3/8" or 5/16" Battery Terminals ?

[mepsnbarry]

I'm getting ready to wire up my new house bank, and I've discovered something different. I want to know what is "normal."

My old batteries (Group 27, AGM) had a negative terminal with a 5/16" stud on them, and a 3/8" stud on the positive terminal.

My new batteries (Group 31, flooded) have 5/16" studs on both terminals.

I would rather have tightly fitting lugs on the terminals. But I don't want to be forced to re-terminate or drill out to 3/8 when I later replace my batteries.

Are there two (or more?) standards? Is one old and one new? Please give me more data--what will I find when I need to replace these batteries?

Thanks!
Barry

[donradcliffe]

Barry,
The lugs are the same except for the hole size, so if you are worried about it (and I wouldn't be), get the 5/16 lugs and be prepared to drill in the future.

[Blue Stocking]

A 3/8 lug on a 5/16 terminal will work. All lugs should be fitted with correct size brass/bronze washers under the nut IMHO.

[hellosailor]

Barry, I've found the same thing. "Old" batteries used different sizes for the + and - fittings, but the new ones have gone to the same size. Which I suspect makes life simpler, easier, and cheaper for all parties. You should be OK to use the old cables on the new batteries, the amount of contact area is still roughly the same and having a clean tight contact should be the only consideration. Of course this means buying new wingnuts, maybe it is a ploy to put some life in the wingnut industry. (Even though they're just not supposed to be used in vibration-prone areas.)

[noelex 77]

Originally Posted by hellosailor

Of course this means buying new wingnuts, maybe it is a ploy to put some life in the wingnut industry. (Even though they're just not supposed to be used in vibration-prone areas.)

If you cannot replace it with a nyloc nut a small cable tie across the wingnut will help stop it vibrating loose. There is nowhere that is "vibration free" on a yacht IMHO.

[xymotic]

The ABYC code has changed a couple times in the last few years. both terminals 5/16 with nylocks on it is what you should find to be 'normal' going forward.

I wouldn't use wingnuts, because you WILL have insurance and survey problems going forward. And the dang things aren't any easier anyway, when they are on good you can't get em off by hand anyway... so you might as well use a wrench :-)

[hellosailor]

Last time I said "nyloc" it was a dirty word, apparently the nylon portion can melt if the terminal overheats and then there goes the whole ball game.

Split washer and double stainless bolt? Or wingnut and terminal cover to hide it?<G>

[xymotic]

Originally Posted by hellosailor

Last time I said "nyloc" it was a dirty word, apparently the nylon portion can melt if the terminal overheats and then there goes the whole ball game.

Split washer and double stainless bolt? Or wingnut and terminal cover to hide it?<G>

Yes, well the O.E.M. ones we sell @ west marine come w/ nylocks so

I have a gut feeling that if you get it that hot, the battery is long dead anyway. but again dunno.