3s BMS charging rate - Way too Low?

[overdose]

Hi,



I want to understand something.



I made 2 DIY bluetooth box.



1.



4s ebay BMS, on ebay 18650 2000mAh cells, on a 60w 16.8v transformer.


Batteries are fully charged in about 4h, and it draw about 18W.

2.



My second box, got a ebay 3s BMS, with Boston Power 4400mHa batteries , on a 12.6v 30w transformer.



Batteries get fully charged in about 30hours, and only draw 4w.
9.6v to 12.6v in 30+h... way too long.



[Q] What could limit the charging level ? Battery can take 8A, transformer can push more, connected on the amp I had 32w peaks.



defect battey ? not impossible but they are quite new, and they hold 4.2 v.

thank you

 

[SemperFi]

Yo! This DIY AUDIO not DIY RC hobby or DIY rebuild my bicycle to E-vehicle.

 

[overdose]

wait what, who's talking about RC?


Its an integral part of a DIY portable audio system, and known as a power supply by definition, since is supplying power...


in topic, and pretty sure someone qualified in that can answer me here.