[fordem]

want33s wrote:

I ran a fuse between my aux batt and winch as well as one between starter batt and dual batt controller.

I used two of the fuses pictured below but rated at 400A.
They will blow with any more than 40A dead short or up to 400A load.
Saved my car from melting when the winch winding shorted out.


Held in these...

Good value at only $13 each

I'm always amused by claims such as this ...

Let's start with what is a 40A dead short? A short circuit that is somehow limited to 40 amps? A short circuit will flow what ever current the source can deliver - in this case a car battery, even the smallest, will deliver well in excess of 40A.

A fuse has no intelligence and cannot determine the difference between a 40A "dead short" and a 400A load - any fuse that can handle a 400A load - will NOT clear with a 40A "dead short" - not that it makes much of a difference, fuses are fire protection devices, and any properly installed circuit with a 400A fuse, will handle 40A without even getting warm.

[want33s]

You can be as amused as you like.
I'm no auto electrician, I'm just repeating what the manufacturer/supplier told me.

[Dr_Snapid]

I'm with fordem on this.

A fuse will blow slowly at around it's rated amperage. At amperages far above the value, it blows faster. A short will blow it right away.

I can't see how a fuse could work the way you described, want33s. Got a link?

[Dr_Snapid]

Mind you I do like the look of those fuse holders and fuses. Where did ya find those?

[DMAC]

Fuses are a little more intelligent than you may think depending on construction.

An interesting read.

http://ep-ca.mersen.com/fuseology.html

I know you can get slow blow and fast acting fuses I am talking 11,000 volt fuses though.

Bottom line is use a fuse to stop stuff catching fire.

[want33s]

Dr_Snapid wrote:

I'm with fordem on this.

A fuse will blow slowly at around it's rated amperage. At amperages far above the value, it blows faster. A short will blow it right away.

I can't see how a fuse could work the way you described, want33s. Got a link?

I was told by the supplier about the dual rating thing when I rang to make a replacement order.
I have been looking for a site that will back up his statements but no luck yet.
Like I said I am no auto elec and am just repeating what I was told.
I can't understand how one strip of metal can blow at two different A ratings either.

ANL fuses and holders are sold at every decent electronics or car audio suppliers.

I found my supplier has an Ebay store so have sent a question. Will report the answer back here.

[stocker]

want33s wrote:

You can be as amused as you like.
I'm no auto electrician, I'm just repeating what the manufacturer/supplier told me.

From what i read there is no amusement to be read. But here we go.

As for Crimping and soldering to the Body + the lugs You are barking up the Wrong Tree.

Crimping With a decent set of Hexagonal Crimpers will be more than sufficient... Cabac Hexagonal Crimpers from an Electrical Wholesaler $150
I would offer mine, but you are clearly a long way from me...

Ps: I would be connecting the Winch + and - Directly to the Terminals on the Battery As they do draw alot of current.

If you have anymore questions about the installation of your dual battery setup send me a pm and i'd be happy to try and help i have installed alot of dual battery setups

[Dr_Snapid]

ANL is the magic letters. Now I know what to ask for but funnily enough i've never seen them on the shelf, or perhaps I have just known what I wanted and didnt pay much attention to anything else.

If they can exhibit the behavior you suggest then they would be ideal for dual batteries and also winches.

For the benefit of the OP though, my vote is for a fuse between the two batteries positive terminals (2 in fact as descibed earlier)

I would not do away with the protection of fuses for the 1 in a million chance that I get myself bogged somewhere, unable to start the engine, and also 1 flat battery. This is the only circumstance I can think of where the winch will need to draw mega current across the main battery link.

[Dr_Snapid]

Its got me wondering what the ideal solution is though

[got_bar_work]

Best bet for a winch is to put the controll box right next to the batt and have incab isiolator and control switch
That way if sometbing happens u just turn off the relay
Circuit protection devices have 2 ratings
Overload which is where u just keep pluging more stuff in and in the end it gets hot and melts
And the second which is short circuit protection
Short circuit current is controlled by two things
The short circuit current of the batt and the fult loop impeedence
The the second one is wat we can controll
Its determined by cable size
The bigger the better
The ka rating and the amout time rated current of the fuse is wat we need to know
How much current does it take to instantly blow that fuse. We need to make enough current flow in the circuit to instanly trip but not to much to go over the ka rating of the fuse
It sounds like u had a 40a fuse that had a 10x rated current instant trip

[Dr_Snapid]

A 200 amp draw from a winch would blow the 40A fuse though. Thats what a 40Amp fuse is designed for.

[britvit]

If I was fitting a winch to my vehicle I would find out the absolute maximum number of Amps the winch will use under full load. Some one earlier mentioned 175A, for this winch I would use cable that could carry at least 200A. I would then fuse the cable at 200A which is more than the winch can use. The only way the fuse would blow is either a fault in the winch or a short in the wiring.

Again- fuses are only there to protect the wiring. A wire with no fuse is like a car without brakes.

Volt drop should also be a consideration, more so if you are using multiple batteries in different locations.

If you decide to run unfused cables for a winch or anything else and the worst does happen, will your insurance pay out if there is evidence of dodgy wiring?

It costs a little bit more to run bigger cables and fuses but not as much as a burnt car.

[Bugsta]

40 Amps is 40 Amps, dead short or no. In fact, the reason a fuse blows, other than under rated for the job or too many devices connected, is beacuase there is a fault in the system causing reduced resistance to ground, or indeed, a dead short to ground. A fuse will not blow at 2 different currents depending on the path it flows from the fuse.

The fuse needs to be rated higher than the maximum required for the device and the wire needs to be rated higher than that.

[britvit]

Bugsta wrote:

The fuse needs to be rated higher than the maximum required for the device and the wire needs to be rated higher than that.

Winner

[got_bar_work]

Most winches are rated up near 400a
That would be somewhere near 95mm2 cable
I have never seen a winch come with a fuse
Shouldnt they be supplying corectly rated fuses for the size cable they supply
Problem is they supply only 25mm2 35mm2 cable with most winch and it is not even close to holding 400 a for any thing more then a few sec

[Dr_Snapid]

400amps is almost 5000 watts... Yes 5kw! About 8hp!

Electric motors are very efficient. If it draws that much energy, I produces nearly as much output. I can't recall seeing any with 8hp motors.

If my math is right...

[shep]

Dr_Snapid wrote:

400amps is almost 5000 watts... Yes 5kw! About 8hp!

Electric motors are very efficient. If it draws that much energy, I produces nearly as much output. I can't recall seeing any with 8hp motors.

If my math is right...

according to the handbook i got with my 6500lb winch it uses 450amp at max pull and the little 2500lb jobbie on my trailer is 175amp

[Dr_Snapid]

Holy crap!

[shep]

oopppss i was wrong, it is 430 amps

http://www.t-maxwinches.com.au/document ... csheet.pdf

[want33s]

FUSE discussion carried on here.....
viewtopic.php?f=5&t=32395

[ZookFan]

Rusho wrote:

ZookFan wrote:

He needs to have some time for his Jim

So what did he do? Put a tray in it and leave? Sounds like all the hard work is still to be done

No he tried to solider and connect the lugs to the cables for the termianls on the battery... but his solider did not work ...he tried two other soldiers..but they were either not working or not hot enough for melting the cable onto the lug
Also he gave me a free earth cable for the 2ND BATTERY..
he also installed the relay for me..
Also he did not have a crimper small enough for the job

He was a great help mind you..

[Dr_Snapid]

ZookFan wrote:

Also he did not have a crimper small enough for the job

Dont ya hate it when your tool is too big?

[ZookFan]

Yes

[britvit]

A gas blow torch can be used to solder larger cables.

[Bugsta]

You'd think of all the soldering irons, I could get it happening. 2 big old style 240v irons and neither working properly, 1 not at all. 2 gas irons but just not enough heat for the cable size.

That cabe was just a left over from an old wiring harness and should be more than big enough.

[Bugsta]

britvit wrote:

A gas blow torch can be used to solder larger cables.

Yep. Had a soldering iron on the terminal and a gas torch as well. Still no go.

[ZookFan]

Yes

[britvit]

I have got to do another twin battery set up in our other Vit. Same as the other set up, just for a fridge and lights when camping no heavy loads and I always carry jump leads for emergency starts.
Do any of you electronic gurus know if it would be possible to put a diode in the cable between the batteries to prevent the aux battery sending current via the link cable to the starter? I would still use a relay fed from an ignition source so the batteries are only connected when the vehicle is running. My current set up uses a 2nd relay to open circuit the link cable when the starter cranks, I am trying to think of a way to simplify the system.

[got_bar_work]

Thats a old way of doing it and u get a voltage drop across the diode
U will need a big power diode which will be hard to find nowdays i would say
U could just get a voltage sensing realy or one off the fancy electronic ones

[Blakey]

britvit wrote:

I have got to do another twin battery set up in our other Vit. Same as the other set up, just for a fridge and lights when camping no heavy loads and I always carry jump leads for emergency starts.
Do any of you electronic gurus know if it would be possible to put a diode in the cable between the batteries to prevent the aux battery sending current via the link cable to the starter? I would still use a relay fed from an ignition source so the batteries are only connected when the vehicle is running. My current set up uses a 2nd relay to open circuit the link cable when the starter cranks, I am trying to think of a way to simplify the system.

http://www.ebay.com/itm/DC-Power-Supply ... 5ae663e533

can get them easily off ebay. can also go up to 500A if a larger one is required.

larger ones do get more expensive tho.

easier just to go with a large changeover relay. or similar