I agree with @Adrian_Joachim, in that you probably don’t need it. Maybe you shouldn’t even want it.
Some background:
On the FW13, the following bios-functionality is available:
- Charge limit (see FW bios releases, from version 3.07)
You can set it to for example 80% to save your battery life. - Battery disconnect
Available since the first version. - Boot without battery (see FW bios releases, from version 3.06)
There are a few buts though:
Option 2. resets when you plug in a charger again, as also said before. It is meant for when you are opening up the laptop.
With bios version from 3.06 (option 3.), you can run the FW13 without a battery attached. Perfect if you want a Framedeck or use the FW13 Coolermaster-case.
This limits availabe power though (depending on the charger you use).
- With a 60W charger + battery:
The laptop can boost above 60W without a power failure: it will also drain the battery a (tiny) bit, depending on how long this boost holds. - With a 60W charger, without the battery:
You will be limited to 60W. You can however use a 100W charger to overcome this problem.
With the FW16, these options are not confirmed (nor denied) at this point, although I would definitely expect options 1 and 2 to be available from very soon on in the bios.
If these options are available, I would recommend gaming with the battery attached, to be able to briefly get more power out of the laptop. Or possibly use a higher power charger.
In the end you will be limited to the cooling capacity of the laptop and maximum temperatures before throttling of the CPU/GPU. Loads however are not continuously the same, so the extra boost is nice when the temperature allows it.
Coming back to battery wear, what Adrian_Joachim said earlier is definitely true:
It is way worse for battery wear to cycle from 100% to 0% once than to cycle around 70% a hundred times.
For a Li-Ion battery, a charge/discharge curve typically looks like this:
Large drop between 100-90%, almost flat between 80-20%, and again a large drop between 20-0%.
These large drops cause the worst wear. Charging/discharging in the flat area almost none.
So, if you set the charge limit to say 80 or 70%, you will be in the flat, low-wear area and yes, the battery will charge/discharge a bit for higher loads, but without a noticeable impact.
Concluding:
If you set the charge limit right, battery wear in desktop mode due to charging/discharging should not be noticeable, but it will allow higher boosts.
For reference: I have a FW13 as a daily driver for 1.5 years now, most often used in desktop mode and the charge limit set to 80%.
According to linux’ upower, I have 52 charge cycles.