Battery drain problems

[Iowa Guy]

I have axillary switches for my driving lights and extra tail lights. When I forget and leave them on when I am just piddling around town after about the 3rd stop the battery doesn't have enough juice to start the bike. On the highway, no problem, but I've been caught 3 times now and my wife is getting bored already with rescuing me.

 

Any fix for this besides an better memory?

 

Iowa Guy

[GigaWhiskey]

You may need to invest in LED bulbs. You may need to upgrade your battery (example: PC680). You might want to check the charging ability of your alternator. Check and or replace your battery cables. Lower the wattage of the bulbs in your driving lights. Use your ignition in the loop for your lights, so when you turn the key off, they go off too.

 

Just a few suggestions

[Tupperj]

One suggestion would be a latching relay for the lights, and a momentary push button to turn them on. That way, when you stop and turn the bike off, the lights would remain off until you hit the button again.

 

Where to get a latching relay? Can't help there, did a quick search on RadioShack and didn't find anything.

 

Might not be much help, but may point you in a direction.

 

Paul

[GigaWhiskey]

Btw, TupperJ is the man with the cables. One of the best investments for your 1st gen.

[Dano]

Run them thru a relay (30 or 40 amp- Autozone), and power the relay from your ACC feed off your fuses. That way when the key is off, so are they. You can still use the switches to control when you want them on or not. All you are doing is controlling when the power is going to them. The reason you don't have much battery power after a short run, is the stator doesn't develop the required voltage till about 2-2500 rpm's. All of your short jaunts tend to run everything off the battery and not the stator, so the battery is not getting full charge. Leaving the lights on with the bike not runnin' don't help either!!!!

 

Hope this helps ya,

 

Dan

[GeorgeS]

Have you checked the Charging Voltage at the + Battery Stud with engine running at about 2000 RPM, With a Digital Volt/Ohm meter ??

 

Should be between 13.5 to 14.0 Volts, DC. Don't believe the Meter on the Instrumtment panel.

 

Have you Charged your battery latley, with all the prblems, I'm sure it needs the water level topped off, and a Good Charging, with a Real Battery Charger ( not a trickle charger )

[mbrood]

I would think you can drive a relay from a zener diode (like a 13 volt, 1N4743a).

 

In the reverse direction they won't conduct (breakdown) until the voltage exceeds the devise threshold... so... as long as there is 13 volts at the battery the relay would stay energized, except you want a relay with an "extra pole" so you can build your own "latching" relay.

[MasterGuns]

Highly recommend exactly what GeorgeS said; check your charging system out first. I also ride a 1st gen with bunches of extra lights and 35 watt driving lights and don't seem to have the problem you are describing. At idle with all the lights on the voltage at my battery runs about 13.2 and when everything is turned off (that is everything that can be turned off; all extra running lights, the driving lights and the audio system) the voltage at the battery at idle is around 13.8. If revved to 2000 or so, it jumps up to about 14.1 or a little more. I think this is just about right. Check yours out this way and if you are getting less than these numbers, you may have a weak battery and/or weak stator/rectifier. Good luck.

[Gearhead]

I'm not sure if you're saying you accidentally leave the lights on when parked or if it just runs down due to insufficient charging in city stop-and-go driving. If it's the former, the relay is your answer. Run the main power to the relay right off the battery, thru a fuse or circuit breaker. Then trigger the relay off the ACC fuse. Better yet, trigger the relay off the headlight. That way your extra lights will shut off when you hit the start button, like the headlight does. The trigger wire can also go thru your toggle switch.

 

If your problem is the latter mentioned above, that's trickier. Check out the charging system, certainly. All connections on these old bikes are suspect. Just a little corrosion can cause significant voltage drops which hurt charging performance. Even when everything is hunky-dory, these bikes don't have huge charging capacity. I have a pair of 55W driving lights. With those on and with steady driving I am OK. But add the 3-amp draw of my heated grips and I am marginal, even in steady driving. City driving will catch up to me with just the driving lights, resulting in push-starting the beast. I need to install 35W bulbs in my driving lights to reduce the load.

 

Jeremy

[mbrood]

Almost any relay can be made to latch...

 

This is a quick diagram where the headlight power provides the "switched" power source.

 

If you are idling and the voltage drops below the zener, the relay drops out and the momentary switch lamp does as well... once you are going, you would have to press the button again. You "could" use the zener direct to the relay but you stand a chance of the thing (at threshhold) bouncing the relay on and off... on and the headlights kick in... dragging down the voltage that drops out the relay which lets the voltage go back up... kicking on the relay. The dual contacts for headlight power is for "insurance" and you still want the single pole amperage rating to be about 1/2 the expected headlight draw.

 

http://www.bergall.org/temp/venture/latch.jpg

But I also agree with George... insure your charging sytem and battery are working properly and up to snuff... ours isn't the strongest by any means but with good parts, clean and tight connections, your regualtor should lock in at about 1500-1800 rpm. I have a lot of running lights so any time at a stop light (brake light on and at idle) and in a turn lane (blinker blinking) you could easily see my voltmeter down around 12v and twitching with the turn signal. Changing the running lamps to LED gave me back almost 120 watts... 32 4 watt bulbs against 32 1/4 watt LEDs.

Edited September 5, 2008 by mbrood

[Condor]

I'm trying out a Chinese AGM battery, and on the last ride I used the Tape Deck a lot. After a while I noticed that the bike bogged when starting. I turned off the deck and after a bit the bog disappeared, and it was business as usual. I'm sure the battery doesn't have the highest CCA rating, but just how many amps does that tape deck draw anyway??

[6m459]

Hi,

 

This brings to mind a similar incident that happened to me, a couple of years ago, that you might want to think about.

 

I won some electric gloves in a draw. Lucky me! When I used them though, I used them flat out IE full on all the time, since I didn't win the associated device to regulate the heat by varying the duty cycle of the applied power. (I regulated the temperature by unpluging them when it got un comfy)

 

Long story short, not long after that, I needed a new stator coil. Now it might be that it was the coils time and it all would have happened anyways but, I blame the heavy load from the gloves for killing the coil. I have no measured facts & figures to back up this suspicion but it remains my operating theory. The old stator (RHS in the pic) was quite dark and crispy looking on removal.

 

Your lighting load may be causing you similar future troubles. That extra current has to originate at the stator coil city or highway. The stators on these bikes are only rated for so much current and beyond that, all bets are off. Your bike might be trying to tell you a more important message. I'd lighten the current load as a first line of defense by using LED lighting where ever possible.

 

Just a thought, hope it helps.

 

Brian H. C.E.T.

Uxbridge Ont

[Gearhead]

I have a question about stator load. In systems like ours where the magnet is permanent, doesn't the stator always put out the max that it can, and the regulator dump the excess to ground? If so, then does heavily loading the electrical system really make any difference to the stator?

 

Jeremy

[mbrood]

Gearhead,

 

I think you have it together... just like a grade school experiment with a coil and magnet... hook the coil to a light bulb and move the magnet... more movement, more voltage... but remember that the current is dependant on the load...

 

I think the term is total loss... one way or another, the rpm dictates the output potential of the alternator and it's up to the regulator to regulate the "output" to 14.5 volts and everything else gets shunted to ground... one of the reasons it's bolted to the frame and it's in the breeze.

 

The rectifier assembly is just that... full wave rectifiers, three leg... and the regulator internals aren't shown anywhere but it's fairly obvious that the result is basically as you stated.

 

I think the alternator is rated for 300 watts.

Edited September 6, 2008 by mbrood

[Gearhead]

Thanks. Per the manual, the "AC generator" is rated for 14V, 30A at 5000rpm, which is 420W. However, it also says the Rectifier has a capacity of 26A, which @14V is 364W. Dunno what the rectifier does with that extra 4 amps that it's not rated for.

 

I understand why higher RPM produces more current. My question is this: if I run the motor at 5000rpm with no electrical load vs running it with a huge electrical load, is the current through the stator any different? Or is stator current just "what it is", and in the first case all the excess goes to ground (which serves as the load) while in the second case it gradually drains the battery?

 

Jeremy