Marine Electronics Forum - What size nut for battery post

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View Full Version : What size nut for battery post


larrym
03-25-2012, 01:05 PM
Somehow I lost the wing nut that went to the negative terminal. Does anybody know what size nuts are used for both terminals?


Mist-Rest
03-25-2012, 01:09 PM
I can't remember if it's 5/16-18 or 3/8-16. I want to say 5/16.

Karl in NY
03-25-2012, 01:31 PM
They can be almost anything, depending on brand and type of battery.

Common: pos/neg both 5/16-18
Also common: pos. 3/8-16, neg. 5/16-18

Less common: 1/4-20
Less common: M6x1 Metric (Cabelas AGM batteries)

Also, wing nuts are pretty-much frowned upon for this application...nylock hex nuts are the preferred choice.


fishpimp
03-25-2012, 01:43 PM
dont use wing nuts

baltifrank
03-25-2012, 01:48 PM
Don't use stainless steel. It is a poor conductor. Find some silicone bronze instead.

The Hat Island Pirate
03-25-2012, 10:16 PM
Wing nuts are no longer ABYC compliant and have not been used by (Marine) battery MFG's for over 5 years.

Clam_Alert
03-26-2012, 08:10 AM
A little off-topic, but related. What's the curent state of thought about using nylock nuts as suggested by Karl? I recall a thread a few years back where I think Glen E (who is very knwoledgable about such things) advised against it because the terminal post could heat up sufficiently to melt the nylon. I don't beleive there was consensus either way (but is there ever on THT?). I use them, and they've been just fine.

Karl in NY
03-26-2012, 09:17 AM
Even if the nylon was to melt, the nut would still be held by the threads.

The nylon is basically just an anti-vibration feature.

cred
03-26-2012, 09:34 AM
If the battery is fairly new 3/5yrs the nut should be 5/16

Birdman
03-26-2012, 11:33 AM
Also, wing nuts are pretty-much frowned upon for this application...nylock hex nuts are the preferred choice.

dont use wing nuts


Wing nuts are fine as long as you use a lock washer under it.

C Skip R
03-26-2012, 12:03 PM
Depends on the brand of battery. On my Odysses batteries one terminal threads were different than the Optima batteries that were in the boat before.

marlin driver
03-26-2012, 12:51 PM
Wing nuts are fine as long as you use a lock washer under it.
Per ABYC:

E-10.8.3: Battery cables and other conductions size 6AWG and larger shall not be connected to the battery with wing nuts.

mwardncsu
03-26-2012, 01:05 PM
Depends on the brand of battery. On my Odysses batteries one terminal threads were different than the Optima batteries that were in the boat before.

The AC Delco Voyager deep cycles that I have are 3/8" (I think) on both terminals.

I'm getting ready to crimp battery cables - regardless, I guess I better not use 5/16" on the negative side terminal in the event a new battery goes in later that has the same larger size post on both terminals else I'd have to drill out the ring terminal or crimp on a new terminal, etc.....

Bayfly
03-26-2012, 06:09 PM
and all of this BS about using nuts with nylon inserts, or not is just that. I just save my wing nuts off my old batteries when I trade them in for cores, and proceed on. I've never had a problem with wingnuts on my batteries, but maybe someone that doesn't use a pair of pliers to tighten them does. Like my signature says, "Life is tough, but it's tougher if you are stupid".;?

Mist-Rest
03-26-2012, 07:03 PM
Give me a friggen break.

When was the last time any of you had a loose nut holding the stud type battery cables on your boat?
A wing nut finger tight??? Maybe.
A wing nut tightened down with an open wrench??? Very unlikely.

I'll continue to use a wing nut always because...
Most any tool (including a pocket knife) can get the nut off quickly if there is a problem and secondly, I'm not running high current diesel starters.



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