charging issue

Haven't been on the site for sometime, my apologies. Everything on my 73 850 Commando has been working fine. (Actually great until recently) Trying to make this brief. About a 2 months ago went out for a ride and battery measured cold (No load ) 12.87 V checked fluids and tires and off I went. Great ride. A month after decided another ride was in order, checks as usual revealed battery at 12.35V???? I knew something was wrong.(battery motobatt AGM MB9U 7 months old. Went out anyway and returned, good ride . 12.20V at end. Since then have performed several tests on battery. Measures cold just fine. Load test shows 9.6-9.8V. Have another tester a A topdon BT-50 tester. Cold shows Good, Cranking test -Good, Charging test "LOW" loaded 12.61 V unloaded 12.98 V Ripple 14mV. LOW. When starting bike shows 12.5 and above, however, once started, multi meter shows 12.75v or so, NOT, the 13.5 to 15V it should? Other 2 bikes I own, both Kaw triples, show at least 14.1 to 14.5V at idle, my Norton doesn't. Fully charged battery via a Ctek charger in AGM mode, a little better. If I Rev engine multi meter display will show maybe 13.5 V , give or take??? Bought a new Stator and TRi spark Regulator from Greg Marsh this past week, also spoke with Motobatt person about battery. He stated all sign s point to a weak battery, but.overall not a BAD battery. Since then today, replaced old POD tronics regulator )it even emasured GooD!!! with a new Greg marsh unit, trying to eliminate anything at this juncture. Tried to measure output from stator per GREG, didn't have much luck?? Hooked all up today, NEW Voltage regulator, old battery (7 months old) and stator which is at least 18 years old. Results Cold battery measures fine, 12.7V, same 9.7V loaded, bike started right up, but, showed 12.7 volts at idle, where my other bikes show 14 plus Volts at idle. I may just buy New battery to eliminate that possibility, which just leaves the stator. Starting to stress now!!!! Any help will be much appreciated. I am just assuming that the 850 should be showing at least 13.5 to 15V at start=up???? and increase upon adding throttle Robert Shaw TN

It should NOT show 13.5v to 15v at startup or idle! Charging a battery simply means that you supply it with a voltage higher than the batteries unloaded voltage.

A battery that is not fully charged will keep the voltage down below max while charging. Also a battery that is not fully charged causes the stator/regulator to provide the power needed by the bike while it is charging. It is not uncommon for a Lucas equipped bike to not actually charge at idle speed. A 3-phase stator and Tri-spark regulator help with this but do not change reality. Everything you've said means that the system is working and that a new battery is in order.

A battery that measures 12.5v with the bike off and 12.75 with it running at idle is showing a charging system that is better than expected. When if reving the engine it shows 13.5, it is excellent for an AGM battery that is not in top condition!

Buy a $30 AGM 12N9 battery, stick it in and quit worrying about it!

As Greg said, the stock stator is not a powerful charging component, so it's not going to put out 14 or 15 volts even at it's highest RPM's. It probably won't even exceed the battery's voltage unless the RPM's are closer to 2,000. The aftermarket 3 phase stator is considered the best upgrade for better charging at lower RPM's.

I have a ammeter wired into my bike. It shows the direction of energy flow between the charging system and the battery. At engine idle, it always points into the negative, meaning that the charging voltage isn't supplying enough energy to equal the load of the components, so energy is also flowing out of the battery to make up the difference in component demand. As soon as I start moving and the RPM's rise, the ammeter's pointer passes zero and moves into the positive charging indication, meaning that the charging system is meeting the demand of the components and also putting energy back into the battery.

An ammeter gives an indication of the actual flow direction of energy in the system. People with voltmeters say that once you are used to seeing your volt meter move slightly from changes in RPM, you can infer the same flow of charge back to the battery due to the raise in RPM's on a voltmeter too. I would recommend you get one of the above meters and you will always have a way to quickly glance down and see that your system is charging as it should when it's supposed to be doing that.

A few weeks ago, I went for a ride, got a few miles out and saw my ammeter wasn't moving out of the negative, so I spun around and headed for home. When I got home, I started looking around the bike and found that the wires from the stator had dropped into the final drive chain and one of them was cut. I fixed it (again, as it had happened once before) zip tied it so it wouldn't happen again and checked to see if my ammeter was behaving normally by going for a ride. Fixed!

If you are really feeling like you must monitor your electrical system then you need a meter of some kind or trust the norton idiot light. I like a meter myself. Some people swear that a bike must have an oil pressure gauge and I've never had one of those... so different strokes... but I do like my ammeter.

FWIW, The original (OEM) charging system - zener/Lucas rectifier - supplied .2V greater charge voltage at all RPM than the Podtronics I "upgraded" with.

MexicoMike said:

FWIW, The original (OEM) charging system - zener/Lucas rectifier - supplied .2V greater charge voltage at all RPM than the Podtronics I "upgraded" with.

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That’s good, if the Zener voltage was too high.

Podtronics vs OEM was the difference between battery drain at low RPM and not. The voltage (OEM) never exceeded the proper limits. I did a complete post of this with the relevant voltages RPM here many years ago. IOW a Podtronics was a DOWNGRADE as far as charging is concerned.

MexicoMike said:

Podtronics vs OEM was the difference between battery drain at low RPM and not. The voltage (OEM) never exceeded the proper limits. I did a complete post of this with the relevant voltages RPM here many years ago. IOW a Podtronics was a DOWNGRADE as far as charging is concerned.

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Yes, and the Podtronics drain on the battery when off was not great when I tested, see: https://www.accessnorton.com/Norton...egulator-installation-mk-ii.35064/post-647424 (just noticed that I listed the 5th and 6th worst out of order).

The value in a solid-state regulator is less wiring and complexity. The Podtronics single-phase was no improvement in function over the original equipment in any way and as you said, actually worse at charging, but did get the job done.

The Tri-Spark MOSFET has essentially no drain when the bike is off. When used with a three-phase stator provides more available charging current across the RPM range. I'm sure this is true of the modern regulators on Japanese bikes as well.

Thank you all so much for the responses. Greg, thank you so much for the parts and all the information you shared during our call. I feel a little stupid thinking that my Norton should have the same electrical characteristics as my Kaw's. I have used the 12n9 before and some have fried with an old Battery tender charger which I do not use any longer, (old Technology) use Ctek now and have had no issues with them, with the Motobatt. The motobatts and I have had a Love/Hate relationship, (durability/ longevity) No leakage though. I'm curious when I receive the new battery and fully charge it, what the numbers look like. Any aftermarket ammeter gauges recommended, and install locations (brackets,etc) as my 73 doesn't have one in the headlight shell. Thanks to all again. Robert TN

Robert Shaw said:

Thank you all so much for the responses. Greg, thank you so much for the parts and all the information you shared during our call. I feel a little stupid thinking that my Norton should have the same electrical characteristics as my Kaw's. I have used the 12n9 before and some have fried with an old Battery tender charger which I do not use any longer, (old Technology) use Ctek now and have had no issues with them, with the Motobatt. The motobatts and I have had a Love/Hate relationship, (durability/ longevity) No leakage though. I'm curious when I receive the new battery and fully charge it, what the numbers look like. Any aftermarket ammeter gauges recommended, and install locations (brackets,etc) as my 73 doesn't have one in the headlight shell. Thanks to all again. Robert TN

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I buy AGM batteries from Amazon. With tax they've gone up to just under $32. If I didn't have a heated shop, I would take them in the house in the winter. The only difference in MotoBatt and the others is they are yellow and WAY more expensive. I was using Power Star, but they have gotten more expensive, so I switched to this: https://a.co/d/cdnnxPa They are the same rating as 12n9. Once in a while you get a bad AGM battery - they seem to charge but drop off very quickly so it is confusing (that's what he meant by "weak"). Depending on your ignition system, the bike will start with lower voltage. For instance Tri-Spark is rated to start down to 8.5 volts - points even lower. I think Boyer and Pazon require higher voltage but I don't work with them, so I don't know.

I'm sure the meter you have has ammeter capabilities. Just be sure if using it on a running bike that you select a 10-amp range - not a ma range. I don't know what meter(s) you have so I can't be more specific.

Do not charge - put in the bike and go for a ride! AGM and Lithium batteries do not need to be charged before use. Neither should ever be use with a charger that does not have a specific mode for them. My old charger that I've used since 1970 still works on wet Lead/Acid batteries and charges them very fast, but destroys AGM and probably would cause a fire with Lithium! I NEVER use a trickle charger! On those rare occasions where I feel the need to charge a battery, I use this: https://a.co/d/ifsk6uP and once it shows a full charge or near it, I disconnect it. I follow the instructions and make sure that it discovers the battery type automatically - if not, I set it and then keep an eye on it.

Since you asked about an ammeter and I am the person who brought it into your thread, I'll give you the lowdown as I understand it.

An ammeter in your harness changes your wiring somewhat if you have a model commando later than mine (1970) which has the ammeter in it's wiring diagram. As you can see the ammeter is between the battery and everything else, so it's basically wired in series (except the horn for some reason)



I've heard people say that if your ammeter breaks, then your bike is kaput, so some people think it's a risky practice to run the entire system through an ammeter. They might be right, but my model has always had one in the diagram so about 40 years ago I drilled the headlight shell and wired the ammeter into the bike and have never had an issue with it. The first owner of my bike grafted a disc brake front end on to my early commando and the original ammeter was removed when I got the bike. I like the ammeter. It always shows the "flow direction" of current, but does NOT tell you your battery voltage. It only tells you if it's charging or discharging, and how strong or weak that flow is.

Alternatively, some people install a voltmeter in their bike. It doesn't show the current direction, but it does show the voltage.... So if you put the key in your bike and turn the system on you get the battery voltage alone without the addition of the rotor/stator contribution. Lets say your voltage is 12.5 volts with the key on. Now you start the bike and it's still 12.5 volts, but when you rev the RPM's to almost 2000, now the voltage is 13 volts. You can't see the direction of current like an ammeter, but it makes sense when you look down that your alternator is working because the voltage is higher than the resting battery voltage. The big advantage of wiring a volt meter is that it doesn't have to be wired in series like an ammeter, because it's not showing flow direction, it's showing voltage and flow direction (charging of the battery) is just inferred because the alternator raises the system voltage above the known resting voltage. And since we know that shit, water, and also electricity all flow down hill, then you can extrapolate that your battery is charging from glancing at your voltmeter while your engine is running at 2000 RPM's or greater and noting the higher than resting voltage.

Here's mine... It crowded my headlight reflector, so I made a delrin bezel to raise out of the way. I like it. It's turned me around twice when I went on a ride and glanced down at speed and saw that the current flow was negative when it should be positive. Both times it was the same cause.... the wires from the alternator drooped down and one was cut by the final drive chain. Both times I made it home on battery charge only because I was only a few miles from home when the wire was damaged.... hopefully the zip tie I employed saves me from a third episode...

A good option for these old bikes is fitting a charge warning LED in the stock warning lamp position on the headlamp shell. I have used one by SparkBright which used three different colours and blink rates to indicate charge (voltage) as discharging, low, good, too high. Not sure they are still available. Currently using another one from ImprovingClassicMotorcycles...single red led with blink rates according to discharging, low and good....also has rapid blink for oil pressure warning if hooked to a pressure switch (Madass140 on this site sells a pressure switch kit).

At idle, using a 3 phase lucas stator, trispark reg/rec, my 74 850 shows solid red (low charging) until rpms go over 1300 or so.

For us on the eastern side of the pond, the different colour LED battery status monitor, sold by aoservices and norbsa02 in the Uk is available. Have it on one bike, works great.

Tornado said:

A good option for these old bikes is fitting a charge warning LED in the stock warning lamp position on the headlamp shell. I have used one by SparkBright which used three different colours and blink rates to indicate charge (voltage) as discharging, low, good, too high. Not sure they are still available. Currently using another one from ImprovingClassicMotorcycles...single red led with blink rates according to discharging, low and good....also has rapid blink for oil pressure warning if hooked to a pressure switch (Madass140 on this site sells a pressure switch kit).

At idle, using a 3 phase lucas stator, trispark reg/rec, my 74 850 shows solid red (low charging) until rpms go over 1300 or so.

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Sparkbright are no longer, but the website is still up, so don’t order anything from them as you stand to lose your money.

Tornado said:

A good option for these old bikes is fitting a charge warning LED in the stock warning lamp position on the headlamp shell. I have used one by SparkBright which used three different colours and blink rates to indicate charge (voltage) as discharging, low, good, too high. Not sure they are still available. Currently using another one from ImprovingClassicMotorcycles...single red led with blink rates according to discharging, low and good....also has rapid blink for oil pressure warning if hooked to a pressure switch (Madass140 on this site sells a pressure switch kit).

At idle, using a 3 phase lucas stator, trispark reg/rec, my 74 850 shows solid red (low charging) until rpms go over 1300 or so.

Click to expand...

I also have the warning light from ICM with the oil pressure sensor from Madass that I have used for over 3 years and really like it also.No drilling install of the h/l shell and straight forward instructions.Works nicely
Mike