Charging capacity 1978 180 Jota

T

Tetley Laverda

Senior member
How long would you need to ride a 1978 180 Jota to recharge the power used to start the engine using a Witt DMC ii ignition/charging coil upgrade

Many Thanks
Tetley
 
How long is a piece of string?  :)

You could guesstimate it, cranking amperage is often at least 150A, x12V = 1.8Kw.
If it fires straight up it's cranking for say 2 seconds, lets leave it in applicable units and say 3600ws.
Charging coils are ?? 150W?, minus ignition, around 20W max = 130W
3600/130 = 27.  So if all the above ideal situation applies then 27 seconds.

BUT, unlikely to be actually that, especially actual alternator output.  If the bike is running at low rpm it will barely charge at all. etc etc  Refer to string comment. :)
 
I have recently being having short runs out of around 15 - 30 mins no lights used and I am finding the battery isn't getting charged and requiring a top up . I am below 4000 rpm most of the time in traffic so your explanation explains my situation
Many Thanks
Tetley
 
Common enough problem, the original only charges when you're doing a decent clip.  The attempts to solve the problem go a long way back, the '75 spaceframe racers used an external alternator, others have followed suit over the years.  John Wilson came up with a neat integrated conversion using a Kawasaki alternator and Red has since perfected and productionised that concept with alternator rotors and stators made to his specs.  Well worth the asking price.
Cheers
SteveB
 
no lights used
Click to expand...
brake light? indicators?  All adds up!  You need to be running at out of town speeds (4000rpm+) to keep things topped up.  Old alternator means weaker magnets, further reducing output
 
I recently installed a new DMC ignition with the charging coil upgrade and a new 30ah battery in my "78" 1000. The battery was bench charged to full charge before installing. With setting up the ignition and working on carburetor problems I?ve probability starter the bike 20 times and have only ridden about 20 miles. (Still have carburetor problems). After reading your post I checked the charge with a charger and still almost fully charged. From this I assume the charging system is working great.
Are you sure the new coil is installed correctly? Yellow to yellow and yellow/black to yellow/ black and all connections are good? Is your battery good?
 
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