PMA test question charging/running battery vs not

[madeindetroit]

New weird issue.
full custom bobber and wiring so nothing stock is being used here.
Pamco and PMA.

Battery connected bike runs like a raped ape.

Disconnect battery OR have low voltage battery and bike idles fine but you cant rev it. It just pops, could not drive it this way.

it will kick start and idle without a battery but same issue as above, it will idle but backfire when you rev it, and cant drive it.

I test the voltage when idling (no battery just pma) and I'm about 5-7 volts.
I test the voltage when idling (battery connected) and its at 14v and when I rev it it slightly drops. Runs perfectly.

Test rotor (all 3 wires and i get .7, .7 and .8/7)a

It SEEMS to be charging at idle.

My concern is if the battery were to die, I can not drive this bike like is stated with a benefit on going to a PMA.

Is everything in check? Or is something not working right when my battery is disconnected.

Thanks.

 

[TwoManyXS1Bs]

Your PMA is putting out 3-phase a/c to a ("diode-trio") rectifier, which still has significant ripple. If you were to hook-up a dual-trace oscilloscope, chan-1 to +batt, chan-2 to ign, you may find that ign occurs while +batt is high, but slides into a +batt valley (low voltage) when ign timing goes advanced. The regulator sees this, and may to try to regulate in this ripple environment, so it's influencing this too. So you need battery or capacitor to smooth this ripple (fill-in this valley). We used to reposition H*nda rotors to allow batteryless ignition, which meant cutting another keyway. Not sure XS650 PMA has proper waveform to handle 20°-30° timing sweep...

 

[madeindetroit]

So what your telling me sounds like it just cant keep up without a battery.
So at idle its fine and with the battery/cap it smooths it out.

 

[TwoManyXS1Bs]

Pretty much, the pulsing output of the PMA is probably out-of-phase with the ignition, not your fault, just the way they're made. If you do a forum search for "capacitor" or "PMA" or "battery" or "8-cell" you may find more info...

 

[pamcopete]

It gets worse. If you run the PMA without a battery or capacitor, the regulator will go ape shit and could produce a very high Voltage, like 20 + Volts and fry the electrics, including the PAMCO.

The battery or capacitor is like the shocks on the rear suspension. Imagine what the ride would be like if you had springs but no shocks.

If you have the standard PAMCO, then there is no electronic advance and no syncing issue, pro or con. If you have the latest PAMCO with the E-Advancer, then it will shut down when the voltage is low and go through it's startup routine when the voltage gets to about 6 Volts. In any event, both versions of the PAMCO are designed to work with a steady DC voltage of 5 to 18 volts which requires a battery or capacitor on the output of the regulator. There is no attempt at synchronization with the regulator nor is any required.

I think that we should sticky this thread as this quesiotn comes up about 50 times a month and the answer is always the same!

 

[madeindetroit]

Thanks guys, I understand how it all works. I just didn't understand how other people could be running no battery and mine wont run without one.

Thanks again for the inside that a battery/cap is needed regardless what you read on here.

 

[retiredgentleman]

Thanks guys, I understand how it all works. I just didn't understand how other people could be running no battery and mine wont run without one.

Thanks again for the inside that a battery/cap is needed regardless what you read on here.

When other lads say they are running a PMA without a battery, they are telling the truth, but they should also say they are using a capacitor to replace the battery.

 

[Jon1wdsmen]

Man I'm such a noob at this!! Hope the new complete system that is coming has instructions for dummy's lol

 

[XSLeo]

If you get your PMA from HHB then it has about the best customer support out there.
If you are getting a Pamco ignition the install is at Pete's ignition web site, www.yamahaxs650.com
And with that, you get customer support that top notch too.
Leo