Electrics help

[peteremc]

Up front I'm admitting I know very little (like next to nothing) about electrics, other than the very basics, but have a problem that the brains trust here may be able to help me with.

I have an 82 R65LS which has been off the road for a couple of years, but has been recently revived. All was good when I took it off the road.

Current problem is that I've ridden it for a couple of days, ironing out small problems after being garaged for so long and today it stopped.

Just prior to this I had done about a 20 klm (12 mile) ride and when I went to start it after 20 klms, the battery did not have enough power to turn the starter. A push start was easy and much appreciated. At about 19 klms on the return trip (yep, close to home, but not close enough! was where it stopped. The battery was completely dead. Nada, zero, zilch, nothing.

The rescuing service helped by jump-starting bike. The dead battery was holding about 10 volts and then tested the charge the bike was providing and this came up at just about 11 volts.

So, to my simplistic mind, the bike's charging system is not providing enough power to run the bike and is therefore relying on pulling some charge from the battery which is eventually going flat.

Any comments, observations, fixes, advice…?

From someone who knows little in this area, any advice will help to build my knowledge.

Thanks

[Lucky_Lou]

How old is the battery ? I would check the connections to the battery and starter relay I don't  think you would register a much higher voltage on the generator if the battery is toast.
Lou

[Barry]

The rescuing service helped by jump-starting bike. The dead battery was holding about 10 volts and then tested the charge the bike was providing and this came up at just about 11 volts.

So, to my simplistic mind, the bike's charging system is not providing enough power to run the bike and is therefore relying on pulling some charge from the battery which is eventually going flat.

I'd fully charge the battery then have it load tested to access it's condition.

You can't make an accurate assessment of the charging system unless the battery is truly fully charged so you can't judge it properly on that 11 volt reading.

If the battery tests out OK or with a new battery take the voltage measurement again at 3-4000 RPM. If the result is not at least in the high 13's then you will know for sure that you have a problem.

[Bob_Roller]

When you turn the key to the run position, does the red GEN light illuminate ??

[peteremc]

Lucky Lou - Brand new battery – 2 weeks old. Not exactly a reputable brand but when you’re lucky to get 2 years out of any battery these days, I’m wary of throwing a lot of money at them.

Thanks Barry, these are the sort of practical tips I need to isolate the problem.

Bob, I have installed a single unit speedo/tacho with warning lights included, but the only thing it does not have is a charge warning light. But, I have the wires installed to take one and we hooked up a test light which did exactly what the charge warning light did when I took the bike off the road i.e. light lit up in the run position and when the bike was at idle and as soon as the revs came off idle the light went out.

I have to add that I am suspicious about the battery. From the seller it seemed like it was very slow to take up charge. It was on charge for most of the day at the mechanic’s workshop last week and trickle charged overnight that night and still only got to 11.5 volts. Maybe a dud battery.

So, from here I’ll fully charge the battery and run the test again at around 3-4000 rpm and see what that tells me.

Cheers

[wilcom]

trickle charged overnight that night and still only got to 11.5 volts. Maybe a dud battery.

Better get a "fresh bullet" . A charged battery should read 12.7 volts. Check your meter to make sure that's not the culprit. Go measure your car battery and make sure your meter is giving good readings.

You could have a dead cell and 11.5 is all it can do with 5 of them working. Let's cross our fingers that the Batt. is the only problem, but maybe not. With a good battery you should be able to see 12.7V not running and high 13's to mid 14's running at 3000K at the battery

good luck

[Barry]

Not exactly a reputable brand but when you’re lucky to get 2 years out of any battery these days, I’m wary of throwing a lot of money at them.

I think that's a good philosophy in a hot climate and even though I don't live in a hot climate it's what I do.  Something in me refuses to pay more for an 18AH bike battery than I do for a car battery 3 or 4 times the size. I'm nearly 3 years into a cheap generic battery that cost £30 and it still performs like new.

Does sound like you have a dud battery though.

[Bob_Roller]

When you ride the bike, there is nothing connected to the wires for the red GEN light

You just connected a test light to check the system out ??

Without a bulb, or resistor in that circuit, the charging system does not work .

An LED bulb will not work either, unless a resistor is in the circuit as well .

http://www.bmwmotorcycletech.info/genlampresistor.htm

[Tony Smith]

Bob, I have installed a single unit speedo/tacho with warning lights included, but the only thing it does not have is a charge warning light. But, I have the wires installed to take one and we hooked up a test light which did exactly what the charge warning light did when I took the bike off the road i.e. light lit up in the run position and when the bike was at idle and as soon as the revs came off idle the light went out.

The thing will not charge unless there is a bulb or a resistor of the right value in the circuit - the rotor coils ground through the warning light circuit.

I have to add that I am suspicious about the battery. From the seller it seemed like it was very slow to take up charge. It was on charge for most of the day at the mechanic’s workshop last week and trickle charged overnight that night and still only got to 11.5 volts. Maybe a dud battery.

Assuming your meter is accurate, that battery is toast and not worth bothering with further.

So, from here I’ll fully charge the battery and run the test again at around 3-4000 rpm and see what that tells me.

By 3,500 you should be seeing at least 13.8volts. Any less and you should start suspecting the regulator or the brushes.

[Bob_Roller]

So, for your current condition, I would place a resistor from the light blue wire for the GEN light to a ground, or earthing point to get your charging system operating as it should .

The link I provided has a range of resistor values you can use, depending on what is available in your area  .

[mrclubike]

Like  Bob and Tony basically said

DO NOT!!!  waste your time doing anything else until you get a proper charge light hooked up pertinently  and then go from there  

Charge the battery up with a good charger or if you have to Jump start it and go ride it for a couple hours and then check your battery voltage
with engine off and running at 3500 rpm and tell us what you find

If you can get a volt meter hooked up as you ride it that would tell you a lot
If the battery voltage is low after you start it that isnt necessarily bad but as long as it keeps rising and gets to 13,8 or more depending on what type battery you have that is good
(if you have a AGM battery it would be better to have it top out around 14.3 volts but you will need an adjustable regulator  or high output reg to get that )

Also the more charged up the battery is be for you start the engine the quicker it should  get to 13.8 volts

[peteremc]

Thank you all. Brilliant help and well spotted that I didn't have a light on the wiring for the GEN light.

Battery is on charge for one last try - just in case. If no luck, I'll be back to the point of purchase for a discussion.

Thanks for providing the figures I’m looking for from the charging system – at least now I know what I’m looking for!

Thanks for the link to Snowbum’s article, Bob. Is there anything this man doesn’t do in minute detail? Love his work and it’s a great place to learn lots – if you can actually find it among all the words.

My first preference to remedy the central problem would be to install a warning light as this looks like it will have the double benefit of completing the circuit to enable the charging and will provide me an indicator in the future of any problems. I would prefer not to use a resistor/LED light, but I’m having trouble locating a warning light with a 3W incandescent bulb! Everything is LED these days, it seems.

Wondering if Tony might have any tips for a local outlet that may have what I’m chasing?

Thanks again for all the tips. I can’t get back to do much about this until next week (bar charging the battery and sourcing a light, I hope), but will let you know how I get on.

Cheers

[Barry]

The charge lamp wattage isn't at all critical and actually changed from 1.2W early models to 3W on later models.

What lamps can you find ?

[Tony Smith]

Wondering if Tony might have any tips for a local outlet that may have what I’m chasing?

Sadly, no, except that I am sure that SuperCheap or AutoBahn will no longer carry Bezel mount indicator/warning lights. You could try Repco or Asdown Ingrams, but I am merely guessing

[montmil]

Peter, Scroll down to the FAQs section and check page two for the details on creating a simple GEN lamp auxiliary circuit. Pictures and parts for you. Maybe $2.00USD at the most.

If you do not have the GEN lamp circuit included with your aftermarket gauge, you will never get a charge to the battery. You may get a day of riding from the battery alone but don't stray too far from home.