Battery Drain

[jnclem]

I just got my 1958 R60 last summer. Ive got a couple of questions about the charging system.

I have noticed that even running on the highway, the battery will be significantly drained after a few hours, maybe as little as two hours. I do run the headlight on high all the time, and I have a slightly higher watt headlamp than standard. I am 100% confident in the tech that owned this bike prior to giving it to me. He has been riding and working on these bikes since the 1960’s, and runs those bulbs in all his /2 and earlier bikes, so that bulb is acceptable, but it does draw more power than standard.

Can someone tell me what voltage I should see at the battery when the bike is running say, 2500 or 3000 RPM? Is checking voltage at the battery in that way a reliable way to see if I have a charging system problem?

I also installed one of the LED taillight modules from Vech. The taillight is much improved, but the brake light is pretty much invisible. I don’t mean that the light goes out when using the rear brake, it just doesn’t really get any brighter. At idle, it won’t change at all when the brake lever is pressed, but with the bike revel up a bit, you can see a change if you are in a dark garage and look closely.

I never ride at night, especially on that bike, but I would like to have a brake light. The original taillight was pretty much invisible all the time, so this is still an improvement. My solution so far has been to simply connect the bike to a smart charger when it's parked, but I'd like to have it working right.

I would like to address these problems as soon as my garage approaches 30 degrees, which may not be for another month or so, but I'm collecting information now.

Thanks for any help you can provide.

[MikeL46]

RE: Your brake light. Are you sure the brake and taillight are not reversed?

Mike

[jnclem]

Yes. Checked that carefully at the time, and I was confident that I had it right according to the instructions that came with the unit. However, I've done stupid things before, so I have no issues with checking it again once I can get the bike running in the Spring. I'll put that on my list.

Like I said, with the bike reved a bit, you can see a slight increase in brightness when you press the brake lever. It’s just not very noticeable in daylight. My wife riding behind me can’t tell when I press the brake. With the bike at idle, it doesn’t change at all. That led me to think the connection at the BL switch might be dirty or loose, but they seemed fine. Testing the wires at the taillight, you could definitely see that the BL side was getting juice when the switch was closed.

[schrader7032]

If still running the original 6V system, the voltage at the battery with engine at elevated RPM should be 7V if not a tad higher.

[jnclem]

Thank you. That's what I figured, but it’s good to have a number. Now that I'm thinking through all this, I wish I could go out now and check this stuff out, but sadly, it's January.

[schrader7032]

Just curious...what's the static reading right now on the battery?

Of course it's well know that the battery is really only used in the electrical system to power things like the lights and horn when the engine RPM is low, say around idle. When the engine is spinning faster, the generator is supposed to provide power to the bike as well as charge the battery. So, in your case, you could have a faulty generator not outputting enough to keep the battery charged or coupled with that, you have too high of a draw from the added things to your electrical system that is just too much for a perfectly working generator to keep up with.

[jnclem]

Static is 6.18

It needed a battery when I picked it up from my brother in Montana, so the battery is new and was checking out very well when I put it away a couple of months ago.

My suspicion is that the generator is going to need brushes or just need to be cleaned up. The bike starts beautifully and is in great mechanical condition. This is really the only issue it has.

[Discogodfather]

I just replaced my 6V standard battery with this sealed lead model:

https://www.batteriesplus.com/productdetails/slaa6=14t2

It's a little smaller than a standard battery but it's awesome. It holds a charge well without a tender and it charges more easily as well. No more dribbling problems. I can't believe I didn't do this years ago. Also makes strapping the battery in with that rubber strap about 10x easier. I did need to cut of the H connector and replaced it with a S style connector.

[jnclem]

6.18 is a bit low. I don’t know if it being 20 degrees in the garage would make a difference or not. It’s certainly possible that the battery isn’t good even though it’s new. There’s a lot of that going around these days.

[Beemer100]

6,18 is indeed a little on the low side. However, you still should see the brake light. Are you sure the rear/brake light unit is for 6V? I know, stupid comment but still worth to check.

These generators were not meant to supply the bike with permanent driving light. Remember these bikes were built at times with little traffic. Means, the output of the genny is pretty much border line if you use the front light permanently. This is even more the case, if you run I higher Watt bulb. You can easily make the maths and calculate the Watts you need. And then you need to consider that the genny output mentioned in the specs needs a certain amount of revs, which you don’t reach in town traffic.

Take off the front cover and check the brushes. Could also be the springs which press on the brushes. Both are cheap parts. As Kurt says, at running speed, you should easily see 7.2V or so.

I am running most of my bikes on 6V and you can easily see the brake light. Not as good as 12V obviously (in particular in daylight) but still.
You maybe want to use your voltmeter and check all the way from the battery to the taillight and see how much you loose at every junction.

Safest obviously is to convert to 12V (new genny and battery plus new bulbs, horn can stay)

Hope that helps
Klaus