Triumphrat

DAVE M

ride above 2000rpm

DerryUK

<It might even be the same problem i had.The rotor had lost nearly all its magnetism>
Thanks for the reminder. I should have said, if the output voltage is low, you have weak rotor magnets. Allegedly if your rectifier fails it can allow battery current to flow through the stator which may demagnetise your rotor.

I tested some Lucas alternators here ... http://www.scribd.com/doc/102021181/Lucas-Stator-Log-4

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DerryUK

'69 T100S being rebuilt - very s-l-o-w-l-y
VFR800 VTEC

motobob

It is very easy to ruin an AGM battery with the wrong kind of charger. You need a constant current charger that puts out a current larger then the standard charge rate posted on your battery.

koan58

So many opinions and tests etc, bet you're still trying to unravel it all!

In a nutshell, your alternator in new condition is rated at ~120W output, only delivered at high revs, say 5000 rpm. At 3000 rpm (~50 mph in top) it may only output perhaps 80-90W or so.

Your demand on the system is constant 55W headlamp, ~10W tail & sundry, ~35W ignition (not much difference EI or points) - total say 100W.

The equations don't work at those revs/speed usage, even if all the bits (alternator, rectifier, zener) are working 100%.

So if only riding <45mph in town, either do it in 2nd gear, or reduce the demand. Do you need anything more than a halogen 35W dip bulb? Use LED bulbs for tail etc.

IMHO the best solution is a 3-phase alt, with solid reg/rect, which will give the power in the rev range you are using, as it produces more max power(180W) and the output climbs in a steeper curve from tickover upwards.

3-phase uses the same alt rotor. It is unlikely that your rotor has signifiantly lost its magnetism, unless it has been seriously shocked with a hammer or stored in isolation (not inside the stator).

Even if you elect to keep the single phase alt, don't waste your time with zener/rectifier, use appropriate reg/rect box.

Dave

motobob

I test charging systems every week on a variety of bikes. I cannot stress the importance of checking your battery. If your alt and reg/rect aren't working correctly you can easily ruin an AGM battery. When you put in the new components the bad battery can cause your new components to fail because of increased duty cycle.

Charge your battery. Let is sit for a little over an hour. You need to see 12.8 volt minimum. Better yet, take it down to your local shop. Most of them are now equipped with a computerized battery tester.

I like to use an automotive zero-center type ammeter (not the POS one in the headlight). You can then observe the rpm when the battery goes into positive charge.

If your system checks out good, take the bike out for at least an hour ride and check it again while it is still hot. Both alt and reg/rects can fail after getting hot.

DerryUK

<At 3000 rpm (~50 mph in top) it may only output perhaps 80-90W or so.>
Dave I tested a stator that I think is like John's and it gave 129W output at 3000RPM.

True that when unloaded the alternator will double it's output when you double it's speed, see http://www.scribd.com/doc/116748386/...as-Alternators but when loaded the curve flattens off and you don't get a lot of increase above 3000. I wonder if this is why Lucas seemed to choose 3000 RPM for testing or was it just to keep the noise down!

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DerryUK

'69 T100S being rebuilt - very s-l-o-w-l-y
VFR800 VTEC

johngreco

In the end I've decided to upgrade my charging system with a Sparx three phase alternator kit (upgraded rotor, stator and voltage regulator). Im hoping it will increase my low RPM output and be able to handle the electronic ignition and halogen headlight while still charging the battery.

Although the installation instructions are clear enough I'm trying to better understand how the battery receives the charge that the system is producing. The red (+) wire from the voltage regulator unit is grounded to the frame, but the black (-) connects to a wire (brown/white) that feeds back into the wiring harness. In my mind that the black (-) would feed directly to the battery to charge it.

Clearly this isn't how it works, so my question is what happens to the charge that is being produced by the regulator from the time it leaves the unit to the time it reaches the battery to charge it?

Thanks.

DerryUK

John looking at my circuit diagram brown/white goes to the ignition switch and the ammeter. From the ammeter it goes to the fuse then battery. Brown/white also goes to the old zener.

So there is a direct connection between black and the battery.

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DerryUK

'69 T100S being rebuilt - very s-l-o-w-l-y
VFR800 VTEC

DerryUK

I am not familiar with your bike but I was looking here http://www.classicbike.biz/Triumph/R...nual-63-70.pdf page H30.

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DerryUK

'69 T100S being rebuilt - very s-l-o-w-l-y
VFR800 VTEC

johngreco

Thanks, Derry. That makes sense. It also makes sense that I would connect the black (-) directly to the battery. So I contacted the shop that I purchased the unit from and they agreed that the directions don't make any sense. When in doubt, ask someone who has actually used one and don't follow the directions.