Interfacing 4 Gauge Wire to Relay?

I installed an auxilliary battery in my 2005 Dodge RAM to power my toys (CarPC, Router, USB Hub, & IP Camera).  I used a Sure Power battery isolator, then ran 4 gauge wire from it to the aux battery.  100 amp circuit breakers used at each end of the positive cable.

Connected to the aux battery is a 12 position Blue Sea Systems fuse block.  I used short lengths of 4 gauge wire from the positive and neative terminals of the aux battery to connect it to the fuse block.

Now I want to install a small dash mounted switch to cut the power at the input of the fuse block.  I have 30 amp relays with and without diode as well as the switch I want to use.

Question is, what is the best way to interface huge 4 gauge wire to the male spade terminals of an automotive relay?  I did not buy a wiring harness/connector for the relay but I could pick one up.

Technically, I don't "need" to use 4 gauge from the battery to the fuse block.  I had the wire and I had the copper lugs and solder slugs as well as heat shrink, a torch and heat gun so I used what I had and made it nice, if not over-built for my small overall load.

I was thining of make a short jumper with a female spade terminal on one end and a ring terminal on the other end.  I'd connect the spade terminal to the relay (pin 30) and bolt (?) the ring terminal to the copper lug fro the 4 gauge battery jumper.  Does this sound viable?

In fact, when I was wiring in the battery isolator, I removed the Dodge supplied output jummper from the alternator to the battery.  Interestingly enough, it was about 4 gauge and reduced way down to a ring terminal to connect to the bolt on the starting battery terminal clamp.  So I guess this has been done.  Maybe I should just use that jumper and replae the ring terminal with a female spade?

Just worried aout the stress applied to the relay terminals by medium to heavy gauge wire.  Maybe the harness is the way to go.

Any input/validation is appreciated.

Thanks,

Jim 

Try a Ford Starter Solenoid olr a Wench Solenoid,

http://www.ecovantageenergy.com/catalog/items/item1585.htm

I would stay away from the ford starter solenoids as they are only for intermittent use. The one hotwaterwizard linked to specs out as continious duty.

Jim

Could you use a distribution block to convert the 4 gauge to as many outputs as needed ?. Something like this which car stereo shops have but do not have as many outputs.

http://www.bussmann.com/library/bifs/1117.pdf

Jim

A tiny relay will fry!

A solenoid is another name for a big relay.

Just a fancy name.

A big relay can handle big loads. I would never hook a 4 gage wire to a little cube relay.

As soon as you run a big load the relay will melt and possibly catch your car on fire.