Cable size for inverter

[Trichards]

Hi all, hoping for some advice

I’m fitting an ASP-2000 inverter and made the mistake of googling cable size so now my mind is blown

I have a crafter so I am having to run about 1.5-2m from battery terminal under passenger seat to offside of van. I am running it via a split charger.

So roughly 1.5m from battery to batteries and split charge system, then upto another 1m from split charge to the inverter itself.

What would you pros reccomend as a cable size? And also would the smaller sections of cable between leisure batteries and split charger need to all be the same stuff?

Thanks a lot

 

[dunnah01]

At 4kW cables will need to be the biggest you can find.

 

[StillGoing]

Cable size calculator

 

[Trichards]

At 4kW cables will need to be the biggest you can find.

Its rated power is 2kw and it will mainly be used for charging bits and bobs and a small heater , shouldnt need the surge power should it?

 

[Lenny HB]

Its rated power is 2kw and it will mainly be used for charging bits and bobs and a small heater , shouldnt need the surge power should it?

Forget about using a heater it will zap your batteries in no time.
For small items far more efficent to buy 12v chargers, sounds like you don't realy need an inverter.

If you do fit a 2kw inverter you should cable it for maxium output so for a 2m run 70mm sq cable.

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[DBK]

Based on your figures you should be able to get away with cables 35mm2. I would measure the distances accurately and have cables made professionally with the correct terminals. The people I used don't seem to be trading anymore so I can't suggest anyone but there must be others offering this service. Don't forget to include a suitable megafuse close to the batteries.

I don't think you need to upgrade the battery links as the runs are so small.

 

[RogerIvy]

Some of the apps will suggest thinner cables based on the understanding that your cables can warm to over 60decC
But Lenny's suggestion of 70mm is in line with Victron specs and with a 70mm cable you'll have very little heat buildup compared to 50mm or 35mm.

 

[autorouter]

As I understand it, the wire from the leisure battery to the inverter is in two sections - one 1.5m from the leisure battery to the split charge, and the other 1m from the split charge to the inverter. I think for a 2kW inverter both of the sections need to be adequate.

Obviously you are fitting a new wire from inverter to split charge. But you ought to be upgrading the other section from the battery to split charge. The existing wire is probably specced for around 40A or 50A, but the inverter will pull over 170A at full power, which is a serious increase. If you use 70mm sq cable then the voltage drop over 2.5m will be about 2%, which is fine. But if the 1.5m section is 16mm sq then the total voltage drop will be more like 6%, which is a bit high. It's recommended to keep to 3% or 4%, and 2% is better.

Also you'll need a big fuse on the wire near the leisure battery. For a 170A current maybe a 200A Mega fuse. Actually you may find it easier to run a 2.5m 70mm sq wire all the way from the inverter to the leisure battery directly, which will avoid all those upgrading problems. No need to touch the existing split charge wiring in that case.

 

[Sandancers]

The inverter will give a maximum cable size that will fit into the connectors. See what that is, you certainly can't go above it.