Need Circuit Schematics - Page 1
Forum section: electronics / projects

author: dellsam34
author_rank: Regular Contributor
timestamp: September 20, 2021, 10:37:04 pm
content: I have off the shelf BMS, Voltage converter and 6 function remote switch receiver that I want schematics for so I can merge all of them under one single schematic to be put into a circular PCB about the size of a CD (I used CD analogy because the PCB will have approximatly the same size and a center hole as well).My online search so far came up empty since most of the scematics are for different devices with different Amp ratings, I've included pictures of both sides of the devices I have now for testing purposes but I'll be moving to the design stage once the testing is done and put all the PCB's in one single PCB.Basically the circuit works this way:A Li-Ion pack (4S-2P) powers up a set of 6 independently controlled devices, The devices require a steady 13V so a buck converter is used to convert the voltage from whatever voltage state the battery pack is on to 13V, then a multi function switch is used to turn ON and OFF the devices individually and remotly using a 6 button RF remote control.If anyone used these exact PCB's and have schematics please share them with me, Thank you:Top - 4S Battery Management System,Middle - Buck Converter,Bottom - Multifunction Switch Receiver:

author: dellsam34
author_rank: Regular Contributor
timestamp: September 23, 2021, 08:32:10 am
content: Anyone used this gadgets before?

author: aewm96
author_rank: Newbie
timestamp: September 23, 2021, 01:40:11 pm
content: I would be a little surprised if you managed to find the schematics laid out if I'm honest.I am making an assumption here so take it with a grain of salt but the boards seem to be 2 sided PCBs so you could reverse engineer the boards based on the tracks, continuity testing and looking up component datasheets. The component data sheets tend to have recommended circuits which is often what these companies will use. I hope this is for DIY because then reverse engineering would be fine but if it's for commercial then it's a real grey area.Unfortunately, I've never used these boards before!

author: Terry Bites
author_rank: Super Contributor
timestamp: September 23, 2021, 03:43:13 pm
content: This should be a simple reverse engineering job. The PCB with the power transistors appears to be a subtantially made of identical circuits. Ditto the relay board. The wireless unit is very likey a low cost generic module and not worth the time.Start by looking at the LTC1625 datasheet and figure out what topology they have used. Id'ing the other 20 components around the control IC should be pretty straight forward. See Dave Jones excellent RE videos eg

author: dellsam34
author_rank: Regular Contributor
timestamp: September 26, 2021, 04:42:03 am
content: Quote from: aewm96 on September 23, 2021, 01:40:11 pmThere is an intent for mass production as a final product that is used for another purpose, the assumption is that these circuits are generic and don't hold a patent, But I may have to do some legal consultation before attemting to get serious.

author: dellsam34
author_rank: Regular Contributor
timestamp: February 20, 2022, 06:18:27 am
content: Anyone willing to take the job? Please send your questions and estimate via a PM.

author: strawberry
author_rank: Super Contributor
timestamp: February 20, 2022, 09:16:11 am
content: Quote from: dellsam34 on September 26, 2021, 04:42:03 amI think china dont have patents at all or any regulationsThese particular circuits are decades old and can be found in appnotes or on web

author: daisizhou
author_rank: Super Contributor
timestamp: February 20, 2022, 01:15:38 pm
content: I would never buy this circuit。Because it is mass production, although lithium battery cells can be controlled, the consistency of each cell cannot be guaranteed.I'm assuming you bought it on Alibaba's website?

author: strawberry
author_rank: Super Contributor
timestamp: February 20, 2022, 01:54:01 pm
content: BMS OVP and UVP works fine if it has onebalancing works only if all cells are fully charged above threshold. small resistor will do it slowlyshort circuit protection is not good at all(permanent MOSFET explosive failure) if it has one

author: dellsam34
author_rank: Regular Contributor
timestamp: February 20, 2022, 11:19:54 pm
content: Thank you guys for the reply, I just need the schematic design, I don't have a problem with the Li-Ion battery pack part.Short circuit protection should be implemented offcourse, Even the buck converter I used has already one.