Help!!! Charging system is pissing me off!!!

[yamaman]

as I found out by disconecting the battery. Blew the headlite bulb right off the socket.Also fried my regulator assy.

Gordon, I think that when you disconnected your battery, you removed the sense voltage for the regulator to work. Without that, the regulator wont regulate. As revs increase, so will voltage.......This is what probably happened.

Welcome back dpmphoto (aka xstwin) good to see you've lost none of your passion for these bikes & you still have that wonderful warm way about you that gives us all a glow!

 

[81-650chopper]

XsTwin I soooooooo agree with you!!!!! There are thousands of posts on the Internet about weak or poor charging systems on these bike. But like you said all these people defending it are kind of condesending by also saying that they have upgraded to better or alternate charging componants. Well by doing that you are no longer using the full stock system. Don't get me wrong not everybody out there is doug this but a lot are. I love this bike except this charging system. Like I've said i'm really good with wiring but this is rediclulous. I can't solve this problem. And I've seen first hand how much power these bikes can drain while everything is on. And wow! No surprise it has charging issues. I've also have had advise given as use a small watt headlight, led taillights and anything else I can do to reduce voltage use. That's why I have led tailights, and my lights are on a toggle so when I start it and let it warm up so my lights don't kill my battery while idleing. I've found it will not produce enough voltage to supply the lights until I'm driving! I'm about ready to mount a belt driven chevy alternator to run off my rear tire and say piss on the stock system!!!!!!! Lol that would be funny! All BS aside the charging system on this could use some improvement!

 

[yamaman]

This'll fix it xsvolts

 

[81-650chopper]

Ha Ha Ha Ha that's what I'm talking about!!!!!!!!!!!! That's funny ass hell! Although I don't want mine to look so cobbled together that would be the simplest fix! Once I said that joking. I've been doing some thinking and I think I know of some shallow alternator that could be mounted on that shaf and still hide under the cover. Might have to replace the center bearings inside to the size of the shaft on the bike but I think it can be done!

 

[yamaman]

Like this

 

[Sundie]

hm. Looking at the numbers, sitting there idling (at the designed 1200rpm) to warm up, you'd need around 60w. Or 5 amps. Which the stock rotor definitely does. And perhaps (before you throw a 90 amp car alt on) you should consider that a:same design, with brushes, so same wiring and b:if you're generating enough power to light up everything same as stock at 2000 rpm, your idle is going to be hard to tune since you're putting a load on the engine at idle

My point is that the system isn't "weak", it's "matched". No point throwing a 30 amp alt in there if you're only ever going to use 9.

The other issue with going permanent magnet is that you can't use tci any more.

Ps - my bikes are totally stock, although i'm going to install a Pamco this year. But only really because it's easier to debug issues without points.

 

[inxs]

My point is that the system isn't "weak", it's "matched". No point throwing a 30 amp alt in there if you're only ever going to use 9...

...The other issue with going permanent magnet is that you can't use tci any more.

- matched, but problematic
- the TCI is also 30 odd years old, no parts and more or less unfixable...a push waiting to happen

 

[pamcopete]

Just love these family get togethers....if we could all agree to drink the same brand of beer we could save a lot of money...

gordon, it's not that the battery absorbs the extra power from the alternator. The battery acts like a giant capacitor to stabilize the voltage. Without the battery, the regulator chases the voltage and never catches it, so the voltage swings are extreme.

Think of having springs on the rear suspension without the shock absorber. The battery is the shock absorber in the electrical system because it does not react immediately to the ups and downs of the voltage from the alternator.

The capacitor does the same job in a PM system.

Speaking of which, if you are installing an alternator of any kind that produces more than the nominal 15 Amps of the stock alternator, then you should also install a larger battery.

The battery is charged by the excess available current after all of the load is taken care of, but a battery has a recommended charging rate of 1/10 of its Amp Hour Rating. So, with the stock alternator of 15 available amps at 5,000 RPM and a load of,say, 12 amps that leaves only three amps to charge the battery, but that's fine because the recommended charging rate is just 1.4 amps for a 14 AH battery.

However, the recommended charging rate is for a discharged battery with 10.5 volts available. That is about right for the battery right after it has operated the starter motor, but it's not likely that you will then immediately surge to 5,000 RPM to obtain the 3 available amps and over charge the battery.

So, lets use the 3 amps, or twice the recommended charging current when installing a higher capacity alternator.

If you were to install an 20 amp alternator with a 12 amp load, that would leave 8 amps to charge the battery at 5,000 RPM. Using the double charging rate theory, you should then install a battery with a 40 AH capacity. That's a really huge battery for the XS650, and finding a place to mount it would be a real problem. I think there are some garden tractor batteries of that size.

Someone in this thread said that the stock charging system is balanced, and it is. You have to match the size of the battery to the alternator capacity. Just look under the hood of a car with a larger capacity alternator than yours and you will see that the battery is also larger.

All the more reason to use a PM alternator with a capacitor!!

 

[81-650chopper]

Yeah we are talking stock application charging. But like I've said mine is a custom chopper. I understand that at stock 1200 rpm's is idle. Which first seems a little high and unnecessary. Second my bike has drag pipes (sorry I should have specified that) it's eejetted and tuned for the shorter free flowing pipes. How loud do you think my bike is at 1200 rpm's??? Loud!!!! Too loud for idle. So therefore I have my idle set between 600-800 rpm's depending on how warm out it is. I believe that the only reason the say idle is 1200 rpm's is becaus they are covering up the fact that it won't charge below that. I set my bike at 1200 rpm's wheni had the stock exhaust on and holy shit! It sounds like it's gonna take off!!! There's no reason for it to idle that high except to make the charging system run!!!

 

[pamcopete]

81-650chopper,

Well, I think that the carburation on the earlier models with the BS38 carbs, and the crude points ignition, made it impossible to idle below 1200 RPM. The output from the alternator is not enough to sustain the load at that RPM and the battery voltage slowly sinks below 11 volts at a long stop light.

With electronic ignition, either the factory TCI or an aftermarket electronic system and the BS34 carbs, you can reliably set the idle below 1,000 RPM.

I still keep the idle at 1200 because the other factor is the anemic oil pressure and oil flow at idle. Like, zero pressure when the engine is hot.

However, I have installed a relay that shuts off the headlight when in neutral so the battery voltage stays at 12.5 when stooped at a long light. I also installed an LED tail light which makes a huge difference.

We tend to think that the low output from the alternator is yet another indication of a poor charging system, but you have to remember that in an automobile system, the alternator pulley is less than half the diameter of the crank pulley, so with the engine idling at 600 RPM, the alternator is probably doing 1500 to 2000 RPM.

 

[xstwin]

Pamco say there"s nothing wrong with this charging system buuuuttt And I qoute "I have installed a relay that shuts off the headlight when in neutral so the battery voltage stays at 12.5 when stooped at a long light. I also installed an LED tail light which makes a huge difference". Banshee flywheel $50 rest of the parts $100 riding your bike with bright blinkers and not having to worry about a long red light priceless. Ever gone fishing with a not so great motor on your boat and u shut it down to fish and then the whole time your trying to relax and fish u cant because your afraid this boat motor might not start back up? I hate that feeling and don't want it when I"m cruising on my bike.

 

[pamcopete]

xstwin,

Well, what is the battery or capacitor voltage with any other system at idle?

 

[Sundie]

I gotta say - if your voltage doesn't stay over 12.5 (which is a proper working battery voltage) with all the lights on, for at *least* an hour, replace your battery. There's something wrong with it.

 

[pamcopete]

Well, a 14AH rated battery will decrease to 10.5 volts in one hour with a constant 14 amp load. The typical load for the XS650 is about 10 Amps, so the voltage on the battery will drop to 10.5 volts in 14/10 = 1.4 hrs so it has to pass through all the other numbers on it's way to 10.5 so I think you would be lucky if it maintained 12.5 for an hour.

Here's a chart:

Looks like the voltage gets to about 11 volts in an hour.

 

[Sundie]

Fair enough - soooooooooooo... How long *are* the stop lights in your neck of the woods?

From your graph, it looks like the battery will pass 12v after .35 of an hour, or 20 mins, give or take. So, yeah - sitting there idling for 20 mins and your battery will go below an effective voltage - but who does that?

It's only my opinion, but i think going to the lengths of hooking up a relay the the neutral switch to turn off the light is a *bit* over zealous, and solving a problem that doesn't really exist.

 

[pamcopete]

Sundai,

Well, the 20 minutes can be cumulative because the battery may not have sufficient time between lights to recharge completely in heavy traffic. You also have to keep in mind that the maximum output from the alternator is 15 amps, but that is at 5,000 RPM, so recharging the battery in city traffic can be problematic. There is only 3 amps available @ 5,000 RPM to recharge the battery. Much less at lower RPM's.

Also, the relay on the neutral switch serves another purpose. I have an '81/H and it does not have a light switch like my '78/E does and it bugs me that I cannot check my headlight without having to start the engine, so I can now turn on the headlight just by putting the bike in gear without having to start the engine.

The other issue that Yamaha forgot about when they eliminated the headlight switch is that there is no way to turn on the headlight at night if your alternator should fail so I can just turn it on after I start the engine by selecting any gear. Also means that I can conserve power on my way home with a bad alternator by selecting neutral while stopped at all the lights that are gong to turn red just because I'm trying to get home in a hurry.

Not that the alternator will ever fail, but if it does ever fail, we all know that it will be at night and more than 20 miles from home.

 

[650Skull]

Fair enough - soooooooooooo... How long *are* the stop lights in your neck of the woods?

From your graph, it looks like the battery will pass 12v after .35 of an hour, or 20 mins, give or take. So, yeah - sitting there idling for 20 mins and your battery will go below an effective voltage - but who does that?

It's only my opinion, but i think going to the lengths of hooking up a relay the the neutral switch to turn off the light is a *bit* over zealous, and solving a problem that doesn't really exist.

I'm not to sure where i got this from but i think Pamcopete posted this info on 650rider

14 volts, 11amps @ 2000 rpm = 154 watts
14 volts, 16 amps @ 5000rpm = 224 watts
with the bike using around 160 at any one time... high beam on, tail/brake on, turn on, in N,
headlight 40/50w
tail/stop 8/23w
turn bulbs 27w x2 54w
neutral 3w
Indic. warning 3w
high beam indicator. 3w
instrument lamps 3wx4 12w
brake wear 3w
brake warning 3w

Having a cut out through the neutral switch for the headlight and using a LED tail light will dramatically help the charging system if you use the bike in the city, commuting or get stuck in a traffic jam or any idling time at all

 

[Sundie]

The other issue that Yamaha forgot about when they eliminated the headlight switch is that there is no way to turn on the headlight at night if your alternator should fail so I can just turn it on after I start the engine by selecting any gear. Also means that I can conserve power on my way home with a bad alternator by selecting neutral while stopped at all the lights that are gong to turn red just because I'm trying to get home in a hurry.

Not that the alternator will ever fail, but if it does ever fail, we all know that it will be at night and more than 20 miles from home.

Oh yeah - been there. The stator gave it up on the highway at night and i was still 30 clicks from home on an 80 special. "Why is my light out? Aw, hell." Good bike though - got me home and died in the driveway, which was totally acceptable, though the light being out on the highway was non-amusing.

 

[pamcopete]

Ah...great......another convert!!....

 

[Sundie]

I'm not to sure where i got this from but i think Pamcopete posted this info on 650rider

14 volts, 11amps @ 2000 rpm = 154 watts
14 volts, 16 amps @ 5000rpm = 224 watts
with the bike using around 160 at any one time... high beam on, tail/brake on, turn on, in N,
headlight 40/50w
tail/stop 8/23w
turn bulbs 27w x2 54w
neutral 3w
Indic. warning 3w
high beam indicator. 3w
instrument lamps 3wx4 12w
brake wear 3w
brake warning 3w

Having a cut out through the neutral switch for the headlight and using a LED tail light will dramatically help the charging system if you use the bike in the city, commuting or get stuck in a traffic jam or any idling time at all

actually, you should only count turn signals once, since they're approx 50% duty cycle. That alone will give you plenty of elbow room.

I can't envisage a situation when you have the high beam on with the brake, at idle, for any significant length of time.

When your alt can't provide enough juice to power what you do have on, that's when your battery supports the load.

You're basically looking at some *really* weird situation - how often will that happen, and for how long? Do you *really* need to plan for that? After all, these are consumer grade bikes, not milspec. (else, we'd be diesel to remove all this electronics anyway)