Nintendo Switch left Joy-Con disconnects frequently. Fix?

This is a known design flaw which is only effecting early models of the Switch.

It's something to do with electrical shielding (or something technical).

First try these steps to make sure you are using the Joy Con correctly

Joy Con Not Responding or Responding Incorrectly When Used Wirelessly

If that didn't work, talk to Nintendo and they will "fix your problem for free" - which means you send in your joy con and they fix it and send it back. This can take up to 2 weeks.

Here are some helpful links for support:

Contact Nintendo Support in America

Contact Nintendo Support in Australia and New Zealand

Contact Nintendo Support in Europe

I have exactly same issue. Left JoyCon, lag most of the time, sometimes disconnects. Try to sit close to the console (like 1 meter) - this seems to helps a little but even then it happens every now and then.

Otherwise you might want to consider exchanging to a different Switch console in the shop.