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Discussion Starter · #1 · (Edited)
5 Cell 2 AMP 20.8V

Build :
Based on the Linear LTC4012
4Layer 2oz FR4
PIC 18F14K22
700 Lines on C Code.
4D Systems OLED Display

This was a lot of work. Now I wont be at the mercy of stock chargers...:D

Dwight
 

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That certainly is impressive!
Is is set to 5s batteries or will there be options / software changes available for smaller batteries?

I like it as I use 5s batteries!
 

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Awesome work. Nothing beats being able to make your own boards and having something designed exactly to "your" needs/specifications :)

Will
 

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Discussion Starter · #11 · (Edited)
Formatted Screen.

The design will support 3s,4s,5s packs with varying current from 0-4amps. 95% eff ->(Synchronous Buck). Minimal heating with all components under 40C @ Worst case (45watts). To be honest its surprisingly stable and well behaved. The LTC4012 does most of the heavy lifting and the PIC monitors time,temp, voltage and current. The PIC basically tracks the process, updating the OLED, and stops the process if the time gets to long, no current, over voltage, over temp, and termination 0.1C of charge. The OLED from 4D systems is really nice and dead simple to control with serial commands. OLED's look great.

I was using an Digital RC Charger since cheapo 5S chargers are few and far between. Plus the RC chargers did not play nicely with the batteryspace PCB protection design. I had difficultly starting the charge process after the PCB disconnected the (+) due to low pack voltage. Also, Very Few of the digital RC chargers support unbalanced charging.

One word of warning... The Microchip MPLABS IDE XC8 (aka Microchip C Compiler) is not for the weak of heart. It might be FREE but It will make you work for it.... And please avoid the sprinf()..it a hot mess. I have to admit it has a very nice debugger :D

PCB Layout Software and Boards are from PCB Manufacturer in Aurora Colorado Manufacturing Annular Ring, Printed Circuit Board Fabrication, Printed Circuit Boards, PCB Prototype Circuit Board's Its FREE...Tinny Tiny learning curve but once past it , I have really enjoyed designing PCB.

Dwight
 

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Nice work. That's a new PCB fab house that I haven't heard of, will have to file that away for future reference. I've always used PCB Software | PCB Design Software | Sunstone PCB123 and don't really have any complaints, but I'll have to compare prices next time I do a board.

One word of warning... The Microchip MPLABS IDE XC8 (aka Microchip C Compiler) is not for the weak of heart. It might be FREE but It will make you work for it.... And please avoid the sprinf()..it a hot mess. I have to admit it has a very nice debugger :D
That's good to know about the microchip free 'C' compiler. I've always used the CCS C compiler for PIC chips, and it's quite good, but it's not free. I had thought about switching to the Microchip compiler but think I'll stay put.

I'm also using AVR processor more and more now. The free tools are good and there seems to be more freely available software libraries and other goodies available.
 

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Discussion Starter · #16 · (Edited)
Finally finished the charger. Works nice. the OLED screen was a train wreck. 4d Systems, The Manufacture, changed the firmware so I had to rewrite the software and the PCB. Using the enclosure as a heat sink turned out well...fan-less. Only took 10 months to complete.. :cool: Time to focus on the bike lite..

Dwight

Li-ion Charger 1.JPG Li-ion Charger 2.JPG
Li-ion Charger 3.JPG
 

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Very nice. Beyond my skill/patience lvl but luckily I kept my good charger from when i was big into rc.

Sent from my HTC Sensation Z710e using Tapatalk 2
 
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