Leisure /Marine batteries threaded post size please ?

[Capt Popeye]

Hi I embarked on my re installation of a Bilge Pump , plus replaced the Leisure /Marine battery ; Well this battery has dual posts fitted , thats 2 x Poss and 2 X Neg ; the Poss and the Neg have a threaded post , I thought it would be 8 mm but its NOT , at a guess it could be a 5/16 but whats the thread type ? A 8 nut mm will only partly thread onto the threaded post ,before locking up tightly , so its NOT a mm thread sze ; so if its a 5/16 is it Whit or BSF or what ?

Anybody know what the actual thread is ? my thought are its either a Whit or a BSF thread

Many thankls (oh tried googling but so far not no help , only info is its either a 5/16

 

[Daverw]

Don't know the exact size but mine on the last battery were imperial

 

[Tranona]

Hi I embarked on my re installation of a Bilge Pump , plus replaced the Leisure /Marine battery ; Well this battery has dual posts fitted , thats 2 x Poss and 2 X Neg ; the Poss and the Neg have a threaded post , I thought it would be 8 mm but its NOT , at a guess it could be a 5/16 but whats the thread type ? A 8 nut mm will only partly thread onto the threaded post ,before locking up tightly , so its NOT a mm thread sze ; so if its a 5/16 is it Whit or BSF or what ?

Anybody know what the actual thread is ? my thought are its either a Whit or a BSF thread

Many thankls (oh tried googling but so far not no help , only info is its either a 5/16

The battery specification will tell you what the thread size is. Surprised it has not come with nuts. What battery did you buy?

 

[PaulRainbow]

Hi I embarked on my re installation of a Bilge Pump , plus replaced the Leisure /Marine battery ; Well this battery has dual posts fitted , thats 2 x Poss and 2 X Neg ; the Poss and the Neg have a threaded post , I thought it would be 8 mm but its NOT , at a guess it could be a 5/16 but whats the thread type ? A 8 nut mm will only partly thread onto the threaded post ,before locking up tightly , so its NOT a mm thread sze ; so if its a 5/16 is it Whit or BSF or what ?

Anybody know what the actual thread is ? my thought are its either a Whit or a BSF thread

Many thankls (oh tried googling but so far not no help , only info is its either a 5/16

5/16 UNC for the negatives, if the positives are bigger they will be 3/8 UNC

 

[Capt Popeye]

The battery specification will tell you what the thread size is. Surprised it has not come with nuts. What battery did you buy?

Hi Tranona ; bought a Lucas LX 27 a 95 ah Leisure battry , at £99.00 inc VAT and delivery ; with a 4 year warranty ; weighs about 21 kg Phew ; intend to use the main Posts for engine starting and the aux threaded posts for Bilge pumps x 2 off , set a slightly different heights from hull skin ; so hopefully the bilge pumps will be activated by the bilge water levels at different time ; guess that the earlier Bilge Pump was running too much

Thank you CP

 

[andyc352]

Hi I embarked on my re installation of a Bilge Pump , plus replaced the Leisure /Marine battery ; Well this battery has dual posts fitted , thats 2 x Poss and 2 X Neg ; the Poss and the Neg have a threaded post , I thought it would be 8 mm but its NOT , at a guess it could be a 5/16 but whats the thread type ? A 8 nut mm will only partly thread onto the threaded post ,before locking up tightly , so its NOT a mm thread sze ; so if its a 5/16 is it Whit or BSF or what ?

Anybody know what the actual thread is ? my thought are its either a Whit or a BSF thread

Many thankls (oh tried googling but so far not no help , only info is its either a 5/16

Don’t know the thread but definitely not metric on these. I’ve bought several similar batteries over the years and they’ve always come with nuts. It’d be worth getting back in touch with the battery supplier as the nuts should be included.

 

[PetiteFleur]

Mine are both M8 - I thought that was the standard? I've also fitted my own M8 and they fit.

 

[Capt Popeye]

Mine are both M8 - I thought that was the standard? I've also fitted my own M8 and they fit.

Yes well , I thought they were M8, so went into my local friendly very well stocked Hardware Store , and asked if I could borrow one , to try it out ; yes well an M8 will start to screw down but stops just as the M8 starts to show above the tip of the Thtreaded Post ; oh bgr it

 

[Tranona]

Hi Tranona ; bought a Lucas LX 27 a 95 ah Leisure battry , at £99.00 inc VAT and delivery ; with a 4 year warranty ; weighs about 21 kg Phew ; intend to use the main Posts for engine starting and the aux threaded posts for Bilge pumps x 2 off , set a slightly different heights from hull skin ; so hopefully the bilge pumps will be activated by the bilge water levels at different time ; guess that the earlier Bilge Pump was running too much

Thank you CP

So you have gone off the idea of having a dedicated battery for the bilge pump as many of us suggested. You now run the risk of flattening your engine start battery unless you have a means of charging when the engine is not running. You did not need to buy a battery that size to start your engine and 2 smaller batteries with a split charge system from the engine or a solar panel for the pump battery would have been a better choice.

 

[VicS]

Hi I embarked on my re installation of a Bilge Pump , plus replaced the Leisure /Marine battery ; Well this battery has dual posts fitted , thats 2 x Poss and 2 X Neg ; the Poss and the Neg have a threaded post , I thought it would be 8 mm but its NOT , at a guess it could be a 5/16 but whats the thread type ? A 8 nut mm will only partly thread onto the threaded post ,before locking up tightly , so its NOT a mm thread sze ; so if its a 5/16 is it Whit or BSF or what ?

Anybody know what the actual thread is ? my thought are its either a Whit or a BSF thread

Many thankls (oh tried googling but so far not no help , only info is its either a 5/16

Unlikely to be Whitworth or BSF. More likely to be UNC

Are both the same size ?
I have found info which suggests 3/8" x 16 tpi for for the positive and 5/16" x 18 tpi for the negative. They are UNC and Whitworth sizes but the thread forms are different

( M8 is very close to 20 tpi )

.

 

[Tranona]

Unlikely to be Whitworth or BSF. More likely to be UNC

Are both the same size ?
I have found info which suggests 3/8" x 16 tpi for for the positive and 5/16" x 18 tpi for the negative. They are UNC thread sizes

.

Already covered in post#4

 

[VicS]

Already covered in post#4

I didnt see a post #4

 

[PaulRainbow]

I didnt see a post #4

It's between posts #3 and #5

 

[Boater Sam]

Anything made in the last 30 years and sold in the UK will be metric. Are you sure you have an 8mm metric nut? I have never found one on a battery that was anything else.

There is no post #4

 

[Sandy]

I've just replaced a few of those silly wing nuts with M8 nylocs.

You could buy some battery terminals, Halfords should have them, and fit standard stuff.

 

[PetiteFleur]

Anything made in the last 30 years and sold in the UK will be metric. Are you sure you have an 8mm metric nut? I have never found one on a battery that was anything else.

There is no post #4

Indeed, and ss nuts are usually stamped A2 or A4.

 

[Tranona]

Anything made in the last 30 years and sold in the UK will be metric. Are you sure you have an 8mm metric nut? I have never found one on a battery that was anything else.

There is no post #4

I can see it very clearly and it says 5/16 UNC for the negative and if the positives are bigger then 3/8 UNC quite normal to have different sizes (as in SAE battery posts) to avoid wrong connections.

 

[Capt Popeye]

So you have gone off the idea of having a dedicated battery for the bilge pump as many of us suggested. You now run the risk of flattening your engine start battery unless you have a means of charging when the engine is not running. You did not need to buy a battery that size to start your engine and 2 smaller batteries with a split charge system from the engine or a solar panel for the pump battery would have been a better choice.

Thank you T ; Well no not given upon the plan to have 2 batteries , just trying to find out why boat bilges became over flooded ; still evaluating the pumps capacities and battery vunerability , owing to the low height of ots fitting , into the bilge , me knackered at the mo , owing to yesterdays manhandling of the over 2 kilo batteries , on /off the boat and berthing pontoons , into /out of car plus garage

Initial findings are that the Fitted Bilge pump rating is a bit on the low L/P/H , my current guess it that the Rainfall was greater than the Pump could manage , accoring to the Yard Hands , it rained Cats n Dogs over the Christmas Festive period , when i could not manage a visit to yard

; But my interntions are to have to have 2 batteries in final solution

 

[PaulRainbow]

I can see it very clearly and it says 5/16 UNC for the negative and if the positives are bigger then 3/8 UNC quite normal to have different sizes (as in SAE battery posts) to avoid wrong connections.

Boater Sam cannot see post #4 because he has me in his block list for correcting some of his misinformation in another thread.

in post #14 he states "Anything made in the last 30 years and sold in the UK will be metric. Are you sure you have an 8mm metric nut? I have never found one on a battery that was anything else. "

This is absolutely 100% incorrect. The OP has already said the studs are not metric. I know for an absolute fact that battery studs are commonly UNC, there might be few exceptions where they are metric, but i've yet to come across any.

 

[Boater Sam]

I have never seen a battery with 2 different size threads but then I would never buy a Lucas battery.
I remember all the ones that went open circuit due to poor welding of the cell linking busbars
Best day was when Lucas closed all the factories in the UK and stopped making rubbish.