Thanks for your detailed post, Ian. Good idea re: the voltmeter. I'll get one.
Is your replacement alternator bigger and did you notice an effect on mpg/power?
They dont make anything for my bike and from what you say it could lead to other issues so I've decided to minimise my consumption instead.
Like John I've swapped my backlight and indicators for LED and have just got a Rigid Ind. LED front light from Zen.
My bike (GS500) is a permanent headlight jobbie, though I plan to disable that and maybe turn the headlamp off to rely on the Rigid lamp if running the vest on cold nights with the voltmetre sagging. All this is hypothetical at the moment. My bike's output may be fine though I read it's 235w @ 8000 which doesnt sound too promising. Never get anywhere near 8000.

Chris S

I use an LED voltage monitor. It's a single LED fitted somewhere visible to the rider, wired to a switched live and earth. It changes colour according to the system voltage - green is (from memory) 14V and up, then amber, red and flashing red. Overcharging is indicated by alternating red and green flashes. I got mine from Sparkbright products on eBay - one man operation, very professional and a super guy to deal with. I think they were 10GBP plus postage. Good value and much easier to locate on the bike than a dial instrument. All my bikes are going to have these in future. Highly recommended. No connection except as satisfied customer, etc.

Here's the monitor:



And here it is on my XT (strapped to the idiot lights with ins tape):

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I've seen those for sale on ebay and they look very good - a lot neater than the version I made myself about five years ago which only cost a couple of quid less and involved hours of soldering and fiddling around trying to fit it all into a small box. Over the last five years the device has proved its worth a few times and I've caught a number of electrical problems before they proved terminal (). One time in France the main battery earth came loose on the engine and the change in light pattern warned me early enough that something was wrong that I could find it before I ground to a halt. My latest project bike is only 6v though so I've now got to find or make a 6v version.

Yes the new alternator is 400W the old one was around 230W, I don't notice any difference with power/mpg

If you have a look at the link below it shows a graph detailing alternator output versus engine RPM for a BMW R100GS with an Endurolast alternator (I couldn't find a graph for a GS500 and from what I understand this is typical for all alternators). The curves level off so that after a certain engine speed the output doesn't change all that much. So an output at 3000 RPM may not be all that much lower than at 8000 RPM.

BMW Electrical & Maintenance Parts | Moto Guzzi | Ducati Motorcycles | EuroMotoElectrics.com

But it sounds like your option of lowering consumption is a good idea. The link below might be worthwhile to confirm what capacity you can get from the alternator.

Calculating Excess Electrical Capacity - Learning Center - Powerlet Products

I like those LED voltmeters I will have to get one of them for testing.

All the best

Ian J

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Hi,

Load reductions.

Your indicators, brake lights are only 'on' for short periods of time so reducing the load here is not that effective.

Your headlight

• * may be on all the time the bike is running. Putting a switch here is a very good idea, even if legally in some countries you cannot use it while travelling! You can, in any place, use it while starting the engine - when the battery load is highest and you may need that little bit of extra energy to get going. And in places where you may turn it off while travelling you then have that option.
  
• * Scooters use a 36 Watt light - some 20 Watts less than the common bike lights of 55/60 Watts. They have a similar base to the H4 globes in common use ... but you'll need to modify something to make them fit (I'd go for the the mounting in the headlight rather than the globe as the next globe would also need modification). This saves you 20 Watts. Of course it won't be as 'bright' as the 55watt globe, but then you could always swap it back if seeing rather than being warm matters? I do not recommend this if running at night, but for use during the day I think it is fine. As any traveller knows, travel at night will take you through the best scenery of your trip when you cannot see it.

Heated vests consume about 60 Watts on full blast, most of the time you only need 20 Watts or less. So get and use an efficient regulator for it.
Same goes for other heating things.

Regulators
Shunt regulators, as has been said, remove the excess energy from the charging system by dissipating it as heat. This is very efficient when high loads are present. They will get hot with small loads.
Series regulators limit the energy flow through them from the charging system to suit the load. Very efficient for small loads. They will get hot when used with large loads.


Unless you know what you are doing leave your system alone, or have large pockets to pay for your mistakes.

Voltmeter! An extremely good idea, particularly if running close to maximum load.

I really hope someone can point me in the right direction. I have a 2019 Apollo Enduro 250 and it seems even replacing the factory battery with an interstate battery and once a month I have to charge it because it starts getting weak. Is there an aftermarket stator or something to boost the charging system?

Greetings Walt

I think your chances of finding a higher output alternator as a drop-in replacement are slim. If Apollo don't offer it as an option I can't see third party companies investing the time and money to develop one.

I did a quick search on your bike to see if other riders were having the same problem and I see that you had been to the same site (chinariders) before me.

If you are slowly losing charge over a period of weeks I would be looking at why that's happening?

Either you have a fault or there is a design issue and that's going to to be a difficult fix.

Are you doing a lot of short rides? stop/start city riding? Something that doesn't allow the battery to charge completely?

If you have some basic electrical skills you could do the following

- Make sure that all the connections in the charge path are tight and free from corrosion, especially check the any ground/frame connections.

- Temporarily fit a voltmeter on the handlebars and connect it directly across the battery and see what's happening at idle and at speed.

- check to see if there is any leakage current from the battery when everything is switched off. Be careful when you do this, when you use a voltmeter in it current measuring mode it basically becomes a piece of wire that is connected in series with the battery.

***** Do not turn the key on, you could blow up your meter ******

***** Do not connect the meter across the battery when it's measuring current. It will short out the battery *******

If your measurements indicate poor charging voltages, swapping out the regulator is the easier next step, but not the cheapest.

If the headlight uses an incandescent bulb you could swap it out for an LED type.

Finally these bikes are built down to a price and they will use the smallest gauge wire that they can get away with to save money.

If you had a electrical diagram of the bike and you really, really really knew what you were doing you could see if there were any significant voltage drops in the charging circuit and then install some heavier gauge wire but that's a last chance desperate move and is unlikely to improve the situation much.

Good luck

Ian J

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While I agree with Ian on the diagnosis, these bikes are Chinese knock-offs of old Honda's. The parts are appalling quality but the Honda design did work. I would be dredging through XR/XL/CRF 150/250/250 catalogues for a stator and above all a VR. This, plus a rewire might solve it for less than just buying a 5 year old Honda, but I think you have to consider setting a point where you stop trying to achieve a mirror finish on a pile of droppings.

Andy

Greetings Andy

Fair call, I knew that they are most likely copies but I don't know these bikes well enough to suggest part swaps from other brands so I didn't mention that. Then again I can't imagine what bike a Hondu 125 that I saw in Central America is based on

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