Honda R/R sense wire question

[Hornswaggle]

I'm replacing the stock R/R on my 450T with a Honda 6-wire unit and followed the great instructions on BassCliff's website. I also soldered in new ground wires and connections and replaced all other charging system bullet connections. My question is what to do with the extra sense wire that is on the Honda unit. Before I fire it up is it critical that this get connected somewhere? If so, from what I've been able to search it sounds like some people have wired it directly to the positive terminal on the battery. Is that correct?

Thank you!

[tom203]

You can connect sense wire to the rear brake switch so it only senses voltage when key is "on"- others have just wired it to battery positive, apparently it draws a insignificant amount of current , but this method might be a problem if your bike sits idle for weeks.

[Hornswaggle]

Got it, I understand now. Thank you!

[bwringer]

The sense wire should be connected to a switched positive, not directly to the battery. It's fine to hook it up directly for temporary testing, but over time it will drain your battery when the bike is off.

If you attach the sense wire to a wire with a significant voltage drop, it will over charge. Compare the voltage at the wire you want to use with the voltage at the battery, and make sure they are as close as possible -- ideally under 0.2 volt difference. If there's a large voltage drop, clean all the connectors and switches, and consider using a different circuit.

[koolaid_kid]

If you have an accessory fuse box, like the Eastern Beaver PC-8 or my Blue Sea 5028, or have done the coil relay mod, that is the best place to put the sense wire.

[Suzuki_Don]

As Brian said the sense wire directly to the "+ive" side of the battery can drain the battery over time. I found with the sense wire connected to the brake light switch the R/R was over charging as there was a voltage drop through the ignition and kill switches.

I have connected mine directly to the battery, and with a battery tender plugged in all the time I am not using the bike it replaces any voltage leak down that occurs.

Hope this helps.

[chef1366]

If you have an accessory fuse box, like the Eastern Beaver PC-8 or my Blue Sea 5028, or have done the coil relay mod, that is the best place to put the sense wire.

I agree...
On the Relay part.

[koolaid_kid]

I agree...
On the Relay part.

Thanks. All of the mods I mentioned use a relay as a starting point. One of the purposes of the relay mod is to provide full charging voltage to something, whether it is just the horns, the coils, or a distribution box (such as a fuse block). So the voltage will be the full charging voltage, which is what the sense wire needs to know.

[chef1366]

Thanks. All of the mods I mentioned use a relay as a starting point. One of the purposes of the relay mod is to provide full charging voltage to something, whether it is just the horns, the coils, or a distribution box (such as a fuse block). So the voltage will be the full charging voltage, which is what the sense wire needs to know.

I hooked my sense wire into the brake switch wire and it was overcharging since there was a loss on that wire.
Jim (Posplayr) suggested I run it to the ouput of my coil/ignition relay.
Works great!