Battery warning light....

I got my 81 xj750 seca not too long ago and the battery warning light likes to flash when i'm at idle fully warmed up.
Goes away when i rev it.

I read up and found that a sensor in bank 4 of the battery detects the level and i assumed it's just a little low so i toped it up just a slight bit in all 6 of them to sit at the upper level line.

worked like a charm when i reinstalled and started her up.
no warning light whatsoever.

but then i started fooling around with the cockpit to change a bulb in there.
After i reassembled everything I started her up to make sure everything works.

tilted the bike off the side stand and the warning light flashed. leaned her back down and the light went off.

back up again and warning light came back on. took her for a ride and light went off untill i got to the end of the block.....

now the light is on no matter what.......

driving me nuts

battery is a year old, charges fine, no drain, level's fine, hold's its charge fine as far as i can tell...... longest she's sat for was 3 days.

she's a hard one to crank over when shes stone cold. turns over fine but doesn't light to catch on.... first bike so not sure if that's just the case with these older bikes or if it could use some new plugs or what.

but the battery has never failed me even after 3 days and cranking away for 30 seconds


can i just dissable the warning system somehow? i assume that if it is triggered by acid level then it's rather pointless anyways

 

That sucker should start right up every time. Might require "choke" when cold, but no long cranking should be necessary. Oh, incidentally, when you get a chance, make a signature and put your bike's make in there, saves time.

Your battery can read decent voltage on a meter but still be a little weak, starting a bike takes amps, but your meter usually shows volts, likewise that's what the sensor sees, I think. Because volts is a little easier to measure, since amps is volts over resistance, and you don't usually know the equivalent resistance of your entire ignition circuit. Ohm's law and all that good electrical stuff. But your issue could be several things. Old wiring, weak battery, problem with coils, etc.

BUT, if all you are worried about is the warning, here is the solution, and it's awesome because you still save the "low voltage" part of the alert system. Many bikes have had after-market batteries put in with no place to attach the sensor, so a workaround has been mentioned many times on this forum, I've done it too.

Get a regular battery with no sensor port, next time you get a battery. Then, if you want, cut off the sensor, take that wire, I believe it's white with a red stripe, and here's what you do: get any combination of 1/2 watt resistors(available at any radio shack or other electronic nerd type store) that adds up to 2,000-2,200 ohms of resistance, and you solder those where the sensor was.

Now, attach that to a keyed 12 volt wire, usually people use the tail light wire because it's under the seat next to the sensor wire. The idea of the resistors is that otherwise you're just sending a full jolt to the computer, where it's designed for ONE cell of the battery.

I mention this because some folks have done this trick just running the sensor wire straight to another 12 V wire. Sure, that will prevent the warning, may also kill the computer, and not only that, the beauty of this bypass is that if your battery gets low, you'll still get a warning. In my case, any time the bike sits for a while, I'll get a warning until the battery charges, then it goes away.

 

You can put the sensor wire straight to the + side of the battery to stop th red light, mines been that way for about 3 years no probs. I read it here first. ..and we got the same model.. so it oughta be th same.

 

...or you could just buy a battery sensor bypass kit from Chacal and not have to cut anything at all.

 

True, good idea if you're not much for soldering. For me, this is a pretty easy mod. The head warning was trickier. I'm all for buying stuff if necessary, but I bought nothing for this since I have tons of resistors and wire on hand. That bypass kit is nice, but I don't buy nothin' if I don't have to

 

did the trick. all good now.

Thanks guys.!!

now i'm trying to sort out the cold start issue..... gonna start a different post when i get a minute and post the link up here or smth!

 

For my cold start problem.....


http://xjbikes.com/Forums/viewtopic/p=3 ... tml#349976

 

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The most effective way to "Bypass" the Battery Warning Light is with a jumper wire.

Fabricate a Jumper Wire.
Run a length of wire from the TAIL-LIGHT Power Supply Wire --
Splice-in a [ 2K Ohm 1/2 Watt Resistor ]
With an additional wire from the Resistor connect the Jumper to the Battery Warning Wire on the Wiring Harness.

You need a +12V Source that is "Switched"
The Tail-light is ON-OFF with the Ignition
The Resistor protects the Circuit from overloading the Integrated Circuit in the Instrument Panel

 

If you didn't fuse that connection, you may want to consider it.