Hello,
I hope i will find some help here.
what i am trying to do is to charge my surface pro 2017 from a external Li-Ion battery pack instead of the AC charger.
the rated values from the AC charger of my surface are 15V , 2,58A
i am using 12 x ( 18650 cells ) in 3 series and 4 parallel config so the output of the pack is 10,8 - 12.6 V (Max discharge current 5A per cell ; 20A for the pack ).
I am using a 3s BMS for the pack and, a buck-converter (Max current 4A) to boosted the 10,8- 12,6V to constant 15V.
the good news is it works ! the bad news it charges too slow !
when i measured the charging current i found that it is significantly less than the measured charging current when using the AC charger!
some mesurments results :
when charging using the pack -----------> Iboost ~ 0.8 A @15V
when charging using the AC Charger ---> ICharger ~ 2.3 A @15V
and now my actual question is:
i don't understand why the surface drowse different current if the Voltage is the same (ohms low !) !?
how could i possibly solve this problem !?
I hope i will find some help here.
what i am trying to do is to charge my surface pro 2017 from a external Li-Ion battery pack instead of the AC charger.
the rated values from the AC charger of my surface are 15V , 2,58A
i am using 12 x ( 18650 cells ) in 3 series and 4 parallel config so the output of the pack is 10,8 - 12.6 V (Max discharge current 5A per cell ; 20A for the pack ).
I am using a 3s BMS for the pack and, a buck-converter (Max current 4A) to boosted the 10,8- 12,6V to constant 15V.
the good news is it works ! the bad news it charges too slow !
when i measured the charging current i found that it is significantly less than the measured charging current when using the AC charger!
some mesurments results :
when charging using the pack -----------> Iboost ~ 0.8 A @15V
when charging using the AC Charger ---> ICharger ~ 2.3 A @15V
and now my actual question is:
i don't understand why the surface drowse different current if the Voltage is the same (ohms low !) !?
how could i possibly solve this problem !?
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