A reminder of Valve’s FAQ, given recent article on Websites trying to contradict (e.g. https://www.slashgear.com/...):
If your device has been left on the charger for long periods of time, it may report less than 100% charge. This is normal. We allow the battery to slowly discharge after long periods of time under charge to optimize long-term battery health.
I’ve had my deck since last April and it sits on my bedside table, plugged into the charge pretty much 24/7. Last time I had it off charge in the car (2 weeks ago) the battery behaved perfectly normal and gave me around 3 hours playing fallout NV. So I can confirm my deck is perfectly safe being left on charge.
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