Battery not charging

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youngfolk
Posts: 22
Joined: Fri Jan 28, 2011 1:17 pm

Battery not charging

Post by youngfolk »


With the R50/2 the battery doesn't seem to charge. I have include x2 6V batteries and wired them up so they can support the lights better. Supposedly a longer output but it wont charge. When fully charged it works well bright lights, 2 hours into the ride and you look as if you put candles into the light housing :)

Any ideas if it could be Wiring, Generator or Magneto.

thank you
Sven
South Africa
Sven S.A
r50/2 1963

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Darryl.Richman
Posts: 2087
Joined: Fri Oct 27, 2006 3:00 am

It's not the magneto! Don't

Post by Darryl.Richman »

It's not the magneto! Don't touch that. Other than relying on the engine and transmission cases as a ground plane, the ignition system is entirely separate from the rest of the electrics on these twins. (The singles have battery/coil ignition, so the ignition is linked to the generator on those.)

You might look at this thread for some ideas: http://www.vintagebmw.org/v7/node/6941
--Darryl Richman

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RainyRider
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Joined: Fri Jun 12, 2009 12:25 am

1. Did you, (by chance), wire

Post by RainyRider »

1. Did you, (by chance), wire the batteries in "series" rather than "parallel", (i.e. 12V rather than 6V)? If so, it won't charge.
2. Two batteries in parallel (6V), especially if discharged, might draw too much current, and roast the generator/voltage regulator....Check your generator voltage outputs.
3. You may also have a missing ground or a broken wire....

good luck


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Bruce Frey
Posts: 536
Joined: Fri Oct 27, 2006 3:00 am

Without some special kit

Post by Bruce Frey »

Without some special kit (like boats use for multiple batteries), two batteries wired in parallel will not charge correctly. Try it with one battery and see if it works. More is not always better.

Bruce

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youngfolk
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Joined: Fri Jan 28, 2011 1:17 pm

Its Working

Post by youngfolk »


Well after much checking tugging the Blue wire point 61 on the generator was found to be broken and wasn't making contact, after 1 hour
of checking testing all sorts its the simple things that get you. :)

Regarding the batteries i was told that the R50/2 runs off a 6V and to add additional support for the lights i should run x2 6V batteries in parallel which I've done. Taken the 2 positives and created a bridge to one. Is this totally bad and with the R50 being 6V will 12V not do damage if i run this is series?
Sven S.A
r50/2 1963

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schrader7032
Posts: 7402
Joined: Fri Oct 27, 2006 3:00 am
Location: San Antonio, TX

As others have said, having

Post by schrader7032 »

As others have said, having batteries in parallel might present an interesting look to the generator. I've heard that there's no guarantee that charging will happen as you think it might. I'd suggest googling this sort of thing on the web and see what you find out. Then report back!!

Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

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Darryl.Richman
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Joined: Fri Oct 27, 2006 3:00 am

Common Misinformation

Post by Darryl.Richman »

Well after much checking tugging the Blue wire point 61 on the generator was found to be broken and wasn't making contact, after 1 hour
of checking testing all sorts its the simple things that get you. :)

At least it wasn't an expensive fix!
Regarding the batteries i was told that the R50/2 runs off a 6V and to add additional support for the lights i should run x2 6V batteries in parallel which I've done. Taken the 2 positives and created a bridge to one. Is this totally bad and with the R50 being 6V will 12V not do damage if i run this is series?
The twins don't "run" on anything. The magneto ignition is independent of the rest of the electrics on the bike, and will work regardless of their condition. The battery is present essentially to act as a ballast to the electrics, to absorb the vagaries of the generator/voltage regulator (which will make your bulbs last longer); and also to provide power when the generator is turning below about 1500 rpm, so your lights stay bright at idle.
--Darryl Richman

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youngfolk
Posts: 22
Joined: Fri Jan 28, 2011 1:17 pm

I found this out after

Post by youngfolk »


I found this out after looking into the batteries not charging, running them in parallel and fixing the charge ignition light.

Regarding the red ignition (charge) light, it should work as follows:

When you push the key in, a sprung steel curved strip pushes down onto a brass plate and closes the battery - generator - regulator circuit. It is wired such that the red light illuminates when the key is on, the battery is not charging. Once running, the battery should be charged by the generator (who's charge is regulated to 6,8V no matter the revs) and the light should go off. It is red because it is a warning and should it come on while riding to indicate that the battery is not being charged and your lights will eventually die.

Regarding one or two batteries, the regulator should put out a regulated potential difference (Voltage) of 6,8V. The current (Amps) will however be determined by the draw, which increased with light use, higher revs, flat batteries and short circuits. The batteries merely act as a reserve and buffer of energy and having two in parallel doubles this buffer. The rating of the battery is printed on the battery casing and is given as the number of hours it can deliver 1 Amp at 6V and so a 7,2 Amp-Hour (Ah) battery for example means that one should expect a fully charged battery to deliver 7,2 hours of 6V with a draw of 1A. If your park light draws 1A, you can expect it to stay illuminated for 14 and a half hours (2 x 7,2Ah). Your generator and regulator should be robust enough to charge both batteries easily. Positive to positive and negative to negative as you have it is correct (parallel). If you put them end to end, positive to negative and negative to positive (series) you end up with 12V, blown lights and burned points and coil. Not cool.
Sven S.A
r50/2 1963

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