Adding a fan to testing/charging station?

[harrisonpatm]

I used an ATX power supply to plug in my 1 Opus and 3 Liitokala as I am charging, testing and sorting reclaimed laptop batteries. I am using low currents on the first charge prior to the self-discharge test, and higher currents once I weed out the bad cells. So far I got only 1 or 2 "heaters," for discard. Some of them get warm, but within acceptable limits. The other day I thought that, since I'm using a power supply anyway and I have extra 12v lines, why not stick a fan on the station?




I'd mount it correctly later, but I wanted to ask the community, are there any reasons why I shouldn't? Since I'm testing used cells, I am checking for any excessively hot ones. Perhaps I'd want to keep hot ones obvious? Although it's not a huge fan, and while it certainly helps cool the cells (this is in a cooler portion of my house anyway, so the air blowing over the cells is always nice and cool), I can't imagine a single PC fan would be enough to mask a bad cell heating up too much. I was also thinking that the Opus has a built-in fan for cooling, and scaled up systems like Tesla have extensive cooling systems for their batteries.

Anyway, just wanted to get some opinions on it. Honestly, I'll still probably be going ahead and adding a second fan to the right side and mounting both. Just curious if there's anyone else who's tried this setup.

 

[OffGridInTheCity]

I don't see any problems. I have 3 x OPUSs and without an external fan/cooling I'm not able to do 1000ma discharge on each slot at room temp.

I find heaters by simply touching them as the get near full charge - mostly heaters are bad/self-discharging cells. After processing 10,000 cells I find that heaters aren't random but occur predictively in the particular type/style/batch of cells I'm processing.

For example - I'm currently processing 2000 Samsung ICR18650-26F (pink) cells and the pattern is that 0v-0.1v/High-IR cells are often self-discharging as they reach full charge and heat up. Anything over 0.5v/Nomral-IR as I crack them out of the cases have a pattern of being OK.

 

[Korishan]

Adding a fan to the opus is one of the recommended mods, actually. It keeps the Opus from "stopping" if it gets too hot. This stopping changes the results for the discharge test.
There's actually several bottom 3D designs that will make room for a fan.

The other mod is to open to the unit up, and take a wire and solder it from the Neg contact plate to the connection on the pcb instead of relying on the spring for contact. This actually helps the IR testing feature out a bit.

I'm not sure, but I think the LiitoKala's would benefit from these mods for the same reasons.

 

[floydR]

I have always heard you want the air to be sucked from the bottom and not blowing on the cells. I just have my three opus's laying on top of three 125mm whisper quiet fans with holes a few slots in the back cut out. Moving the cells into cell holders off my opus I have set up for LiFePO4 cell testing really helped with the A123 26650 cells and heat.
Later floyd

 

[italianuser]

If I don't add a fan some of my chargers just switch off every now and then, when outside it's over 38°C / 100°F (south of Italy, nice and hot in summer!). I put a 14cm / 5.5in fan on one side making sure all chargers get some air (I added some rubber feet to all chargers).

I also used my ATX power supply, the label says 12V 28A, good enough to connect quite a few chargers.