I have a few that are 3 years old and they don’t have that warning. I have a Folomov A1 magnetic USB charger and I sometimes use it to charge the Olight batteries. The negative contact on the positive end is recessed enough where it should go into most chargers without problems. With the A1 charger if you’re not careful you can get little sparks. But if you just put the positive magnet off center so it is touching the positive post and the wrap it works fine.