Products > Test Equipment
ET5410 Electronic Load mod: add external sense
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klausES:
I meant how the Kunkin would react, but if the ET5410 reacts as you write, this info is even more valuable.
Thank you for that.
Now i just have to wait until it is delivered.  :)
DaneLaw:
What is the weight of the newer ET5410A+..? (just the unit alone)
andobovsayvkub:
2940 grams (my 2 banana extra slots included)
andobovsayvkub:

--- Quote from: cybermaus on June 21, 2024, 09:54:51 am ---The external sense however is still very important. You really need to either have HUGE cables and clamps, or correct for the cables voltage drop.

--- End quote ---

I've tested batteries in both modes (2p and 4p) and the difference in capacity was about 1%.


* 18V-4Ah with 10A current and 2meters cable (4mm2) - 0.5% of Ah and 1% of Wh.
* 18V-4Ah with 10A current and 1.8meters cable (0.8mm2) - 1.2% of Ah and 5% of Wh.
* 48V-12Ah with 6A current and 2meters cable (4mm2) - 1.1% of Ah and 1.1% of Wh.
I'm guessing a 4-wire circuit isn't necessary for battery testing if you have decent cables.

Could you explain where the areas when this is really important? Power supply testing of course, but what else?
cybermaus:
Well, your 0.8mm2 cable will have 5x the voltage drop of your 4.0mm2 cable in absolute sense and if same length.

So when ones focus is on voltage, this is important, but even then, how significant it is depends on the total voltage
0.2V vs 1.0V (random examples) on a 3.6V single cell is significant. But on a 48V pack (your last example) less so.
Maybe you also remembered to use really short cables

You soften the impact even more by discussing energy, because as voltage rises, current drops, which means the voltage drop drops... [sic]
Meaning on equal energy/power, the impact of the cable is indeed the inverse-square of what it was when one focused on voltage drop directly

But even then: You describe a 5% deviation. Not very precise now is it?
But indeed, maybe good enough for causal battery checking, if so, then indeed 2 wire is good enough.





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