More electrical problems

[Tyrone ORourke]

I thought it was all over, but my bike (jawa 634 with 6V 100W electronic ignition) is still draining the battery after a few 100km.

I re-grounded the reg/rec and this makes the system run better, ie with lights bright and nice all the time the engine is running even at idle.

Switch the engine off, and the battery is dead.....

Now, the battery will charge, as taking the main fuse out and running the engine for a few minutes was rewarded with a nice amount of charge in the dead battery.

As soon as I ride off, it goes dead again... Is this just the result of an overtaxed system(45W in constant use, and an extra 45 in intermittant use), to small battery to cope with the power output, or just some damned 'leak' of electricity?

On a side note, this is the official wiring diagram for my replacment ignition/charging system:

http://www.powerdynamo.biz/wiredias/72xr.gif

The red wire (marked rt) that goes from the regulator joins the wiring harness just after the fuse... Would this not blow the system as the battery is further back on the harness, and the two opposing + charges would confict???

This is an important point, as my system is wired with the red lead from the alternator straight onto the battery...

Thanks in advance.

[TechTMW]

my system is wired with the red lead from the alternator straight onto the battery...

You are putting AC into the battery??

[Tyrone ORourke]

my system is wired with the red lead from the alternator straight onto the battery...

You are putting AC into the battery??

Sorry, my mistake, I meant to say, red lead from the reg/rec...

[TechTMW]

If you are sure you are only drawing 45w under normal running, then that should be fine. Have you tested this, or are you just going on the manufacturers written specs of the bike?

Are you riding it long enough distances to charge the battery fully? You say it's discharged after a few hundred KM - are those all at once, or are they short periods of time?

[Tyrone ORourke]

If you are sure you are only drawing 45w under normal running, then that should be fine. Have you tested this, or are you just going on the manufacturers written specs of the bike?

Are you riding it long enough distances to charge the battery fully? You say it's discharged after a few hundred KM - are those all at once, or are they short periods of time?

45W are being drawn from the 35W headlamp, 5W rear-light and 5W pilot light, the ignition is on a seperate circuit.

The battery when fully charged on a charger will survive a 110km trip without going flat, if the battery however is a little less than fully charged, the same trip will faltten it by about the 100km mark.

Small trips make the battery last longer.

This being true I can think of only two things:
1) some component is overheating on longer trips and failing (reg/rec, battey)
2) there is some small short circuit that is slowly draining battery power as the bike runs and this is capable of flattening the battery quicker over longer trips.

[TechTMW]

I think you need to do some dynamic testing. Test the output of the stator when the bike is HOT. Also test the Reg/Rec. Your setup looks like it probably uses a thyristor to throw off excess voltage. I don't think I've heard of one faliling like this, but you never know.

I think you should also test the amperage at the main fuse when the bike is running and calculate the exact amount of watts you are consuming.

To me, it sounds like the stator isn't putting out enough juice. BUT if it is putting out the proper amount of voltage When HOT, Then I think the problem may be your reg/rec. The Regulator SHOULD be putting out at least 7 volts. Have you tested the battery at the terminals w/ the bike hot?

[Tyrone ORourke]

I think you need to do some dynamic testing. Test the output of the stator when the bike is HOT. Also test the Reg/Rec. Your setup looks like it probably uses a thyristor to throw off excess voltage. I don't think I've heard of one faliling like this, but you never know.

I think you should also test the amperage at the main fuse when the bike is running and calculate the exact amount of watts you are consuming.

To me, it sounds like the stator isn't putting out enough juice. BUT if it is putting out the proper amount of voltage When HOT, Then I think the problem may be your reg/rec. The Regulator SHOULD be putting out at least 7 volts. Have you tested the battery at the terminals w/ the bike hot?

Will do as you suggest with the hot testing.
I am having a little trouble with my multimeter that does not seem to measure the amps, but then maybe its doewn to me forgetting my physics, voltage is measured across an object, and current through, so the ampmeter should be in series?

[thespirit]

Will do as you suggest with the hot testing.
I am having a little trouble with my multimeter that does not seem to measure the amps, but then maybe its doewn to me forgetting my physics, voltage is measured across an object, and current through, so the ampmeter should be in series?

Yes, the ampmeter needs to be in series unless you have a clamp on style meter that just has one single lead that has a clamp that wraps around a wire.

You should be able to easily test the regulator/rectifier, just take the bike one a long trip that would get it hot (don't shut it off) and read the voltage at the battery. If it's 13v or above, you are charging and the rectifier is working, if you rev it and it doesn't go above 14v (I think most are 14.5v) then the regulator is working. If it goes about 14 - 15v, the regulator is bad and you could be damaging the battery. You should also flip the multimeter into AC voltage mode and check to see if you are getting a lot of stray AC current. You will get some, but if you are getting a lot, you need to replace the rectifier.

I think you just have too much power being taken up by the lights. Hopefully this isn't the case and I'm wrong... If I'm right, you may need a new high output generator.

Aaron

[Tyrone ORourke]

I think a higher output generator would be a good idea anyway, as 35 watts is not much for a headlight at night. I could easily do a 12V upgrade with a similar system giving out 150W, or it might be possible to fit the generator from the next model of my bike, which has a nice 210W's.

[Tyrone ORourke]

To finish off this part of the saga, and I truly hope its the last, I did some 'hot' testing of the reg/rec and its all fine.

What I did find however while testing literally everything with the multimeter, was that there was a voltage being measured between the positive battery pole and the plastic top of the battery, especially around the third cell cap. On a suggestion the battery was fully cleaned and now has no stray voltages.
I also rewired the charging system as per the correct wiring diagrams refered to in the start of this thread, and incidentally found that the live wire to one of the rear indicators that goes through the frame tubes had a piece of insulation missing.

All this fixed and a test through an hour of stop and go traffic with few rpm and lots of brake light use, a situation that used to be lethal to the battery, and all was fine. Came home with a headlight stronger then ever.
So fingers crossed, things might be better