Aolithium discharge cable terminal hole too small for 3/8" bolts. Recommendations?

[flammafeuer]

I've already seen recommendations not to drill the terminal out to fit the bolt (on my disconnect and on t he bus bar). I'm not sure that I have the tools to cut this cable and put a new lug on it, and I don't have 3/8" lugs for 4 AWG cable, yet. Are there other coupling suggestions to get from this 5/16" lug to a 3/8" lug?

 

[NVS]

If you have a car Audio installer near by, have them install new ends on for you.

 

[400bird]

I've drilled out lugs with a step bit before, worked fine.

However, you lug looks torn right where it starts to taper down from the cable to the flat. I'd replace that one and maybe all of them from the same vendor.

 

[flammafeuer]

I've drilled out lugs with a step bit before, worked fine.

However, you lug looks torn right where it starts to taper down from the cable to the flat. I'd replace that one and maybe all of them from the same

That is the peep hole for ensuring the lug is on correctly, for that kind of lug. You don't feel like drilling out loses you important surface area for current?

 

[flammafeuer]

If you have a car Audio installer near by, have them install new ends on for you.

I bought some lugs and a tool, so we'll see how it goes first

 

[400bird]

That is the peep hole for ensuring the lug is on correctly, for that kind of lug.

Ah, the angle made it look different. I can picture it now.

You don't feel like drilling out loses you important surface area for current?

Look at the lug specs from a vendor (mouser or somewhere with actual specs sheets). They often sell multiple lugs with the same outer dimensions and different hole sizes.

 

[glandpuck]

Drill it out and use flat washers on top and bottom along with lock washer to bolt it the threads.

Or, purchase new lugs, some heat shrink tubing and a crimp tool for the size cable. But, I think you should be able to find a company that can easily replace for you. For instance, a company called American Battery may be in your local area or look for a truck stop mechanic or diesel repair facility. those engines have big batteries and big cables and the mechanics there are always replacing battery cables and making crimps. A welding shop may also do it for you.

 

[400bird]

Don't put a steel washer between the lug and whatever you're connecting too!
Maybe a copper washer, but putting the current through steel will cause excessive resistance and heat.

 

[glandpuck]

Don't put a steel washer between the lug and whatever you're connecting too!
Maybe a copper washer, but putting the current through steel will cause excessive resistance and heat.

Hmm, I didn't know that. My stainless steel posts, lock nuts, washers and nuts all have hundreds of amps go through them with the copper lug sandwiched in between. Also if lead acid batteries in use, I apply Kopr Kote. Never had a single issue with connections in 8 years of running a big battery bank. And my master electrician never said that was wrong.

Amazon sells this:

Stainless Steel Battery Bolt Kit - 0.25" X 1.00" Bolt, Flat & Split Washer & Nut, (2 Pairs for 2 Batteries), KSOL Power

Essentially that's how I do it. and the lock washer prevents loosening. Always tighten, wait 5 minutes and tighten again to spec.

 

[sunshine_eggo]

Hmm, I didn't know that. My stainless steel posts, lock nuts, washers and nuts all have hundreds of amps go through them with the copper lug sandwiched in between. Also if lead acid batteries in use, I apply Kopr Kote. Never had a single issue with connections in 8 years of running a big battery bank. And my master electrician never said that was wrong.

You're likely misinterpreting.

The use of stainless steel washers isn't the issue. Placing a steel washer BETWEEN a terminal and a copper cable is a huge no-no. Placing one on top of the cable to sandwich it to a terminal is no issue.

Copper is 27X more conductive than stainless steel, so the idea that having a stainless steel washer in the current path is okay is foolish. If your "master electrician" doesn't know this, that's proof that sometimes even those with vast experience and education may be lacking in the fundamentals.

This mistake and resultant high resistance in the connection has been documented several times on this site.

 

[Quattrohead]

use flat washers on top and bottom

Nooooooooo

 

[400bird]

Hmm, I didn't know that. My stainless steel posts, lock nuts, washers and nuts all have hundreds of amps go through them with the copper lug sandwiched in between. Also if lead acid batteries in use, I apply Kopr Kote. Never had a single issue with connections in 8 years of running a big battery bank. And my master electrician never said that was wrong.

To add to what sunshine_eggo said:
Current flows through the faces of the connections, directly from the lug to the terminal, the nut, bolts, and hardware are there to clamp the conductive faces together.

I've seen steel, stainless steel, and aluminum get heat damaged and melt when placed in the current path. The bolt, nut, and washers on the ends of the stack don't carry current*

A small portion of the current will flow through thr hardware, but that's not the important part of the conductive path.

 

[DIYrich]

Cut the lug on the far end away from the wire. Spread the barbs so it fits over the lug. That way you don't loose surface area drilling the lug.

 

[glandpuck]

You're likely misinterpreting.

The use of stainless steel washers isn't the issue. Placing a steel washer BETWEEN a terminal and a copper cable is a huge no-no. Placing one on top of the cable to sandwich it to a terminal is no issue.

Copper is 27X more conductive than stainless steel, so the idea that having a stainless steel washer in the current path is okay is foolish. If your "master electrician" doesn't know this, that's proof that sometimes even those with vast experience and education may be lacking in the fundamentals.

This mistake and resultant high resistance in the connection has been documented several times on this site.

Placing a steel washer BETWEEN a terminal and a copper cable is a huge no-no.

Perhaps I wrote out incorrectly or confusingly what I do with the lugs and terminal. I place the lug directly on the flat side of the threaded terminal, then a stainless washer and lock nut on top and then the nut. The lug is in direct contact with the terminal.

Here is where I think what I wrote got confusing. If you have a terminal like on a Trojan T-105 RE where the leaded terminal is flat with a hole in the center, you have to supply the bolt, washers and nut. In that case, the lug goes up directly against the terminal face. The bolt thru both and on one side a washer and nut and on the other side a washer, lock nut and the bolt head. This keeps the bolt torqued down and the lug is directly up against the terminal face. If you have 2 lugs to this type of terminal, I usually install a lug on each side.

I did not mean for the current path to ever travel thru the washer, lock nut, nut or bolt head.

 

[sunshine_eggo]

Drill it out and use flat washers on top and bottom along with lock washer to bolt it the threads.

This statement can easily be interpreted as placing a washer on top and bottom of the ring terminal and is the reason we responded as we did. Maybe edit for clarity?