DIY: Build your own positive battery cable 9456836 for the 850

[Redneck]

Thank you for the write up JReed. I am doing this repair right now. I have a Voltage drop of .6V on the positive cable. Negative cable is good .05V but I plan to make that cable too.

I bought 1/0 AWG wire instead of 1 AWG. Do you think 1/0 AWG wire will fit in 1/0 terminal together with 6 AWG wire, or should I buy 2/0 battery terminal instead? I have just ordered the wires: 1/0 AWG and 6 AWG, but I haven't ordered the battery terminal yet.

Is your soldering holding up so far?

I don't like the straight battery terminals, but I spent half a day looking around and haven't found any better ones than those that you used. I wish I could buy the bent ones similar to the original Volvos. I am worried that it will be difficult to run the wires around the battery. My battery is also one size up from the OEM. Long heavy wires sticking out to the side will introduce moment/torque and dynamic load on the battery terminal when everything vibrates. It may cause damage to the battery terminal over time.

[tryingbe]

I bought 1/0 AWG wire instead of 1 AWG. Do you think 1/0 AWG wire will fit in 1/0 terminal together with 6 AWG wire, or should I buy 2/0 battery terminal instead? I have just ordered the wires: 1/0 AWG and 6 AWG, but I haven't ordered the battery terminal yet.

Doubt it.

[jreed]

Hi Redneck –
Thanks for asking. Yes, so far the soldered terminal seems to be holding up fine with no issues noted. I haven't measured the voltage drop during starting lately so I don't know if there has been any degradation.
I applied heat shrink tubing and and wrapped self fusing silicone tape around the terminal connection to help provide strain relief.
Regarding the size of the terminal to buy, my memory is that there was not a large price difference between the two sizes you are considering. If that is true then it might be better to get the larger size, although this would mean that you need to add more solder to fill up the gap which will make for a worse joint.

If resources permit, you might consider buying both terminal sizes and then see with the wires you have which one fits the best.

[Redneck]

Thank you for the quick replies.

I have just looked at all the connections and I am so not looking forward to cutting the existing cables and taking them apart just to replace them if they are good. I may just solder that positive cable first and see how that reduces my voltage drop. Voltage drop changes when I wiggle the battery cable going into the positive battery terminal. I will build the cables for fun, and maybe one day when I do another big repair, I will install the new cable. Should I do 3ft from the alternator to starter and 1ft from starter to battery positive for the thick cable? I think the alternator is much closer to the starter. How long should I cut the thinner positive cable? The shorter the better. The resistance increases with length given huge amperage that these cables need to carry. I plan to solder, crimp when still soft, then heat it up again to melt and prevent cracked cold joint. I'm not sure how practical my plan is. I may use more powerful propane torch. Butane is not as powerful.

I was hoping to add an extra positive cable that goes to the fuse box, but it is unclear to me where it connects at the fuse box and how/where to access it. I can't access the terminal from the fuse box like in some other Volvos. Has anyone with similar model to mine done it? My model may have the same configuration as Jreed's. Jreed, have you thought about adding an extra positive cable to the fuse box? Does anyone have some good pics or a write up:) for that cable and Volvo 850 GLT 1996-1997? I bought 10 ft of that 6 awg cable and many cable terminals. I want to build some new connections:)

Thanks for introducing me to self fusing silicone tape, JReed. It looks very useful. I definitely need to buy it. I am curious about that tape how it is performing in the hot engine bay. Is it still intact, or is it coming off due to the heat? How is it self-fusing? If I only solder the current connection, I may use that tape to wrap around the wire and connector to seal off moisture. I could use liquid electrical tape, but I like to have the option to remove it completely If I needed to fix that connection again. .... I'm now watching some infomercials about the self fusing silicone tape. Not sure if I can trust it.. anytime there is an infomercial for something, it looks questionable to me. But it looks good if true.

I like tryingbe's battery terminals too. I see many of them on eBay. They caught my attention due to that bolt pointing up. You can pile up other cable terminals on that bolt and secure them with one nut. Do you know the diameter of that bolt?

[erikv11]

For any existing cables that you replace, consider just leaving them in there. No need to cut and disassemble the wiring harness, you will just create more headaches.

[MrAl]

Hello there,

I can add a little to the info here...

Long time ago i learned that a crimp is better than solder. Solder has 8 times the resistance of copper. Solder is not considered mechanically stable either.

However, in spite of all this, before i 'learned' that i soldered a battery terminal too and if i remember right it was on a 1964 Pontiac with 389 cu in motor. Not a small motor, yet the soldering outlasted the car.

The real trick is to tin everything. That means the inside of the connector and also EACH strand of the wire. The strands can be soldered together forming a big mass of copper strands and solder which makes it more like a bar than a wire, and it becomes very very stiff at the end.
The connector is then reheated and also the wire end, and inserted into the connector and literally fill up any space left in the connector body. It's near impossible to pull that thing out after it cools

My reasoning for why it works is because there is SO much solder that it grabs the wire firmly and tightly and it is enclosed inside the connector body where there is then no wiggle room. Also, although solder is 8 times as resistive as copper when it is as thin as the space between strands and the space between the strands and the inside fo the connector body it doesnt matter as much, especially since that also makes the cross section pretty big. Overall i think it conducts just as well as a crimp when done right.
To test this we would have to do one crimp and one solder, then run a huge current through the wire and test for voltage drop with a good meter with good resolution. I have a feeling it wont be too much different.

I have never tested it per se, but i have done it on a real car with a big engine and never had a problem after that. Before that it was always touch and go with the cheap clamp on terminal (not a crimp).

A final note:
If the wire is old then the strands are dirty. They can be cleaned with the back edge of a razor type knife until they are bright and shiny. Each strand must be done one at a time so it takes some patience, but it works wonders. They take the solder much better, and use lots of flux too and make sure to heat it enough so the flux all boils out before it cools.

Good luck with yours.

[Redneck]

What troubles me actually, is my alternator output. I can't get more than 13.9V from it measured at the alternator terminals without any accessories on. I rebuilt the alternator myself using correct and genuine Bosch components. I replaced: Both bearings, slip ring and voltage regulator. I did not replace the rectifier and coil. I would hate to have to replace the whole alternator after all the work. To keep the existing alternator, I would need to replace the remaining parts: 1) coil - that means replacing everything again and lots of extra work + cost or 2) only rectifier - not as bad. I wonder if old rectifier may be causing lower Voltage output. Do you guys get over 14V in your old Volvos? Is it just my alternator that is weak? or is it typical in our Volvos? Maybe the ECU in our Volvos, or just in my car tells the Voltage regulator to output lower voltage. My battery is AGM. I wonder if it has anything to do with it. Probably not because the ECU doesn't know what battery I have. I read somewhere that AGM batteries need a bit lower voltage to charge.

[Redneck]

I have Volvo 850 GLT 1996. I bought the wires already, but need to cut them to the correct size.

Can anyone tell me how long should I cut the positive wire between:
1. Alternator and starter?
2. Starter and positive battery terminal?
3. Battery positive terminal and fuse box? Where do I connect the wire at the fuse box?

I will be routing stiff 1/0 AWG wire for the alternator/starter/battery positive terminal. 6 AWG between battery positive and fuse box.

I hope someone with my car did the exact replacement and can tell me the lengths. I want to avoid having the wire too long. Longer wire = more resistance. I hope to get it just right.

It is not easy for me to take the car apart and measure because I don't do the repairs at my home and I need the car to get anywhere outside home. I would like to know the wire lengths in advance, so that I can make the cables prior to the repair and replace them when I take things apart for the first time. I may not replace all the cables at once either. Since I will have borrowed the crimper tool for a limited time, I wanted to cut and crimp + solder all connectors in advance.

[Sommerfeldt]

What troubles me actually, is my alternator output. I can't get more than 13.9V from it...

13.9V isn't low, but that doesn't really matter, as long as it's 12-14. You have to measure ampere output. With a Bosch alternator, you should have between 55 and 120, depending on which exact one is in your car.

- S

[tryingbe]

I have Volvo 850 GLT 1996.

Can anyone tell me how long should I cut the positive wire between:
1. Alternator and starter?
2. Starter and positive battery terminal?

This will have the length you need, plus the two ground cables.
http://www.ebay.com/itm/181074818504?ss ... 1497.l2649

Connectors
http://www.ebay.com/itm/261298170208?ss ... 1497.l2649