Technical On 6 volt systems, what are you using for battery cables?

My 53 Ford with a flathead V8 cranks pretty slow. I’ve been told that I need to put in 00 wire to replace the original battery cables.

Is 00 overkill? What are you running?

Did you install a ground strap? What is it made from? Where is it connected?

 

Used 1/0 welding cable for all battery/starter/ground connections on my C59A. Block is grounded from threaded hole near PS water pump to chassis near battery. Got a large lug hand crimper just to do those cables. Still cranks slow, but starts.

 

We had a Merc like that at work last week. Cranked slow cold, and when hot cranked so slow it would not start. The owner had just replaced the starter with a new one which made no difference. We replaced the solenoid as there was a small voltage drop there, the pos and neg battery cables, as the ends looked questionable. All that made no difference. The owner had talked to the guy who built the car and he said it was always like that, just wait 15 minutes when hot and it would start. As a last resort, we had a crusty flathead that had been sitting in the corner of the shop for at least 10 years, that had a starter on it. We swapped the crusty starter for the new one on the car and it works perfect. Cranks fast when cold or hot. We took both the bad starters apart, and could not see anything visible wrong with them. All we could figure out was when hot some of the windings would short out, but who knows.

 

I worked a '54 Pontiac for a local fellow, all original one owner car. It was starting slow, so I had some 4/0 cable from work and made up a couple battery cables for the car. One ground cable right to the block and the positive cable to the starter. It would turn over better than it ever had he said, started no matter what the temp was. I left all the factory cables in place, just made sure the ends were all clean. 4/0 was over kill, but it was free and worked, not sure you can go to big when sizing cable!

 

00 cables including 00 ground cables from batterycableusa.com

 

00 wire, solder pellets, and terminals from Brillman.

 

My '29 AV8 avatar has a 59ab and always cranked slow. I had put new brushes in it when I first got the car and was resurrecting it. After several years it just began to not crank sometimes. Finally I grabbed a good looking used starter I had, tested it and seemed fine. Pulled the offending one and installed the good one. Cranks way better than the other ever did!
I have large cables on it by the way. No little 12 volt things. 6 volt needs big cables. Half the voltage, twice the amps.

Dave

 

I use the original 6volt 1940 style flat battery cables. Car is 12V. Works great for last 40 years.

 

Just let Brillman make a set of cables.

I use 00 on my car and it is 12V!!

Ben

 

I have big cables made at the local John Deere tractor place, but any brand shop will probably do it.

Also make sure there is clean, not freshly painted metal where the starter bolts on for good ground.

The little support bracket makes ground too.

 

00 cables from Batterycables USA. 1951 Plymouth 6v + ground with an alternator. Cranks like it has 12v going to it.

 

I'm still using up 6v size cables salvaged over the past 50+ years. I'll have to check into Brillman's - some of the clamps are worn.

 

I ordered a hydraulic crimper and 2/0 terminals from Amazon. I am going to pick up wire today… on sale at Princess Auto right now. I may need to change out my solenoid too but we will see.

Lengths appear to be:

11” battery to frame
~24” battery to solenoid
32” solenoid to starter
12” frame to bell housing bolt

 

Consider battery to bellhousing bolt, and then use a different bellhousing bolt to go from frame to bellhousing bolt.

My reasoning: You want the shortest path from the battery ground to the starter - Battery > frame > bellhousing bolt is a longer length, with additional cable terminations. All contributing to Voltage drops.

Russ

 

You do realize that 4.0 wire is a lot smaller and carries a hell of a lot amps than 00 or 1 0 ? The added non corroded cable to the originals that were probably corroded is what helped.

 

I believe the writer saying 4/0 could also be written as 0000. Both are rated at 600 amps at 100 feet. The next size is 250 MCM or million circular mills.
4.0 is readily known as #4 which makes a nice alternator feed wire.

 

Voltage drop is the enemy of all automotive electrical systems, especially 6V. When current goes up, so does voltage drop. As mentioned, the cable length to size relationship is highly important; longer means bigger. Grounding is critical also; having bare metal attachment points can make or break performance.

But something I rarely see mentioned is armature commutator service. Slapping a new set of brushes in will only partially help. Unfortunately, a few special tools are needed. First is one you can make. Cleaning out the slots between the commutator segments should always be done when installing brushes in either a starter or generator. Grinding a hacksaw blade down to narrow it to the slot size can be done for a home-brew tool. As the brushes wear, those slots fill with powdered carbon from the brushes along with powdered copper off the commutator. This introduces a partial short circuit between the segments, effectively diverting current to all of the armature poles, not just the ones needed for a loss of power.

Second, truing the commutator to remove visible wear so the brushes seat properly. DO NOT use abrasives like emery cloth or sandpaper for this. They will shed grit that embeds in the soft copper which will accelerate brush wear. This really needs to be done on a commutator lathe. It can be done on a regular lathe but you need a razor-sharp cutter taking very light cuts to do so. The dedicated commutator lathes usually also had a cutting attachment to clean between the segments, but how many of those machines are still out there is hard to say. Again, you can use a regular lathe to do this with the right tooling, but you may have to grind up your own cutter. The hacksaw blade trick works but is a very slow process.

Unfortunately, the shops that know how and did this are few and far between these days, plus there is only so many times you can do this before you get beyond the commutator wear limits.

 

I took my cables and terminal lugs to my local hydraulic shop for crimping. They charged about $8

 

It still VOLTS, AMPS AND OHMS.


When you only have six volts of pressure to push amps thrugh the line the resistance = ohms needs to be reduced and larger cables and good clean connections reduce the ohms between point A and Point B just as using the shortest comfortable to use cables does.

Back when I was teaching I had a bunch of old Mopar training slides/videos that I used a few of in class and one was on volts amps and ohms and while it was a bit hokey from around 1950 it did a good job of explaining volts amps and ohms to even the slowest student in the class. it also compared it to a water system and water hose. Think of this, you have X pressure on the water system in the house or your shop. Go fill a gallon jug at the kitchen sink and time how long it takes to fill it, then go and fill the same jug at a hose bib outside or using the bath tub faucet. While the kitchen sink faucet is usually pretty slow (due to the skinny hose from the pipe to the faucet under the sink) the bath tub faucet or outside faucet fills the jug a lot faster because there is far less restriction in the line. Amp flow in your car works the same way, Less restriction = easier amp flow over the same distance.

Old battery cables and old wiring can be corroded inside especially the battery cables at the battery connections. That used to be far worse when we had to top off the acid levels in the batteries all the time and the posts and clamps tended to get corroded quicker. That turned green woven ground strap from frame to engine is going to have more restriction than a clean one. Rust and corrosian at contacts all through the system all have to be taken care of.

I've made a grown man cry because I pulled out my knife and scraped the multiple layers of pretty paint off that was under his ground strap on his freshly built "won't crank over" engine. He had so much paint on it there was no way that the ground cable was going to make decent contact to carry enough amps to start, Simply running the ground lead to the block or a head rather than a bracket can make a difference. No it might not be the way the factory had it but the factory didn't put six coats of fiz can paint on the brackets either.

 

Yes, I was talking about 4-0 cable, 0000 about 3/4" or bigger in diameter. Pulled it out of a scrapped school bus.

 

Learned of the importance of proper grounding when it came to military radio installations in our vehicles. That’s a whole other level…

 

When I first got my car I cleaned and added a bunch of grounds, it made little difference in cranking speed with the ratty 1 gauge cables.
I had batterycableusa.com make me a set of 00, including solinoid to starter, and now it cranks with significant confidence, very comparable to an average factory 12v car. I have also noticed that times that require excessive cranking no longer get the cables hot.

 

I picked up the 2/0 wire tonight. The crimping tool and terminals arrived during the week. I will get the new wires built and installed tomorrow and post the results. I have a new solenoid on order that won’t be here until next week.

If this doesn’t work, I will get my started rebuilt.

 

Welding cable makes an excellent battery cable.

 

Exactly, everything on a 6v system needs to be up to snuff for it to work effectively. Cable size and clean grounds (or all connections) are only part of the equation. This is why a lot of people convert to 12v as it's more forgiving.....to a point.

 

I find a lot of people neglect the ground side of the system; even some of the factory battery cables and ground straps are inadequate. I had an OT 1982 Pontiac J2000 that was slow to start and slow to recharge the battery. Turned out GM used small copper-clad aluminum cables on that one. I built a set of heavier copper battery cables, added a good grounding cable from the motor to the frame and a Ford solenoid, and solved both issues.

Someone once gave me a set of jumper cables that were garbage. The insulation was a good 1/2"+ in diameter, but the wire inside was 16 gauge. Those ended up in the scrap bin.

 

On my woodie I have all NOS parts and a AGM battery and it does great. My Tudor I have NOS ground cable and Dennis Carpenter cables everywhere else and it does just as well with a 6v tractor battery. Just make sure all of the connections are clean and secure, but if you still have issues then look at the starter and get it rebuilt.

 

I made up and installed the 2/0 cables with my new hydraulic hex crimper yesterday and it made some difference but not enough. I’m going to check voltages while cranking to determine if this is the solenoid or starter. I have a new solenoid coming already as well as starter brushes.

Once running, the truck runs awesome.

 

I used standard battery cables from tractor supply, I had the same issue with limited cranking power. It ended up being the ground was not good enough. I moved it to the frame and used a body grinder to remove all paint and primer.