I prefer the BMSBattery products.
Suit my needs and at a reasonable price.
The packs are well-constructed single units complete with advanced BMS. Charger included.
The specs overall meeting, again, my needs.
As for weight?
I tried numerous times to submit a comment but with no success. Was told by Annie Lei that the comment system wasn't operational. But my message regarding pack weight did hit home as the site page was updated to the correct weight of 7 kg. from the original, and erroneous, 4.8 kg.
Page seen here…http://www.bmsbattery.com/48v/249-48v-1 ... -pack.html
Here's what Annie Lei wrote to me…
"Just check the weight of the battery, it should be 7KG, they write the wrong weight on the website. Sorry for that! We will check carefully in the future. For the comment page, it seems it never works; I try it also but no work, I will check with the technician department next week."
And I've been using my packs on a daily basis for just over six months with no issues. Many of the rides are up to 175 km.
There hasn't been any reduction in capacity at all. First battery still at 19.6 Ah while the second is still at 20.4 Ah.
As for the size of the latest packs?
Slightly larger due to different cells being used.
Here's what Judy Liu wrote to me…
"Different battery pack ( different cells ) has the different dimension. Now the order #3115 is 300 X 185 X 75mm more or less. Thanks."
The packs overall are great.
I'm completely satisfied and will definitely buy again.
Good luck with whatever buying decision(s) you make.