DC charger cable sizing - confused...

ozzie

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I am getting prepared to connect up an Adverc 24V to 12V DC 10amp charger, but I am not sure on the cable size to use. Adverc recommend 4mm2 56/0.3mm cable, which relates to 32amp rating. To me this seems to be overkill for a 10 amp charger and a 3m cable run. The charger was previously used and came with a fuse block attached with short lengths of cable attached. The spade connectors on them are blue which I believe relates to a cable size of 2.5mm? To further confuse me the cable I have found is rated differently again. Their twin core thin wall 4mm is rated at 42amp and 2.5mm 29 amp!! I didnt intend doing this job myself, but I have been let down so I will just get on with it, hopefully with some expert guidance on this cable!!
 
If you fuse the circuit at 10A, then a 2.5mm2 cable should very easily carry the maximum load. I suppose they may have recommended 4mm2 to reduce the voltage drop, which is a function of a particular cable type resistance and length of run. Even so, 4mm2 seems significantly overkill IMO.
 
Yep - I would use 4% acceptable loss if it were me, so at 12V and 10A, from the calculator, that would give you a run of 3m, using 2.5.....

There are lots of other factors of course like type of circuit protection device, circuit grouping, temp surrounding cables, etc., which clearly the calculator has had to estimate, but unless the run was very long, I would probably go for 2.5 myself, would I criticise someone for selecting 4mm2 nope.
 
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