I am putting my toolkit together that I will carry with the bike. Right now, it is a slime tire plug kit, the nice snap on tool set from Harley, zip ties, duct tape, and a li-ion battery back for jump starts. Standard toolkit for any of my bikes.

Interesting issue with the Fat Boy, that from what I can tell is an issue with any 2018+ Fat Boy.

What are you doing to expose your terminals so that you can jump start it if needed? Getting to the battery terminals to do a jump start is just not going to happen. Especially on the road. The 2018+'s have the battery pretty nicely hidden away so it is hard to get to. The SAE wire cannot handle the load. I am considering using a WARN winch connector to expose the terminals so I can get to them, and then I could clamp on to those. Similar to this:
Any better suggestions?

 

Are you able to get to the batt cable at the starter with your jumper cable??

 

I can't see how to get in there to the positive terminal. However, I think I have a better solution!

I checked to see if companies that build these Li-Ion packs have battery cable adapters that plug into their seemingly proprietary connectors. Turns out, Noco makes one. The Noco unit looks a lot like the Harley "Booster Portable Battery Pack". They may be the OEM. Not sure. However, here are the parts:
cable: https://no.co/gbc007
Li-Ion pack: https://no.co/gbx45. (one of the four supported models for this config)

Quick compare of the Harley device with the Noco GB40
https://www.harley-davidson.com/us/e...ack/p/66000130
https://no.co/gb40

 

Remove the right side cover, move the rubber cap aside, hook up to the starter lug shown with the arrow. This would be your positive lead, then ground anywhere.

 

I had the right side cover off on a 2018 Fat Boy the other day, I was looking for the starter terminal. I didn't find it. I think because of the wide rear tire that it may not be as accessible on the Fat Boy as it is on the Heritage. The NOCO Boost X with the Eyelet cable looks like a good system. No right side cover removal.

 

As mentioned in previous posts above and added yet another pic from an old post.

 

I’ve already got a Noco jump pack so I just picked up the leads that hood directly to battery for that wired up. Pull off seat and hook and all good

 

Yep, that's my post, you can easily get the NOCO/H-D Boost on those two points, I have the H-D versions basically as it is identical to the NOCO as I got a great discount on it that made it cheaper, I have the NOCO storage case though as that is cheaper than the H-D version.
I also use those points when using the battery tester too!

My wife's '18 FLDE was jumped started by the recovery guys with no problem using those two points when the battery went flat overnight, you don't need to remove the seat just the right hand panel!

 

Is that a Fat Boy? The OP's Fat Boy has the external preload adjuster mounted under the side cover. Could possibly limit access to the starter lug?

 

You can get to the top of the battery on any 2018+ Softail by removing the seat and using a big ol' screwdriver to get to the positive terminal. Put the positive jump clip on that. It works, but it's a less than ideal solution.

The best solution is to buy a Noco (or similar) permanent battery harness for $25 and fit that to the battery, then stash the connector under the seat. 30 seconds to remove the seat, connect the harness to jump pack and BAM. She's good!

https://no.co/gbc007

Of course, you will need the same brand jump pack. The Noco GB40 is pretty small, powerful and works well.