flippy said:
virtrually no ammeter has a DC inrush mode
Sorry dude that's a complete crock!
Not talking min/max but peak hold, something like 400 samples in 100ms? can capture a peak lasting only 1 ms
peak vs inrush not quite the same, but in this case either are useful
Flukes can and do measure DC inrush just fine, 375 / 376 and remote display 381 for example.
https://youtu.be/2xIsmRkpQLA
http://support.fluke.com/find-sales/Download/Asset/1629920_6115_ENG_B_W.PDF
Keysight U1213A also
Hioki also
https://youtu.be/P0Ho_va9Lk0
https://youtu.be/jXERSwlQdoM
http://hiokiusa.com/wp-content/uploads/pdf/28674-CM4370_en.pdf
Been around long enough, even some Uni-T / Mastech / Extech at the high end prolly do too by now.
Apparently the manuals aren’t trustworthy on that topic.
flippy said:
john61ct said:
Higher
But as above, it's not so relevant to sizing cables, ACRs etc in practice since for such short bursts.
Of course when the captain's cranking for longer than a few seconds due to engine issues, then risk increases of overheating at high-resistance points, so oversizing never hurts.
BSS ML ACR specs set a great example, never heard of one failing from cranking overcurrent
https://www.bluesea.com/products/7622/ML-ACR_Automatic_Charging_Relay_with_Manual_Control_-_12V_DC_500A
cable size is very important
Obviously, not sure where you got the idea I said otherwise.
The heat safety issue being completely different from V drop, many device types can tolerate lots of drop so NBD for bursty loads, but
for sensitive devices and continuous usage need to go to big cables, sometimes AWG 00 or even fatter, say cranking big diesels from a bank 20' away.
The BSS app Circuit Wizard is good for sizing, breaks out all the variables for you.