Flat battery or something else

faceman

Having what I think is battery problems but wondering if it could be something else.

Battery doesn't seem to hold a charge anymore for more than a day or two. It's a few years old. I charged the battery on Thursday night (bike hadn't been used in a week) and took it for a long spin that night. Then commuted to work Friday. It was locked up for the weekend and took it out today and battery was flat.

If it's just a battery I can do it myself but could it be something else?

Forgot to say, it's an 03 Deauville.

Bandito909

Sounds like a bad battery alright. Do you have a multi meter? You could check your charging system and the battery itself.

Battery should be about 12.6-12.8V after a slow charge. Check it after a few hours of charging it to see if it's holding it's charge.

Check to see what the voltage is with the bike running at about 3k rpm, should be about 14.5 Volts, if it's much less that this, you're probably looking at a problem with your charging system somewhere.

CJhaughey

Deau's suffer from the usual Honda crap Reg/rec and associated problems.
If the reg/rec has gone bad it can lead to over charging which will kill the battery in no time.
Or it could undercharge which will lead to your symptoms.
The easy way is to just change the unit for the same one from Honda.
Or you can ensure long term reliability and fit a Mosfet Regulator from another machine that uses one.
When you replace the battery don't buy a YTX9BS, they aren't really man enough for the job instead a YTZ14S will fit and give you better battery capacity.
Before you do too much check all the connections from Battery onwards are good and tight with no corrosion on them.

rock22

CJhaughey wrote: »

Deau's suffer from the usual Honda crap Reg/rec and associated problems.

Can you expand on "the usual Honda crap Reg/rec and associated problems?

i have never had a problem with charging on a Honda. Current m'cycle has 21 years on original battery .

bladespin

Plenty of VF and CBR issues around reg/rectifier. Well known weakness.

Richard tea

My Cb400 also had reg rec issues

CJhaughey

Its a well known problem on Honda motorcycles.
I know, I have two models that suffered from this myself.
NT650 and NX650, I like Hondas but this is a known weak point on otherwise reliable bikes.
You can be lucky and in fairness 21 years on a battery is good going, but the problem with a bad regulator leads to other bad things happening, stators burn out, batterys overcharge and leak and acid damages things.
General stuff that can be avoided by fitting an Eastern Beaver reg rec cable set and a Mosfet Reg/rec unit FH prefix.
Last year I saw two bikes that were in the middle of a touring holiday knocked out of action due to reg/rec failure, one was a VFR800 and the other a CBR1100XX.
Fix it while its not a problem and enjoy your travels in confidence.

TeaBagMania

Bandito909 wrote: »

Check to see what the voltage is with the bike running at about 3k rpm, should be about 14.5 Volts, if it's much less that this, you're probably looking at a problem with your charging system somewhere.

do this first

if your bike is parked up for more than a few weeks get one of these http://www.batterytender.com/Motorcycle/Battery-Tender-Junior-12V-0-75A.html

I use them on my bikes and cars during the winter months

Hotblack Desiato

The Lidl ten quid battery charger is just as good and is safe to leave connected all the time if you want.

faceman

Turns out it was just the battery. Two of the cells were dead.

Hotblack Desiato

faceman wrote: »

Turns out it was just the battery. Two of the cells were dead.

A basic voltage check would show that. You lose about 2.1V for each shorted cell. It's impressive that you got it to run at all