Questions About Battery Cables For Home Use Standby Generators

[hotajax]

Pardon me for asking this kind of question, but I'm kind of lost. I need cables for my 7KW generator, and it has a group 26 battery. I know little about electric wiring.
Question 1: What gauge cable should I be using? Maybe a 30 inch length cable at the most. It is my opinion that when Generac assembled these models, everything was done on the cheap cheap, and probably could have used a heavier cable. The cable that is currently installed is a hair over 1/4" in diameter, including the outer insulation. Very cheesy. Could be 6 ga or even lighter. Only God knows how much copper is inside.
Question 2: When measuring the diameter of the cable, do you include the insulation as well? Or is the cable diameter only the copper strands?
Question 3: If I have to make up a cable, are those universal terminals ( you attach the cable to the terminal and tighten down a bar that holds the cable in place ) any good? Or are they high risk for corrosion?
Question 4: Any tips for installing the universal terminals? Like tinning the ends, or using a heavy coating of dilectric grease?

Thanks in advance.

 

[Maintenance Chief]

Cable measurement is the core only, I personally like to use welding lead as battery cables ( its flexible and about MC350 in size ) it'll handle about 400amps. It can be had at any welding supply store.
They make a spray sealer for cable ends and terminals, can be purchased at the auto parts store as well as dielectric grease.
The marine grade terminals are brass and higher quality than the regular.

 

[JB-PlantHeirloom]

I use to be a Federally certified class 7/8 truck mechanic and here is how I do repairs when I only want to do them once. My goal, achieved, was 0.05% non-starts out of 400+ trucks in the dead of winter on our lot. So, I know a few things about battery wiring.

Use marine wire (already tinned), you can buy it on-line, though I suggest using a real marine store such as westnmarine.com and not amazon or e-bay. I buy it by the foot when possible. For one job, I would get it already assembled. You should not use it for tight turns in very cold climates.

32" length, 4 gauge, red 3/8
https://www.westmarine.com/buy/anco...able-assemblies--P009_272_004_003?recordNum=2
"Ancor builds each cable using their marine grade stranded tinned cooper battery cable."

When you order black, it should be 5/16 lug.

This matches up to REAL marine terminals , 3/8 (+) 5/16 (-). Tin coated brass, brass, or lead, your choice. I prefer brass as the cheaper lead ones tend to split. A real marine battery will have the (+) post bigger then the (-) which will match real marine battery terminals. I use di-electric grease on the fittings. I use the green red pads for acid, not sure they actually do anything other then collect stuff so it does not sit on the battery.

I have been using the marine duracell battery for my small SUV with a 5k winch, and it has been fine.

SLI24MDC Duracell Ultra BCI Group 24M 12V 500CCA Flooded Marine & RV Battery
https://www.batteriesplus.com/productdetails/sli24mdc

If you use the add on battery terminals, you can use the smaller posts for a battery tender or trickle charger.

 

[huskihl]

How many horsepower motor is on the generator? Probably 16 to 18 HP? It’s not a very big unit, the stock cables are probably more than adequate for only being 32 inches long

 

[Al Smith]

I'm in a lot different situation than most. I was able to "scrap pass " an amount of number 4 welding cable in both red and black colors that I have used on occasion for battery cables on small engines plus made jumper cables from them . A small engine doesn't have much of an amperage draw like say a diesel starter .