Aftermarket Airhead Charging System

[Bob_Roller]

I was going through the Euro Motoelectric website this afternoon and saw their aftermarket plug and play replacement charging system .

Same design as the OEM Bosch charging system and 400 watt output .

 http://www.euromotoelectrics.com/EnDuraLast-II-400-Watt-Charging-System-p/edl400-altkit107.htm

Lowest price I've seen so far for an upgraded system .

[Armen]

Yes, but for a little more, you get a much tidier permanent magnet, higher output system.

http://www.euromotoelectrics.com/product-p/edl450-altkit.htm

Have one on my R100 for over 10K miles and it's great. Bought one for the R65, but haven't run the bike yet.
-Armen

[Luca]

Though it takes a while, permanent magnet rotors will eventually lose enough magnetism that they need to be replaced.   Old Honda's were known for this, and their 4 cylinder engines were smooth (vibration kills permanent magnets).

One of the upshots of a completely wound system is that it can be rebuilt.  Not sure if the same can be done for permanent magnet rotors.

[georgesgiralt]

Another one is that a wound system does not draw power when not needed. A permanent magnet system draws maximum power all the time which is then converted to heat in the "regulator". Given the poor efficiency of such systems, for 400 W electricity produced, I bet it needs more than 4 times  that figure mechanical energy. All this to make heat into the regulator...
And do you know from where comes that mechanical energy wasted ? From the petrol you put in the tank. And it takes more than 3 times that wasted mechanical energy to get to the fuel .... given the efficiency of the engine.
I, for one, will stick to the standard system and if not powerful enough one day, will buy a wound device with it's output proportional to the load.  
But it's your money, you pay for gas, and you may need the 400 W permanently ? Who knows ?

[Luca]

A permanent magnet system draws maximum power all the time which is then converted to heat in the "regulator".

That caused big problems with the Kawasaki Vulcan 750, which had a permanent magnet rotor.  Those things would burn out stators all the time because the regulator/rectifier was between the battery box and the crossover pre-muffler.  As best I can gather, when the regulator couldn't dump the excess heat, it would fry the stator.

The proper procedure for replacing a stator on one required dropping the engine!

[Tony Smith]

Over the years I have seen aftermarket charging systems come and go. The overwhelming view I have formed is that the best charging system for the Airhead is the one that BMW and Robert Bosch dreamed up together.
 
My reason for this is that every alternative involves a compromise and that usually the cost of the compromise is not worth what is gained.
 
My view on the matter is, keep your brushes in good order, replace the metal can type regulator with a modern solid state one, buy the best battery you can afford and accept that you cannot run a 100w headlight and multiple 100w spot/driving lights. For what it is worth for many years I ran a 55w driving light and a 55w spot light on the crash bars - I only ever used one at a time in conjunction with a 55/50w headlight and I never once felt I had inadequate lighting (hint buy good quality driving/spot lights Hella or CIBE) nowadays if I was stil likely to ride anywhere at night other than a built up area I'd buy an LED system.
 
Last comment, BMW themselves made a regulator which allows a slightly higher output voltage - this was produced essentially for police bikes fitted with lights and radios. The compromise you pay for the higher output is generally a shorter battery life unless you find a battery that will not be damaged by being charged and floated at nearly 15 volts instead of 13.8. The BMW "Police" regulator is in my junk box, I have used Bosch Australia RE50 and RE55 regulators now for more than 20 years.
 
Snowbum has some interesting comments on Airhead alternator output and soem very interesting photos of how people have mounted quite big external alternators to an airhead. Personally I am of the view that LED lighting has totally overtaken the need to be overly concerned with the less than stella output of the OEM alternator, given that you can get the same effective lumen output from a 20w LED as you get from a 100w filament bulb.

[Barry]

I tend to agree having never been inclined to invest a significant fraction of the bikes value on the charging system. I'm easily pleased though because this is the best charging system of any bike I've ever owned.

The original mechanical type regulator can with care be adjusted.  I have set mine to 14.3 volts but unless you have the test gear needed and are stubborn enough to want to experiment it's probably easier to buy a high set point or adjustable electronic replacement. All the info is on Snowbum's site for any of these options.  

Setting it at 14.3 volts seems to improve low speed charging. My charge light is out at 1000rpm and stays out. It doesn't mean you get extra maximum output (14.3 volts x 20 amps = 286 watts) because the alternator may not be able to achieve that. Conversely if your regulator is set at anything less than 14 volts then the charging system can't possibly produce it's rated output.

After 5 or 6 years running at the high set point I've never had a problem with the battery as long as it's kept topped up.  Although if the police regulator was 15 volts then I can imagine that really would shorten the battery life.

There is a mixed blessing of slightly brighter lights with a shorter lamp life though one replacement tail lamp every 5 or 6 years is a compromise I can live with.

I wonder if some dissatisfaction with the charging system is due to setting off with a partially discharged battery from irregular use. That isn't a fair senario to judge the system by as you are asking the alternator to run everything and charge the battery at the same time. It will do that eventually but only given many hours of running. In fact much the same length of time a normal battery charger will take. To expect it to fully charge a battery much quicker is a misconception.

[Luca]

If you want to run heated gear/grips or substantial auxiliary lights (although LED's are helping that), a higher output system does make sense.  It will also help out with keeping the battery charged on short or infrequent trips, although at a much higher cost than a battery tender.

Sure, the new whirly bits are expensive compared to the whole bike, but if you own a bike long enough then the sum of the parts will probably exceed the cost of the whole, provided it doesn't become collectable.

On a side note, going from the standard rear lights to the beacon II unit (shameless plug for www.motoelekt.com) noticeably improved the RPM at which the gen lamp goes off, and it puts out way more light.  The license plate lights illuminate a patch of pavement behind the rear tire

[Armen]

Permanent magnets fail? Yes, in the 70's Hondas and Brit bikes lost their juice.
Every Harley and every Ducati uses a permanent magnet alternator. As do countless Japanese bikes.
Yes, they waste HP, but I'll trade that for brain free, cleaner operation.
YMMV

[Bob_Roller]

I know with the '81 model year bikes, the voltage regulator is solid state, don't know when the change was made from mechanical type regulator .

Remove the tape from the case of the regulator, remove the top and have a look inside .

I have an aftermarket higher voltage regulator, have it on the Guzzi now .

Going to install it on the '81 R65, it has two PIAA 40 55 watt auxillary lights, those put a big load on the alternator and not too much left to charge the battery, even at highway speeds .

[Ed Miller]

Do alternator brushes wear faster when running a heavier electrical load?  I just wonder if there's a downside to it, assuming you have enough alternator output to power the extra stuff and still keep the battery charged.

[Barry]

Do alternator brushes wear faster when running a heavier electrical load?I just wonder if there's a downside to it, assuming you have enough alternator output to power the extra stuff and still keep the battery charged.

I doubt the alternator load makes much difference to brush wear. It's the staionary field coils that see the high current load. The brushes are only used to exite the rotor with a much lower current which is turned on and off rapidly by the voltage regulator.  The Peak current through the brushes does not change with increasing load but the average current does because the mark space ratio of on and off changes.  Brushes last a long time in any case.

[Bob_Roller]

My original brushes were wore out at 55,000 miles, 90,000 km .

I pulled the brushes on the Guzzi a few weeks ago, same Bosch charging system as the airhead bikes, it was about 25 % worn at 22,000 miles, 36,000 km .

[georgesgiralt]

The brushes are actually copper on alternator (no or the least resistance possible)  so they are able to last a long time. It is an entirely different matter on motor's brushes because they have to prevent shorting one loop with the other when the motor turns. So they have a lot of grphite added to the copper to provide a resistive piece and in turn are much tender and prone to wear. DO NOT EVER use alternator brushes on a motor ! You'll fry everything.
I change the springs more often on the alternator than the brushes. THe pressure needed is important and I think the springs wear too much ...

[montmil]

LED driving lights draw far less power than do the halogen models. For a pair, the OEM charging system will be more than adequate. If you want/need heated grips, clothing and espresso machine, you will have to throw some money at a charging upgrade.