reference the battery charging question.

Is it necessary to disconnect the battery from the bike before charging it?
My 650 Transalp has a power socket under the seat that would make charging
very easy - book says disconnect battery. I never did it when I charged car
batteries.

John

 

eatmorepies formulated on Saturday :

A modern bike should not suffer any damage if a modern charger (voltage
limited) is connected without disconnecting battery from bike. If using
a very old charger (not many about now), then certainly you should
disconnect it.

 

What he says, mostly. As with the reply to TOG, you need to know what fuse
is connected to the accessory socket. If it is factory fitted then you
should find the rating in the handbook. If it is an aftermarket one then
find the inline fuse and check it's value. Anything over 10A should be
fine. If the socket was fitted with a low current device in mind, and has
wiring to match then proceed with care, as you could generate heat, smoke,
fire...

If using an Optimate then just connect it - they only pump out 0.8A
maximum.

 

My optimate came with interchangeable leads, you can swap eyelet termials
that bolt to the battery lugs for the regular alligator clips. That seems to
imply that Optimate consider their product suitable for hooking up to an
under seat plug, without the hassle of disconnecting the battery.

There was some mention in the instructions that some electrical systems draw
enough parked current (clock, alarm etc) to give a false fail indication.

 

only an issue for a deep discharged battery, where any active devices will
suck in all of the Optimate's output. In that instance, it would be best to
connect another battery in parallel with the bike battery until the
Optimate gets past the diagnostic cycle. Once the optimate is in charge
mode you can disconnect the other battery.

 

No

 

Except doing all that is just as much hassle as just unbolting the negative
lead, and in the case of a sulphated battery it would defeat the de-sulphate
phase.

 

<threads passim>

Disconnecting the battery can be a PITA: see Gyp's post. Applying jump
leads in parallel can be simple: see my reply to Gyp re. starter motor
solenoid.

Sometimes, the Optimate is too clever for its own good, declaring a
perfectly viable battery dead. Doing the parallel battery thing overcomes
the false negative. Also applies if using an optimate to recharge a large
capacity battery where the large inrush current sets the optimate into
panic mode.

I use an Optimate as my only battery charger. It is an excellent device but
the control circuitry is flawed and should not be relied upon without
corrobatory evidence from applying basic physics.

 

Horses for courses I suppose, I have several different types of battery
charger - some home made, and they all serve some purpose or other.