Battery warning light

:?:
Recently, the battery warning light comes on when I first start up the 81' Seca 750. After riding a couple of blocks it goes off. Buddy of mine suggests a short, but wouldn't it stay on. Bike can be warmed up and when I start out again, it comes on. The battery seems seems good as it starts right up and doesn't seem to be draining when light is on. Another separate issue. I turn on the brights and the light warning light comes on. I believe this was occurring before the battery light came on. I usual don't use the brights.

 

That pesky warning light. And then it’s distracting sidekick the warning control switch.

You wrote:
‘I turn on the brights and the light warning light comes on.’

The warning light is always (at least should always be) associated with an item listed in the panel. I assume it’s the BATT listed when you click on high beams. Likely because the high beams draw more juice from battery and the flaky battery sensor sees the change.

The battery sensor’s purpose is to monitor water level in the battery. Yet the battery has 6 water reservoirs and sensor in only one of those. And it’s flaky. You also must struggle with compatible new battery install with using that sensor.

Your experience with the warning light (BATT) coming on at random times can be due to the water level in battery changing as you ride. Water flip flops across the sensor threshold. Then leads you to distraction with the warning control switch.

I eliminated the use of the battery sensor by cutting it off it’s wire and splicing a wire extender to connect to the positive post on battery. On my bike (XJ750RJ Seca 1982) the wire to the sensor is white with red tracer.

 

Thanks MD. I just been busy/lazy to actually pull off the battery cover to check connections or water level in the battery. Partly because I have strap holding on my side covers - kind of a safety backup as I have already lost the right side cover while driving. I will pull the cover off to check the battery level. Sometimes I forget things it has done before. I had the water level get low and the light came on in the past after charging for the winter season. In Wisconsin, this is from October till June - haha. We're in monsoon season this summer. Since I choose not to ride it in the rain, I have plenty of time to check it out. Thanx again.

 

Finally got back to the bike and checked the battery. Was somewhat low on water. Was able to slide the battery out without disconnecting and fill up with dist. water. Put back in and wouldn't turn over. Still had light. Pulled battery and charged. Put back an hour later. Still nothing. Checked connections. Inadvertently and stupid owner (me) disconnected what I can only believe was starter. Snapped in and started right up. Even my wife remembered me needing to add dist water to battery previously. Not sure why this is going down about 1X per year, but fixed problem and running great - in between torrential rains.

 

Water evaporates. The battery heats and cools along with charging cycles and the rest of the bike. That's what the vent tube is for. A Glass mat battery is the only true fix for not wanting checking water levels.

 

I just ran into this after picking up a 1983 Seca 750 off of c.l. After removing the recent looking Yuasa, I disconnected the white w/red tracer wire coming from the main harness at the bullet connector, removed the caps and probe, and have it on a 2 ah charge. The probe is looking for electrolyte level in its particular cell, and nothing else.