Battery Charger cable type & size

Question

Hello, 
 I need to replace an original cables which are too short from an industrial generator (Stamford PI734D1) to batteries Cummins 12V 1400A 220Ah (0416-0439) connected in series so 24V 
 Sorry but my knowledge and experience on this subject is very limited. The cables supplied by the manufacturer are AWM 3340 or 3374 150degC 600V 
 My question is whether H07 or Coil and Lead could possibly be used as a replacement for the original ones? What size would be sufficient for this scenario? 
 The batteries will be standing about 4 meters away from the generator.

mapj1 · Accepted Answer

This really is not much more than a 12V lorry battery, albeit a rather heavy and in the UK at least a very pricey one. There will be a massive starting current for some seconds, maybe tens or so, while the engine is being cranked by the starter, and then it will sit idle, charged by more or less normal 12V alternator spun by a belt from the engine, not much different to a traditional car. Cable selection will be decided by the area of copper needed, and the environment - heat. oil, fuel etc. And then finer stranded cable is used compared to normal fixed wiring, to resist vibration. 
 The wire nos you mention cover a range of high temperature soft rubber covered (EDPM) cables . 'AWM 'just means Appliance wiring material and really does not say a lot - almost all 'wire' could be AWM unless it is specially something else. 
 There may be an AWG code on there, but if not depending on the engine size, which is a proxy for starting current we can probably assume we need the AWG equivalent of 25-35mm2 (AWG 4,2 or 1) 
 Or measure the OD of the old cable and compare with the table here. 
 https://www.interstatewire.com/ul-awm-style-3340-and-3374-config.html 
 So - why has the original cable failed ? (heat ? perished rubber? abrasion? ) This is what needs to be guarded against, and it may be that like-for-like repair is not the brightest decision, if it fails again in the same way, and/or that some sort of re-routing or mechanical protection is needed. 
 If you can get a bit more detail about the cable and what has happened to it, we can point you at something suitable, that more helpfully will be readily available in the UK. 
 The number you give for the alternator 
 https://www.raad-eng.com/techdata/stamford/PI734D.pdf 
 Tells us it is a 1,6 MVA unit at 50Hz, when spun synchonously, but not the engine size, so while we can guess a cranking current, it is a guess. 
 
 Sanity check - battery is one of these ?

Mike

broadgage · Answer

Are these cables to carry the engine starter current ? If so then voltage drop under starting conditions is the main concern. In view of the extra length, I would use AT LEAST one size larger, than the original cables, two sizes larger might be better. 4M is rather long for an engine starter circuit. 
 Very substantial currents are involved when starting a large diesel engine and voltage drop should be minimised by use of generous cable sizes. Tri rated pvc cables, or welding cable, or single core HOFR may be used.

Battery Charger cable type & size

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