Alternator Upgrade

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JaggeryJoe
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Alternator Upgrade

Postby JaggeryJoe » Fri Mar 27, 2020 5:49 pm

Hello All

Hope you are all keeping well, I am self isolating in the garage with my motorcycle, although not keeping two metres apart, my spanners are not that long.

I was wondering if some kind soul would be able to advise me on the best? Alternator Upgrade it seems that the most readily available are either a 400W or a 650W kit available at well known part suppliers. The 400W works out cheaper, but reading Mr Snowbum's article he does not rate the 400W.

As the original equipment is rather old, rusty and very tired the charging circuit needs replacing. An upgrade kit works out the same or cheaper than buying standard parts and was wondering what the knowledgeable habitues of the forum would recommend.

Many Thanks

Anthony

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Rob Frankhamr
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Re: Alternator Upgrade

Postby Rob Frankhamr » Fri Mar 27, 2020 8:30 pm

My recomendation, for what it's worth, is only upgrade if you require extra power. The stock charge circuit is well proven, reliable and easy to get parts for. It is more than adequate for normal consumption on the bike and the only time it will struggle is if you require too much of it. If you're not fitting a lot of extra lighting, heated grips and/or using heated clothing the additional power available is irrelevant. It won't charge your battery any quicker, it won't make your bike go faster and it won't make your fuel go further. If the bike doesn't have a solid state regulator, fit one. Make sure all of the contacts and connections are good, check the diode board, stator and rotor, replace the brushes. I would lay odds that you can have a fully functional charge circuit without spending out more than £50.00

Rob
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Tincan3
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Re: Alternator Upgrade

Postby Tincan3 » Fri Mar 27, 2020 8:55 pm

My 1975 R75/6 was not capable of running heated gloves on the original alternator. I also have a sidecar so there are an extra set of dip and main beam headlights and sidelights. Eventually the alternator failed on a foreign trip and I decided to upgrade. The new alternator can now run my heated gloves! Quite expensive, but worth it in my case because of the sidecar. I wrote it up on the forum at:
viewtopic.php?f=44&t=27711
Hope that helps!

JaggeryJoe
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Re: Alternator Upgrade

Postby JaggeryJoe » Sat Mar 28, 2020 12:46 pm

Many Thanks for the replies they are very much appreciated.

Both the stator and the rotor are a ball of rust due to being stood for over 12 years, so replacement parts are needed, the diode board is in quite bad condition with visible signs of diode failure and the voltage regulator is the original 1977 item. So I thought that rather than buy original replacement components separately, a kit with all the bits and new connecting wiring would work out cheaper, £50 does sound nice though.

One other query, the large cable that runs from the battery positive terminal to the starter solenoid also has a thick brown wire (which due to corrosion has lost its spade connector) that runs to the starter relay base, but although it enters the large cable, it does not leave the cable, is there some sort of diode within the cable before it joins the +V side of the circuit? I have looked in Rick Jones's book on charging circuits but it is not included.

The bike is starting to look like it is nearly ready for the road, its not but there is light at the end of the tunnel.

Many Thanks

Anthony

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Rob Frankhamr
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Re: Alternator Upgrade

Postby Rob Frankhamr » Sat Mar 28, 2020 1:10 pm

Hi,
Can you tell us the model and year of the bike... there are several variations in the wiring around this point... a picture would also be good.

However, could the wire be red and faded? On most models, there is a Red wire connected to the positive battery terminal which is the main power feed to the bike cicuits and goes to terminal 87 on the starter relay. On some models, this is a seperate wire but on others, it is incorporated into the main starter feed as you describe and doesn't have a seperate ring at the battery end. Check to see if there is continuity between all of the ends in the loom.

If it is that wire, then it needs to be repaired otherwise none of the bike circuits will work...

Rob
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Jockboxer
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Re: Alternator Upgrade

Postby Jockboxer » Sun Mar 29, 2020 8:24 am

As Rob says, unless you are planning on adding stuff which will make significant demands on the charging system, then I'd go for sh oem stuff. On my old GS with original system, I can run it with headlight AND heated jacket and no sign of any stress on the system.

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Rob Frankhamr
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Re: Alternator Upgrade

Postby Rob Frankhamr » Sun Mar 29, 2020 10:15 am

Possibly a little off subject but...

There are two things that many people neglect when dealing with charging issues.
  1. Many charging problems are caused not by the alternator, or the diode board, or the regulator but by the wiring in between the three and out to the battery. Just because a wire appears continuous when tested with a meter doesn't mean that it doesn't have a comparatively high resistance when passing a substantial current. The same goes for connectors, a connection that appears good may well present a high resistance when passing current. Even when the charging circuit components are working perfectly, resistance in the charging wiring can reduce output a lot. When dealing with any charging issue, the first thing should be to check all of the wires and connections in the circuit. We should also not neglect the ground path. This is the return path for current and must be as free of stray resistances as the charge path to the battery. In principal, the ground path goes from the diode board to the engine mass then from the gearbox to the battery via a hight current cable. A good path on the face of it but is it? On examination, the ground current has to go from the battery to the gearbox then from the gearbox into the crankcase, then from the crankcase into the front cover before it connects to the diode board. In some cases, especially where the front cover has a finish applied, it is necessary to add grounding pigtails to the diode board. Each of these electrical junctions is subject to corrosion and resultant high resistance. You can check for excessive path resistance by checking for voltage drop, with the engine running at charging revs and a load (e.g. headlight) switched, on between a) the positive pole of the battery and the positive output of the diode board and b) the negative pole of the battery and the ground plane of the diode board. There will be some drop in both cases... neither copper nor aluminium alloy have a zero resistance... but this shouldn't be in excess of about half a volt total. As far as the ground path issue goes, my solution has been to add a direct heavy duty cable from battery to diode board - full description here... https://robfrankham.com/about-earthing ... This account requires an update as, on reflection, I have added a 40 amp fuse in the additional the ground line to protect it from starting currents in the event of failure of the main earth.


    ­
  2. Don't give too much credence to the reading on an OEM voltmeter. The meters themselves aren't particularly reliable and the wiring as standard seems almost designed to introduce voltage drop between the battery and the meter. It shares most of it's current paths with relatively high current loads (headlight, indicators, etc.). If your voltmeter drops when you switch on a load, you may think that the voltage at the battery is dropping and that, therefore, the charge circuit is weak. It will be dropping a little but probably nowhere near as much as the voltmeter indicates. The only way a voltmeter will give an accurate reading (of voltage at the battery terminals) is if it is connected direct to the battery with wiring that isn't used by any other load. Always check any conclusions derived from the OEM meter by testing with an accurate meter connected to the terminals.

If you've got this far, thanks for reading... blame COVID19 for making me bored :lol:

Rob
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Roy Gavin
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Re: Alternator Upgrade

Postby Roy Gavin » Sun Mar 29, 2020 11:26 am

Most of us are getting a bit fed up with this already.
Wonder how we will feel in six months time?
It is autumn here 26C, flat calm, not a cloud in the sky and the trees ablaze and us oldies over 70 have just been told to stay indoors at all times and get someone else to do our shopping - presumably one of the domestic staff .
Or maybe I need to get a nice young Chinese AuPair to do it for me - must have a look on Bangood and see what they have---!

Your comments re extra the potential danger of extra earths is noted, but for me too late.
I was using all the terminals on a four terminal Motobatt battery , and forgot to disconnect the second earth when I disconnected the main earth to the gear box.
One slip and a large percentage of the harness was scrap!
Not to bad a result really, I should have replaced the crappy old harness years before anyway and it just forced me into doing something sensible for a change.

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Re: Alternator Upgrade

Postby John Marshall » Sun Mar 29, 2020 11:50 am

You need to train a Kangaroo to collect the shopping in its pouch. This would also stop you getting bored. In lieu of a suitable marsupial I have taken to polishing my spokes.
The points about ensuring good connections and earths are very useful. I have known the main earth cable to fail even though the terminals were visibly OK.

Mjolinor
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Re: Alternator Upgrade

Postby Mjolinor » Sun Mar 29, 2020 12:02 pm

Damn this Miley Cyrus for giving me the time to read it all looking for spelling, technical and grammar mistakes.

I found few. :)

JaggeryJoe
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Re: Alternator Upgrade

Postby JaggeryJoe » Sun Mar 29, 2020 12:51 pm

Thank you for the replies and advice

On the subject of OEM parts, the Stator is no longer available at either Works or Bins so a 'kit' it will have to be.

The bike is a May 1977 R100/7, or it was in the distant past before I discovered the joys of graduated improvements and upgrades. It does make sense that the Brown wire is a faded Red cable, as there is a heavy gauge Red cable (which due to corrosion has also lost its connector) on the relay base, ( I will confirm by testing for continuity after my daily exercise to the garage), which by the description passes through the relay to power the rest of the system. So if the Starter relay goes, so does the rest of the electrical system. I will have to carry a spare when I go touring - already making plans.

The comments concerning degraded cables makes me think that a Hicap starting upgrade kit (oh joy, another upgrade) might be a good idea.

I have found that a very small drop of silicon helps with inserting the handlebar loom grommets into the headlamp shell. also a helamann sleeve stretching tool is an excellent remedy for recalcitrant grommets. Looks a little like the implement found in doctors surgeries that make us chaps wince.

I have to commiserate with the antipodeans, nice weather and having to stay in doors. Perhaps a drone with your shopping list sellotaped to it?

Again many thanks

Anthony

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Re: Alternator Upgrade

Postby Mjolinor » Sun Mar 29, 2020 1:38 pm

I don't see anything in the thread that makes me think you need to replace anything. The chance of faulty wiring is orders of magnitude more likely than the rotor or stator in the alternator being faulty. At the very least you should test them.

There are always a few original, used on ebay anyway but the only moving parts that wear out are the brushes, bearings and slip rings. It doesn't matter what it looks like, check it all before replacing anything or you may be in the same boat with a new one fitted anyway.

JaggeryJoe
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Re: Alternator Upgrade

Postby JaggeryJoe » Sun Mar 29, 2020 4:56 pm

There is no fault, the bike has not been started since 2004. As I am rebuilding it, each system in turn is checked and those parts that either by measurement or observation are defective are repaired, refurbished or replaced. Where upgraded alternatives are available, they will be considered. I do like improving and upgrading, so that is what is being done. If it was a RAT bike or a winter hack then yes, anything would do. But it is not and therefor I am choosing parts on that basis.


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