Thread: Help needed on Routing Batt cable into cargo area.

<span style="color:blue">through the floor and along the top of the chassis rail.....
(between the floor and the chassis rail)

and tied so there is no movement from road vibrations so it doesnt wear through....
it should be out of harms way above the rail.....and its even safer in some split
flexible conduit for even more protection......



well thats my idea....im sure others will have some others....</span>

Hi Owen, Zook’s suggestion is the quickest but not the best. Sorry Zook, don’t mean to shoot you down.

Although a much bigger job, for safety reasons, you are better off laying the battery cable through the vehicle next to the existing wiring and in your case, with your intended location of the auxiliary battery, you will actually save some time by not having to find or drill a hole to bring the cable up from under the the disco.

Next, a 100 amp circuit breaker needs nearly 200 amps to cause it to trip in any form of quick time. if you haven’t bought them yet, I would consider getting much smaller ones. Even with an AGM battery, you are unlikely to ever need as much as 40 amps to an absolute extreme maximum of 50 amps with the fridge running.

A 30 amp circuit breaker would be big enough and a 40 amp would be a maximum size that I would use.

A 30 amp circuit breaker will easily take surges of 70+ amps and not trip so it would do what you want and give you the safety protection you are looking for.

Cheers

Originally posted by drivesafe
A 30 amp circuit breaker will easily take surges of 70+ amps and not trip

Why, then, is it called a 30amp circuit breaker :?: :?

Hi Vlad, the rating on an automotive circuit breaker is based on the circuit breaker not tripping at the stated current in say under four hours ( for example ).

NOTE unlike domestic ( 240 vac ) circuit breakers which are rated at an 8 hour operation, there are no mandatory guide lines for defining the operating requirements for automotive circuit breakers ( and the reason it pays to only buy quality brand circuit breakers ).

So if a circuit breaker is rated at 30 amp, if 30 amps is applied to it, it should not trip for at least 4 hours.

Then if 35 amps is applied it should not trip in under 3 hours.

Then if 40 amps is applied it should not trip in under 1 hours.

Then if 45 amps is applied it should not trip in under 20 minutes.

Then if 50 amps is applied it should not trip in under 5 minutes.

Then if 55 amps is applied it should not trip in under 1 minutes.

Then if 60 amps is applied it should not trip in under 20 seconds.

Then if 70 amps is applied it should not trip in under 10 seconds.

Then if 80 amps is applied it should not trip in under 5 seconds.

AGAIN NOTE these are not accurate figures, they are just intended to give you a very rough idea of how they work.

It may seem strange for circuit breakers to work in this manor, but there is a very good reason for both domestic and automotive circuit breakers being designed to work just this way.

When many electrical devices are first powered up, such as light globes and electric motors, they require a very large current surge for 1 or 2 seconds to start them off and if circuit breakers tripped as soon as the current got over the stated rated current level, they would trip before the device could get going and the devices current draw settled down to it’s normal continuos operating current level.

Hope this helped, cheers.

Vlad just BTW, fuses work in a similar manor with the difference being, YOU ONLY GET ONE GO. :wink:

Originally posted by drivesafe
Hi Owen, Zook’s suggestion is the quickest but not the best. Sorry Zook, don’t mean to shoot you down.

Although a much bigger job, for safety reasons, you are better off laying the battery cable through the vehicle next to the existing wiring and in your case, with your intended location of the auxiliary battery, you will actually save some time by not having to find or drill a hole to bring the cable up from under the the disco.

Cheers

I know we are talking about a disco here, but Zooks advice is right for a fender? I think the wiring runs through the chassis in a fender. I did a bit of a rush job before our big trip and I've been meaning to do it properly some time

In regards to the fuse, we just put a 20A fuse in and it's been plenty for our little engel

Hi Captain, are you feeding to a second battery or just the fridge.

Cheers.

Originally posted by drivesafe
Hi Captain, are you feeding to a second battery or just the fridge.

Cheers.

Sorry, just the fridge.