Battery project, suggestions welcome - Page 1
Forum section: electronics / projects

author: RienL
author_rank: Newbie
timestamp: July 13, 2025, 03:10:13 pm
content: For a battery related project I am looking for suggestions and tips on how to start this up. I have an electronics education, but have been out of this sector for many years. As such, the amount of currently available measurement devices and software is daunting and quite chaotic at first glance. Some assistance could go a long way to speed up the project.The goal of the project is to develop a recipe for a DIY Nickel-Iron (Edison) battery.To achieve that the charge and discharge cycles should be controlled and measured in some detail.Obviously I will need measuring device(s) for voltage and current. As well as software controlled current drivers.What are the currently available options on the market for: recording voltage & current (simultaneous, say once a second, over a couple of hours duration) Both hardware and software.And are there any current drivers that are completely software controlled? Is there software that can control the current drivers for several hours out?All hints and idea's are greatly appreciated.Btw: the target OS for all of this is Linux. Open source projects are strongly favored.PS: I realize I could build the above myself, but that takes too much time. The goal is to start working on the core project asap.

author: ledtester
author_rank: Super Contributor
timestamp: July 13, 2025, 05:34:00 pm
content: What charging/discharging currents will you be dealing with?

author: RienL
author_rank: Newbie
timestamp: July 14, 2025, 05:19:55 am
content: Initially very low. Just a single cell, and a small one at that. I.e. less than 5 V and less than 1 A.Later on it will become bigger, but nothing has been decided on just yet.If I have to guess, 40V and 100A should be the absolute max.For now, I'd be happy to get the design & chemistry right. For which 1 cell should be enough.

author: Paradroid
author_rank: Contributor
timestamp: July 14, 2025, 12:04:29 pm
content: For that single cell, I'd start a design with the RPi Pico. It has a few analogue-in pins and you can use precision resistors as shunts, making an easy transition from current to voltage, which you record with the AD converters of the RP2040 (or maybe the RP2350, as the RP2040 has an errata for the AD converters that affects linearity if I remember right). For switching, you can use FETs that allow direct connection to a logic pin. The USB interface of the RPi Pico lets you make the connection to your Linux PC and transfer measurement data.For 40V and 100A, the same principle applies, but you'll have to choose more beefy FETs and at that kind of juice, it'll have to be separate gate drivers. There's no FET that accepts logic level on the gate and can switch 40V/100A. At least not a silicon FET - maybe GaN does the trick? Anyone with experience?

author: ledtester
author_rank: Super Contributor
timestamp: July 14, 2025, 01:53:42 pm
content: Quote from: RienL on July 13, 2025, 03:10:13 pmThere are electronic loads which have a serial control interface. On the cheaper side the DL24 available from Aliexpress (and possibly Amazon) comes to mind:- Python code to control and log readings:https://github.com/dimas/DL24-pythonYou can find a lot of discussion of the DL24 on this forum on the web.

author: ledtester
author_rank: Super Contributor
timestamp: July 14, 2025, 02:21:25 pm
content: For charging are you going to charge using CC until the battery gets to a certain voltage?You could use a lab power supply that has a serial control interface.On the cheaper side there are numerous buck converter modules available which have a CC mode and some of them have a serial interface.Here's an example:-https://web.archive.org/web/20200824183853/https://benjames.io/2018/06/29/secret-uart-on-chinese-dcdc-converters/-https://github.com/qcasey/drok-https://github.com/bengineer19/BuckPSUAnother one to investigate is this one:https://www.droking.com/dc-buck/250W-Voltage-Regulator-DC-6-55V-to-0V-50V-5A-Programmable-Power-Supply-Module-Adapter-With-USB-Bluetooth-Communication-BoardAlso, the SK120, SK150, SK150X buck-boost modules are MODBUS controllable:https://www.aliexpress.com/i/3256808015329433.html

author: RienL
author_rank: Newbie
timestamp: July 15, 2025, 11:59:22 am
content: @Paradroid That is an option, but for this project I would really like (if cost effective) to refrain from DIY electronics just so that I can concentrate myself on the core project and not get distracted by side-shoots. (I am known for that to happen!)@ledtester Yes the Nickel-Iron must be charged with CC instead of voltage levels. Its thermal response to charging is decreased the voltage, creating possibility for thermal-runaway so I read. Thank you for the links, I will check them out.Edit: 2025.07.19 Changed the original text concerning CC charging

author: ledtester
author_rank: Super Contributor
timestamp: July 15, 2025, 12:57:45 pm
content: For recording voltages here's an old thread with some suggestions:https://www.eevblog.com/forum/testgear/cheap-data-acquisition-device/For measuring current you probably will have to supply your own current shunt and use a differential voltage measurement. Some of the DAQs mentioned can do diff measurements but if you need to amplify the signal you might have to do that yourself.Then there's always using an Arduino and a INA226 module.

author: RienL
author_rank: Newbie
timestamp: July 16, 2025, 12:18:05 pm
content: Thanks ledtester, the DATAQ DI-1100 in that thread looks perfect. I really need the differential measurement channels the DI-1100 has. And its price is very reasonable.

author: RienL
author_rank: Newbie
timestamp: July 28, 2025, 08:42:24 am
content: I found this product that seems to be the answer to my dreamshttps://www.westmountainradio.com/product_info.php?products_id=cba5Next up is my holiday...Will be continued.