Wattage output for my '78 R80/7 ???

[larrylarry75]

I'm bumbling around with my new electric vest setup, need to find out the bike's output wattage if anyone knows? I looked in the dinky little owners manual but it's not listed. Sure would appreciate any info anyone might have, got some real weird things going on.
Thanks - Larry

[Burnszilla]

The fiche shows:
part #12311244637 generator (12V17A) $585.00

So it looks like 17amps.
12 volts x 17 amps = 204 watts

[barryg]

Larry, I'm no electric expert by any stretch of the imagination, but I think the output of the stock alternator of the /7 is 280 watts. I like your new bike. What kind of weird things are going on? Barry

[Burnszilla]

If it's three phase then the calculation comes out to: 282.6624 watts.
I did the single phase calculation.

[jdiaz]

Use 14V for the calculation.

/5 is 180 watts.
/6 and /7 are 240 watts
Post /7 are 280 watts.

[manicmechanic]

Get an Omega system, then you won't have to worry about it anymore.

[Bob_M]

Went for a nice ride on Sunday on my 82 RS. Had the gloves (22W), the vest (45W) and my driving lights (2 x 35) all going at the same time. Still I had 100W as a buffer. On the Washington Side of the Columbia River Gorge by The Dalles I was quite comfortable (until I got the performance award) even though there were frozen seeps encrusted on the road cuts. The Omega system allows this level of creature comfort on our old but graceful motorcycles. At best I am a "shade tree" mechanic, but after buying a good soldering iron the installation of the Omega system was easy. The better iron heats hotter, faster so one does not melt wire insulation while waiting for the solder to melt. (only 3 connections). Who ever regrets buying a good tool?
See ya Larry

[Boxerkuh]

On my 93 R100R (which I should have never sold :nono ) I was always calculating how much power I was using. On my 86 R80S, the first improvement that I did in 2003 was to install the 400 watt Omega kit. No more counting now... just use what I want and forget it.... After 20 years I was thinking that this is also a safe replacement so that you don't end up on the side of the street. :cry Get it and forget it about it....

[Tonyc]

I recently upgraded to the Endurlast alternator system on my 83RS, very pleased with the low RPM output...no more dead batteries from my Gerbings jacket....
tony

[The_Veg]

Omega's definitely wonderful. Rick at Motorrad Elektrik is great too- stands behind his stuff and supports it to no end. My Omega kit had a tricky problem with the rotor, and Rick went many extra miles to make it right. From all the asking around I've done, I think I'm the only person who has ever had a problem with an Omega and that problem has been banished. I'd definitely buy it again if I ever get another Airhead.

[Boxerkuh]

Veg stated: "I'd definitely buy it again if I ever get another Airhead." You can say that again. This is a must when you go into the electrics... :drink All my future Airheads will have it....

[larrylarry75]

Larry, I'm no electric expert by any stretch of the imagination, but I think the output of the stock alternator of the /7 is 280 watts. I like your new bike. What kind of weird things are going on? Barry

Weirdness as in: The temp controller display goes away when I start the engine, and then comes back on when I turn it off. Also on occasion just one of the display segments goes out, which to me would indicate voltage dropping below whatever the minimum requirement is. Considering the vest is the only accessory on line I find it hard to believe the system won't support it. Thinking that there might be a problem with the controller the factory sent a replacement controller right away but it didn't help, same problem exists. I've written to them for help but no response in two weeks. (Anticipating the obvious responses to the latter, before writing these guys off I want to give them every chance to sort this out before taking it up with my credit card company)

As a final caveat the bike is stock except for the upgrade to Dyna 000 Electronic dual-plug ignition, perhaps that's put an extra load on the alternator?

Thanks for your suggestions and help,
Larry

[larrylarry75]

If it's three phase then the calculation comes out to: 282.6624 watts.
I did the single phase calculation.

Thanks, much appreciated!
Larry

[larrylarry75]

I recently upgraded to the Endurlast alternator system on my 83RS, very pleased with the low RPM output...no more dead batteries from my Gerbings jacket....
tony

Thanks Tony, I may have to do just that.
Larry

[larrylarry75]

On my 93 R100R (which I should have never sold :nono ) I was always calculating how much power I was using. On my 86 R80S, the first improvement that I did in 2003 was to install the 400 watt Omega kit. No more counting now... just use what I want and forget it.... After 20 years I was thinking that this is also a safe replacement so that you don't end up on the side of the street. :cry Get it and forget it about it....

Sage advice, thanks very much.
Larry

[larrylarry75]

Went for a nice ride on Sunday on my 82 RS. Had the gloves (22W), the vest (45W) and my driving lights (2 x 35) all going at the same time. Still I had 100W as a buffer. On the Washington Side of the Columbia River Gorge by The Dalles I was quite comfortable (until I got the performance award) even though there were frozen seeps encrusted on the road cuts. The Omega system allows this level of creature comfort on our old but graceful motorcycles. At best I am a "shade tree" mechanic, but after buying a good soldering iron the installation of the Omega system was easy. The better iron heats hotter, faster so one does not melt wire insulation while waiting for the solder to melt. (only 3 connections). Who ever regrets buying a good tool?
See ya Larry

:thumb OK Bob you rascal, I guess I'll have to take the advice you gave me a couple of months ago and spring for the Omega. Besides, I never pass up an opportunity to buy another tool so which soldering iron/gun/stage did you buy for this project?

BTW, I've made that same river run many times and it's really neat. If you haven't gone as far as Bickleton up in the Horse Heaven mountains you should do so. Head east out of Goldendale; it’s around 18 miles up through some great canyons and over the open range to town. Last time I was there it was snowing and you couldn’t see the road, made for some great choices as in where to turn, etc. Fortunately I was in my cage at the time; otherwise I’d still be out there. Just in case things haven’t changed, the pavement ran out a couple of miles out of Goldendale but the gravel was pretty good.

[pmdave]

quote: "...Considering the vest is the only accessory on line I find it hard to believe the system won't support it."

Believe it. Perhaps you were thinking that an airhead is a contemporary vehicle with a high-powered charging system. I almost hate to puncture your balloon, but even brand new, airhead charging systems were weak and barely able to keep the bike going in stop-and-go traffic.

If you do periodic maintenance, keep the battery charged when parked, replace the battery every three years or so, keep the revs up, don't sit at stoplights with the brakes on, and avoid adding extra anything, you can keep an airhead running. My vintage R75 has the stock system except for an LED taillight, but I rarely ride it at night, and I never use any additional electric gadgets. My R100 has an Omega system (after years of trying to squeeze every watt out of the stock alternator)

If you'd prefer to be able to add a few electric devices and still have lots of capacity to spare, spring for the Omega system.

pmdave

[larrylarry75]

quote:
If you'd prefer to be able to add a few electric devices and still have lots of capacity to spare, spring for the Omega system. pmdave

Thanks Dave, I've decided to bite the proverbial bullet and do the upgrade. What the heck, why bother to leave an extra $600 to my kids, they'd just blow it on stuff for their own bikes, right?
:gerg

[Boxerkuh]

Thanks Dave, I've decided to bite the proverbial bullet and do the upgrade. What the heck, why bother to leave an extra $600 to my kids, they'd just blow it on stuff for their own bikes, right?
:gerg

You are absolutely correct. Isn't it great to get sound advise from people that think just like you? :bottle :hungover

[pmdave]

Being a little paranoid about enough "juice", when I converted to the Omega charging system, I also installed a separate "gen" light to eliminate all the potentially troublesome connectors, circuit board, light bases, etc. in the instrument pod, and allow easy replacement of the bulb.

I happened to have a nice surplus aircraft light unit that allows the bulb to be replaced from the top. One side of the light unit connects to the wire that used to go to the instrument cluster; the other side goes to the wire that comes from the light in the cluster. The only "connections" are the actual bulb contacts.

I also checked the wattage of the stock bulb, to ensure that the replacement was in the ball park. (I don't remember what it is)

Remember, you're only paranoid if they AREN'T out to get you.

pmdave

[larrylarry75]

I also installed a separate "gen" light to eliminate all the potentially troublesome connectors, circuit board, light bases, etc. in the instrument pod, and allow easy replacement of the bulb.
pmdave

Dave, besides the factory instrument pod my bike has a VDO voltmeter as installed by the previous owner and it all works great. Is there something about the Omega system that would degrade the reliability of these components or were you just being cautious? Thanks - Larry

[PAULBACH]

Consider a battery tender. I always hook up one to bike's battery even during the summer. It keeps the battery at full charge, shuts off when fully charged and will not cook the battery.

Much cheaper than the cost of a new batter and the battery will last longer. Had one on my R100. Bike was sitting for three months and it started immediately. :dance

I keep a BT on each of my bikes. Cheap insurance and never a dead battery. I have even used on to "recharge" the battery on my Ford Taurus after I left the XM radio on and it drained the battery. It took over a day but retirement does have its advantages.

Paul

[pmdave]

I wired around the gen light just because the circuit board and bulb sockets tend to fail with age. You can ride with a flickering or dead neutral light or turn signal indicator, or high beam light, but if the Gen light fails your alternator loses it's exciter current. The Gen light circuit doesn't affect the voltmeter or other circuits, although the voltage can drop if the wiring is loose or corroded.

pmdave

[larrylarry75]

I keep a BT on each of my bikes. Cheap insurance and never a dead battery. I have even used on to "recharge" the battery on my Ford Taurus after I left the XM radio on and it drained the battery. It took over a day but retirement does have its advantages.
Paul

Me too Paul, I have several including the one on the airhead. Now if I could just remember to plug them in.....

[larrylarry75]

I wired around the gen light just because the circuit board and bulb sockets tend to fail with age. You can ride with a flickering or dead neutral light or turn signal indicator, or high beam light, but if the Gen light fails your alternator loses it's exciter current. The Gen light circuit doesn't affect the voltmeter or other circuits, although the voltage can drop if the wiring is loose or corroded.

pmdave

The factory generator light is in series with the exciter circuit? Huh? Or is it just part of the load factor? Like yourself I have a number of aviation type pilot lights that mysteriously appeared in my parts box a long time ago so maybe I'll have a go at a change out when I do the Omega. Thanks again for the info, much appreciated.
Larry

[cjack]

The factory generator light is in series with the exciter circuit? Huh? Or is it just part of the load factor? Like yourself I have a number of aviation type pilot lights that mysteriously appeared in my parts box a long time ago so maybe I'll have a go at a change out when I do the Omega. Thanks again for the info, much appreciated.
Larry
The gen lite is in series with the field winding. If the light bulb goes out, then the field doesn't get its kick start. When the alt is spinning at rpm, then the field current comes from the three small diodes on the three phase stator windings. I've never been sure that the rotor doesn't maintain enough magnetization to kick start itself anyway, but recently, many have worried about it and put a resistor across the bulb to make sure. I'm guessing, but maybe about 220 ohms or so with a one watt rating or more. It only dissipates power at the same time the light is on. The bulb looks like about 50 ohms when it's hot.

[larrylarry75]

The gen lite is in series with the field winding. If the light bulb goes out, then the field doesn't get its kick start. When the alt is spinning at rpm, then the field current comes from the three small diodes on the three phase stator windings. I've never been sure that the rotor doesn't maintain enough magnetization to kick start itself anyway, but recently, many have worried about it and put a resistor across the bulb to make sure. I'm guessing, but maybe about 220 ohms or so with a one watt rating or more. It only dissipates power at the same time the light is on. The bulb looks like about 50 ohms when it's hot.

I guess I can see their design logic but it leaves an opening for system failure without much of a warning to the operator. Boy I don't miss having to deal with that stuff any more! Anyway I've got most of that stuff laying around so I'll attend to it when the Omega goes in, some time after our generous government returns some of the money I've loaned them this past year. :)
Thanks again for your advice, much appreciated.

Larry

[larrylarry75]

Thanks to everyone who responded to this thread, I've taken your collective advice and ordered an Omega system for the beastie. From what everyone tells me the installation is manageable at home so I'll have a go at it myself.

As a point of interest you may have read about the EXO2 Storm Rider vest and controller in this month's BMW Owner's News, page 88. That's the exact package I bought and it's been the reason for all the consternation with the R80/7's output wattage. In her article Sandy Cohen say's "And this vest also uses less power which makes it a good choice for Airheads with marginal charging systems." According to Bill Carrigan of EXO2 (b.carrigan@exo2.co.uk) "The vest will draw a maximum of 60 watts at 13.5Volts." Hmm....does that mean my bike has undisclosed issues I'm unaware of? I don't think so; I think Rick Jones of Motoelekt will probably realize a few more sales of his Omega system. Maybe that's not such a bad thing either; for me, now I can start looking into a pair of driving lights....

[manicmechanic]

If you don't watch out you'll even have enough spare watts for an electric liner for a passenger! :brow

[larrylarry75]

If you don't watch out you'll even have enough spare watts for an electric liner for a passenger! :brow

Passenger? Eh? Vas ist das?

[PAULBACH]

Let us know how the installation went.

How were the directions? :deal

Was the installation easy? :banghead

What were the results? :thumb

Thanks in advance :wave

[beemerPhil]

:type
According to my BMW service books, the output was 180 watts for the /5's system (without the "wye" terminal, and 280 watts for all the later /6 and /7's except the R90S. Feeling that the R90S was likely to be ridden in a somewhat sportier style, and would thus be subjected to greater loads and a higher resulting degree of crankshaft flex, BMW engineers specified a slightly smaller diameter alternator rotor for this model, increasing the clearance of the rotor inside the field (stator) and reducing the chances of contact during operation. The resulting output for this model was 240 watts. All of these ratings are spec'd at 2550 rpm.
:deal

The "Gen" light is wired in series with the rotor, not the field- this makes it a fairly useful troubleshooting aid, although it is certainly not foolproof. A dead generator light will most often indicate an open rotor winding, a common failure on hi-milers esp. in hot climates. If you've been paying attention to your ride, the brushes shouldn't be a question; they last next toforever, cost about $3 and are easy to replace when needed. If you look at them every other year, you'll be plenty ahead of replacement time. A bad regulator can do this too, but this is easy to check; unplug the regulator and bridge between the blue & black wires in the plug, and start your bike. If the regulator is your problem, the bike will charge. Note, however, that you can really upset things by running like this for even a minute! :nono

When the system was introduced, it was the most powerful alternator on a production motorcycle- there were no heated hand grips, vests, chaps, gps's, or 100-watt headlights on the market back then, so it was plenty strong enough for the job, IF it was properly regulated- this last part was apparently a challenge for BMW for many years......an aftermarket regulator is one of the best things you can do for your boxer,esp.if you ride early/late in the season and need to start it up in cold weather.

Hi-miler airheads will often have enough residual magnetism in the rotor to charge without exciter current- I rode 450 miles without a regulator on my way to Lima last year, and had no trouble starting the bike. (You must turn off the headlight to get this far!)
When I found a decent hardware store, I made a "squeeze switch" on my left hand grip by which I could control the alternator manually- when the voltage got low, I'd squeeze the contacts until it got back up where I wanted it, then release the switch. Worked great til the REAL rain came- after my gloves got wet, I'd get a little jolt every time I released the switch!
:uhoh
There is a way to almost double the output of the stock system (35 Amps vs 20!) with a fairly minor wiring change, but charging doesn't begin until 2600-2800 rpm, so it's really not practical for street use- your battery will discharge pretty fast around town. One of the aftermarket solutions is a better bet.

[cjack]

:type
.
:deal

The "Gen" light is wired in series with the rotor, not the field- this makes it a fairly useful troubleshooting aid, although it is certainly not foolproof. A dead generator light will most often indicate an open rotor winding, a common failure on hi-milers esp. in hot climates. If you've been paying attention to

Just for the sake if clarity, again, the rotor IS the field on the alternator, and it rotates. The field current is supplied by the two slip rings and cause very little wear on the brushes. It is possible and is used in some small applications to use permanent magnets for the rotating field which require no brushes. Also the generated voltage would vary directly with the speed of the rotor. But back to the alternator we use...the stator windings, although stationary cut thru the field as it rotates and current is generated in these stator windings. The point of this configuration is that a troublesome segmentated commutator is not required and the stator winding current (sometimes large current) is commuted to dc by diodes. There are three stator windings and the average dc voltage produced by them is about 95 percent of peak. The why of using three phases. The speed dependent voltage is controlled by regulation of the field current and the field current source is obtained from the stator winding by additional small diodes. The startup field current is obtained from the battery (thru the charging light bulb in our case).