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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: TomC on April 24, 2018, 07:52:19 AM

Title: Battery Cables
Post by: TomC on April 24, 2018, 07:52:19 AM
I'm getting close to having to wire up my inverter and house batteries. What about making cables out of welding cable? Good Luck, TomC
https://www.wireandcableyourway.com/Welding-Cable/ (https://www.wireandcableyourway.com/Welding-Cable/)
Title: Re: Battery Cables
Post by: richard5933 on April 24, 2018, 08:38:10 AM
That's what I use. Much more flexible and easier to work with. I splurged on a hydraulic crimper, which makes it much easier to install the lugs.
Title: Re: Battery Cables
Post by: bobofthenorth on April 24, 2018, 10:40:33 AM
I can't think of one reason NOT to do it that way.  I won't tell you exactly how I'd do it because that would start a massive thread war but I'd definitely make my own and I'd use welding cable to  do it.
Title: Re: Battery Cables
Post by: DoubleEagle on April 24, 2018, 11:43:38 AM
One of the drawbacks to welding cable is that the strands of copper are very thin (which makes the wire very supple) and are corroded more easily if unprotected. There was welding cable on my 1982 that was so corroded I could easily yank the wire off the terminal connector because the insulation had shrunk back over the years, leaving an exposed gap. Welding cable is not SAE approved for automotive use, and the insulation is not oil resistant. A better cable is SAE SGX or SGT-M which have higher heat ratings, are oil resistant, and are not as expensive as the tinned marine cables. Tinned marine is the ultimate in cost, but SGT-M is rated for marine use, and has self-extinguishing insulation. If the terminals are professionally done and the cable is totally protected, there is less justification for tinning. If the welding cable is constantly exposed to oil (now how could that happen on a two-cycle?), the insulation will swell and get weaker. It might work for years, but then cause problems down the road.  ;)
Title: Re: Battery Cables
Post by: richard5933 on April 24, 2018, 11:56:26 AM
Regarding the insulation on the terminals/lugs...

There are two types of shrink tubing. One is just a plain shrink tube, and the other has heat-activated adhesive inside. My experience is that the shrink tubing with adhesive makes a very good seal against the lug and should help eliminate corrosion. Just my experience, and I have no idea if this is SAE or not. I've only been doing this on my battery bank, which is in a clean location, so oil/grease contamination are not really an issue.

I just checked the product description on the cable I bought (from Crimp Supply), and here is what it said:

     Operating temperatures is -58°F to +221°F (-50°C to +105°C). Rated to 600 volts. RoHS Compliant and meets SAE J1127.

From my layman reading, this would indicate that this particular welding cable would hold up with exposure to oil/grease. I'll have to do more research to state anything definitively though.
Title: Re: Battery Cables
Post by: DoubleEagle on April 24, 2018, 12:32:20 PM
Nope, those standards would not address oil resistance. J1127 refers to proper copper content per gauge, and RoHS concerns absence of restricted ingredients such as lead, mercury, cadmium, etc. The principle types of battery cables are stranded bare copper with PVC, Rubber, TPR or Cross-Link Insulation. The lowest maximum temperature rating is for SGT at 85 degrees C, then SGR at 90, and SGX at 125 degrees C. Battery cable is rated to 60V; welding cable at 600V. Welding cable is not SAE rated. Welding cable is very supple because of the fine strands and the soft insulation, which can crack in time and let corrosion agents in.
Title: Re: Battery Cables
Post by: TomC on April 24, 2018, 01:41:18 PM
Class W looks more like it.
Title: Re: Battery Cables
Post by: kyle4501 on April 24, 2018, 03:52:16 PM
I looked at the cost of tinned marine battery cable VS the non-tinned battery cable. The difference was such a small percentage of the total cost, it was a no brainer to use the marine cable.
I also upgraded to 4/0. (After loosing 2 starters due to hidden corrosion, I wanted as good as I could get.)

The adhesive heat shrink is what stunned me at the cost, man, that stuff was expensive!

While you are at it, make sure you get the good tinned lug ends. The cheaper ones can allow acid & moisture to enter thru the bolt end.

I also used a silicone dielectric grease inside the lugs & worked it inside the wire ends before crimping.
Title: Re: Battery Cables
Post by: TomC on April 24, 2018, 04:53:15 PM
Don't need all that anti-corrosive stuff when using AGM batteries.
Title: Re: Battery Cables
Post by: gumpy on April 24, 2018, 05:11:47 PM
I made mine using 4/0 Welding Cable with the adhesive shrink tubing. Have worked great for about 15 years now.

Check out www.waytekwire.com (http://www.waytekwire.com).  Been awhile since I've looked at their site, but they had a good selection, decent prices, and good service way back when.
Title: Re: Battery Cables
Post by: eagle19952 on April 24, 2018, 06:30:57 PM
A whole herd of heavy highway construction maintenance welders would have crapped out more than a few miles of welding lead if it wasn't oil resistant.

Some ship welders too

And pipeline too.
Title: Re: Battery Cables
Post by: Jim Eh. on April 24, 2018, 06:32:26 PM
If your cable is too "supple" when used on a mobile application will it not "swing like a rope"? I would think that would tend to wear on anchor points and bulkhead isolators.

I don't think there is any shrink tube that will bond completely to wire insulation unless it is similar material. Plastic doesn't seem to bond to rubber very well. Plus it has to be darn near surgically clean before shrinking. Any mold release (in the case of non natural rubber jacket) left on the outer surface and I don't think it will bond or seal.
Title: Re: Battery Cables
Post by: kyle4501 on April 24, 2018, 07:26:02 PM
Quote from: TomC on April 24, 2018, 04:53:15 PM
Don't need all that anti-corrosive stuff when using AGM batteries.

Battery acid ain't the only thing that contributes to corrosion. The corroded connection that caused all of my problems was no where near the batteries. . . . . So much for that theory.

Welding cable insulation can be neoprene, EPDM, or PVC ( Standard, Semi-rigid, or irradiated ), so not all welding cable is the same. If you don't know what the insulation material is, you can not possibly know how it will perform.

Sometimes, ignorance is not bliss . . . .  ;D

Cables can be adequately secured to prevent unwanted movement, the more supple, the more supports.

As for the adhesive heat shrink, I bought Ancor marine battery cable & the Ancor adhesive heat shrink. I made some test connections & cut them apart to verify the quality of the crimp & heat shrink. The heat shrink bonded so well with the cable insulation that the joint could not be seperated. With the correct lug ends, the wire was fused together in the crimped lug.
Title: Re: Battery Cables
Post by: Iceni John on April 24, 2018, 07:43:20 PM
Everybody here is talking about the cable and heatshrink (obviously very important factors), but what about the actual crimping process?   I've seen plenty of cables, including high-current starter cables, whose lugs are attached by those hammer crimpers, assuming such a tool deserves to be called a crimper!   To prevent moisture wicking between the strands, and to assure the best possible electrical contact between cable and lug, the lug ideally should be squeezed on all its sides so it compresses onto the cable so tightly that it and the cable have effectively cold-welded themselves together into one solid indivisible fused mass of copper.   No hammer crimper will do this  -  all they do is dent the lug down into the strands of wire, leaving individual strands still separate from their neighbours.   No bueno.   I purchased a FTZ 94284 circumferential crimper from K.L.Jack after reading about it on a boating website http://www.pbase.com/mainecruising/battery_cables (http://www.pbase.com/mainecruising/battery_cables)   It easily squeezes the lug on four sides to produce a completely solid joint  -  I test-cut one such joint apart to look at it, and the individual copper strands and lug had fused so tightly together that I couldn't pick them apart or separate it at all.   Very impressive.   The crimper's dies can be set to any lug size and thickness;  if I'm not sure what will work best I start with a looser crimp, then change dies to make it progressively tighter.   If you're making more than a few cables (I've made literally dozens so far, and I'm not finished yet!) then it's well worth buying a good crimper.

Also, don't cheap out on the cable cutter.   If the cut end is ragged and uneven it makes it difficult to get all the strands inside a tight-fitting lug.   I use a long-handled Temco cutter that's rated up to 250-size cable, much bigger than 4/0, and it cuts 4/0 welding cable like a hot knife through butter, leaving a perfectly flat smooth end.

Making cables is fun, and you can make them exactly how you want, with the lugs' orientation or even the cable's intended bend all part of the process.   Watching how some "professional" marine and vehicle techs make their cables made me quickly realize I could make mine better myself!

John          
Title: Re: Battery Cables
Post by: kyle4501 on April 24, 2018, 08:06:50 PM
John,
While you make an excellent point (that I agree with), I don't think that someone who is worried about the cost difference between welding cable & tinned marine boat cable is going to be able to understand the value of the proper crimper and wire cutter.  :(

At least they have been exposed to a more robust way.  ;D
Title: Re: Battery Cables
Post by: eagle19952 on April 24, 2018, 09:28:40 PM
Quote from: kyle4501 on April 24, 2018, 08:06:50 PM
John,
While you make an excellent point (that I agree with), I don't think that someone who is worried about the cost difference between welding cable & tinned marine boat cable is going to be able to understand the value of the proper crimper and wire cutter.  :(

At least they have been exposed to a more robust way.  ;D


Anyone turning there back on properly crimped cable is probably making a lot of critical mistakes.
Title: Re: Battery Cables
Post by: richard5933 on April 24, 2018, 09:50:02 PM
Like I mentioned in my earlier post, I anted up for a hydraulic crimping tool when I added the battery box and cables to our current bus. I didn't get the best out there, but it does a great job and only cost about $50 on Amazon. I had previously used the hammer/anvil method, but you guys are correct - there is no comparison between the two. Not only does the hydraulic crimping tool do an infinitely better job, another advantage is that lugs can be properly added to cables in the field if necessary without access to a solid surface for pounding.
Title: Re: Battery Cables
Post by: neoneddy on April 24, 2018, 10:56:02 PM
Maybe I'm a monster. I crimp and solder. I figure if I have a good connection I won't build heat and then the solder will hold fine. Been Rock solid this last year.


Sent from my iPhone using Tapatalk
Title: Re: Battery Cables
Post by: Oonrahnjay on April 25, 2018, 05:17:52 AM
Quote from: Iceni John on April 24, 2018, 07:43:20 PMEverybody here is talking about the cable and heatshrink (obviously very important factors), but what about the actual crimping process?   I've seen plenty of cables, including high-current starter cables, whose lugs are attached by those hammer crimpers, assuming such a tool deserves to be called a crimper!   To prevent moisture wicking between the strands, and to assure the best possible electrical contact between cable and lug, the lug ideally should be squeezed on all its sides so it compresses onto the cable so tightly that it and the cable have effectively cold-welded themselves together into one solid indivisible fused mass of copper.   No hammer crimper will do this  -  all they do is dent the lug down into the strands of wire, leaving individual strands still separate from their neighbours.   No bueno.   ... 

    I'm in the middle of the cable process myself.  I was loaned a "hammer crimper" by "someone who knows everything and it's 'good enough' " and I was thoroughly underwhelmed by the quality of connection.  I cut a connection (on 2/0 cable) and found that the wire strands were (mostly) circular but the terminal sleeve was D-shaped.  There was a pinch where the dent made by the hammer crimper pushed into the cable strands but there were big areas where there was little-to-no contact at all.
    Next day, a Harbor Freight ("Horrible Fright!") ad popped up with a hydraulic crimper on sale.  I'm not much of a believer in HF, but some of their stuff is OK for a "hobbyist" -- it will never live in a pro shop for day-after-day use, but this crimper will probably for 10 years for the guy who picks through the tools in my shop after I die. 
    I'm just not going to have loose or improperly crimped connections on my bus.
Title: Re: Battery Cables
Post by: scanzel on April 25, 2018, 05:34:28 AM
Because my battery bank is 24v with 8 AGM batteries wired to pos/neg bus bars I needed many battery cables made up. By the time I figured out how much red/black cable I needed plus all the connectors and heat shrink I found that my local battery supplier could make them better and less expensive and quicker. I just supplied all the measurements and he made all the cables for about $300. The only issue is before I went this route I bought a real nice American made adjustable head lug crimper that set me back $125 now I have no use for it.
Title: Re: Battery Cables
Post by: eagle19952 on April 25, 2018, 09:11:32 AM
Quote from: scanzel on April 25, 2018, 05:34:28 AM
Because my battery bank is 24v with 8 AGM batteries wired to pos/neg bus bars I needed many battery cables made up. By the time I figured out how much red/black cable I needed plus all the connectors and heat shrink I found that my local battery supplier could make them better and less expensive and quicker. I just supplied all the measurements and he made all the cables for about $300. The only issue is before I went this route I bought a real nice American made adjustable head lug crimper that set me back $125 now I have no use for it.

buy a bunch of lugs.
take them to a rally.
offer a upgrade service
charge 5$ and a beer
soon someone will buy the tool :)
Title: Re: Battery Cables
Post by: DoubleEagle on April 25, 2018, 10:29:59 AM
Quote from: scanzel on April 25, 2018, 05:34:28 AM
The only issue is before I went this route I bought a real nice American made adjustable head lug crimper that set me back $125 now I have no use for it.

Is it the TEMCo TH0005, by any chance? It gets pretty good reviews.
Title: Re: Battery Cables
Post by: windtrader on April 25, 2018, 11:09:06 AM
I look forward to the day when my coach gets to the point where the finer points of battery cables is on top of my punch list!!!  ::)
Title: Re: Battery Cables
Post by: belfert on April 25, 2018, 03:22:17 PM
Why is SGT cable considered so much better than welding cable?  It appears to just as fine stranded as welding cable.
Title: Re: Battery Cables
Post by: kyle4501 on April 25, 2018, 07:09:56 PM
Quote from: belfert on April 25, 2018, 03:22:17 PM
Why is SGT cable considered so much better than welding cable?  It appears to just as fine stranded as welding cable.

Insulation is as important as the wire stranding !!!!

http://custombatterycables.com/info_pages/wire_types.htm (http://custombatterycables.com/info_pages/wire_types.htm)
Title: Re: Battery Cables
Post by: DoubleEagle on April 25, 2018, 07:27:29 PM
Quote from: belfert on April 25, 2018, 03:22:17 PM
Why is SGT cable considered so much better than welding cable?  It appears to just as fine stranded as welding cable.

It is SAE rated and can take higher temperatures and oil exposure. Some versions of welding cable have insulation that can take oil exposure, but have not been certified by SAE. Welding cable would need more support to keep from drooping or flopping around. Many people get by with welding cable, but it is not optimum. I would not use it in the engine compartment, or where salty road spray can hit it.
Title: Re: Battery Cables
Post by: belfert on April 26, 2018, 03:08:36 PM
I thought the issue with welding cable is the fine strand.  An earlier post mentioned welding cable failing at the crimp due to the finely stranded wire.
Title: Re: Battery Cables
Post by: DoubleEagle on April 26, 2018, 04:27:07 PM
Quote from: belfert on April 26, 2018, 03:08:36 PM
I thought the issue with welding cable is the fine strand.  An earlier post mentioned welding cable failing at the crimp due to the finely stranded wire.

That is one of the issues if the connections are not completely covered. The fine strands can corrode relatively quickly if they are not protected - much more exposed surface area. It's the fine strands and soft insulation that makes welding cable so easy to whip around the floor and loop on a holder. Those are traits are not needed in a coach environment, in my opinion. The reasons for choosing one cable type over another are usually cost and/or the desire to have the long term best.
Title: Six Foot Long 80 Pound Mother Of All Mechanical Crimping Tools ...
Post by: HB of CJ on April 28, 2018, 04:34:13 PM
We had our 6/0 cables custom made using the available like new condition multi strand mining cables.  The insulation was like new.  Seems the hard rock mining companies just replaced the cables whether or not they actually had any visible wear?  Perhaps it was done every so many hours of usage?

The rented Mother of all mechanical cable crimpers was about 6 feet long, weighted at least 80 pounds and looked like a very very large pair of bolt cutters.  The connections were crimped but not soldered.  The shrink wrap was yellow if memory serves.  A rose budd propane hand torch was also rented.
Title: Re: Battery Cables
Post by: chessie4905 on April 28, 2018, 05:10:28 PM
Some additional information here.
https://www.homepower.com/articles/solar-electricity/design-installation/inverter-battery-cables (https://www.homepower.com/articles/solar-electricity/design-installation/inverter-battery-cables)