Hardware Joycon draining switch battery

[Rasa39]

So I know this probably isn't a big issue for most people, but I've recently started using the switch in handheld mode more often and I've noticed that the joycons are constantly fully charged from the main unit.
This is really annoying now that I've noticed it, as I use a pro controller in docked mode, I never need the joycons to be charged at all when undocked as the switch will certainly die before they do, then it's back to docked mode charging for all 3 batteries. (I mostly move around the house so the dock is nearby)

According to Nintendo the switch is not supposed to power the joycons on handheld mode if it is low on battery, but mine seems to charge regardless.

Spoiler: Nintendo UK

I always have 100% charged joycons even if my battery is 5%.

Being from the UK means I have a 3 pin power adapter which is chunky af, so even if I got a second charger for my switch (rip off at £25) it wouldn't be very portable and I don't want to mess about with third party chargers/battery packs when I just want a little more time in handheld, which I feel could be had if the unit wasn't constatly charging the joycons.

Is this common and is there any homebrew solution that I'm not aware of? (my searches mostly find people complaining about lack of charging, rather than my issue), appreciate any help.
I updated the system to 7.0.1 yesterday and just noticed there is a new controller update, so I'm hoping this fixes things but no guarantees.

 

[Kubas_inko]

It will charge their batteries and then the joy-cons will use power from the switch battery. So they are not charging, they're just using the Switch battery as power once they are 100%.
There is no homebrew to stop joy-cons from charging IIRC. But it would be pretty useful (and also very useful the other way around, cause joy-cons together have about 600mah, that's like 15-20 of the switch battery)

 

[Rasa39]

It will charge their batteries and then the joy-cons will use power from the switch battery. So they are not charging, they're just using the Switch battery as power once they are 100%.
There is no homebrew to stop joy-cons from charging IIRC. But it would be pretty useful (and also very useful the other way around, cause joy-cons together have about 600mah, that's like 15-20 of the switch battery)

Oh so that's how it works, well that is equally as dumb considering it defeats the purpose of the whole "not charging if switch battery is low" feature that Nintendo have built in. Thanks for the info.

But that being the case, is there any known way of having the joy cons connected, whilst not being detected as on the rails? I know this was a "feature" with modified joycons before they started bricking. (I have an unused reed switch mod so never had that problem).

I'm no developer, but maybe an "easy" way to achieve the sort of homebrew I'm thinking of, would be to disable the rails on the switch itself (or joycons), so that you can slide then on the rail whilst only being connected as bluetooth like how those fat fake-cons work. And therefore not draining the battery. (Maybe as a sysmodule that can be toggled on/off or can autodetect docked mode and re-enable the rails.)

Also sorry for posting this in the wrong section, I didn't even realise.