DC and also controls the voltage level output TO the battery. Nominal at idle should be around 12 VDC and at full voltage, about 14.5 VDC (3K rpm or so). The battery requires a voltage above 12VDC to maintain charging.

The alternator puts out AC pulses. The rectifier converts the AC pulses to DC pulses. The battery smooths out the DC pulses (which is probably what Bountyhunter meant). Without the battery, it's possible to have 20v or higher peak pulses.

The regulator regulates the AVERAGE voltage, but doesn't control peak voltages. So it is important to have a battery or capacitor to smooth out the pulses into a steady, useable DC voltage. Even with a battery or capacitor the DC will have a ripple to it. The ripple may be as large as 2v Peak-to-Peak. But without a battery, the pulses may be 20v Peak-to-Peak or even much higher when the regulator starts to interfere. Then you have a problem. I posted a discussion about the problems associated with pulsed DC and how it can do harm:
kzrider.com/component/option,com_joomlab...,4/id,184674/#184674

There is also a condition called "load dump" which we all who design electrical systems to be used in cars must meet: if a battery is disconnected from the system while it is running, a voltage spike of upwards of 200V (maybe 50 milliseconds in duration) occurs on the car's electrical system.

It is caused because the alternator has current flowing in it to the battery when it is disconnected. Current flowing in an inductance can not stop abruptly, and produces a voltage which is proportional to the amount of current and how quickly it stops flowing.

This is the same principle used to creat the spark for the spark plug: the points open and break a current flow through an inductive winding and create a high voltage which is stepped up to an even higher voltage on the transformer secondary which connects to the plug.

Suffice to say, when you have current flowing in the windings of generators or alternators which have high current capability, the potential to creat huge voltage spikes is always there.

Post edited by: bountyhunter, at: 2008/02/08 14:03

I'm in way over my head here. We don't need no technical college, just KZ Rider.