2023 MT-07 - Accessory Port Not Supplying Enough Voltage for USB Charger

[BenaroDinero]

Hey folks! First post here, been riding a 2023 MT-07 for just over a year now and been loving it (pics of Yamanatha attached). 

However, I've been trying to kit it out for some longer rides and the accessory port under the left side tank cover is giving me some real trouble. So far I've tried connecting 3 different USB adapters to it, and none of them worked to charge my phone.

My current impression is that for some reason, the accessory port is simply not supplying enough voltage to get past the battery protection circuit on the chargers. Has anyone else had this problem before, or have any thoughts on what could be wrong?

Some of the things I've tried/observed:

- 2 of the 3 chargers have power indicator lights that turn on, so I know it's getting power (but the indicators also show it doesn't have enough juice to start charging) 

- the first charger (Tecmate SAE to USB with MT-090 connectors attached) works perfectly fine when it's connected directly to the battery instead of the accessory port 

- the third charger (Koso brand) switches back and forth between red (not enough voltage) and blue (operational) the entire time it's running

- accessory port fuse is intact and not blown

- bringing the battery up to full charge with a trickle charger did not change things 

For reference, I do have TST Halo GTR turn signals, as well as the TST tail tidy and integrated tail light. My only other thought is maybe these are drawing too much power already? 

[Triple Jim]

My 2020's accessory power connector charges my phone fine.  Is the engine running when you try to charge?  The accessory port has power only with the bike running.

[BenaroDinero]

21 minutes ago, Triple Jim said:

My 2020's accessory power connector charges my phone fine.  Is the engine running when you try to charge?  The accessory port has power only with the bike running.

Yep, the engine's been running when I tried using the port. I also tried riding around for at least an hour with the adapters to see if that will bring the battery up to charge and there's been no difference.

[ElGonzales]

How about simply measuring the voltage at the aux connection with a multimeter? It must be the same voltage that you measure with the probes connected to the battery contacts with main switch on. The motor does not have to be running (around 14V when the motor is running, otherwise probably around 12.4 - 12.8V).

The electric path is only:  battery - (main fuse) - main switch - aux fuse aka terminal fuse - accessory port - ground - battery
Thats all, no magic, no electronics.

If you really have a significant voltage drop from the battery to the port you can carry out further investigations like for a bad electrical connection somewhere. Or let the dealer fix it on warranty

Edited August 26 by ElGonzales

[BenaroDinero]

15 hours ago, ElGonzales said:

How about simply measuring the voltage at the aux connection with a multimeter? It must be the same voltage that you measure with the probes connected to the battery contacts with main switch on. The motor does not have to be running (around 14V when the motor is running, otherwise probably around 12.4 - 12.8V).

The electric path is only:  battery - (main fuse) - main switch - aux fuse aka terminal fuse - accessory port - ground - battery
Thats all, no magic, no electronics.

If you really have a significant voltage drop from the battery to the port you can carry out further investigations like for a bad electrical connection somewhere. Or let the dealer fix it on warranty

Thaat makes sense, thanks! I was worried there was going to be some kind of computer doohicks in the accessory circuit but that's good to hear. I'll have to borrow a multimeter from work and see what's up in there. 

Worst case, what's the likelihood that the dealer will see all the TST goodies and find a way to blame it on me? I was pretty careful mounting everything and they're all plug-and-play, but I feel like all you hear about nowadays is companies trying to get out of warranty coverage. 

[BenaroDinero]

Well this is good news but also embarrassing: 

Turns out I was using the wrong port this whole time. The correct accessory port had white connectors and was electrical taped together, deeper towards the center. It was a pain to get it pulled out but it worked perfectly as soon as I connected the USB adapter. 

 

The port I was originally using had grey connectors (exact same shape as the accessory port), and was closer to the exterior of the bike. Maybe it's a diagnostic/maintenance port or something. 

 

Feels pretty stupid right about now, but hopefully this helps in case someone else makes the same mistake with their 2023. 

[Triple Jim]

That's interesting.  I don't remember the other connector, but maybe I got lucky.  Thanks for the update!

[ElGonzales]

I think it might have been the connector for the optional switch sensor. In the wiring diagramm it has the same shape, but the wires are violet (or something like that) and black. The wires of the dc accessory port are brown and black.