Draining Battery / Weak Starting

groan, electrical issues...

So here's the history:

So earlier this spring I bought a new battery, because my last one "wasn't holding a charge" and "was having difficulty starting the bike". The new one was installed, I got like a week or two of riding daily in and then I went on leave from work and only rode it once during my 2 months off. Fast forward to earlier this week when I tried to take it out Monday, and the battery was dead. It had been over a month since I'd ridden it, so even though it shouldn't be "dead" I shrugged and charged it back up. On Tuesday I rode it to work after it barely started in the morning, and then the starter wouldn't even turn the engine over when I tried to leave work. I push started it, and after struggling to stay alive for about 5-10 seconds the bike behaved normally for the ride home. Since then I haven't ridden it, just done diagnostics.

So here's the current situation:

The battery, isolated from the bike seems to be able to hold a full charge (12.6V-12.5V right?) for at least a night. While connected to the motorcycle the battery will lose the vast majority of its charge in several hours, talking 12.6V to 12.2V over 8hours, and into 11V territory if left overnight. When the battery is freshly charged, at 12.6V, the starter still sounds like it's being driven by a dead battery, slow and laborious. Once started however, the bike runs fine, and testing the charging system across the battery, it'll output 13.9V from idle up to and past 5000rpm (which, according to the irrefutable electrosport motorcycle charging system fault finding diagram, is a "perfectly OK"). I've tried measuring current in between the battery and the motorcycle leads, but I can't see anything with my meter, even if I get the clock to turn on it's like a second or two of a couple milliamps and then nothing.

That's what I've done and what I know so far. The only thing I can think of is checking the RR diodes, despite the charging system working fine. Any other ideas?

Update: It was the battery, apparently it was defective in an annoyingly inconsistent way.

 

For starters have you done "the Drill" on this, might indicate what is going on? I'm assuming that the R/R positive is live from the battery all the time and this could indicate a diode failure in the R/R as you indicated. Problem now is that with the drain rate you say it has and you left it for a couple of months then being left totally flat for that long will kill the battery. This is why it seems to struggle to turn it over, battery may indicate charge but will not stand any load, that is why the clock shuts off

 

Sorry, the clock doesn't turn off when trying to start. The reason I mentioned it turning on is because when I'm testing for current leakage, it means that the multi-meter successfully completed the circuit.

But yeah, for sure I'll be checking the RR's health, and I should watch the charge of the battery when I try and start. Apparently if the battery voltage drops below 9.5V while starting, it has low capacity.

 

Alright, just got done testing the RR, it passed. Not surprising, since the charging system works, and it has no trouble keeping the bike alive, even with a dead battery...

 

Okay so, new development.

So after I did the RR and stator tests (which all passed) I left the battery in the bike and watched the voltage over the course of a few hours, it held fairly steady around 12.6V. It started fine later and I took it for a ride to my parent's house, about 25mins away, mix of city and back roads. After sitting for about 4 hours I tried to start it to ride home, and it barely started, clearing the clock/trip meters in the process. I had to get gas on the way home, so after 20mins of riding, the backroad portion and some city, I stopped for fuel figuring that fresh off of running it wouldn't have any trouble starting. The bike didn't want to restart, it cleared the clock and trip meters again, and would barely manage to turn over two to four times before I gave it a rest. I got it push started and rode the remaining 5 city minutes home.

Here's where it gets stupid. I get the bike in the garage, pull the seat, check battery voltage: 12.7V. I think "whatever, the bike was just running, I bet it has no capacity", so I leave the multi-meter connected to watch the voltage plummet as I try to start it. I press the starter and boom, fires right up like nothing is wrong.

So my question to you guys is... what the fuck?

 

Check all the battery earth connections, remove them, clean them and refit

 

Then charge the battery. It should measure >13.0V when charged. From your descriptions if sounds like your battery is probably bad and won't hold a charge. You need a good battery to do any further testing.
If there is a voltage drop only when the battery is connected to the bike then check for current leakage. The manual calls for current leakage to be a max of 2.5 mA. You'll need to find the short if the current leakage is higher than this...

 

Is there a good resource for finding all the ground locations?

 

Alright, I cleaned up the ground points on the frame, put them back together, covered them in Vaseline, cleaned up the battery connections, put them back together. Battery voltage was 12.5V with the key off, I turned the key on (didn't try to start the bike) voltage dropped to 9V. Could hear the fuel pump start fine and then begin to labor. I turned the key off and the battery voltage slowly bounced back to 12.3V.

I'm pretty sure it's the battery at this point. I'm going to see if I can get this one replaced since it's only a few months old.

 

Go back and remove the Vaseline and replace with dielectric grease. There is a recent thread on dielectric grease and someone there posted some issues with using Vaseline. No need to create more issues while trying to resolve this one. Your symptoms sound a lot like my two stator failure but you say it tested out fine so I can;t offer anything else that is credible.

 

Take the battery back to where you got it and get them to load test it, they would do that anyway before they considered replacing it anyway

 

Update: Royal Distributing apparently has a 1yr warranty on batteries, so it was an easy replacement. The new battery charged up to 12.9V on the first charge, started the bike instantly the first time this morning, and again in the afternoon. After getting home the battery voltage is still a nice 12.95V.

So in summary: 'twas the battery.

 

That's great!
But... You're not done. IMO you should check voltage at idle and higher RPM and then test to see if there is any current leakage! You'd be mad at yourself if your new battery dies an early death due to a circuit short somewhere. And I'd suggest adding a volt meter to your bike.
Just sayin...

 

While I probably will check the charging system again soon, I think my half dozen tests from last week will still hold true. I'm just going to watch the battery voltage whenever I'm home and make sure it's not varying too much. And as for current leakage, if I set my multimeter to anything less than the 10A mode I can't get the bike computer to turn on, so I can't measure current draw in increments less than 10mA. So I'll settle for careful observation for now.

 

Do you have a volt meter fitted to the bike, this way you can monitor your charging system all the time so you get a warning if things are not right

 

It is not safe to put an ammeter in-line with a live machine. The ammeter, as you see, alters the circuit.

With the ignition off put the ammeter between the negative terminal and negative cable. There you should get 3 mA or less.

I am unsure of how many non-energized components this neglects to test, but then we hope they would blow a fuse or otherwise shown signs of not working properly.

 

I don't have a voltmeter installed, and I the ignition was off whenever I was testing current leakage, but I can't measure current on the bike at a resolution of less than 10mA.

 

Maybe I misinterpreted but your prior post sounded like the reason you could not go to a smaller resolution was that the bike display failed to turn on due to the ammeter connected. That is how I interpreted it. Why can you not go to a smaller resolution? Is it just that this ammeter goes only to 10 mA? Make sure and get a new one when you can, as one with the smaller values is not expensive. I think these are a $10 coupon Harbor Freight item for example.

 

Okay, so my multimeter has 3 positive lead sockets, the voltage/resistance/diode socket, the 10A current socket, and the 200mA/uA current socket. On the multimeter rotary selecter switch, the current measuring zone has a 10A position, and then strangely only positions for measurements in multiples of uA and muA (??). Measuring current with the 10A socket and the rotary selector set to 10A works fine, the bike's display turns on, I see a 0.02A draw for a second and then it drops to an indicated 0.00A. But switching to the mA/uA socket I can't get any of the rotary selector positions to turn on the bike display, and the multimeter always displays 0 current draw.

And anyway, I'm not THAT worried about leakage. My previous battery was obviously fubar, and I'll be keeping an eye on the new one.

 

But what do you mean "the bike's display turns on"? The key should be off. The ammeter should be from the negative cable to the negative terminal. (?) Nothing should be powered on the bike.