WTF - Watt the fock?

[Rob Frankham]

Actually PAS that's where the confusion comes in. Those new light weight lithium batteries like to be charged at a greater voltage than we usually use on traditional batteries.

For maximum life and reliability, Lithium batteries in general need a completely different charge regime to any form of lead acid battery. In the best batteries, designed for vehicle starting, this is managed by electronics in the battery itself but most of the 'reasonably priced' items you find on the web don't have those electronics which is why using 'cheap' Lithium batteries is seldom a good idea.

Rob

[jackonz]

Am sorry but in this case you are wrong.

Justify...

Rob

First and formost all batteries have changed a lot since these bikes were manufactured, in addition there were few if any additional electrical items you could purchase to add on, in my caase my R80 was built in 1978 and we had good old fashiond Wed type batteries, now we have AGM, Calcium and VRLA (Valve Regulated Lead Acid), all these batteries are types of lead acid.

Modern batteries require a charging voltage between 2.15 and 2.35 volts per cell, so a 6 cell battery needs between 12.9 and 14.1 volts to charge, the current output of the generator or battery charger determines how fast a battery will charge to full capicity, low current will mean it will take longer to re charge the battery as long as the voltage is high enough.
On the bike if you have electrical draw greater in total to the maximum output wattage of the generator you will depleate the battery as you are drawing more current than is generated.

Now to the regulator that Motorworks offer, it allows a higher voltage at lower RPM, it will NOT change the current output of the generator but will allow the battery to charge at at lower RPM than the origional regulator, this was the major fault the previous owner had with the bike in question he went through 2 batterys in one year as he was only using it around town, as the battery was an AGM it went below 7 volts and were unable to be recovered, in addition there were voltage drops across the battey ground and positive leads that have now been replaced.

Where I work at a polytech teaching apprentice Mechanics and Auto sparkies this is a common issue on older vehicles where 1970s alternators cannot keep the charge in a Calcium battery, here in NZ it is just about impossible to purchase an old style wet battey.

The other thing to note here is not to use an old style charger on thses new batteries as in most cases it will make them gas and reduce the life of the battery, on the flip side is that if you do have a new electronic charger and you do have a newer battery that has gone down below 11.2 volt these chargers will not charge the battery, the trick is to fool the charger by jump starting the battery from anothe battery in parrell, with the charger on the dead battery in most cases it will re charge and the charger will de sulfate the battery.

Warning sulfuric acid is dangerious and always wear a face shield gloves and so on, if you are unsure then leave it to someone who knows what they are doing. all at your own risk.

[Zombie Master]

and:

https://www.google.ca/search?q=parallel ... EPqsiGyAc3

[Rob Frankham]

Am sorry but in this case you are wrong.

Justify...

Rob

Now to the regulator that Motorworks offer, it allows a higher voltage at lower RPM, it will NOT change the current output of the generator but will allow the battery to charge at at lower RPM than the origional regulator, this was the major fault the previous owner had with the bike in question he went through 2 batterys in one year as he was only using it around town, as the battery was an AGM it went below 7 volts and were unable to be recovered, in addition there were voltage drops across the battey ground and positive leads that have now been replaced.

Leaving aside the developments in batteries over the years, would you please explain how a standard type voltage regulator can increase the maximum output of an alternator (at any revs) when that maximum output is defined by the current through the rotor. Any knowledge of electronics at all, will tell you that the arrangement of the regulator in the circuit can only decrease the current through the rotor, never increase it. The effective element of the regulator is a set of contacts or a bipolar transistor or a Mosfet (dependent on the type of regulator you are using) that cuts current to the rotor in order to ensure that it doesn't increase beyond the set charging voltage.

To put it another way... as the engine revs start to increase, the output from the alternator will gradually increase (due to current through the charge lamp and, increasingly, current from the 'D+' terminal of the rectifier) until the off load voltage exceeds battery voltage (measured at the D+ line), at which point the charge lamp goes out. The revs at this point depend on the electrical load but are normally somewhere in excess of 1500RPM. It should be noted that no charging occurs whatsoever until this point is reached.

As revs increase beyond this point, the output voltage and current from the alternator will increase at at rate dependant on load until the output voltage reaches the cut off voltage of the regulator. One might expect this to be around 2,500 or 3,000 RPM. Up to this point, the regulator does nothing at all... the alternator is always producing it's maximum output for the revs.

Once the voltage output reaches the cut off point, the regulator comes into play and reduces current through the rotor so that it (the output voltage) doesn't rise beyond the cut off. In this way, overcharging is prevented.

The only difference with the so called 'hi output' regulator is that the cut off voltage is set slightly higher (14.2 volts as opposed to 14 volts). This means that the charging voltage is higher (given that the alternator is capable of supplying the higher voltage into the load at the time) at revs above - say - 3000 and right up to the red line but not at lower revs.

In conclusion, I stand by my statement that the 'Hi output' regulator (no matter what the vendors say) does not and cannot increase the output of the charge system at low revs (say below 2000 rpm). It also does not and cannot start charging earlier in the rev range. It simply increases the charge voltage (and, therefore, current) at mid and high revs within the capacity of the alternator.

Rob

[jackonz]

Then you explain to me wht when I measured the voltage with the old regulator compared to the new electronic item not only has the voltage gone up but it is at lower RPM, and all this was done with Fluk multimeter and and post replacing the battery leads on the bike.

[Zombie Master]

Hey Phil:

I see you are from Nelson! I was there a few years ago and loved it.
The NZ Classic Motorcycle Collection was just about to close. What a collection!

[Rob Frankham]

Then you explain to me wht when I measured the voltage with the old regulator compared to the new electronic item not only has the voltage gone up but it is at lower RPM, and all this was done with Fluk multimeter and and post replacing the battery leads on the bike.

Easy... Dirty eroded contacts on the the old regulator... that's one of the downsides of the mechanical regulators over time. Could also be dirty connections at the regulator connecting block which would have been disturbed during replacement. Doesn't take much in the way of stray resistance to limit the current flow through the rotor.

I have pondered for a numbers of years on how to get the stock airhead alternator to produce charge at idle and low revs. The only way I can see to do it is to force more current through the rotor. Unfortunately, this would mean feeding it with a voltage well in excess of battery voltage. This isn't impossible, of course... all you need is a buck-boost convertor... but it would undoubtedly lead to a much shortened rotor life and, in any case, due to the inefficiency of the alternator at low revs (no matter what the rotor current) the result would be unlikely to be worth the effort.

If you can come up with any way, using a standard regulator (of any sort), that will allow the alternator to produce more current at low revs, I would gladly listen and would be very happy to carry out practical tests but, working from first principles and experience, I will stand by what I say... there is no way that the low rev output of the alternator can be increased by substituting the regulator with a so called 'hi output' unit.

Rob

[barryh]

I have pondered for a numbers of years on how to get the stock airhead alternator to produce charge at idle and low revs. The only way I can see to do it is to force more current through the rotor. Unfortunately, this would mean feeding it with a voltage well in excess of battery voltage. This isn't impossible, of course... all you need is a buck-boost convertor... but it would undoubtedly lead to a much shortened rotor life and, in any case, due to the inefficiency of the alternator at low revs (no matter what the rotor current) the result would be unlikely to be worth the effort.

Rob

Arguably an electronic regulator could be worse than a mechanical regulator at low revs. Mechanical contacts in good clean condition present negligible resistance to the rotor current where as a power transistor will always have a small voltage drop (VCE sat) which would reduce rotor current. It's directly analogous to points vs electronic ignition which given the same ignition coil results in an electronic ignition passing slightly lower primary current than points, an instance I have actually measured.

[Rob Frankham]

Arguably an electronic regulator could be worse than a mechanical regulator at low revs. Mechanical contacts in good clean condition present negligible resistance to the rotor current where as a power transistor will always have a small voltage drop (VCE sat) which would reduce rotor current. It's directly analogous to points vs electronic ignition which given the same ignition coil results in an electronic ignition passing slightly lower primary current than points, an instance I have actually measured.

Believe it or not, I was trying to keep this simple .

I accept what you say for the early (metal cased) electronic regulators that use a bipolar power transistor... although the feedback nature of the circuit would mean the affect would be minimal. The later (plastic cased) regulators use a MOSFET which is quite different.

Rob

[harris5950]

I am new to the forum and hesitant to jump in to this thread but I would like to say this. Alternator's output is relative to RPM. If you are consuming a fixed number of watts and the alternator can't supply it, then it has to come from the battery. This energy has to be replaced to the battery at some point. Larger batterys demand a larger output from the alternator to recharge. In the end the alternator has to supply the energy consumed. When you have a limited supply, you need to conserve demand. I would say install that relay and use led's.