Battery Drain while riding

[devildrums]

Hey guys, I have a 77 xs650D and the last few times I have ridden it has drained the battery. I had changed to PMAG last year and we checked the charge and was working fine. I am going to check a few things I already saw but also had a quick question; will running it with the high beam on constantly cause the drain? The normal bulb died and that was all I could use. New lamp is on the way. Thank you.

 

[Paul Sutton]

If you have an H4 55/60W headlight then this will drain the battery if travelling at less than say 2500rpm for too long. You could try riding with the headlight off to see if this is the issue, but I would first check to see what voltage you get across the battery at 2500 - 3500 rpm just in case the rectifier/regulator has gone all moody on you. You should be getting somewhere in the region of 14.2 - 14.7V.

 

[Superjet]

If it was charging before and not now check wiring if something has disconnected or something failed. My bet is reg/rec overheated.

 

[devildrums]

If it was charging before and not now check wiring if something has disconnected or something failed. My bet is reg/rec overheated.

That's what I was saying, we checked last week and still charging. I will check it again today to see if it still is. It ran fine a couple times with no lights on, that is why I asked that question.

 

[devildrums]

If you have an H4 55/60W headlight then this will drain the battery if travelling at less than say 2500rpm for too long. You could try riding with the headlight off to see if this is the issue, but I would first check to see what voltage you get across the battery at 2500 - 3500 rpm just in case the rectifier/regulator has gone all moody on you. You should be getting somewhere in the region of 14.2 - 14.7V.

I have no idea about the light, just it is a Koito. Don't see any other markings. Got new one coming from mikes.

 

[Superjet]

When you checked last week were you getting values within the range on what Paul suggested above? With headlight on?

 

[650Skull]

Brain Storming and some questions............

What wattage is the PM??

PM's put out full voltage at very low revs and generate a lot of heat in the Reg/rect.............a good way to lower the output and help to lower the heat on the Reg/Rect is to use incandescent bulbs................

Reg/Rect controls the voltage to the battery............if it fails, the battery will overcharge, get hot and fail......worst case scenario........ BOOM..........

If the regulator part of the Reg/Rect is working then something else is causing the battery to drain..........short in the main switch, or down stream as well as a wonky main switch ???

 

[Paul Sutton]

On my 81 SH model the original headlight unit was a Koito sealed beam and 50W seems to ring a bell. I changed it to a H4 system and found the 55/60W bulbs were just too heavy a load for my typical riding at 2000 - 3000rpm. I swapped to H4 35/35W bulbs and had no more charging issues. I also had a rewound rotor at the time so the issue was not a poor rotor. In my searching I found data indicate that H4 35/35W bulbs give out a similar amount of light as the 50W Koito sealed beam unit.

Those small bike mounted voltmeters are very handy for keep track of the charge system. I had one on my SH and it showed me there was a charge issue with the 55/60W bulbs. In fact I was so impressed with it that I fitted one to my Virago which has PMA. I fitted a quality modern PMA Rec/Reg (£80) and the meter sits solidly at 14.3V with headlight on and it is always just warm to the touch. The old style technology stock Rec/Reg always ran like a furnace.

 

[devildrums]

Super jet - Range was good, hadn't thought about light yet, will be part of my tests tomorrow.
650skull - Don't recall PM wattage, will look it up tonight. The reg/rec is less than 6 months old so hopefully that is ok. Gonna check fuse box.
Paul - Thanks for the bulb info and when it is running again I will check the temp.

Thanks for the help guys.