My experience with the BT-2 spans over a year. After finding emails for US based staff for Renogy, I ended up interacting (via email) with an Engineering director in China. Environment and background: I'm in California. Prior to the series of activities associated with the BT-2, I had purchased various Renogy products including five LiFePO 100 amp-hour batteries, six solar controllers, ten or twelve solar panels (all at least 100 watt, hard-framed and flexible), 12v DC power 1000 watt inverters, and various cables, tails, fuses inline power meters and BT-1 modules... all to build a few solar generators Pros: The panels, cables, LiFePO batteries have been behaving fine. All but one solar controller have been fine. Cons: This Ratings link is for the BT-1 and BT-2 modules. Unless the person writing the rating specifies which they are reviewing, it is impossible to know which is being reviewed. There is nothing in Renogy's documentation that says current firmware must be present/active in the Renogy LiFePO battery to which it is connected. Updating old LiFePo battery firmware is challenging, at best. There has been no way, until now, to know what firmware is active in the Renogy LiFePo battery. The BT-2 does not do a lot - it is the connection between the app (smartphone) and the Renogy LiFePo battery. The BT-2 module itself seems to be OK, but the (iOS) app was not so OK. * After accessing the BT-2 app, leaving the app did not tear down the Bluetooth connection. (this was resolved during my year of working through what was originally a BT-2 issue that ended up being a LiFePo battery firmware issue). * There is a "social media" part of the app that is unnecessary. But you can earn points for products. There is no way to know what safeguards are in place from a data security perspective. * Renogy customer service first contact was horrible. Winding through the maze via emails was time consuming, but somehow I ended up with the Engineering Director in China - This person was great. * When the iOS app is connecting to a battery, if "1 batteries" is selected, the app won't recognize that single 12v 100 AH battery. If "multiple batteries" is selected, the iOS app will connect to the single 12v LiFePo battery. (I specify iOS app because I don't know if the Android app behaves similarly.) Ultimately, I ended up sending all of the (in-service) batteries back to Renogy (US) for firmware updates. After a few months, all battery firmware updates finally got done. One of the reasons it took so long was these batteries were all in service supporting the solar generator in which they were installed. I had to replace the Renogy LiFePo batteries with 100 AH lead acid batteries to remain in service to get the updates done. Swap one or two batteries, send them to Renogy to get updated, wait, get the updated battery back, swap with lead acid battery, move on to the next solar generator. The iOS app + BT-2 + current LiFePo battery firmware are behaving relatively well. Getting here was time consuming and frustrating. If you purchased your Renogy LiFePO batteries 2+ years ago and are having problems getting the BT-2 to work, my guess is it is not the BT-2, but the battery firmware version. Good luck getting the battery firmware updated. To top it off, the chronology I had posted with the excruciating detail of the challenges getting through this ordeal was deleted. I did not received any notice from Amazon or Renogy as to when or why. I still like Renogy products, but won't be buying from them anytime soon... Without good customer service first contact, I no longer recommend buying from Renogy.
