The BSA A7-A10 Forum

Technical => Lucas, Electrical, Ignition => Topic started by: Snowy on 04.04. 2019 12:20

Title: Getting there! Charging
Post by: Snowy on 04.04. 2019 12:20
First "big" ride out on the "loan" A10 I have, getting it up together for a neighbour.
Run to Kidderminster Motorcycles to get some bits, good times!
On return journey after snack stop at Ironbridge, suffered a couple of stalls at junctions on tick-over, then started missing like a pig.
It was only at third stop that I put me foot on the rear brake, and noted lamp supplying only a faint red glow!
So, must be charging issue, and a looping combination of push, start ride like an idiot, stop, psh etc.etc. I finally made it home!
So, battery on charge for 24 hours (12v, brand new Lucas battery) Just added the new bits from Kidde and thought better check charging voltage.
No drain, ignition off, battery at 12.4v across the terminals.
Engine running meter varies from 11.9 to 12.1v, issue verified, it ran till the battery gave up for sparks!
Bike setup, 12v, +ve earth, Boyer Bransden Mk3 ignition (nowt to do with charging but for info!) and Boyer Bransden "Power Box" regulator.
Can anyone out there remind me, step by step, how to locate lack of charging? Long time since I've played with DC charging.
Is it just the Power Box (they any good?) regulator stuffed or dynamo not giving enough out?
If it's not about 14V at the battery when running I'm stuffed!
Any help appreciated!

Title: Re: Getting there! Charging
Post by: Greybeard on 04.04. 2019 14:42
Hi Snowy. Please, will you go to introductions when you get a minute and give us a short Bio with pictures if you can.

Sorry I know nothing about electronical ignition on these machines. Take a ticket and have a seat; someone will be along to see you shortly.
Title: Re: Getting there! Charging
Post by: muskrat on 04.04. 2019 20:47
G'day Snowy  *welcome*
Yes charging is very important when running electronic ignition. I have Boyer on both of mine. Once voltage drops to about 10v the timing goes into full advance mode. Tell tale sign on the move is a miss when you put the rear brake on. A charged 4ah battery will power it for about 45-60 minutes without any charge going in.
To test dynamo for output. At the dynamo make a wire that connects to both the D & F terminals. Use a multi meter between that wire and earth. Start bike and with a few revs it should read voltage, it can go as high as 20. Don't run it like this for long (short as possible to test) as it's running flat out with the D & F wired together.
If not showing a charge check the drive chain and sprockets. The large drive sprocket can sometimes spinn on the shaft.
If showing charge the Power box is next down stream. I don't know how to test that (I have DVRII's) other than swapping it out for a known good one.
Make sure all wire connections are good and the earth lead is well attached (I run one to the frame and one to the motor and one to the handle bars/headlight bracket). And the polarity is right.
Title: Re: Getting there! Charging
Post by: morris on 04.04. 2019 20:57
Hi and welcome Snowy.
The coils from an electronic ignition sap away quite a lot of power.
My SA has a Pazon ignition and my guess is that it consumes about 25-30 watts from the available 60 (ish)
In daylight I run it with the 10w pilot light on and a 3w LED rear/stop light combination. The charge just keeps up then and the Yuasa AGM battery stays on 12.5v
But if I run it with the headlight on (35 w halogen) the battery goes down to somewhere between 10-11v after a good hour of riding and then it starts to misfire.
The dynamo is still on the 6v setup
Title: Re: Getting there! Charging
Post by: Snowy on 02.05. 2019 14:48
Sorted! Well, hopefully!
After fears of rewinds / regulator replacement and so on decided to go prodding with me meter!
Whilst disconnecting various connectors pulled the brown / white connecting dynamo to alternator and the wire just pulled straight out of the bullet!
Classic case of the "dry joint" going back to me Strowger days! :) (one for the old hand telecomms folks there!)
Needless to say all soldered up and at last I see the Ammeter indicating charge on the + side - thought it was just a dodgy ammeter previously!
Cheap fix, we like those!
Just need another grand day out to see if not charging how long a full battery will last again!  *eek*
Anyone doing the British Bike run from Newport 12th May? Desperately trying to get a day leave off shift! *whistle* .........possible sicky?
Gotta shun this thing called a conscience!
Title: Re: Getting there! Charging
Post by: Greybeard on 02.05. 2019 16:00
Anyone doing the British Bike run from Newport 12th May?
Soz; I'm planning to attend the Cheshire BSAOC weekend, 10th to 12th May. I hope to meet Paul ?, Simon ? and others from this forum and also the leg-end that is Andrew Guttman of Priory Magnetos. I will be wearing my forum tee-shirt.