Battery punishment

[Anorak_ian]

How often do you get a dead battery?
Bearing in mind that a stationary engine is supposed to use a car battery.
This is something that has been nagging at the back of my mind for a while.

It looks to me like a Japanese bike is fine tuned with just enough power to the coils, trickle charge the battery, idiot lights, indicators. And when lights are needed the L (load) from the reg/rec comes in to play. But what if you have led lights (tail & pilot) all that extra power is now going to the battery. Take away the coils (diesel) and even more power to the battery.

Harley Davidson don't have an L from their reg/recs just a sledge hammer of a battery that takes a hell of a lot of punishment (normal batteries die in a few months). Problem is they are expensive large and heavy.

I guess what I'm asking is; as we can't have a car battery on our bikes shouldn't we have some kind of limiter that limits the rapid charge of the battery? Use a diode on the lighting cable, before the L cable joins it from the reg/rec? Or just not use the L cable?

[Sphere]

I visited a Dutch guy with a Sommer. He buys a new battery every year. I still need to decide on a battery, will let you know what comes of it.

[Nanko]

Car charging systems also dont have a current limit circuit.
50 -60 Ah batteries are charged with a 60 -80 Amp alternator
But only when a battery is discharged , as soon as battery
voltage reaches 14,4 V , charging stops because the regulator
limits the voltage.
Under and overvoltage kills batteries , ordinairy lead acid types
should be charged till 13,8-14,4 Volt.

Another battery killer is vibrations , especially the wet , plate
types are sensitive.

[Anorak_ian]

Yes your right, but I was thinking of when the starter has been used, the rapid re charge to a smaller than intended battery would surely damage it, wouldn't it?

[Nanko]

If your battery is 5 aH and your alternator charges with
25 , maybe yes.
But charging with 1,5 times the battery capacity seems to be
harmless.
Also only on max rpm the alternator produces its highest
current , and if you treat your engine well you keep
rpm low during the first minutes
And charging current is alternator current minus headlamp etc.

[IgorVigor]

I agree with Nanko...

I wouldnt worry if you have some current pull from the battery...

I dare say you ride with your headlight on dipped beam?

if so, that is a normally between 35w and 55w.
35w@14.4v = 2.43 amps
55w@14.4v = 3.82 amps

most tail lights and sidelights are 5w (21w brake) which is 0.35 amps @ 14.4v

so @ 14.4v charge, you will most likely be pulling between 2.5 and 5 amps to run the electrics...
thing is, at lower RPM, you will pull more which will put more load on your battery...

the coils on a petrol bike dont pull much power at all, thats not how they work...

and frankly most japanese bikes dont have enough power really...
common mod on a lot of them is to put a higher Ah rated battery in them...

I personally would just make sure the headlight is on when your riding so some load is put on the battery...