I have spent literally every spare moment I've had today researching batteries, alternators, wiring etc. I am blown away by some of your guy's contributions and effort in this forum, especially @TooManyToys. on this subject... amazing. My truck has the common pass side battery failing and after testing my alternator with a multi-meter, it seems to be giving low output. I can't look at a monitor currently because someone stole my old android phone that I used the Torque Pro app with but only getting mid to upper 12s after the truck has been running for 20 minutes and having to charge the batteries to start. Truck has been parked for the last few days because of this.

I found a L-N 230a locally at a shop I know at online prices and my only other options are box stores. Can I install that for a couple weeks without modding any wiring and be alright? I'm having a hard time following everything, mostly because it's over my head, and my brain can't absorb all of it. I have a general idea on the wiring and a couple threads to go back through but may need to ask a couple questions just to nail it all down.

I don't really know if I need that big alternator but it's available and would like to drive it ASAP. I do pull a trailer with lights/brakes 90% of the time around town. Also, occasionally will only drive 15-20 minutes every few hours in a day and I know it's not ideal (for really anything on the truck) including the charging system. I plan to get a solar trickle charger now after my reading.

 

I know of a person who has run a 190a alternator on the stock wiring without a failure. The stock 4ga can handle the 90 seconds of high amps. The stock alternator to battery cable uses 2 12ga fusible links for protection.

Each bank of the glow plugs has one 12ga fusible link and handles 100 amps each side for a short time. Fusible links are used because they are a slow blow, and Preece's calculation shows 12ga can handle 235a for 10 seconds before blowing. So the two paired together as they are should be OK for the L-N output, but while I like going all R&D, that is a PITA to fix if they blow.

You could go to a NAPA store or other, the shop that you're buying it from, and get 30" of 4ga cable to parallel run from the alternator to battery that would be cheap. You don't need the big A** wiring all over the place. And when you get a chance buy the marine fuse for $35 or so to protect the circuit.

 

 

Jack always gives great advice. If he says to buy 30" of 4 GA wire, then do it. The extra protection will give you peace of mind.

 

Jack, do you have a link to the fuse? Is this for both wires or just the newly added wire?

 

You could get by with one of these and the associated fuse holder. At 250 amp, it should be sufficient.


You only need to add fuse protection to your new wire.

 

nice, thanks

 

There are a couple of ways to fuse protect the cable.

The ideal way is to splice in two 12ga fusible links in series as Ford did. It works and you never have to worry about contact corrosion increasing resistance and losing millivolts. However, you have to be really good at splicing, and most people are not. since you are mating different diameters.

The method above (post 6) works and one of the more cost effective, but you can't mount it directly on the battery.

This is another method, a Blue Sea holder and fuse, it's what I've used.

Any of the three work. With fuses, I've run all different sizes with the 230a size alternator, from 100 to 250a and have never blown pushing 230a out. The 250a was when I used a 2ga cable ONLY for the alternator to the battery.

Marine supply stores have these, Amazon does, and so does GenuineDealz who also sells cables made to order.

 

I'm not sure where to find the "✔"

I got the L-N along with a premade 29" 4ga wire from NAPA for $8 installed last night with the help of my 15 year old. All went smoothly, minus one socket that fell into a black hole. The multimeter was in the house (thought I still had it in the truck) and it was 11PM so I didn't check voltages but I let it idle a while with no other electronics on and didn't notice any fluctuating... maybe the new batteries were low and sucking the extra amperage but I'm happy. I did notice a little whine that I haven't before and wondering if it's the belt being slightly tighter. Thanks Jack and I'll be ordering a fuse tomorrow hopefully.

Does anyone have a favorite and reasonably priced terminal clamp? My drivers side has the old school lead ones and when I add the extra wiring would like to upgrade those.

 

That looks very neat.