Sealed battery box?

[LeeRoy]

The alternator in the diagrams above is also hooked up in series with the alt and the battery so while cranking the alternator is also turning and i dare say providing some current to the alternator so its full draw would not be coming through the circuit breaker. How much current an alternator produces on such a low rpm i wouldnt know though.

Just out of curiosity, do those circuit breakers trip on both directions or only for current flowing one way? I know the alternator wouldnt trip one on the up flow though as it would never reach the cut off amperage.

[MWP]

The alternator in the diagrams above is also hooked up in series with the alt and the battery so while cranking the alternator is also turning and i dare say providing some current to the alternator so its full draw would not be coming through the circuit breaker. How much current an alternator produces on such a low rpm i wouldnt know though.

But whats turning the alternator during cranking.... the starter.
Your talking about perpetual motion here

Just out of curiosity, do those circuit breakers trip on both directions or only for current flowing one way? I know the alternator wouldnt trip one on the up flow though as it would never reach the cut off amperage.

Trips both ways.

[MWP]

How it looks so far...
Over >120 rivets in this thing.





It takes a N52 (~550CCA) battery.

[blacktop]

Top effort mate, that looks pretty good

[clubagreenie]

The rivets aren't symetrical in the corners and the chequer plate pattern doesn't line up.

[ed]

curious to see if the cranking trips the 120A
let me know, as ive gone much heavier in the past, but would like to know if the lighter duty stuff works

[Draven]

that box is hot stuff. not my preference, but kudos for the work that's gone into it.

[harolto]

K-mart sell battery boxes now, and are only around $20, not sure if they are sealed or not, they are just the black ones you see at repco/marine stores etc.
-Jake

[MWP]

that box is hot stuff. not my preference, but kudos for the work that's gone into it.

Thanks, actually im not sure its mine either... too ricey.
Oh well, itll do the job its made for.

[LeeRoy]

Looking good dude, What are you using to hold the lid down? Some wingnuts might be a good idea if you havent already looked into something.

[Kyosho]

An alternator doesn't provide THAT much excess current.

It basically has enough to run the whole car, plus a little bit left over to charge the battery up a bit.
Battery charging isn't done at high current either...
And I think you'll find the alternator is in parallel with the battery, other wise you'll end up increasing your voltage, not current flow.

Also, the box looks good, what sort of seal do you have down the side? Bit of rubber?

[MWP]

Looking good dude, What are you using to hold the lid down? Some wingnuts might be a good idea if you havent already looked into something.

Yup, thats what i was going to do

[MWP]

Also, the box looks good, what sort of seal do you have down the side? Bit of rubber?

None as yet.
Will seal it up with Sikaflex on the inside then line the whole box with rubber sheet.

[cambelt]

You shouldnt run a circuit breaker at all for starting currents , a slow blow 400A fuse is ok for starting currents , Some car starters pull 200A cont.
Dave

[LeeRoy]

That is correct but that means running a seperate wire for the starter motor from the battery as most battery in boot setups run the alternator and starter on the same wire. Also, a standard setup doesnt have a 3m power cable running through the car with carpet and plastic and other easy to ignite things.

Ideally, no fuse would be best but in a matter of safety, a fuse is necessary. As stated above also, although a starter pulls a few hundred amps, it only does so for a short period of time. By the sounds of things too, these circuit breakers are designed to take that, and as mentioned also, people have successfully run these for their starter motors without any problems.