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- Battery Cable Upgrade, 2AWG -

8K views 22 replies 9 participants last post by  Forcedinduction 
#1 ·
Well known for being one of the most common sources of electrical problems on our W123s, the decision was made to go ahead and replace most of the old electrical components starting with the cheapest and most basic upgrades first.

Battery Cables and Fuses typically seem to be the weakest links in our electrical systems. The easiest of those to fix is the negative battery terminal cable, second the fuses (to be covered in a different thread). Many just assume their cable is fine and is not the source of their electrical problems. However, after reading literally hundreds of threads where individuals thought theirs were ok, then replaced a half a dozen parts only to realize it was the original battery cable that was the problem. Moreso than that, aesthetically, mine was looking pretty tired and ugly with corrosion starting to show a bit so I wanted to replace it to match the brand new battery I just got for her.

I chose to upgrade to battery cable to a 2AWG for a far superior ground connection. Another thing I like about the upgrade cables is they have sealed end connectors done properly so none of the copper is actually exposed to the elements, which should minimize corrosion over the long run (unlike the stock cables). Also the angle of the connectors is better than the stock ones.

In addition, I wet sanded the chassis ground surface and also sanded the original bolt & washer to get all the paint/corrosion off of the mounting surface for a better electrical connection. I also used a battery wire brush ($3 at auto part store) on the battery terminal to brush off any potential corrosion and also the inside of the new SAE batter cable connector to ensure it was the best connection possible.

The new cable was purchased on ebay for only $12 shipped and can be ordered in any length possible. I am actually getting a custom set of cables made for the W123 chassis by the same seller that has all the appropriate W123 connectors and etc. For our application, a 12” long cable with loop connector on one end and the standard SAE connector on the other end will work perfectly. Also, the
Conclusion:

Before this upgrade I noticed the cars electrical system would bog when pushing the window switch down, and the windows would roll up slowly. After attaching the new battery cable, I noticed the car cranked up much faster on cold startup, and the windows rolled up faster without feeling as strained. Overall for $12, worth every damn penny.

I will be upgrading the positive cable (purchased a good OEM sample and will be sending it off to be replicated perfectly to OEM standards) and the battery seller should be offering the cable to the W123 community on ebay shortly making the upgrade far easier than ever before for a true OEM plug-n-play solution for our cars. Your welcome ;)

Link:

2 Gauge AWG 100 Copper Heavy Duty Custom Battery Cable Power Wire Golf Cart Car | eBay
 

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#2 ·
I purchased a set of cables from these folks for a small project. I didn't read the description to see that the connectors are soldered vs crimped. Depending your school of thought and application that can be a show stopper. Since the cables were for stationary equipment i decided to just use them. Unfortunately the individual who soldered these allowed the solder to wick way up the wires creating the stiff/weak spot on some areas of the joints, and other areas it was clear the solder did not melt completely and caused cold joint and failure at the connections. Just a word of caution, I'm sure their still better than your original.
 
#3 ·
Icables work perfectly and have made a significant improvement in the cars electrical system. I am very happy with the results and will be upgrading using the new positive battery cable as well which should eliminate any potential for corrosion based shorts etc.
 
#7 ·
Update:

It's amazing what a small difference can make. Now the car seems to start up much faster after sitting for a while. It's almost as if the car is healing itself lol. I have received the excellent condition OEM positive battery cable and will be sending it off today to get replicated so everyone can get brand new higher gauge cables in a simply plug & play OEM style solution for the positive battery cable.

This should solve most of our electrical problems that we face as w123 owners.... Will keep you updated once that company has an official offering for our cars. I will of course test it first on my car to see how much it improves and electrical drain etc.

More updates coming soon
 
#10 ·
I chose the 12 inch 2 AWG black cable with one automotive battery terminal, and the other end the round loop connector.

Will update as soon as the positive cable has arrived as well.

Sure this can be done on the W126 as well, just measure out how much you think you need and order the cable. I am pretty sure 12" should be enough for the W126 as well but just measure the distance between the negative battery terminal and the mounting bolt on the fender to confirm

Hope that helps
 
#12 ·
MTI has received the cable and is currently working on the prototype for the w123 chassis.

I told them to add 2 inches to all the cable lengths just to give a bit more wiggle room so it should work on all w123 chassis. This may even fit w124/126 possibly as well.

The main positive battery cable has been increased by 2AWG and the rest of the cables have been increased by 1AWG as well so should be the most effective battery cable out there.

They told me the cable should be ready by end of next week. Will keep y'all updated
 
#13 ·
Brand new W123 prototype cable is now complete! The cable looks great. I should have it back from MTI and installed back on the car within the next week. Looking forward to finally curing all of the w123 electrical gremlins once & for all (not only for myself but hopefully the whole w123 community)

Pay it forward :angel

More updates coming soon...
 

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#16 ·
They are the company that made it for me. The final cost is still unknown as I had to pay a lot more to buy the original cable and then pay me to custom fab this one up for me.

You guys will be paying a lot less than I did as it will be a mass produced item at that point. My gift to the w123 community :)

Will have all the details in my final writeup once it's done.
 
#18 ·
The final pair of cables (both positive and negative) should cost less than $120 total. For such a massive improvement in the worse Achilles heel for our W123 electrical systems, this really is the best thing you can do for the electronics in your car.

Other than this, Ceramic fuses are also a must. Between those two upgrades you will never ever have to worry again. Excited to get the positive cable installed to join my newly upgraded negative cable and ceramic fuses.

Also, while doing this I am fixing two of my bad window motors & regulators. The ultimate test on the electrical system will be to roll down all 4 windows at the same time. (Before the car could barely handle two windows at a time and they would slow down to a crawl when rolling up or down)

Should be interesting, more updates soon...
 
#19 ·
Great news! MTI said the final price point for BOTH the W123 positive AND negative ground cable will be just $99! It cost me way more but I really believed this was an item the w123 community desperately needed so I volunteering to be the Guinnea pig.

Should be picking up my car from the shop next week. Will do final review & photos of everything once I get her back.
 
#21 ·
2AWG makes such a big difference. I cannot wait for the positive cable to be 2AWG. The other two smaller cables on the factory positive wiring harness are also 1AWG thicker than stock for an even higher capacity. The new cable is top notch quality, especially for the price!
 
#23 · (Edited)
2AWG makes such a big difference.
Its very important to note that 2 gauge cable WILL NOT make a difference in a properly operating starting system. That fact it made any difference to your vehicle means there was corrosion in your cable ends.

The easiest way to tell if there is a problem is to measure the voltage drop across the circuit during cranking (meaning measure from the battery + post to the starter + lug), it should be less than 0.5v. The same can be done from the negative terminal to the engine block. Another check is to measure the alternator output voltage at the alternator and the battery while there is a load on the charging system (headlights, windows, rear defrost, AC)
 
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