TLDR: A diode for 3 amp forward current and possibly 50amp reverse
So i upgraded an old NiCd batteries for a makita drill to run on lithium. The batteries consist of 4x 18650s and a balancing charge controller rated to ~40 or 50 amp peak draw and takes anywhere from 14-17V input to properly charge the system. The batteries work great and were relatively cheap to make at the time.
However, i have had endless problems with the charger i made to go along with it, its a simple setup with a 19v 3.5amp laptop powersupply running into a generic CC CV buck converter to take the 19v down to 17v -ish that the BMS needs and caps it at 2.5 amps. Every so offen however, the charger will trip what i believe is an over current protection in the power supply which i would not think would be a problem. I have found that the battery then powers the light on the buck converter after the charger is unplugged (i had assumed that because the buck converter is setup for solar charging it would have reverse polarity protection, apparently not).
I have tried wiring in a diode i had on hand (a 1N4001 i believe, something small and commonplace) but this drops my charging current down to anywhere between 300-800 mA. I assume this is just because I am sizing the diode wrong so the main question i have is, what is a suitable diode for say 3 amp forward current, a peak reverse of 50 amp (this is the part that i am not sure about) and as the power supply input voltage and the charger output are relatively close, something with a smallish/suitable voltage drop. Of course on top of all of this, something that is also cheap which was the main motivation behind this whole project.
I believe it is as simple as just a diode but then again i have no actual education in electronics other than a single electrical engineering class in University so i may have made a massive mistake, any insight would be great.
Cheers,
SimpleJoe
EDIT, the parts:
CC CV buck converter:
https://www.banggood.com/3pcs-DC-DC...a5ZpOfyc995d2dRoCk-0QAvD_BwE&cur_warehouse=CN
The BMS (I think):
https://www.banggood.com/4S-30A-14_...Board-Balance-p-1140544.html?cur_warehouse=CN
So i upgraded an old NiCd batteries for a makita drill to run on lithium. The batteries consist of 4x 18650s and a balancing charge controller rated to ~40 or 50 amp peak draw and takes anywhere from 14-17V input to properly charge the system. The batteries work great and were relatively cheap to make at the time.
However, i have had endless problems with the charger i made to go along with it, its a simple setup with a 19v 3.5amp laptop powersupply running into a generic CC CV buck converter to take the 19v down to 17v -ish that the BMS needs and caps it at 2.5 amps. Every so offen however, the charger will trip what i believe is an over current protection in the power supply which i would not think would be a problem. I have found that the battery then powers the light on the buck converter after the charger is unplugged (i had assumed that because the buck converter is setup for solar charging it would have reverse polarity protection, apparently not).
I have tried wiring in a diode i had on hand (a 1N4001 i believe, something small and commonplace) but this drops my charging current down to anywhere between 300-800 mA. I assume this is just because I am sizing the diode wrong so the main question i have is, what is a suitable diode for say 3 amp forward current, a peak reverse of 50 amp (this is the part that i am not sure about) and as the power supply input voltage and the charger output are relatively close, something with a smallish/suitable voltage drop. Of course on top of all of this, something that is also cheap which was the main motivation behind this whole project.
I believe it is as simple as just a diode but then again i have no actual education in electronics other than a single electrical engineering class in University so i may have made a massive mistake, any insight would be great.
Cheers,
SimpleJoe
EDIT, the parts:
CC CV buck converter:
https://www.banggood.com/3pcs-DC-DC...a5ZpOfyc995d2dRoCk-0QAvD_BwE&cur_warehouse=CN
The BMS (I think):
https://www.banggood.com/4S-30A-14_...Board-Balance-p-1140544.html?cur_warehouse=CN