We all have Sena and some are very problematic. Started out with 20S 6 years ago on a Goldwing 2005 and they worked good. Still had some issues, but for the most part intercom worked and the SMH10 bike interface also worked. Then entered the Freewire on the scene, this worked better with bike interface. Moving up to the 2021 model, the 20s worked fine and I could connect 4-5 more local riders in group intercom just fine.  I then started having battery issues with one of my 20s. One unit that would go full charge, in about 30 min, say 100% when asked on the headset, but would only last 30 minutes and go dead.  Searched e-bay and bought new battery, but the new battery was faulty.. At the time I was going on a long distance ride the next day, so instead of fighting with batteries, I decided to get a new pair of Sena 50s from cycle gear. These worked great, nicer sound, connectivity was somewhat solid with the 2021 wing. But here is the issues I've had..

1. The headsets have a wind noise problem. (mainly passenger gets more wind now even with the over large F4 windscreen) develops wind noise. tried numerous things but wind noise still an issue.  She (and I) wear a modular helmet.  Even fully closed we get wind noise induced by the contact with helmet.  Firmware and factory reset did not fix.
2. Paring the phone to the bike on bluetooth, sometimes will connect or not. this is intermittent.   

3. Tried Second phone pairing on sena and it works whereas the phone is paired to bike on First phone paring. (AD2P). I pair my iphone to bike normally under phone paring and the bike controls my iphone and i can make and send calls ok. But bike doesn't allow second rider to do the same. So the spouse, pairs her sena to bike using normal pairing mode so she can listen to radio, then pairs her Iphone with her sena using "second" Phone paring mode on sena so she can make and answer phone calls. This works.
3. Next comes the most irritating part.  Connecting more than 4 other 20s EVO Sena users in a group intercom.  Creating more than 3 other users is impossible with bluetooth intercom with the 50S (4 total) 50s has 4 max limitation (including self). In comparison 20S and 20sEvo could do a lot more in a Group intercom (not mesh).

So I have the following scenario,
(Bike 1,Rider=50S, Passenger=50S),
(Bike 2, Rider=20EVO, Passenger=20EVO),
(Bike 3=Rider 20EVO)

Using the smart intercom barcode, The sena app on my iphone crashes, when i attempt to smart intercom a 20sEvo user in the 3rd slot. Just disconnects the iphone from the app. Now only way to connect all 4 (bike 1 and 2) is to use one of the 50S as a bridge. (R-50S <> P50s <bridge> P20s<>R20s and the users at the end of this have really bad connection but it does work. However getting bike 3 in the mix was/is impossible. Even trying a group with the 20s

Next we tried reversing using the Group mode on one of the 20S that supposed to allow up to 8 riders... well it worked for all the 20s users and our 50s would show up in their list, but our 50s would not connect with their group on their 20evo's. So that failed.

Granted, if all were 30K or above, this would probably be no issue using the Open mesh or Group Mesh capability, but when other riders use the 20 it doesn't.

I'm able to get bike 1 and 2 using group intercom using the 50s as a bridge but for some reason, using the smart intercom doesn't work. The app crashes as soon as I connect the 3rd additional user.

So now, comes Sena with their fix of getting the older 20s up to mesh with a B2M (bluetooth to Mesh) adapter.. yep something else to buy.. that allows you to connect a single unit 20sEVO to open/group mesh for a kicker price of 119.00 each. Yep but only one per helmet.. plus now each older unit user would have to stick something else on the bike to make theirs work. Now each of my fellow riders would need to purchase one of these to be able to connect to my 50S group mesh.. Why cant they just make a single B2M unit that allows at least 2 riders to connect to and then transmit open mesh? Why didn't they just leave the 50s with backward group capability?

So, after numerous factory resets, clearing all parings, and getting extremely frustrated, were back to only 4 talking (two of them breaking up badly). And with the 3 new 20sEVO owners not wanting to spend another 119.00 per headset on top of their already expensive purchase. were going to see if we can get the battery in our old 20S to revive it.

And another thing, Sena has come out with the ST but it doesn't fit on the standard 20/30/50s's helmet mounts... why? I'm all for making them better water resistant wise, but really, they could have made a bare ST to interchange with the older standard mount.

I do like the Sena, when they work they do a great job, and we had no issues (or less issues) when we all used the 20s's but things get really complicated when trying to bridge old and new.

That is my 2 cents...
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