Battery Care.

If I don't get out on one or both of my bikes for a while, I'm in the
habit of connecting a 300mA charger to the battery overnight. My logic
is 300mA won't do any harm if it's fully charged and might to some good
if it isn't

I haven't been out on one of my bikes since the autumn and the other
since before Xmas so I figured I'd bung the charger on today. However
beforehand I popped the multimeter on to check the voltages. 12.5 and
12.8 respectively.

Is there _any_ point in bunging the charger on to a battery with 12.5
accross the terminals?

On a related subject, I've often wondered if there is any benifit in
doing a pikey optimate and leaving the lights on all day then
recharging?

 

wrote

Do some sums, use your sense.

0.3A for how many hours? 10 say? 3Ah is about a quarter of the total
charge held in a bike battery. Far too much to be sticking in there
every nigh just to keep it warm. 50mA should be more than enough to
keep the frost off. Cheaper to throw an old blanket over it though and
that will keep dirt off as well as frost.

Not if it spins the starter and fires up like it should.

Absolutely. Lead acid batteries are at their very best when operated in
what you have described, in a Full Float System. Course that really
only applies to lead acid batteries built especially for the environment
they will operate in which, in a Full Float System, ain't under the
seat.



The truly sensible thing to do for you fair weather bikers is to check
the bike over a week before it goes out in the spring to make sure it is
ready for when the rain stops.

 

True. If you want to be anal about it, a cheap charger that
gives DC with a lot of "ripple" might harm the battery a bit.

Yes, there is. After charging you ideally want to measure closer
to 14 volt.

No. Lead-Acid batteries do not have "memory". What kills them
is being stored while being less than fully charged, sulphating
the plates.
What has benefit is getting a Optimate or CTEK or other "smart"
charger. A good investment.

 

I should have been clearer. Not _every_ night. One hit of 10 hours
worth of 300mA.

 

wrote

It wouldn't have helped you any.

Fair enough then as long as you don't overdo it.

Do bear in mind though that the worst thing you can do to just about any
battery, not just lead acid, is to let it discharge almost fully and
then freeze it and then draw, or at least attempt to draw, a large
current from it and then punish it by boiling it's innards for a week
when it fails to work as expected.