Should be out riding ... (Electrical Issues)

[CodingAway]

It's almost 70 in Boston, and we've finally got some sunshine, but ...

I'm trying to debug an electrical issue with my 2003 Honda Shadow VT 600. I've got the Haynes guide in hand, and have the fault-finding diagram from Electrosport all printed out, but I'm afraid I'm a novice here, and am having some difficulty following through.

Battery is good. Is fully charged. When it's in the bike with the ignition OFF, it reads 12.84v. So far, so good. Turn the ignition ON. Battery (at the terminals) visibly starts draining and soon bottoms out around 8.8v. Not good. Bike won't turn on, starter motor just buzzes.

I checked the resistance coming out of the alternator - from what I can tell, it looks like it checks out fine at 0.9 ohms. The fuses all look like they're in good shape. I unplugged the OUT connector from the RR to the harness, but this seems to have no effect on the drainage.

I have also left the ignition on, and checked around for any "hot spots". Nothing seems to be getting suspiciously warm (even though there's a lot of current leaking), and all the wires/connections seem to be in good shape.

To sum up: does this sound indicative of any particular problem? Are there any areas I should be focusing on testing? Stator, RR? Short circuit somewhere? I'd love to be able to figure this stuff out on my own, without having to get it to the shop, so any thoughts or suggestions are most appreciated!

Hope everyone who *is* out today has a good ride!

[dgraves49]

Just because the battery reads 12.8 with no load does not mean it is good. Fully charge it then take it to the auto parts store and have it load tested.
Did you try jump starting, car not running, to see if will crank.

[Motrcyclr]

Originally Posted by dgraves49

Just because the battery reads 12.8 with no load does not mean it is good. Fully charge it then take it to the auto parts store and have it load tested.
Did you try jump starting, car not running, to see if will crank.

+ 1 on this. if you can, try reading the voltage when you crank it. if it drops below 11v, it's your battery. Also, try jumping it like dgraves says, from a car battery, with the car shut off. if it starts then, the battery is bad. good luck.

[CodingAway]

Thanks for the replies, guys! I did have it load tested at the auto store - they said it checked out alright. The battery is about a year and a half old.

I'll try jumping it and getting a reading on it now ...

[CodingAway]

A few results from the jump test ...

Jumped it with the car turned off. Voltage was 12.04 with the ignition OFF, nearly the same with the ignition ON. When cranking, the voltage dropped to around 8.5. Engine didn't turn over, but it sounded like it really *wanted* to.

[VTFatBastard]

Is your engine kill switch on?

[CodingAway]

Well I'll be darned. Popped a fresh battery in there and it started up just fine. I thought I had ruled out the battery by getting it tested, but I suppose the only way to *really* rule it out was to put a new one in ...

I guess I'll have to keep an eye on it to make sure that nothing drains it overnight. Thanks for pointing me in the right direction. Still time to catch an evening ride!

[Earthling789]

I'll assume your ride went okay... and battery still is able to crank the bike afterwards... if so... I'd avoid that auto-parts store for future testing... they missed the fact that your battery had a dead cell (or two), or the plates were heavily sulfated (which is a result of leaving the battery unattended - no tender charging it - for long periods of time, such as over winter storage).

Each cell in your battery is responsible for 2.1V. Your battery dropping voltage during cranking is an indicator of dead or sulfated battery cells. Since you implied that you charged the battery to achieve 12.84V, but it lost 4V on cranking... that would have been the best indication of the battery, itself, being the cause of the problem.

Being a year and a half old, that's pretty good... you got half of its life out of it. Glad it wasn't something worse wrong with your bike... batteries are the cheaper fix!

Now, buy yourself a good battery-tender and make sure you hook it up to your bike's battery anytime you're not going to ride for a few days/weeks/months. A flooded-cell battery will lose 8-40% of it's charge per month if it is not used... or at least left on a trickle-charger / battery tender.

Here is a good chart to show % charge of the battery based on Voltage reading:

• 100% charged = 12.6 volts (or higher)
• 75% charged = 12.4 volts
• 50% charged = 12.2 volts
• 25% charged = 12 volts
• 0% charged = <11.8 volts

So, if you leave your bike unattended for as little as two weeks, you could lose 25% of your charge (based on the chart above, it still shows >12V, but 12.4V is only 75% charged )... and longer periods of inattention allows the battery to begin the sulfation process, thus reducing the life of your battery!

[jimnfor]

Invest in a battery tender, best $40 you will spend. Well, maybe not the best... but you won't regret it.

["Captain D"]

I sure am glad I ain`t gotta worry with my Bike sitting fer a week at a toime without riding...
Good Luck,
"D"