I saw the DJI charging hub is about $60, and I found one on amazon for about 20, it has good reviews, but no one updating about long term. Has anyone used any 3rd party charging hubs and has had no issue with battery health?

Hello and good day Clare_G101. Thank you for reaching out and for the inquiry.  I hope that you will get the best information and recommendation from our valued DJI co pilots who uses the said accessories.  Just a friendly reminder that we do not recommend you to use a 3rd party accessories on your DJI Mavic Pro. Actually, there is a  possibility that this accessory will work, however, since it's not yet tested by DJI we cannot guaranteed the reliability of the said accessory when in use. In addition using 3rd party accessories or devices might cause damage or harm on the DJI Mavic Pro and can void the warranty as well. Thank you for your understanding and valued support.

DJI Stephen Posted at 6-28 16:07
Hello and good day Clare_G101. Thank you for reaching out and for the inquiry.  I hope that you will get the best information and recommendation from our valued DJI co pilots who uses the said accessories.  Just a friendly reminder that we do not recommend you to use a 3rd party accessories on your DJI Mavic Pro. Actually, there is a  possibility that this accessory will work, however, since it's not yet tested by DJI we cannot guaranteed the reliability of the said accessory when in use. In addition using 3rd party accessories or devices might cause damage or harm on the DJI Mavic Pro and can void the warranty as well. Thank you for your understanding and valued support.

That is what I thought, haha. Thank you!

Clare_G101 Posted at 6-28 16:31
That is what I thought, haha. Thank you!

You are very much welcome Clare_G101. Have a safe and happy flying always.