battery sensor bypass

[slaghead]

I am working on a 1983 Yamaha Venture. I just bypassed the battery sensor using the existing diode soldered to the accessory fuse holder. The warning light still comes on occasionally. Is this safe, I do not want to burn out my monitor. I get the same voltage before and after the resistor,shouldn't it be lower.

 

My second question is that my tail lights seem to stop working when my battery is low. But they come back on as soon as my power is back up. Has anyone else run into this problem? Nothing else seems to be affected.

 

Thanks.

 

Dale

[bongobobny]

Uhhhh, what "existing diode??" There s a resistor, not a diode in the stock probe connector. The "mod" is to take a 2000 to 4000 ohm resistor and wire it in series to the Aux connector of the fuse block. With the bike turned on, you should see 12 volts on the aux terminal, and about 6 volts, give or take on the other side of the resistor, and the light should go out. You may have to remove the CMU from the dash assembly and carefully resolder all of the pins of the edge connector for the CMU as the solder is over 33 years old, and normal vibrations also may have taken it's toll on the solder as well!

 

This could possibly account for your strange brake light issue as the brake light switch goes through your CMU as well...

[cowpuc]

Wonder if someone may have stuck LED's in your tail lights or maybe ya got some crud or bad ground on the tail lights that is creating a resistance the lower voltage just cant quite over come...

[Freebird]

I agree with Bob. This is the first that I've ever heard of a diode being use. I don't see any possible way that would work. Here is a tech article on doing the resistor mod. OK....I will recant a bit. I suppose I CAN see how a Diode would work if you had it in the right direction so that it blocks the circuit but I don't know if it would create other problems or not. The resistor is the correct fix.

 

http://www.venturerider.org/forum/showthread.php?489-Battery-Warning-Bypass

[Flyinfool]

It could be done with diodes but the resistor is cheaper and easier.

 

If you have just a diode in the circuit, disconnect it right away, you could end up blowing the CMU.

 

As far as the tail lights, What @cowpuc said.

Also check the voltage across the battery with the engine running at around 3,000 rpm. You should have around 14V even if the battery is drained a bit, if you don't, you may have the beginnings of a charging system problem.

[slaghead]

Sorry for any confusion,I called the resistor a diode by mistake. I am not an electrician, and only know enough to be dangerous. I will choose my words more carefully in the future.

[Freebird]

OK....fair enough. I still don't know what resistor you are talking about being soldered to the accessory fuse holder. I've not seen that before and wonder what you actually did. If you do it like the instructions in the link that I posted, it will work. Since your method is not working, I worry about what you have done and what damage it might do.

[Prairiehammer]

I still don't know what resistor you are talking about being soldered to the accessory fuse holder.

 

The stock wiring for the battery electrolyte sensor circuit included a resistor. The resistor value was quite low, too low to allow a direct connection to 12 volts.

There is no danger in adding the 2-4K resistor in series with the existing stock resistor.

Edited August 4, 2016 by Prairiehammer