Weird Charging

[bunzelburner]

First off, I'd like to start off by saying that I know the voltage number I am about to give, at face value, are well within the expected values of a motorcycle charging system. What is concerning to me is the seemingly sudden change in values. My bike is a 1996 Triumph Tiger T400

I recently completed a long 4500-mile trip from Wisconsin to Florida to Las Vegas. The weather (at least on the bike) was chilly for most of it. Since I'm paranoid about the sprag clutch on my bike, I have a voltmeter mounted on my bike so I can continually monitor the voltage while I am riding and before starting the bike. My charging system produced the following values (from memory) from when I bought the bike until about a few days ago.

Running at above 3000 rpm with all lights on: 14.5 volts
Running at above 3000 rpm with no lights on: 14.7 volts
Idle with all lights on: 14.3 volts
Idle with no lights on: 14.5 volts (not 100% sure on this one)

When I brake the voltage would maybe drop in the 13's but never lower. With the fan on the voltage would drop into the 12's.

Whenever I come to start the bike after letting is sit shortly or even overnight, the voltage is 13 volts, sometimes 12.9.

I reached Las Vegas and the weather initially was cold and rainy but it has started getting warmer, in the 80s the last few days.

The other day I was driving along and was informed that my running tail lights were out and realized my dash lights were out too. Found that the tail light fuse was blown. Could not find anything and put a new fuse in and the lights came on fine. However, my voltage numbers have been different.

Lights on or off above 3000 rpm: 14.5 volts
Idle with lights on: high 13 volts

What's really strange is that I'll be driving along and hit the brake and sometimes the voltage will go up from 14.5 to 14.7

The voltage seems to also take much longer to recover when for example I brake and the voltage goes down. The voltages just seem much less consistent.

I reinspected the wiring again and found that one of the wires leading into the fuse box had the insulation rubbed away in one spot, which I taped up. I also noticed a slight bulge on the short ends of the battery (maybe caused by a short from the exposed wire). I had it tested and the battery came back healthy.

I'm not sure if my alternator is dying or a good way to test it since the voltage numbers aren't in themselves concerning. Could it have something to do with the outside temperature? I'm continuing to look around for any shorts but no fuses are blowing or anything.

[London_Phil]

The accuracy, and to some extent connection location of any meter will affect this. Are you monitoring during riding, constantly via a hard wired voltmeter?
Have you checked against a second meter?
Mine would vary up to about 14.8, with a constantly connected voltmeter, with a checked accuracy +_0.2v against a calibrated Fluke meter.
Over 15 and you need to start looking at issues.
I am  surprised it has high V at low revs though.. Even my Xc800 has a lower value at idle, and they have a massive output in comparison.

[bunzelburner]

It is a hard-wired voltmeter to the battery that I shut off when not using the bike. I thought the same, that maybe something had gone wrong with it so I checked with another meter and everything matched.

I agree, with regards to charging at idle. My friend who had a Yamaha FZ1 said his bike doesn't even charge at idle really.

Even though the numbers seemed to change suddenly, I wouldn't be as worried if it wasn't for the fact that I'll be driving along, hit the brake (yes the brake light goes on) and my voltage will go up. That part is very confusing to me.

[Sin_Tiger]

That is odd and the slight bulge in the battery casing is a bit of a concern. I agree with Phil re the low rpm output.

It is "suggestive" of the regulator in the 25A alternator on it's last legs, early 90's electronic components aren't going to last forever. Checking the rotor brushes and the wiring to them are in good shape is worth while to eliminate anything there, I did have one that the cable insulation had failed and caused a short resulting in a  after a small petrol tap leak (conveniently positioned directly above the alternator). I've had a couple of these fail in the last few years, there are some more modern aftermarket replacements available. Not being an electronics specialist I can't explain exactly how they work compared to the original nor how well they work as I've yet to use one. They seem to be readily available in the US.

https://www.electrosport.com/products/esr025-regulator-nippon-denso-internal-type

There is an excellent write up on these alternators on the RAT forum which explains a lot of detail about the unit and it's workings.

https://www.triumphrat.net/threads/dissecting-the-nd-25-amp-alternator.134079/

[bunzelburner]

I feared as much. However I am relieved to see that there are reasonably priced options. Previously unaware that there are kawasakis that used the same alternator, I was freaking out seeing that a new one would cost $1000 assuming it was even in stock.

I'll open it up tomorrow and order a new or used one if needed. Saw a used one off a kawasaki with 40k miles for $95.

Will report back with findings

[London_Phil]

If your brave, and want output over looks, you can modify the bike to accept the Girly alternator. It is a tight fit, and you can get 2 of 3 screws to line up, and either clamp or dremel the 3rd, then a bit of wiring mod and your away...

https://tigertriple.com/forum/index.php/topic,17168.msg135103.html#msg135103

Was Sin himself what did it.....

[bunzelburner]

Definitely tempting. However, I'm in the middle of a road trip, staying at a friend's in Vegas momentarily, and without a garage. My workshop right now is an apartment parking lot.

I tested components on mine last night and I could not get solid readings on the regulator. They were all over the place.

I found a 1999 ZG1000 regulator that looks in great shape for $85. Went ahead and ordered it and going to continue looking for wiring faults while I wait for it to come.

With regards to the slight slight bulge in my battery, when it was tested everything came back great. Is it okay to keep using it?

[Sin_Tiger]

Battery might have had an over charge for a period, can happen if the RR gets flakey and there isn't a lot of load. If there's no leaks and it gets the OK on a proper load tester, then I'd just monitor the levels in the cells, assuming it's a flooded battery and you can see the levels.

Hope the replacement Reg works out for you 

[Sin_Tiger]

I had a quick search out of interest and found that Sprint Manufacturing (Trevor) is offering a replacement for the regulator that looks quite a neat fit. At £70 it's not cheap but perhaps a better option than a used alternator of unknown heritage.

[bunzelburner]

It's a Yuasa battery so it is sealed technically.

Unsure if it was just the regulator I pulled the trigger on the used alternator. Running into a problem though...

The old alternator is off, ready to swap the centre/paddle thing since the Kawasaki one is different and it will not come off the old alternator.

I've tried heating it, wd-40, and soaking it in acetone, but it will not budge. The one on the Kawasaki alternator slid right off. I'm stumped. Is there something holding it in there that I'm missing?

[bunzelburner]

Took about 10 minutes of direct heat from a blow torch and it finally came off.

Swapped the centre's, installed it and everything runs good. 14.7 volts idle with no lights. 14.3 with lights on. Runs quieter too

[London_Phil]

That idle voltage still seems high, don't know what the idle revs are, but as long as it isn't overcharging, nice one.

[Sin_Tiger]

Sorry I was a bit slow responding, I would only have suggested what you did anyway    I don't think they were fitted with Loctite from original, not on the dozen or so I've dismantled, just that any oil residue gets baked hard with heat and time.

Agree with Phil's comment, I'd be expecting around 13.5V but the slightly higher voltage may also be due to the state of your battery.

Still that's a good result 

[bunzelburner]

Yea in the detailed tear-down post for this alternator on Triumphrat he says it took 30 seconds of heat from a blow torch to free it. Took quite a bit longer for this one.

It is weird that the 14.7 and 14.3 idle voltages are what I've always gotten. Even when the battery was brand new. The battery is the newer version of the one listed in the service manual.

[Sin_Tiger]

Well there are blow torches and blow torches, ideally Ox/Acc with a small nozzle to get the heat into the part you want to expand quickly (so as not to allow conduction to the bearing / seal) is the best option. If that's not an option then a small butane one that uses a disposable lighter as a source can work well for pin point accuracy.

I'd check the voltage again after 30-60 mins of highway riding, you might well find the idle voltage has dropped below 14V once the battery has had a good recovery charge.