Flat battery

[StephenC]

Thanks for the encouragement.

I've put the battery back in and checked the voltage: 13.3V, turned on the ignition: 12.9V and started the bike (!): 13.5V. All within expected parameters. I tried to measure the drain but don't seem to get a reading when I put the multimeter in series across the negative terminal and the negative cable. It only comes with prong connections, not crocodile clips, so maybe I'm not getting a good enough connection.

I'll leave the bike off for a few hours and check the voltage again. I think I'll leave complicated diagnostics for the second time it fails. And if it doesn't, I'll be happy and enjoy my bike.

[ducpainter]

<snip>
BTW, best practice when working on DC is to remove rings and watches. Anybody disagrees with that hasn't worked on DC long enough.

...and everyone that has has a story.

[StephenC]

How accurate is the 'BATT' status on the dashboard?  I've put the battery back in and am planning on letting the bike sit for a week (I'll slum it and drive to work).  I had been checking the voltage with a multimeter using the extra SAE connector I had wired to the battery (for the USB charger), but as I suspect this is the weak point in my electrics have removed it. Now I can only check the battery manually by removing the fuel tank, which is rather a pain.  I know that by turning the ignition on to get the dash lit I am introducing more load to the system, but I should still be able to see a drop in the voltage over time?  I will try and avoid firing the engine, as this presumably stresses the battery lots, unless I the ride to recharge it.

[bagodoosh]

i don't understand how the SAE connector would cause any drain. it's just a piece of wire. it doesn't have any circuitry, no?

my suggestion is to take the battery out of the bike. do a bench test. measure the voltage twice daily for 3-4 days. this would be your no-load base test.
then you can attach the SAE connector and repeat to see if that is causing any more drop.
then put them back in the bike and retest (with a multi-meter).

FYI, the LiFe(PO4) has a max charge of 3.6V per cell (14.4 total), with a resting voltage of ~ 3.3xxV (13.3 total). this means that the voltage should drop fairly quickly from 14.4 and settle to somewhere around 13.3, which shorai claims to be 90% capacity.

here's a visual representation from my own testing (on the bike) for a couple days:


at the end (49H 22M) i measured 13.38V and calculated a drop rate of .002 V/hour. i imagine that rate would get even lower over time.

anyway, i say 13.3+ = excellent

don't use the dashboard to gauge the voltage for this test.
the accuracy doesn't entirely matter. if there's any inaccuracy, it should be linear and spread over all the readings. you wouldn't care about the absolute voltages, only the relative drop.
however every time you turn the IGN on, the fuel pump runs for a variable time (620 manual states 3-5 seconds). then there's the headlite; both significant drains. you'd also have to time how long the IGN stays on and keep it equal across all measurements. it's just not worth the hassle IMO.

[Howie]

Bagodoosh is correct about the SAE connector, it does not consume current.  The only possible issue you could have is a lower reading at the connector than at the battery if you have a poor connection.  Do keep in mind, your voltage reading represents state of charge.  I have never seen a battery capacity test for a Li Fe battery, so no advice there but if they become more than half discharged there is a high possibility of early battery death. 

[StephenC]

Thank you for the information (and safety warnings!).  As it is so much effort to get to the battery I will leave it in the bike for now (and have already removed the SAE connector, as I barely ever used it anyway).  I'll let the bike site for a few days and when I next have time (and room in the garage) I will dissect it again and check the battery.  If it doesn't seem to be draining then I'll probably just get on with riding it.  Otherwise I'll rescue the battery and do the check out of the bike again, just be more patient (I only left it one day before).

I didn't do as frequent checks as you Bagodoosh, but I'm guessing my graph would look very similar.  I got an initial charge of 14V and it quickly fell to 13ish and stayed there.

[StephenC]

UPDATE

The battery has been sitting, plumbed into the bike, for just under a week now. I have resisted the urge to turn her on. Today I lifted the tank and checked the battery: 13.3V off the bike, 13.3V attached and checked via the SAE (after reading the advice above I decided to put it back in).

I'm not sure what drained my battery but I'm going to work on the assumption it was a one off and just get on with enjoying the bike (when the weather stops being foul!). If I have another problem, I will worry about it then.

Thanks again, for all the help.

[StephenC]

Well, it has happened again.  I left the bike for almost exactly one week and now have a flat battery.  It did give me a few attempts at a start this time and then got to the point where the dash went blank.  The voltage across the terminals, when I removed the battery, was very low.  After 24 hours of charging it is back up to 13V and has held that overnight.  I'm taking the bike to a mechanic (the excellent Andy at Whitebridge Sportcycles) tomorrow to get the electronics checked - assuming that I can get the bike started to get it there!  If he thinks the battery is to blame (either solely or as it is damaged by whatever else whet wrong) should I stick with Shorai or move to a different brand?

[stonemaster]

is the weather getting cold at night where you live??

[StephenC]

Yes, last night. But it's Australian Spring so that is relative. I doubt it drops below 10 degrees in our garage ... ever.

[StephenC]

Bike is at the workshop. So I'll see what they think in a few days

[stonemaster]

I had trouble with 45 F and below temps, its a known issue

[StephenC]

I'd be surprised if we were hitting that. Besides, it worked fine all winter and then plays up in the spring!

[stonemaster]

well maybe, also once you "flatten" one of these you have issues from there on out, I revived mine and it did work for awhile but in the end I went back to a regular battery and havent looked back

[StephenC]

I am wondering that.  I believe you are not supposed to let them drain.