How to make a dummy load for testing - Page 1
Forum section: electronics / projects

author: yannickg
author_rank: Newbie
timestamp: February 28, 2020, 04:08:09 am
content: I'm currently working on a battery supply with protection/charging and I would like to test battery discharge but right now I only have LEDs as a load and current use is low so discharge is too slow.I tried adding more LEDs but it seems like the circuit cuts off for some reason.Is there a better way to have a manageable load that I could adjust or calculate to drain my battery at an acceptable rate?I'm using a li-ion 18650 3300mah.Thanks

author: MarkF
author_rank: Super Contributor
timestamp: February 28, 2020, 05:23:22 am
content: Here is what I did:https://www.eevblog.com/forum/beginners/struggling-with-dc-load/msg2698044/#msg2698044Max current 2.5A at about 40W with fan.

author: yannickg
author_rank: Newbie
timestamp: February 28, 2020, 11:52:27 am
content: Would you mind giving a basic explanation of what the circuit does please?Thanks

author: MarkF
author_rank: Super Contributor
timestamp: February 28, 2020, 04:44:00 pm
content: Quote from: yannickg on February 28, 2020, 11:52:27 amFollow the link... Watch the linked video...Basically, the load allows you to set a constant current from the source (i.e. your batteries).

author: yannickg
author_rank: Newbie
timestamp: February 28, 2020, 05:28:52 pm
content: Thanks!

author: wizard69
author_rank: Super Contributor
timestamp: February 29, 2020, 02:22:17 am
content: How variable do you really need? A small selection of power resistors can make a might fine load without any support logic at al. You can also get power rated potentiometers. These are dirt simple solutions. I always like simple when it comes to loads and if you don't need variable a resistor is often the smart approach. If you imagine a resistor decade box but instead set it up with power rated switches and power rated resistors you can have adjustability in steps. Just choose a step size that makes sense.Variable electronic loads are available at a stiff price. I do seem to remember a business in china having more reasonably priced electronic loads. Unfortunately the companies name escapes me. However a Google search for electronic loads might turn it up. Used test equipment on EBay might be worth considering if you can fix the hardware.Another approach is a DC motor. A motor can be a constant load or you can vary the current draw somewhat by loading the motor down. Don't forget the common light bulb too.what works best for you will depend. There are likely more ways to load a circuit.

author: Stray Electron
author_rank: Super Contributor
timestamp: February 29, 2020, 10:06:23 pm
content: I have an aluminium chassis with a bunch of Dale 20(?) watt power resistors mounted in it, each with it's own pair of banana jacks. By combining the resisters in series and/or parallel with jumpers I can make hundreds of different resistance/wattage combinations for PS testing. The aluminium chassis also makes a good heat sink.

author: ocset
author_rank: Super Contributor
timestamp: February 29, 2020, 10:24:26 pm
content: Here is a dummy load bankhttps://www.eevblog.com/forum/projects/off-the-shelf-tube-needed-for-dummy-load-bank/(shown in the attached pdfs)