Values for fuses recommendation

crossflow · Post by **crossflow** » Tue Nov 19, 2013 4:13 pm

I'm about to put the MegaJolt EDIS into my car.
I have planned to put some fuses and a relay in.
What values of fuses should I use ?
Please have look at my sketch.

bmcdaniel · Post by **bmcdaniel** » Wed Nov 20, 2013 2:41 am

Why so many fuses? I just used a single 20 amp circuit breaker in the supply wire from the battery for the whole system.

crossflow · Post by **crossflow** » Wed Nov 20, 2013 3:10 pm

One reason is, I have this nice little holder for the relay.

The other reason is, I can distribute easily the power from one point
to the four devices. Two coil packs, EDIS module, and MegaJoltBox.

How do you connect four wires to one wire ?

For earth distribution I will use this:
I got this from a VW mechanic.

bmcdaniel · Post by **bmcdaniel** » Wed Nov 20, 2013 9:13 pm

crossflow wrote: How do you connect four wires to one wire ?

My supply wire is 14 AWG which connects to a 14 AWG wire to the coil packs and two 16 AWG wires that go to the EDIS module and the MegaJolt. I simply connected them all together with a parallel crimp splice (not a butt splice), soldered the ends and covered with heatshrink tubing. That's also the method I used to connect the EDIS and MegaJolt ground wires to the 14 AWG ground wire I have coming directly from the battery (-) cable. I don't like to use any more terminals and connectors than absolutely necessary, just more connections to cause problems.

crossflow · Post by **crossflow** » Fri Nov 22, 2013 3:15 pm

«
I don't like to use any more terminals and connectors than absolutely necessary«

I totally agree with your statement.
I just could leave two slots for the fuses empty.

Are the wires all on one side of the parallel crimp splice ?
I am confused about crimping and soldering.
I am used to crimp or solder, but not both.

bmcdaniel · Post by **bmcdaniel** » Fri Nov 22, 2013 5:14 pm

The wires can enter one side of the splice or both sides, doesn't matter since they all get crimped into a solid mass. Soldering the ends of the splice is just a way of sealing the connection from the environment. Also it's sometimes difficult to hold together several thick wires while trying to solder them together. Use the parallel splice to hold them together and then solder. My company builds wiring harnesses, some are for automotive use. Some of our automotive customers require that we solder seal crimped connections that will be located outside of the passenger compartment. Technically speaking, if the crimping is done correctly and provides a gas-tight connection it shouldn't be necessary. I guess they like the added insurance. I've just gotten into the habit of doing that.

alexander · Post by **alexander** » Wed Nov 27, 2013 3:06 am

i agree with a single 20A, or just put 10A fuses in your 3 fuse holder. all said and done, they are there to protect your wires from burning due to a dead short. even wires not rated for 20A will survive the brief amount of time it takes for a short to blow a 20A fuse. so it isnt really a critical thing.

alexander.

Not Anumber · Post by **Not Anumber** » Tue Jan 21, 2014 8:37 pm

I am also planning on using 1 fuse for the coil and a seperate fuse for the Mjlj and Edis module.

I am presuming a 5 Amp fuse will be fine for the Edis(4) and Megajolt but does anyone know whether a 10 Amp will be enough for the coilpack please ?

cng1 · Post by **cng1** » Sat Feb 01, 2014 9:16 am

The Megajolt is low current so should be on a separate low-rated fuse, 5Amp is overkill for that really. The EDIS and coils are the bits that needs the higher current fuses. In general people connect both EDIS and coils to a single fuse, 10A should be fine on a 4-cylinder setup but with dual coils I'd probably go out to a 15Amp fuse.