charging

mossop · Post by **mossop** » Fri May 06, 2011 3:18 pm

Hi All, just finished re-commissioning my latest purchase, ajs m16 1955 as seen on the front cover of the classic motorcycle magazine may 1985.

my problem is that the ammeter does not show a charge when riding with the lights on, in fact it does not show a charge with the lights off but will show a charge if you rev it while on the stand.

I've checked the brushes on the dynamo and they look fine as does the C.V.C unit as it opens at low rpm etc.

I have been riding around town in day light with the lights on (approx 80 miles)to see if this drains the battery but it does not, unless this is not enought time to drain the battery.

The only other thing I can think of is the ammeter which is an old britax model (is this the correct unit for the year of the bike ?)and is not showing the correct reading

anyway, look forward to hearing from anyone out there

regards

peter southgate

moley · Post by **moley** » Fri May 06, 2011 3:46 pm

Turn Lights on, run engine, you should see lights glow brighter with the revs, it it does you are charging! ta andy

aobp11 · Post by **aobp11** » Fri May 06, 2011 4:15 pm

Ammeter check: press rear brake, ammeter should go positive and show the brake lamp current in positive direction.
Albert

orgeopes · Post by **orgeopes** » Fri May 06, 2011 5:37 pm

ok i´a m stupid guy! i have the same problem but i tougth if the ammeter is at zero it would not be charging from the batery and has a result my new batery is flat again

so if i ride the bike with the lights on and the ammeter is showing 6 to 8 amps positive i´m charging the batery!?!

i have learned something today!

Don Madden · Post by **Don Madden** » Fri May 06, 2011 6:00 pm

With most AMC bikes the horn & stop lamp switch are connected directly to the battery, not through the ammeter. Since the stop lamp draws the battery down a bit when used, the ammeter usually shows a slight charge to replenish it after the pedal is released.

If the ammeter shows 6-8A charge with the lights on, it is probably connected backwards & is really showing a discharge.

Cheers, Don.

mossop · Post by **mossop** » Fri May 06, 2011 6:21 pm

Hi all

Ok lets go a bit further

Andy, will try your suggestion later tonite when its dark.

Don. If i turn the pilot lights on with the engine not running the ammerter needle goes to the left and shows a discharge and with the head lamp on it then goes to fully to the left. When i start the engine the ammeter needle returns to the middle but does not go over to the plus side even ridding at 50 mph.

g80csp11 · Post by **g80csp11** » Fri May 06, 2011 7:35 pm

Peter , from your description everything is fine , the ammeter should only charge in the positive if the battery is below voltage .
Sounds like your battery is good , and fully charged.
It is likely to just go positive after braking when teh stop light has dragged the battery voltage down , but may only be for a few seconds

aobp11 · Post by **aobp11** » Fri May 06, 2011 10:15 pm

The stop light effect I meant is during the time the brake is activated, not after. When the stop light is on the battery voltage is maintained with extra charging current, ideally equal to the current drawn by the light. The ammeter should go positive when it is otherwise in the zero position. It is only to test that the dial is not blocked in positive direction (questioned by Peter).
Albert
(While on the road this is my way to check that the stop light still works.)Edited by - aobp11 on 06 May 2011 9:19:26 PM

Trefor · Post by **Trefor** » Sat May 07, 2011 4:55 am

Check the battery before and after a ride with a volt meter. That will definitely tell you if the battery is being charged or not.

SPRIDDLER · Post by **SPRIDDLER** » Sat May 07, 2011 11:55 am

Concur with all above comments.
Most ammeters are notoriously innacurate in absolute terms and the needle suffers from vibration etc when riding. They are merely a 'relative' indicator of charge or discharge.
As long as it shows a discharge with lights on and engine stopped and the the needle is central or slightly positive at about 40mph with lights on you're probably o.k.