I'm finalising getting my CBR1000FM road-ready after 5 years in the garage unused. I've just fitted a new lead acid battery and purchased a trickle charger to keep the battery topped up when not in use. I fully charged the new battery before using it. I've been out on the bike for 45 minutes of normal riding and connected the trickle charger. The charger LEDs started showing battery at only 25% charged before progressing quickly to 50% after a few seconds and then eventually on to 75 and 100%. Is this normal or could I have a problem with either my new battery, trickle charger or bike's generator? What/how should I start checking first? Thanks for any suggestions.

 

Dont think thats a problem, just probably the charger sensors find what state the battery is in, when you come back from a ride before you put charger on ,test the battery with your multimeter for volts, I think you will find its OK

 

Wanted to get someone else's view before buying a multimeter. Hope you're proven right, CaBaRet, and it's not a problem afterall. I'll let you know what I find. Thanks for now.

 

The multimeter is going to be one of your best tools for the motorbike, good ones can be found quite cheap

 

You are, of course, right on both counts - and it's of use for other things too. It's just that I have one at home (in UK) but not over here in France..... Always the right tool in the wrong place for me!

 

I've now acquired a(nother) multimeter and taken some readings. They seem sensible to my untrained eye but I'd like to share them and hence check I'm not missing something. All the readings are taken across the battery terminals - hope that's OK ....Ignition on, engine not running - 12.50V; Engine running at 2000rpm - 14.38 V; engine running at 3000rpm - 14.50V; engine turned off again - 13.40V slowly diminishing to 12.80V. That looks to me like the battery and generator are both OK and the business with the float charger starting at 25% charge each time is just "how it works". If someone has a different view (CaBeRet) please let me know.

 

Battery voltage seems low...the no-load voltage on a fully charged 12V battery ought to be around 13V and usually a bit over that. Your 'engine running' voltages look fine.

 

Echowars - Is there anything I could do about the low(ish) battery voltage? Presumably putting it on charge would help in the short term, but if so would it help on a long term basis or is the battery voltage more of a function of the inherent battery capacity itself that can not be altered/improved on a permanent basis?

 

Seems my guesstimation might be a tad harsh for the battery. Yuasa says 12.6V for a fully charged power sports batt, so 12.5V ought to be around 85% of a full charge (disclamer: I'm a car mechanic and a new car batt with a full charge will typically read 13~13.3V). My bad.

Yuasa Batteries - FAQ's

Might see what the battery drops to when starting. Yuasa says 9.5V is bad, but I'd be wary of anything under 11V and with a new battery 11V ought not to be a problem.