Charging system odd behaviour

[CookMySock]

Tried to start bike normally and battery appears flat. Terminal voltage 12V. Cranking volts 4V. Hrm it does this from time to time.. Why?

Put on the charger for a couple of hours and the bike starts really well. Terminal voltage 13V. Cranking voltage not checked.

Bike idling at 1500rpm, headlight flickers slightly, terminal voltage 14V. Raise engine rpm to 3500 and battery voltage drops under 13V and headlight dims. This makes sense - lots of open-road running and the battery goes flat. Idling around and it stays charged.

Test stator continuity check to ground, high ohms - pass. Test stator AC volts to ground, 0V AC - pass, stator is isolated from ground. Stator output voltage 40V++ across any combination of stator outputs.

So why does the battery terminal voltage drop when I rev it above idle? :blink:


Steve

[Hopeful Bastard]

Im not too sure.. But i would love to know why the ol' battery dies when you are doing long rides.. I thought the longer the ride was, The more charge the battery got.. Not the other way around..

[pete376403]

Extra load from the ignition - making a lot more sparks/minute.
Battery will almost always show 12v, even when it's flat as a wet turd. You need a load tester (which I appreciate not everyone has)
40 volts AC stator to stator seems a bit low - my GS1100 does about 70VAC at around 5K revs.
Good fault finding chart - http://www.thegsresources.com/garage/gs_statorfault.htm

[jonbuoy]

An ammeter between battery and rectifier/reg will give you a few more clues.

[CookMySock]

An ammeter between battery and rectifier/reg will give you a few more clues.Yeah looks like I gotta pull some covers off tomorrow and I'll put the clamp meter over it.

I had previously checked the stator output, continuity, and isolation, and it was good. I'm thinking the regulator is poked. Maybe I should replace it before it fucks the stator.

Steve

[Tink]

Tried to start bike normally and battery appears flat.? :blink:


Steve

GO FIGURE... get off the bloody net ya nut...and ride it.. hehe

[neels]

Check continuity between the 3 outputs of the stator to each other, may be an open circuit winding? Or another suspect would be a faulty rec/reg unit.

A quick search on the net found a comet 650 manual, I'm going to leap to conclusions and assume the electrical checks will work, try these, it agree's with pete376403 that 70V is about normal.

[Paul in NZ]

Yup - def should have about 70V AC across each phase of the alternator output.

The two simplest most easily tested items are battery (unlikely) or rect / reg. However, on nearly any bike I'd chuck a few extra earth wires around the place as age / dirt etc play havoc with chassis mounted rect / regs 9eventually)...

[notme]

This doesn't really help the OP, but I have always had a battery monitor on my bikes - a single discretely mounted LED can save a lot of blood sweat and tears - when I had the CBR600RR the light alerted me to a charging system problem and the first thing I did is think that the battery monitor itself was on the fritz! over the next 2 months the batttery slowly got worse and proved me wrong and the battery monitor correct.... :-(

DB, what happens as the revs increase further? You say the charging volts drop as the revs increase, does this continue or does the voltage drop then increase again?

[CookMySock]

DB, what happens as the revs increase further? You say the charging volts drop as the revs increase, does this continue or does the voltage drop then increase again?Thanks allun. Ok, from scratch ;

From 1400rpm idle, the headlight (ordinary incandescent 55/60W H4) flickers at what appears to be 30-40Hz (by eye), battery voltage constant 14V ish. Raising revs to 2000, headlight flicker goes away and light dims ever so slightly and battery terminal voltage drops a full volt to 13V ish. This is confirmed by the attached battery charger as its' output current meter raises from 2A to nearly 3A. Raising revs above 2000rpm does nothing perceptible to any of the meters or headlight behaviour.

I'm pretty sure it's reg/rect failure. Will pull covers off it as soon as I can and put the meter over the reg/rect. I've already checked the stator and it's fine. I'm worried now about burning the stator by running it will a stuffed reg/rect, as it will short the stator hard and force it to disapate its' entire output as heat in its' own windings. Contrary to popular belief, I doubt the stator windings are cooled by oil - there could not possibly be oil in there with the rotor running at engine rpm.


Steve

[howdamnhard]

I would bet on the Reg/Rect being the guilty party . I presume Battery is holding charge. As others have said 70V ac is about normal output from stator. If you have a manual it will have the specs.
Goodluck and let us know how you got on.

[pete376403]

Contrary to popular belief, I doubt the stator windings are cooled by oil - there could not possibly be oil in there with the rotor running at engine rpm.Steve
Suppose it depends what sort of engine you have but GS Suzukis are definitely oil cooled, and will cook their windings (due to particularly shitty voltage regulation system) if the oil level is too low.

[notme]

Hmmmm stator V is ~40V - is this with the RR connected? Sounds like 1/3 of the RR bridge rectifier is shorted.

[CookMySock]

I'm tempted to build a switch-mode reg/rect, but there isn't a 400 watt design available to pinch. I understand the technology, but not well enough for my design to assemble and work first time.

It would put much much less stress on the stator and consume less engine power as well. This idea of burning excess energy as heat in the stator is rather outdated.

Any electrical engineers want to offer a circuit?

Steve

[CookMySock]

Hmmmm stator V is ~40V - is this with the RR connected? Sounds like 1/3 of the RR bridge rectifier is shorted.Thats with it open and the revs quite low.

It's been a while since I did that test. Will pull its covers off and redo all tests when I can get to it.


Steve

[notme]

If quite low revs means idle to 1000 or 2000, then I bet it's more than 40VAC if you rev to between 1/3 and 1/2 of your rev limit....which means it's 1/3 of the RR gone.

[CookMySock]

If quite low revs means idle to 1000 or 2000, then I bet it's more than 40VAC if you rev to between 1/3 and 1/2 of your rev limit....which means it's 1/3 of the RR gone.I'm thinking the same. The last RR did exactly the same, and the bike shop says its a weak point.

Aftermarket RR time I think. Will try and get at it today.

Steve

[pete376403]

There was a thread on KB some time back about electronic r/r. Search for "the great kiwibiker regulator thread" - Dave Reid, around 14/9/8
I've got the pdfs of the circuit, but never built (bought another bike instead)

[neels]

I'm thinking the same. The last RR did exactly the same, and the bike shop says its a weak point.

Aftermarket RR time I think. Will try and get at it today.

Steve
I had to replace the one on my bike a while ago, was slightly different to your fault in that it went open circuit and boiled the battery dry. It was interesting that the replacement had a huge heatsink on it rather than just the metal case, obviously some improvement had taken place between designs.

[pete376403]

On my Suzuki the R/R was mounted to the bottom of the battery case, just above the swingarm pivot. Bugger all airflow there, as far as I can tell. I extended the wires (fairly heavy guage wire, proper crimped plugs and sockets, etc) and relocated the R/R to the front down tubes, just below the steering head. It never got much more than mildly warm after that.

[vifferman]

On my Suzuki the R/R was mounted to the bottom of the battery case, just above the swingarm pivot. Bugger all airflow there, as far as I can tell. I extended the wires (fairly heavy guage wire, proper crimped plugs and sockets, etc) and relocated the R/R to the front down tubes, just below the steering head. It never got much more than mildly warm after that.
I did the same thing with my VFR750. It seems Honda likes to hide the R/Rs away, whereas bikes of yesteryear (and many cruisers) have them out in the airflow. On the VFR, I cut out all the wiring, replaced it with beefier stuff, doubled up the earths and eliminated all the plugs, and mounted the R/R where the horn goes, on some 3mm aluminium plate.

[rogson]

Check what AC voltage the generator should be putting out for your bike (spec should be in the shop manual) - 40VAC seems low to me. Also, check that you have continuity between each of the phases and no continuity between the phases and ground.

If the generator voltage is below spec the R/R won't work.

[CeeBee]

Steve, I doubt you will fry the stator becuase its undercharging...be different if it were overcharging....stator would be coking.

[bogan]

I'm tempted to build a switch-mode reg/rect, but there isn't a 400 watt design available to pinch. I understand the technology, but not well enough for my design to assemble and work first time.

It would put much much less stress on the stator and consume less engine power as well. This idea of burning excess energy as heat in the stator is rather outdated.

Any electrical engineers want to offer a circuit?

Steve

similar problem was found on the hawk forum, something about some stators having different configurations of windings (star delta kinda thing i'm geussing) and the high revs one just wasn't working. I can probably find the post if you want?

Also if you put it through a simple rect and use a switchmode (national.com has a cool webbench designer that lets you pick input and output specs and it generates a parts list and circuit for you, at 85% efficiency or above, hopefully putting together one they designed for me in next few days :D )

edit: just saw its all a month old so you have prolly fixed it already.

[CookMySock]

We swapped the reg/rect for a new aftermarket one, replaced the battery, and seems to be solid so far. The headlight is not doing its' dimming thing now. Will post in this thread if it falls over, but my guess is it will be all-good.

@bogan, yes that makes sense. Dunno if they would handle 400 watts though.

Steve

[bogan]

We swapped the reg/rect for a new aftermarket one, replaced the battery, and seems to be solid so far. The headlight is not doing its' dimming thing now. Will post in this thread if it falls over, but my guess is it will be all-good.

@bogan, yes that makes sense. Dunno if they would handle 400 watts though.

Steve

400W sounds like bloody heaps, thats 30amps at 13.5V, the one I'm making to power all the lights and dials on my electric is only 80W, granted that is on the low side cos I'll be swapping out lights for high efficiency ones, but still 60W headlight, 20W brake light, 15Wx2 indicators, where does the rest go :scratch:

[notme]

@bogan - 400W is typical for bikes, an average car will have a couple of kW or more rated alternator. This is the reason some race bikes run a battery only system, so that they aren't wasting 0.4kW that they could use for winning the race.

Where does the power go? Think about a modern bike.....fuel injectors, all the lighting, fuel pump, accessories, ignition...... it all adds up and automotive alternators are only putting out more and more as vehicles demand more from them with more and more electrickery bits.

[CookMySock]

Search for "watts" on this page.

http://www.motorcycle.com/specs/hyosung/sport/2008/comet/gt650r/detail.html

edit: and on this page, for an even bigger alternator.

http://www.motorcyclespecs.co.za/model/bmw/BMW_K1200LT%2099.htm

edit: @allun, dunno about "a couple of kW or more". I have seen 55-90 Amps. 700-1100 Watts.

Steve

[notme]

DB - check the link: http://store.alternatorparts.com/highoutputalternators.aspx

Crusty old Crown Vic (standard US cop car of yesteryear) had a 160A alternator (2kW) and bigger/more luxury/more accessorized cars will have 210A, 220A units.

The demand is only increasing with more and more gizmos in vehicles, hence the current (hehehe bad pun i know) puich to go to 48V in vehicles to keep the current down.

[CookMySock]

Woh. Yeah I did wonder about modern vee-hickles with all their modern 'lectrical stuff.

Steve

[bogan]

DB - check the link: http://store.alternatorparts.com/highoutputalternators.aspx

Crusty old Crown Vic (standard US cop car of yesteryear) had a 160A alternator (2kW) and bigger/more luxury/more accessorized cars will have 210A, 220A units.

The demand is only increasing with more and more gizmos in vehicles, hence the current (hehehe bad pun i know) puich to go to 48V in vehicles to keep the current down.

wow, kinda makes you think, why do people want all that crap, shouldn't they be paying attention to driving!

[davereid]

Tried to start bike normally and battery appears flat. Terminal voltage 12V. Cranking volts 4V. Hrm it does this from time to time.. Why?


Hi Steve, I've read the entire thread, pleased to see you put a new battery in...

[CookMySock]

Hi Steve, I've read the entire thread, pleased to see you put a new battery in...Actually, the old battery tests perfectly well. :lol:

I bought a new fangled battery charger (I blew the last one up by connecting it to a running computer UPS lol) and its' seven stage blah-blah charging thingy gives it the thumbs up. :niceone:

Fitting the new reg/rect really cleaned things up. Pretty sure thats what it was.

Steve