Stuck at gas station: dead battery

On its own the battery volts fresh off the charger can be a misleading guide to the state of a battery. You also need to see what its dropped to after 24 hours or more - that will show if the battery is holding its charge. If it drops below 12.4 volts then the battery probably needs replacing. Even if you were riding the bike daily, getting anything over 3 years life from a motorbike battery is pretty good going, so by now you are living on borrowed time.

You may want to read through the FAQs here
Motorcycle Battery Frequently Asked Questions from the White Dog Guide to Batteries

NB Once the battery is on its way out, then the RR unit obviously has to work harder - and that may be why things were hotting up. As fitting a new battery is a relatively cheap investment it would be my first course of action, before starting to alter anything on the charging system - which may still be serviceable.

Good luck and let us know how you get on

 

I'm on the same page as the previous poster......install a new battery and it's a good bet that the problems will most likely be over.

 

I'm going to get a battery ordered, as well as the R/R wiring upgrades from Eastern Beaver. The only issue I'm torn on at the moment is the R/R itself. I can always order the correct connectors and crimp them into place instead of the ones for the OEM-style R/R. On the other hand, i'll save a bit (not much), and some hours, and definitely some peace of mind if I just do it all at once... With just the battery in place, and the stock wiring, I should be able to tell a lot, even if I am dropping a couple tenths of a volt between the R/R and the battery.

 

I ordered a battery and charger for Shorai (so I could be sure to have a "fast" charger since my "big" charger's desulfation routine can't be turned off). And then of course I just stumbled across the packs that Jaime is selling... !#$@@ Why didn't one of you guys tell me he was selling those??

It happens.

Although I like the idea of getting 8+ years out of a battery (using the charger to keep things balanced). Monetarily, it might not be as cheap as lead acid batteries, but in the peace-of-mind camp, it's definitely going to be nice.

Once that shows up I'll resume the analysis of the R/R and figure out what to do with it.

 

The Shorai arrived today (I hadn't realized they were here in the Bay Area in Sunnyvale). I couldn't get into the garage tonight, but the battery itself is a very nice unit. The cabling for the charger is a little odd, but I think it's ok (molded connectors would be much nicer, although not as flexible). I took some pics as I unpacked it, and I'll post those up in a writeup later. The battery is so light that it's kinda funny, like there's something missing. Especially since it's in a case to approximate the size/shape of the stock battery. I should have gotten a battery that was physically smaller, and then put the extra space to use for something else.

Anyway, resting voltage when unpacked: 13.83Vdc, which should be well over 90% charged. The charger ran it up to 14.4Vdc, and after a few minutes, declared it 100% charged (at that voltage, still).

This should definitely tell if the issue is the charging system or the battery. Although I am expecting to still find regulation issues, excessing loss through the wiring, and other oddities that indicate that it's time for a new R/R.

 

If you don't mind giving us some update reports on how that new battery treats you I would like to hear about it.
I was interested in the newer batteries but afraid because of the lack of testifiers.

 

Dukiedook, that's the plan.

I'll keep this thread updated with how the charging system as a whole is playing out as I continue to make sure it's all ok. But I'll start another thread in the Mechanic's Garage section to talk about the battery itself.

 

Installed the shorai tonight. Wow.. The bike has never started like this. The speed that the starter turns the engine over is spooky.

http://vfrworld.com/forums/mechanic...ry-lithium-iron-phosphate-install-review.html

After letting it idle up to operating temps:

14.3Vdc at idle, with no bouncing around at all, very stable
14.0Vdc at 2500 rpm
14.0Vdc at 5000 rpm

I'm still suspicious about the dropping voltage off-idle. But it seems happy. I have the voltage meter on the bike, and I'll take the DMM with me in the Givi so I can monitor things when I ride it to work tomorrow.

 

I believe what is causing the voltage to drop is the SCRs in the R/R turning on. At idle, when the stator output is low, the SCRs are probably in an "off" state, so the average R/R DC voltage output is slightly higher. When the stator output rises to the point that the SCRs start shunting the "excess" power to ground, the average DC voltage output is lower but the average current is greater.

My SV does the same thing, FWIW.

 

That could be. Also, it could just be the load of firing the spark plugs at off-idle RPMs.

 

And.... This morning it wouldn't start. Plenty of juice, but I hit the start button and nada, nothing. All the gauges stayed lit, and the voltage meter was showing 11-12Vdc under load from the lights (it's just LEDs, and I haven't characterized the trip points with a bench supply (yet), I'll be doing that asap.

Anyway.

I think it's the solenoid or one of the safety interlock switches. The start button itself seems to be working, as the headlight correctly switches off when the button is pushed. Neutral indicator was lit, so I think that sensor should be ok. Leaving either clutch switch, or something else around the neutral switch. I hadn't realized this bike is only supposed to start in N. Mine has always willingly started in gear, so long as the clutch was depressed. Which tells me *something* is mucked up in that circuit. Or, I somehow damaged the solenoid when removing and re-installing the positive battery cable so that I can flatten out it's shape (it made good enough contact without for testing, but not for long-term use).

So I drove the car, again...

My theory is that this bike will either continue to not be ridable for the foreseeable future, or I'll get it rideable and then the skies will open and we'll finally get the rain that we haven't gotten all winter (but need badly). It's still effectively fire season here. We've had <2", I think. Should be at least 10" of rain by now.

 

I don't think there is anything more maddening than intermittent electrical problems. Either fail or work, damn it! :smile:

I live in the northern extension of the redwoods, and we're just as dry as you guys. I do love winter riding (been back and forth over the Sierra's twice in the last month), but it is time for some rain & snow.

 

Yeah, I'll be digging into it more this weekend to see what I can find. Luckily a MM can tell me a lot about this. It's parts availability that worries me, and the fact that crap like this stops me from doing the projects on the bike that I WANT to be working on.

Ahh, I see a couple more potential culprits (looking at a PDF of the service manual):

- clutch diode
- starter fuse

I'm not hearing any "clicks" to indicate that the solenoid is being triggered, so I think it's all in interlocks and such around the solenoid control.

 

scientific testing is always better than guesses !

 

Turned out to be a loose connector. The retention clips on the solenoid/main fuse body are cracked, and the starter solenoid positive spade wasn't making good contact. When I pushed on it with the DMM probe, the bike suddenly started turning over (probing with the starter button pushed). I cleaned up the contacts, packed with dielectric grease to keep it clean, and it seems to be fine.

Although the voltage drop off idle has me concerned that the new battery isn't being charged well by the R/R. I'm going on a 20 mile test ride today to check it out, before the 50 mile ride to work tomorrow.

 

16 mile round trip ride, and all is well. I just having been giving the battery enough time to recharge after starting for the voltages to be stable enough to be reliable.

Resting voltage before starting: 13.9 (very recently charged)
Resting voltage after ride: 14.2 (~2 minutes after shutting off bike)

Both my DMM and my led battery gauge show that the voltage is pretty noisy (by tenths of a volt). But i think this is due to the SCRs, and the fact that they can't shut off once triggered until the zero voltage crossing. The MOSFET's ability to be turned on/off at any voltage (or even only partially on), allows those units to give much better regulation quality. But I don't think I care enough at the moment to buy a MOSFET R/R.

But as I'm losing 0.5v in the harness between the R/R and the battery, I'm going to order an R/R harness setup from Eastern Beaver. And a headlight relay harness as well.

 

To your comment about voltage at idle- I have noticed these bikes- my 86's and my 73 do not charge the battery at idle, you have to get the rpm's usually past 3K to get useful charging of the battery.
That's why people that do city traffic all day stop and start wonder why their batteries take a dump so quickly.

 

I would have thought so, except that it's running at 14.3-14.5VDC at idle, and dropping to 14.0VDC at off-idle rpm. And since there's no charge controller per se, just the R/R voltage output, the battery will pull down the R/R voltage when it's in bulk charge, and the R/R should be able to produce full voltage (as allowed by the stator output) when in absorb phase. (At least, this is the charging phases for lead acid batteries, but while the new battery is LiFePO4, it appears to follow the same sort of model when watching it's charger charge it up). If the stator output wasn't enough at idle to "charge the battery", I'd expect the voltage to be down at idle.

Of course, the load of driving the spark plugs varies with RPM as well (linearly), and so what might be happening is the load of driving the spark plugs is light enough at idle that when the battery is fully charged, everything is at 14.5VDC, and then when the load of driving the spark plugs goes up with rpm, it drops to 14.0 as the voltage that's sustained by the R/R and stator.

Meh... I want to hook this up to an oscilloscope.

Everything does appear to be in spec, however, and maybe I'm just overly worried about small fluctautions in voltage (for instance triggering the brake light is enough load to also pull it down from 14.5 to 14.0 at idle, but I haven't tried that at higher rpm).

And, now that it's rideable, it's below freezing in the mornings when I leave for work, and we're supposed to get pounded with rain starting tomorrow...