Overcharging battery (2019)

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Okay so on my 1972 roadster I have a shoari lithium battery and a power arc ignition. Bare bones no capacitor or flashers etc. Just the rectifier zienor alternator ignition and lights. The other day headlights went out and my battery died and it sounded like misfiring. The bike cooled off and fired right up. I was in stop and go traffic. I flew home and checked the voltage. It was at 15volts! Wondering if you all had any suggestions where to start looking. I am an electrician by trade but I have been reading that these bikes dont like the lithium batteries? By the way some of fhe members here have been super helpful with my 750s I am building so thank you!!

The trouble maker...



Photo of the progress on the s type!
 
The Zener base connection could be corroded stopping excess power being dumped or as Mayler said defective.
 
Just been reading an older thread on problems using lithium batteries on standard charging setup bikes. Basic issue is the higher charge volts needed for the lithium means greater loading on zener which means higher temps and greater risk of failure.
Search for jeandr's thread showing his oscilloscope testing of various reg/rec types and zener performance. He now runs SH775 reg recs from Polaris as a much better solution for his lithium bike

Here's the thread
https://www.accessnorton.com/NortonCommando/voltage-regulators.19023/
 
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Lithium based (including lithium-ion, lithium polymer, LiCoO2, lithium cobalt oxide and LiFePO4) are 3.6 volts per cell, so you should see 14.4 volts at rest

At 3,000 to 4,000 rpm you’ll see somewhere between 14 to 15 volts DC across your battery with the standard zener/rectifier setup.


In my opinion, you shouldn’t be playing with lithium-based batteries unless you use a series-type regulator/rectifier (like the Shindengen SH775 or the newer SH847)
The Podtronics (short-type) is also not suitable for anything more advanced than an AGM battery either in my opinion.
 
This is all such good info. I do not feel like switching rectifiers or installing a shunt or switching from my power arc ignition system. I have a spare newer lead acid I can swap in. I am curious I may check the input and output of the rectifier just to see what it was running at. Clean the contacts on the zener just to see what it was running with a lithium.
Thank you guys!!
 
Lead acid (including gel, AGM, flooded and drycell) are 2.1 volts per cell, so you should see 12.6 volts at rest

With a lead acid battery at idle with the lights off you should see 12 to 13 volts DC with your multimeter across the battery.
With a healthy pair of coils, you are typically taking out more than your putting in with the standard charging system.

At 3,000 to 4,000 rpm you should see 14 to 15 volts DC with your multimeter across the battery.

Clean the terminal on your zener and make sure it clean and earthed well on the z-plate (no corrosion around the thread, and no loctite or thread lube that may be acting as an insulator - this is essential.
When they fail, they tend to just stop working.
I have never seen them deteriorate.

Same with the rectifier - the original ones are crude, but the technology hasn’t changed.
Overcharging battery (2019)
They are just a stack of diodes that pull DC out of an AC supply. You can easily test the rectifier with your multimeter across the terminals to make sure the four diodes are all good.
Overcharging battery (2019)
 
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Amazing! Thank you should I be getting 12.5 volts on the zener to earth? And when the ignition isnt even on? Its seems happy with the lead acid and I watched the battery voltage go up to 13.6 v at higher from 12.3 then drop back down at idle.
Thank you for all the good info!! This wiring harness is butchered on my 1972 and finally getting around to going through it. It was a total basket case when I bought it. My 750s I'm restoring is all original is easier to track things down.... But all the info I can get is super appriceated!
 
Zener should not be passing current to earth until it gets 12-13 volts. Checking the wiring diagram for a stock bike, the zener is NOT disconnected from battery/charging circuit via the ignition switch, so your readings are possible but indicate zener may be faulty.

Here is the testing method in the Workshop manual:

Overcharging battery (2019)
 
Zener should not be passing current to earth until it gets 12-13 volts.

NO
Zener does not conduct until 14.3V with battery or no battery in system...unless a failed device
The shop manual tests and the failed mode are written quite sloppy.

http://atlanticgreen.com/images/zener.gif
Of course you should always use something like Dow Corning 340 heat sink compound and a cycle thread nut not UNF on a lucas zener. Not just clean aluminum. Electrical as well as thermal conductivity is what will get you home from the bar/pub at 1AM
 
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None is passing through below 13volts.... Just on the hot side I was wondering if its always hot with the ignition off. It actually seems to be working. I belive it was the lithium battery the lead acid is hovering between 12- 13volts and I rode it for a good hour. The power arc ignition system did cut out once on me.... So there is that. It started misfiring and losing power and then died. Voltage on battery was good. Wouldn't start and then all of a sudden it started and rode like a champ again.... It might be in my ignition switch someone suggested. Any other thoughts on this? Charging levels seem good. Anyone have any good tests for why the power arc system would just cut off. Its an oldbritts system. And thank you again everyone for all this info. These systems are really basic. I just never have dug into them. Havent had enough issues until now. So I really appreciate all the help!!
 
My original ign switch was flakey when I acquired my '74 850 1.5 yrs ago. Gave erratic starts. Try hooking up your VOM and jiggling all the wires/key in hole etc. You need to go through all the connections, pull them apart and give them a brush with steel wool etc and a dab of dielectric grease afterwards doesn't hurt. Do this for all the electric connections on the bike. You could have a bad one in the electronic ign path/coils etc. Note the lucas bullet connectors can/do fail esp. the doubles where the metal contacts inside the rubbers cracks in two etc. Basically all old connectors are suspect until proven good.

If your ign is found bad, there are threads on here about rejuvenating them. Replacements are also available (Lucas or re-po). I put an EMGO switch in and took a while to determine it is not wired the same as the original four position Lucas switch...so I could not run the parking light independent of main lights.
 
Been running a Shorai on my Commando for 7-8 years, originally with the Lucas rectifier/Zener and, a few years later, with an Alton E-start/Podtronics. Shorai has been fine with both systems and I am still using the same Shorai battery that I originally installed.

Frankly, I have never had a moto battery on any bike last 3 years let alone twice that... ;)
 
I have run a variety of batteries over the years. On my MKIII I ran the genuine yuasa HD lead acid and it died in the 5th season. Then the bike sat for quite a while. For the Ashville NC rally I put the equivalent genuine yuasa AGM and only got a few years out of it and was disappointed.
The LI batteries can run on the old style charging systems but the main problem is the battery never gets full charged up. That does not hurt the bike/charging system in any way, but may cause the battery to die prematurely being constantly under charged.
FWIW a lead acid and AGM should show 12.8v when sitting after the "cool down" cycle, and 13.2+ right after shutting down from a run. 12.2 to 12.5 when sitting is not too good IMO.

Hard to recommend any battery because I don't trust the distribution network to give you a fresh battey or that battery products are consistent in their manufacture. Sometimes you get a good one and sometimes you don't...
 
Are there any rectifier/regulator devices out there with adjustable voltage outputs? Or, specifically made to output LI battery levels?
 
None is passing through below 13volts.... Just on the hot side I was wondering if its always hot with the ignition off.

No zener current should pass below 14.3v. The zener should always be cool until the battery has charged to above 14.3. With no battery (batteryless running) zener will get hot right away. Running the headlight as a load will take some of the current away from the zener.
 
I have run a variety of batteries over the years. On my MKIII I ran the genuine yuasa HD lead acid and it died in the 5th season. Then the bike sat for quite a while. For the Ashville NC rally I put the equivalent genuine yuasa AGM and only got a few years out of it and was disappointed.
The LI batteries can run on the old style charging systems but the main problem is the battery never gets full charged up. That does not hurt the bike/charging system in any way, but may cause the battery to die prematurely being constantly under charged.
FWIW a lead acid and AGM should show 12.8v when sitting after the "cool down" cycle, and 13.2+ right after shutting down from a run. 12.2 to 12.5 when sitting is not too good IMO.

Hard to recommend any battery because I don't trust the distribution network to give you a fresh battey or that battery products are consistent in their manufacture. Sometimes you get a good one and sometimes you don't...
I live in asheville! And what rally? I need more places to go aside from the mountains. I just moved here a couple years ago!
 
My original ign switch was flakey when I acquired my '74 850 1.5 yrs ago. Gave erratic starts. Try hooking up your VOM and jiggling all the wires/key in hole etc. You need to go through all the connections, pull them apart and give them a brush with steel wool etc and a dab of dielectric grease afterwards doesn't hurt. Do this for all the electric connections on the bike. You could have a bad one in the electronic ign path/coils etc. Note the lucas bullet connectors can/do fail esp. the doubles where the metal contacts inside the rubbers cracks in two etc. Basically all old connectors are suspect until proven good.

If your ign is found bad, there are threads on here about rejuvenating them. Replacements are also available (Lucas or re-po). I put an EMGO switch in and took a while to determine it is not wired the same as the original four position Lucas switch...so I could not run the parking light independent of main lights.
Thank you this weekend I will go through the ignition switch!
 
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