Originally Posted by buddy
1) My TJ has a Durango 136 amp alternator on it, will the additional 50 or 70 amp relay tied into the oil pressure switch circuit be feeding the secondary battery by itself or would it supplement the secondary starter solenoid?
It will FEED the second battery, and allow the second battery to join the electrical system....
Once the oil pressure comes up and the relay closes.
When you are using the starter solenoid, the oil pressure will still be non existent, so the pressure switch and relay will be open and non conducting.
Do you just use a 10 ga. jumper on it from pos 85 to 87
The proper flow through a common automotive relay is terminal 30 to terminal 87 for the heavy current.
The proper flow for the activation current is terminal 85 to terminal 86.
10 Ga. wire is enough for roughly 35 amps continuous, and up to 70 amps for a short period of time.
I use 8 Ga. most of the time, but a 10 Ga. wire is usually enough to charge/discharge the second battery through the normal electrical system.
10 Ga. is all the larger the Fuse Block feed is,
10 Ga. is all the larger the alternator feed is.
Since the second battery should only see as much load the orignal system ever saw at any one time,
(as in self rescue when you are powering everything off the second battery, and it has 100% of the load)
You should be able to use the same size wire the orignal system did, and that was 10 Ga....
(BTW, your fuse block wire has a fusible link that will burn at about 35 amps, so if the vehicle draw is more than about 35 amps, the fusible link with burn and the relay wiring will remain intact.
Just a way I use the vehicle protection to my advantage.)
I'm always for 'A Little More' when I do things, so I use an 8 Gauge wire in my 70 amp relays sockets.
2) What are the functions of you're "factory harness 12, 13 & 14" leads? What would they correspond to in a universal-type application?
Factory harness #12 or #13, depending on what vehicle you have, are the 'Full Power' leads to the ignition coil and module during cranking.
They supply the ignition system with power when the starter is turning.
A requirement on some ignition systems that have breaker points or like on the Jeep/DuraSpark module, that has a separate 'Start' circuit to make things easier to start, then switches over to a 'Run' circuit when you let the key switch drop back to the 'Run' position.
Factory #14 is the activation wire for the starter relay/solenoid.
If it were on a home built system, it would be hooked to the 'starter' push button.
In this case, it's connected to the ignition switch 'Start' or 'Crank' position.
3) Application specific - Where on a 97 TJ 2.5L would you locate or tie in the oil pressure switch?
Application specific answer....
I don't work on TJ's on a CJ forum
Seriously, same place as anywhere, you can 'T' into the oil pressure sending unit source.
I must say that I'm quite impressed by how simple, cheap & robust these diagrams are & while I don't have any problems with using welding wire as a main condutor, I'd also like to recommend marine grade wire.
Marine grade wire is tinned, and has a tendency to not carry as much amperage as virgin copper wire (no alloys).
When working on off shore power boats for races, I use silver bearing solder to seal my electrical joints and ensure a fool proof connection,
A top quality Heat Shrink Tubing, WITH GLUE, for environmental seal, and I really don't have problems.
(And believe me, as snarky as those rich boy power boat racers are, If they failed, I'd hear about it!)
They use a tin coating of some sort to limit the amount of corrosion that will occur in a harsh marine envronment, & they are typically a very fine strand as well. While not usually necessary, I think that marine grade electrical pieces are bulletproof for a hardcore offroad enthusiast.
I would agree with 'Marine' or 'Tinned' wire for low current devices, like gauges, lights, ect., battery cables really are in a different class...
Most off roaders will not subject their vehicles to constants doses of salt water...
For the Desert guys, you have to consider the 'Dry Corrosion' factor that Tin on copper will bring to the table.
Galvanic corrosion from dissimmilar metals will cause problems over time,
Tinned or 'Marine' wire might not be the easiest thing for 'Joe Average' to acquire in the middle of the desert or up in the mountains 1,500 miles from the nearest salt water!
I typically say,
'SOLID COPPER CONNECTORS, VIRGIN COPPER WIRE, SILVER BEARING ELECTRICAL SOLDER' and 'RUBBERIZED HEAT SHRINK WITH GLUE'...
That covers 99.95% of the people that will read this stuff with out problems!
And yes, I still tin the copper terminals and exposed wire in marine or wet applications!
Nothing like that 2% or 4% silver bearing solder to seal things up and tin things out when you need it!