Looking good. Very nice project.
Just a side note while working on my cells in parallel tester I did an resistance check on the style of cell holders I believe you are going to use and was shocked
at the actual resistance. Almost 7mΩ. Maybe yours are different but if not I'm not sure how this could impact your C/D tester if at all.
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Wolf
My two test at 10 and 12mΩ. ±1
At full discharge of 1A the holder could be dissipating 0.025W out of our total 4W, 0.6%
Total of 25mΩ, both ends.
The mosfets themselves are 10-30mΩ across the discharge current range, 0.8 - 1.1A.
Readings are taken after the mosfets
As long as we know we can account for it.
But I think we are talking down in the 0.5% of our accuracy, maybe less.
Starting temperature is going have more of an effect.
Watch for limitations when using a battery at adverse temperatures and how to overcome the effects
batteryuniversity.com
Looks like it is coming along nicely. Please don't take me wrong ... but starting to look like the layout of the MegaCell charger?
Hey could I recommend you to look at 3D printing your own Cell holder based on Watts-on
https://secondlifestorage.com/index...ringslot-18650-battery-holder.5849/post-48201
He has several versions. I personally like the lifting version.
At this stage the only thing in common with the megacell is that it has 16 cell capacity as well
Cell holders, they do look good.
Main issue is anything times 64 adds up quick.
The off the shelf ones are good enough for now for me. Anyone else is always welcomed to Gucci up their build.
Pluses of the MegaCell Charger over this
+Minor setup required. Connect power. Network setup.
++Functional software. It is good until you hit one of the undocumented features.
This over the MCC.
+Cost. You will need to add cell holders, tp5100 chargers, power resistors.
+Open design.
?Accuracy. Voltage and thermal accuracy.
+PCB is not being used as a heatsink.
+Separation of cells should limit thermal transfer of a heater heating up the cell next to it.
Potential accuracy as I do not know what is in the MCC.
Or how much electrical noise my layout will create.
I have tried to keep the low voltage adc signal traces from running in parallel with the high current traces.
Screenshots from this video for close ups of MCC pcb.
Order placed.
ETA in my hands is probably Friday 5th Feb?
Came to roughly us$38 per board delivered. 5x boards $189.
A few small changes on the fly during routing.
Not as tidy as I wanted but should be good enough to test.
I have not done a ground pour to fill in the spaces to assist with initial troubleshooting.
Hopefully I have caught any major bugs.
If anyone is keen on a set to help with coding, I am willing to cover some of the PCB production costs.
Shipping any spares from down here (New Zealand) is going cost too much.