On Thursday, September 10, 2020 at 6:55:22 AM UTC-7, wrote:
On Thursday, September 10, 2020 at 12:48:52 AM UTC-4, wrote:
The bluetooth feature is a gimmick. What really makes these attractive is that they are about 1/2 the price of equivalent the K2 battery!
Some months ago I bought several "PowerSync" (related to "PowerSonic"?) LFP batteries, the non-smart version (no Bluetooth), for about $32 each, from a US seller on ebay. Rated 7.5 AH, and the same standard "brick" size as the common 7AH SLA batteries. At that price, they are cheaper than SLAs (since they will last at least twice as many years). I cut one open, so I can tell you that (1) the ones sold at that price were 2 years old when sold (date stamped late 2017), not great but no big deal, (2) the cells are the small 18650 size, like the ones used in laptop batteries (but LFP chemistry in this case), and (3) yes it includes a full BMS including cell balancing. I've used them in an electric bicycle and in an electric mower, so I can report they work OK in high-drain use (but the BMS shuts off at about 20 amps). In the glider I prefer the larger 12AH battery, but one of these smaller 7.5AH ones is my standard backup plan.

Note that a "7AH" SLA battery that is 2-3 years old will only give you about 3 AH or so if you don't want to damage it by fully discharging it, and the voltage will be pretty low by then. Tested one of these 7.5 AH LFPs by discharging 6 AH out of it, voltage was still well over 13V. The spec sheet claims they are "designed to work with AGM chargers", so you don't even need a new charger if you switch to them from SLAs, although something like the Imax B6 is better.

Powersonic is unrelated to "Powersync" whoever that is. Powersonic is a Japanese company that has been making batteries for decades.

A higher quality charger is the Victron Smart Blue 12V/5A. Will charge any chemistry and is highly configurable through the Victron Connect app. More expensive though.