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Charging a motorbike battery?
shades - 31/5/07 at 06:54 PM

I need to charge my motor bike battery. I have a charger which is rated as 4Amp, but the battery instructions say charge with a motor bike charger rated as 1Amp. Do I need to buy a new charger or will my car one do? Its new and I dont want it to go bang. Anythoughts?

David Jenkins - 31/5/07 at 07:06 PM

Best to get the correct charger - too high a current will generate excessive gas and could break the battery casing (assuming it's a sealed battery, as many bike ones are). You may also distort the plates inside.

You'll find suitable ones at most bike shops, or in Maplins.

HTH
David

Rudy - 31/5/07 at 07:16 PM

Maybe I am wrong but I think you could use your charger, usually battery is charged at 1/10 of tot ah, for example if you have a 40 ah you should charge it at 4 a circa, so if your motorcicle battery is 30 ah I think 4 a is not a problem. And when battery is installed in your car, your alternator will be able to charge at 20, 30, 40 a , so I would not worry about 4 a.

chunkytfg - 31/5/07 at 08:11 PM

quote:
Originally posted by Rudy
Maybe I am wrong but I think you could use your charger, usually battery is charged at 1/10 of tot ah, for example if you have a 40 ah you should charge it at 4 a circa, so if your motorcicle battery is 30 ah I think 4 a is not a problem. And when battery is installed in your car, your alternator will be able to charge at 20, 30, 40 a , so I would not worry about 4 a.


If it's a bike battery i'd very much doubt it's more than a 12ah.

My 700cc Vtwin race bike runs total loss and still only requires a 8ah to get it started with little effort.

For occasional use vehicles that have bike batterites i'd suggest fitting a trickle charger such as an acumen or optimate. they are left permanently connected and should set you back no more than £40

worX - 31/5/07 at 08:23 PM

I will second the sentiments above.

Not only for the reasons that you need right now, but bike batteries aren't the best and if you aren't going to use your car over winter as much, you will probably want a trickle charger anyway!

Most bikeshops have some sort of offer on one or the other stated above, but even so I got my Optimate 3 off ebay for £23 delivered...

hth
Steve

milton - 31/5/07 at 10:00 PM

I agree with with worX the optimate is one of the best used it all the time when i had my bike

shades - 31/5/07 at 10:11 PM

Thanks guys,

It turns out it is already charged, but thanks for the advice I will get myself a trickle charger as reccomended.

907 - 31/5/07 at 10:23 PM

When we used to fly model aircraft we all had bike batteries housed in a "flight box"
which we used to power fuel pumps and starter motors.

A common way to charge them was to use a 12v car battery charger with a headlamp bulb in the circuit. (+ side )
When first connected the filament would glow a dull red and when fully charged it was brilliant white.
About 8 hours was the norm.


Paul G

MikeRJ - 1/6/07 at 01:11 PM

quote:
Originally posted by 907

When first connected the filament would glow a dull red and when fully charged it was brilliant white.
About 8 hours was the norm.


Other way around I'd have thought? Flat battery = greater current = brighter bulb?

907 - 1/6/07 at 02:34 PM

Well, I've been wrong before, and sure as eggs are eggs, I'll be wrong again.

My limited knowledge of matters electrical thought that the filament acted as a resister
while current was adsorbed by the battery, but when the battery was fully charged the
only thing left to use current was the bulb, hence it lights up.

It could well be the other way round.

I haven't got a 55w bulb, or a flat battery to try it on at the moment otherwise I would.


It was several years ago when Saturday nights were spent hooking up all the chargers,
ready for the reign of terror we inflicted on the locals on Sundays.

ATB

Paul G