Thornycroft starter battery size?

[LilCarls]

Hey!

I have a Thornycroft 75, and the starter battery is old and keeps dieing on me. So I'm going to buy a new one.

Any recommendations? I'm just going to go to Halfords to get one, but I have no idea what size. I also can't compare to the old one, as the "starter" battery on the boat is currently a leisure battery

Thanks!

 

[Phil Ambrose]

I have a type 80 and this is only a guess but though I have a 110amp domestic a 80a/h would be ample.

Phil

[bizzard]

Once you go above 90amp batteries become taller, other dimensions should remain the same as 110, 120amp and whatnot. The tall ones might not fit your box if it has a lid. An 80 or 90 will be plenty big enough, but don't go any less.

[Arthur Brown]

Take the box measurements or the battery measurements with you and start physically measuring. Also remember to check the lug style and position lest the wires turn out to be too short for the wrong shape battery.

[alan_fincher]

For a battery used solely as a starter battery, Amp Hours is not really the most important number - that is about how much power it can supply in total at a relatively slow rate of discharge - very important when running domestic services, but not when starting the engine.

 

What matters for a starter is that it can deliver lots of amps for the relatively short times necessary to start the engine. This measure of this is usually referred to as "Cold Cranking Amps", abbreviated CCA. High CCA is good news for starting a reticent boat diesel on a cold day - look for ones at about 750CCA, and above.

 

My preference is also to try and find ones with a 3 year warranty, rather than a 2 year one, even if it is a few quid more. It seems batteries that play up often do so about 2 years and 1 month after purchase!

[Taslim]

For a battery used solely as a starter battery, Amp Hours is not really the most important number - that is about how much power it can supply in total at a relatively slow rate of discharge - very important when running domestic services, but not when starting the engine.

 

What matters for a starter is that it can deliver lots of amps for the relatively short times necessary to start the engine. This measure of this is usually referred to as "Cold Cranking Amps", abbreviated CCA. High CCA is good news for starting a reticent boat diesel on a cold day - look for ones at about 750CCA, and above.

 

My preference is also to try and find ones with a 3 year warranty, rather than a 2 year one, even if it is a few quid more. It seems batteries that play up often do so about 2 years and 1 month after purchase!

Ah! It's not just me then.

[Scholar Gypsy]

Take the box measurements or the battery measurements with you and start physically measuring. Also remember to check the lug style and position lest the wires turn out to be too short for the wrong shape battery.

 

"Hear hear" to this - don't ask me how I know.

 

You might think there is a standard configuration eg with the terminals nearest to you the positive is on the left. Not so.

[Arthur Brown]

Searchable on the internet there are several battery size selection charts, for lead batteries. Put your existing battery measurements into a chart and see what the code number is. Get a battery like that if you want it to fit.

[Phil Ambrose]

Searchable on the internet there are several battery size selection charts, for lead batteries. Put your existing battery measurements into a chart and see what the code number is. Get a battery like that if you want it to fit.

Good idea but won't help the OP because his existing battery is a domestic (guessing a 110a/h)

Phil

[Laurie Booth]

I have just bought a Hancock MF54321 £36.00 inc delivery with 4 year guarantee,

http://www.batterymegastore.co.uk

[alan_fincher]

I have just bought a Hancock MF54321 £36.00 inc delivery with 4 year guarantee,

http://www.batterymegastore.co.uk

 

Actually spelt Hankook, should anyone wish to search.

 

With a cold cranking amps of only 450, this is really rather smaller than ideal for many narrow boat engines. It will probably be OK on most, particularly small ones that start easily, but for most on a cold morning, something with a considerably higher CCA rating would be better.

 

I suspect this battery is more suited to dealing with the considerably lower compression ratio of a petrol engined car, rather than a boat diesel.

[Laurie Booth]

 

Actually spelt Hankook, should anyone wish to search.

 

With a cold cranking amps of only 450, this is really rather smaller than ideal for many narrow boat engines. It will probably be OK on most, particularly small ones that start easily, but for most on a cold morning, something with a considerably higher CCA rating would be better.

 

I suspect this battery is more suited to dealing with the considerably lower compression ratio of a petrol engined car, rather than a boat diesel.

Quite correct Hankook, got comedians on the brain.

[Alan Saunders]

Don't go to Halfords! Try a battery specialist like Bristol Batteries with your maximum dimensions and preferred terminal configuration, they are likely to supply an adequate battery at half the Halfords price.

 

e.g., If your existing battery is 110Ah, leisure there is a 'standard' 95Ah starter battery in the same size package but higher CCA for less money than the leisure battery.

 

Alan

[baranbaran]

I have the same comment as Bzard about that .....nice reply