Sena SR 10 Noise

[Great_Kubuki]

Sorry if this has been covered but I could not find an answer. I have a Sena 20s paired to an iphone for calls, music, google maps. Phone is powered by its own battery or a 12v iphone lead to a wired to battery port for power. Everything works fine on or off charger cord and when the bike is on or off.

 

I have a Sena Sr10 paired to the Sena 20s. I would like to power the SR10 from the bike so its one less thing to charge every night. However, when I plug in the supplied 12v micro usb power cord for the SR10 there is loud buzzing coming through the Sena 20s speakers. Plus any accessory or function involving sound is gone due to the buzzing overpowering it. As soon as you unplug the power from the SR10 everything sounds great, phones, radar detector input to SR10, basically perfect. Plug in the power to SR10 here comes the buzzing. I must note this happens when the bike is running and not running.

 

So I am assuming its a ground loop issue with the BMW electrical system,and not audio issue since the SR10 does this with nothing plugged into it when tested. No inputs are turned on, no music, no radar unit piped in, no gps, its as soon as you plug power into the SR10 that it starts humming in the headsets of the Sena 20s. Its not bike model specific happening both to K1200GT 08 and 08 R1200 GS.

 

Anyone have suggestions? Device or in line filter module?

 

 

Cheers,

 

 

Mark

Edited August 29, 2016 by Great_Kubuki

[Danny caddyshack Noonan]

Just spitballing here:

If that is the USB micro connection, perhaps locate a "CHARGE ONLY" cable and see if that works?

I've prepped for what you're doing, but never needed it yet. I think I've got a charge only cable from some interwebs link for that and phone charging when pulling power due to GPS and apps.

[RT Russ]

Use an audio isolator in line between anything lowered by the bike. I had to do that with the Sena when using iPod and V1 audio through it. Not expensive, just another device taking up valuable space though.

 

Russ

[Great_Kubuki]

Thanks but as mentioned its not an audio issue its dirty power, or GLI on the 12v side. Audio isolator just masks the issue about 85% and then you cant hear whats plugged into SENA SR10 like a Bel 8500 Radar Detector or other items. The Sena SR10 broadcasts just fine without being powered. So its definitely a 12v power issue. Im thinking of soldering in Dc to Dc convertor. Was seeing if anyone else has had issues trying to power SENA off bike while using the Sena SR10.

[MikeB60]

I've had the same issue with a RT and my GT. Not sure why you state that an audio isolator creates an issue where you cant here what's plugged into the SR 10. I have the audio system of the bike and the radar detector plugged into a SR 10 through separate audio isolators with no loss of volume. Absolutely no noise on either input. Its defiantly a dirty power issue but the audio isolators take care of the issue for me.

[RocketMoto]

Mark:

 

We are talking about an SR10, not an SM10, right?

 

What are you using the SR10 for? Radar detector? Bike-to-bike radio? Which audio accessories are connected to the SR10, and are any of those powered from the bike?

 

What are you using for a USB power adapter for the SR10? A Sena cigarette power cord, or the Sena USB cable with some type of USB power? If a power adapter, specifically which one?

Edited September 4, 2016 by RocketMoto

[Brad_H]

Hi Mark,

 

I'm going to be doing the same basic project as soon as Sena gets their new Freewire shipping. I'm tired of the terrible BT on my 2016 R12RTW so I'm going to BT from the speakers to my Sena headset with the Freewire. Inevitably I'll face the same power noise as you or do the multiple recharging every night.

 

In general, you need a large low-frequency LC-filter on the power. While I don't have one tested or selected at this point, I'd look at Ham Radio forums and the like for something like this (http://www.rcdude.com/product-p/hp-fpfltr12v.htm) - again, not a recommendation for this particular product. DC-DC converters are seldom the answer as they are notorious for both conducted and radiated emissions (noise on their outputs and noise they radiate electromagnetically). I avoid them whenever possible.

 

Finally, wiring a shielded-twisted pair directly from the battery might help a little. Ground the shield at the battery end only and use the wires only at the SR-10 power-filter input. Route away from the engine and its equipment as much as you can.

 

Good luck and keep us informed on your progress and pitfalls.

 

Regards,

Brad