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Post by faffer on Nov 6, 2016 18:48:49 GMT
When working out the cable size for the batteries how do i work out the Amps for the cable to carry. I know the Amps=watts/V part, its the knowing how many amps oi will be using, Do i take it if all the system is running together, unlikely, but is that the safe way to work it out. Thanks Wolly  |
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Post by JohnV on Nov 6, 2016 19:04:27 GMT
When you are calculating your battery leads, the current handling capabilities are not the problem.
You are normally more interested in voltage drop and to prevent that the cables are normally way thicker than needed just to carry the current.
I don't know what amount of batteries you are thinking of having so I reckon you need to start from that end .
How many leisure batteries are you going to have ?
what equipment are you thinking of putting on board ?
how are you going to charge them ?
If you are only going to have a basic system with one say 90 Ah starter battery and one say 110 AH domestic and charging just from an ordinary alternator with possibly a small solar cell for topping up then probably 25 sqmm or 35sqmm would be plenty big enough
All depends on what you are planning mate
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Post by tonyqj on Nov 6, 2016 19:12:12 GMT
As above. We really need to know what size batts and how many?
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Post by faffer on Nov 6, 2016 19:49:02 GMT
Ok here we go
two 110amp batteries, outboard will have its own starter. on board will be powering
LED ighting all through
TV and USB charge points
horn 4 amp draw and LED search light
12v fridge ( maybe but not getting one yet )
Charged using a genny as back up and basic charger.
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Post by JohnV on Nov 6, 2016 20:26:51 GMT
for the battery links and the feed to your fusebank I would reckon 25mm would be fine for that Wayne. If you can get 35mm at not much more it would be better allowing for more to be added later.
Welding cable is probably your best bet price wise. You probably will have to use the same colour for both pos and neg leads so you will need to get either coloured heatshrink sleeves or coloured tape to mark it, obviously at the ends but my suggestion would be to mark it a few times along the length as well ....... probably being a fusspot but I always do it
Tony might come back with his thoughts
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Post by faffer on Nov 6, 2016 20:41:03 GMT
Thanks John. Cost is no big deal. I can't see a few metres of cable breaking the bank from what it has cost up to now. It lost me if you have to add all fittings consumption up as I did withe the loom. I am happy with the 1.5 %volt drop so that is what I want for the battery cables.
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Post by tonyqj on Nov 6, 2016 20:57:46 GMT
Thanks John. Cost is no big deal. I can't see a few metres of cable breaking the bank from what it has cost up to now. It lost me if you have to add all fittings consumption up as I did withe the loom. I am happy with the 1.5 %volt drop so that is what I want for the battery cables. You only need a couple of metres so why not go 50mm? If that's too large then sure, 35mm or even 25mm would be ok for your usage. |
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Post by smileypete on Nov 6, 2016 23:52:00 GMT
AFAIK the minimum size for BSS is 25mm2.
I wouldn't go much above that without good reason, 35mm2 should cover a smallish inverter up to 1kW OK, which would be the most I'd want to run from a couple of leisures.
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Post by faffer on Nov 7, 2016 19:04:53 GMT
AFAIK the minimum size for BSS is 25mm 2.
I wouldn't go much above that without good reason, 35mm 2 should cover a smallish inverter up to 1kW OK, which would be the most I'd want to run from a couple of leisures.
I just a quick work out on 25mm and th volt drop will be around 0,25%...will di fine. And thanks for pointing out the BSS reg, i didnt even think to check the bible. Just ordered all the rest of the wiring and bits, well near enough from 12v planet |
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