2005 Jaguar X type 3.0 V6 90k miles- bought two years ago - no problems at all up to this point.

Left my headlights on for two days. Battery dead. Bought a new battery. Car runs for up to an hour then ‘limp mode’ and throws up all kinds of messages on screen.

Searched the forum - learned about the faulty battery cables. Mine look frayed. So, starting there.

Mechanic said $850 USD to replace. Said the average cables from auto parts store are no good. Said the good ones cost more. The mechanic has a stellar reputation with only 5 star reviews and has been in town for over a decade.

Is this a reasonable price? Is there something I’m missing? Should try something else first?

Thanks in advance for any help!

 

$850 seems a bit high. Granted, I would be asking how much the cables are themselves. Installing the cables (both positive and negative) should not take an experienced mechanic more than 2 hours to do. So, that would be roughly $250. So, you are telling me he is installing $600 cables? I would be looking at other places and seeing what they are going to charge.

As for the cables not being good from an auto parts store, there is some truth there, but at the same time, if they last 5 years, you will get your money out of them. Worst case, get your hands on some "plasti-dip" and coat the point where the insulation meets the metal terminal. That is the weak point of the cable from the point of water intrusion which is what takes out most of the cables. Granted, if you have even a little bit of mechanical ability, between this site and your ability, you can do the cables yourself.

 

The OEM cables are assuredly expensive (look at PartsGeeks, SNG Barratt, etc.) Like around $550-600 for both. As Thermo has stated and many other members over the years, they have measured the existing cables for correct length, bought them at a "normal" auto parts store and no one has ever reported problems doing it this way. The cost is SUBSTANTIALLY less and any regular person can do the replacement.
Just me 2 ˘ of guidance.

 

What gauge cable dies Jaguar use? Is it perhaps worth going to a larger gauge?

 

I bought an OEM Jag positive battery cable on eBay for $80 just over 2 years ago. The eBay seller was jaguarpartsplace so maybe worth an email to see if they have any more stock.

Rockauto will sell you a Deka brand battery terminal with 2 or 4 AWG cable of your desired length with a copper lug crimped on the other side for $20. That might get you 90% of the way to a solution for not much money. Deka has a catalog of generic battery cables here.

My last suggestion is a local speed/hot rod shop, someplace that rebuilds alternators, or a marina if you are near the water. These places do custom battery cables all the time for less than a Jag branded part.

 

A larger gauge wire is never a problem with high amperage systems. Now, you can go bigger, but there is going to be a declining return for the money that you are putting in. I would say to go up to say 0 gauge wire, but that is about as big as you should need to go unless you are running some monster amps in the car (but that is a different story). Sure you could go to 00 gauge, but the gain is going to be minimal at best for a lot more money. I would also recommend doing the power wires between the alternator, battery, and starter. Getting power back is no good if you can't push it out.

Another way to look at it is imagining filling a pool from a tanker truck via gravity fill. Would you want to do it with a garden hose, a 4" fire hose, or a 6" fire hose. Obviously, the garden hose would take a long time and be very restrictive. Stepping up to a 4" hose would result in a fairly good fill time. Going to a 6" hose will not result in much more of a flow rate if you just let gravity fill things. Where the 6" hose would show its benefits is if you pressed the tanker up to say 20 psig. But, that would be like raising the voltage in your car up to 30 VDC. Not something that hte car can handle.