can i use this wire
Submitted: Monday, Mar 16, 2009 at 18:36
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zacc
hi all , i have some 6mm , 50amp , 4.58mm2 wire .
can i use this to run 12 volt power to my van ?
if not what can i use this wire for ? cheers
Reply By: Lex M (Brisbane) - Monday, Mar 16, 2009 at 18:40
Monday, Mar 16, 2009 at 18:40
What do you want to run in the van from this wire?
AnswerID:
354371
Follow Up By: zacc - Monday, Mar 16, 2009 at 18:46
Monday, Mar 16, 2009 at 18:46
fridge and lighting . run of the 4by batteries
FollowupID:
622550
Follow Up By: Member - Mark E (VIC) - Monday, Mar 16, 2009 at 20:53
Monday, Mar 16, 2009 at 20:53
Depending on the fridge type (compressor or other) you may need MUCH heavier wire than this to make the fridge work efficiently from the remote power source.
Although I don't have the technical expertise of Robin (and I greatly value his superior knowledge) I would
hazard a guess that even 8mm sq would be a little on the light side for running a fridge with a power lead possibly 8 metres long (x2 for the earth return).
If the fridge doesn't see sufficient voltage things will go pear shaped very quickly.
Cheers,
Mark
FollowupID:
622581
Reply By: Robin Miller - Monday, Mar 16, 2009 at 18:47
Monday, Mar 16, 2009 at 18:47
To small Zacc , you should have 8mm sq at least.
If you have sufficent , run 2 lengths of your 4.58mm sq in parallel.
AnswerID:
354373
Reply By: ABR - SIDEWINDER - Monday, Mar 16, 2009 at 18:51
Monday, Mar 16, 2009 at 18:51
Hi zacc
8mm2 (8 B&S) as a min. Try use 6 B&S 13.3mm3
Use 50A Anderson plugs too as the thicker cable won't fit the 7 pin trailer plug.
Regards
Derek from ABR
AnswerID:
354375
Reply By: Member - Mark E (VIC) - Monday, Mar 16, 2009 at 20:48
Monday, Mar 16, 2009 at 20:48
When you do the actual sums on voltage drop over a length of cable you will realize that you need to use VERY heavy cable for adequate charging of distant batteries, such as in a caravan or campertrailer.
Collyn Rivers' books on Motorhome and caravan electrics are very good resources in planning this.
I used 2 B&S twin core for my setup and yes, it's VERY thick, from memory 35mm sq and still have a (very) small voltage drop along that line.
Remember to factor the length including the earth return in your calculations and ensure you use excellent terminal lugs on the cable ends.
Cheers,
Mark
AnswerID:
354409
Reply By: kcandco - Monday, Mar 16, 2009 at 20:56
Monday, Mar 16, 2009 at 20:56
Hi Zacc
How far from battery to fridge including all bends?
Is frig 12v compressor or 3 way? (how many amps does it use?)
What wattage is lighting?
regards Kc
AnswerID:
354414
Follow Up By: zacc - Monday, Mar 16, 2009 at 21:05
Monday, Mar 16, 2009 at 21:05
three way , and distance about 20 feet all up. the fridge is a 150ltr ,not sure about amperage
FollowupID:
622587
Reply By: Peter_n_Margaret - Monday, Mar 16, 2009 at 22:44
Monday, Mar 16, 2009 at 22:44
Voltage drop = Amps x length (M) x 0.017 divide by mm2.
Keep the voltage drop to 0.5v max.
Cheers,
Peter
OKA196 Motorhome
AnswerID:
354439
Follow Up By: kcandco - Monday, Mar 16, 2009 at 23:10
Monday, Mar 16, 2009 at 23:10
Hi Zacc
Using the above formula.
I calculate that working on a run of 6 metres (12m including return to battery) drawing up to 15 amp (3 way fridges are quite heavy on power consumption) and allowing for a .3v drop in voltage at the fridge, you would need to use minimum 3.6mm diameter (10.18 square mm) wire.
2.8mm diameter (6.16 square mm) would result in .5v voltage drop.
Definitely use 50 amp andersen plugs
regards Kc
FollowupID:
622607