strange charging with E3L - DVR2 – 12v

[mikeb]

Something strange with the charging. I have a E3L - DVR2 – 12v AGM battery negative earth system. the battery negative is directly wired to the DVR2 with another wire going to the dynamo strap and another to frame. I believe the battery is stuffed as won’t hold a charge.

With some revs, a dc voltmeter jumps around quickly, at times showing 17 volts across the battery. (When it shows high volts, the LED indicators also flash brightly and very quickly). An AC meter shows about 2v AC (on top of the dc volts) at about 600hz, revs dependant. A pokey PC soundcard scope shows wild and crazy oscillations when revs produce above 13-ish volts.

I do need to renew the battery but its only a couple of years old. I’m wondering if the weird behaviour above suggests something may have killed this battery. Could the DVR2 be dead? Or maybe an earth fault within the E3L? or other cause? I can't find other wiring faults. Or maybe its just the stuffed battery.

EDIT: disconnecting the E3L for the wiring and connecting the D & F together reveals with revs a steady increase in DC volts on an old analogue meter, as you'd expect, and still shows 2v AC on top of that with the fancy digital meter. I assume its a case of too fancy test equipment and not knowing what 'normal' looks like. Tho the question stands re DVR2 vs battery vs wiring

Any thoughts on this?

Thanks

[Triton Thrasher]

Have you tried an analogue meter?

[bikerbob]

Whilst DVR2 regulators are very good they are not infallable I had one fail a few years ago the voltage coming out of the dynamo was OK but what was going into the battery was erratic up and down replaced the DVR2 with another one and everything back to normal did not damage the battery maybe fixed problem quick enough.

[mikeb]

what was going into the battery was erratic up and down

can you describe that a bit more for me Bob? and what made you even suspect something was amiss?

Have you tried an analogue meter?

its a good question TT as the meter showing weird readings is digital. my old analogue meter (from the late '70s) shows a steady read and i can't see the needle quiver. however the same digital meter is very steady on the other BSA (also DVR2, AGM bat etc).

I'm now thinking the old battery maybe so dead that it doesn't smooth the regulated voltage from the DVR2 or somehow upsets the DVR2 and hence shows the jumping around. So unless someone has another idea, I'll get a new battery, try it and see it all appears settled. This could just be a case of too modern test equipment. Not the first time - I often find digital meters produce strange readings on many things so I often go back to the old analogue gear.

cheers

[Triton Thrasher]

what was going into the battery was erratic up and down

can you describe that a bit more for me Bob? and what made you even suspect something was amiss?

Have you tried an analogue meter?

its a good question TT as the meter showing weird readings is digital. my old analogue meter (from the late '70s) shows a steady read and i can't see the needle quiver. however the same digital meter is very steady on the other BSA (also DVR2, AGM bat etc).

I'm now thinking the old battery maybe so dead that it doesn't smooth the regulated voltage from the DVR2 or somehow upsets the DVR2 and hence shows the jumping around. So unless someone has another idea, I'll get a new battery, try it and see it all appears settled. This could just be a case of too modern test equipment. Not the first time - I often find digital meters produce strange readings on many things so I often go back to the old analogue gear.

cheers

So believe the analogue meter.  The digital meter is not working properly on your bike.  It’s a common occurrence.

[bikerbob]

This happened afew years ago and if I remember correctly what alerted me to the problem was the erratic  behavior of the ammeter it was all over the place. So I checked the dynamo out put which was Ok then checked what was going into the battery sometimes the voltage going into the battery was as high as 17 volts maybe more. I rang Dynamo regulators who I bought it off and he said it looks as though the DVR2 has failed and if I sent it back to him he would test it, I did not bother I just bought a new one and it has worked Ok ever since this must be probably maybe 4-5 years ago.

[rocker21]

i have found that digital meters dont work very well near mag's a good old fashioned anolouge meter is far better.