How to chose a new starter battery?

[pedroinlondon]

Hi

 

I have recently bought a boat with a 40HP Lister-Petter fitted, and the starter batteries left are no longer charging (Yes, plural batteries. There were three in paralel, I suppose for extra reliability, being a lifeboat)

Anyway, as they are no longer useable, I bought a cheapo from Halfords which started the engine with great difficulty, so I want to get a new one.

 

Before I get another not-great one, is there a rule for matching the horse power of an engine (or is it the stater motor that matters?) to a suitable starter battery?

I'm guessing larger engines will require  more amps shoved up their bums in a short amount of time, but is there a rule as such, or just more is always better?

And appologies for question n.2, which might be even sillier: is there also a reccomended upper limit for the amperage discharge at all? Should you absolutely not go over a certain amount?

 

Thanks

Edited April 16 by pedroinlondon

[Tony Brooks]

Three in parallel sounds much more like domestic/service batteries rather than starting batteries, unless you use the same batteries for both. I think we need you to confirm they are three stat batteries, there are other domestic batteries, and, ideally, a photo.

 

A single start battery of around 90 to 100 Ah should be more than enough to start that engine. (Note: Ah is not how start batteries are now designated).

[Tracy D'arth]

Its cranking current that matters for starter batteries..

Beware buying batteries from the likes of Halfrauds, in my experience they are often old stock and not fully charged, they come ready sulphated.

[BEngo]

I have always found that a decent makers 243  or 244 size battery, at about 96Ah and 760 or so Cold Cranking Amps will do the biz.   Shield make a decent battery at a reasonable price, but Tayna and others on line can also supply

 

I suspect the OP's 3 batteries in parallel are/were the entire outfit of his ex lifeboat so also keep the lights on and work any radio until the motor is running.

 

N

[Tony Brooks]

A run-of-the-mill wet 100Ah battery will have a Cold Cranking Amperage of around 700A or a marine cranking Amperage of around 800 amps. You must check that the case size fits your boat and that the terminals are in the same position as your existing setup.

 

A starting battery has a very easy life, so you don't really need anything fancy and expect 8 to 10 years out f a basic starting battery - unless you have poor charging.

1 minute ago, BEngo said:

I suspect the OP's 3 batteries in parallel are/were the entire outfit of his ex lifeboat so also keep the lights on and work any radio until the motor is running.

 

So do I, which is why I think we need it clarified. If it is, so I suspect the lack of proper charging was the base cause.

[alan_fincher]

Yes "cold cranking amps" (or "CCA") is what is most important for a starter battery.  Amp Hours (or "Ah") is far less relevant.

 

This is because you want it to supply very (very) big currents for a short period only, being quite different from a leisure battery which needs to be able  only to supply very much smaller currents, but continuously over a number of hours.

 

A starter battery ranging from (say) 700CCA to 900CCA should be far more than you need,

[pedroinlondon]

Hello gentleman 

Indeed the battery bank must have been used for the lights and other instruments around the boat while in service, as there were no other batteries or battery holders anywhere on the boat.

No labels on the cables neither.

This was the setup, until we connected the Halfords "emergency" battery to get the engine started.

Three Lucas 60ah batteries in parallel with some cables cut. A bit of a mess...

[Ray T]

Just purchased 3 leisure batteries and one starter from here: https://advancedbatterysupplies.co.uk/

Very helpful with their recommendations with next day delivery.

 

 

 

 

 

Edited April 16 by Ray T

[Tony Brooks]

I am not convinced they are all in parallel. I THINK the right-hand pair are, but looking at the left-hand battery positive, the lead with the yellow label does not seem to connect to the other batteries, so this one might have originally been an engine start battery.

 

If it is or was one start battery and two domestic batteries in parallel then the start battery negative is typically connected to the domestic bank negatives, but unless the positive is connected in the same way they are all not in parallel.

 

If this boat is subject to the Boat Safety Scheme inspections, then how many battery master/isolating switches do you have?

 

I fear that you really need to follow the cables and draw a diagram showing what they connect to, then you stand a chance of understanding the system.

 

As long as you have adequate charging and charging regime, there is no reason not to replace the batteries with similar for those that are only used for starting. If they are used for powering the domestic systems, then you really need to do a power/energy audit and charging calculations to ensure you have enough batery capacity.

 

I am not sure that you don't have a charging problem, that might be simply not enough, so the batteries are ruined.

[jonesthenuke]

The blue item in the far bottom left of the photo looks like a diode splitter, if so that needs to be included when drawing the schematic. Also if only one battery is now installed, how has it been connected (so looking at the photo of the original setup may be a distraction?}.

[blackrose]

Depending on how you're charging the batteries, another thing to consider might be whether you should match your domestic & start "battery types".

 

For example, if your domestic batteries are sealed maintenance-free and your start battery is open/flooded and you were charging both banks from a single battery charger on shore power, then you may well be overcharging or undercharging one or other bank during the absorption phase depending on what "battery type" you'd set on the charger. Although many battery chargers have multiple outputs for different battery banks, many chargers only have one "battery type" setting.

 

The same may be true for other charging sources such as solar controllers which charge a single bank but where a VSR has been used to connect a second bank.

Edited April 16 by blackrose

[Alan de Enfield]

11 hours ago, Tony Brooks said:

I am not convinced they are all in parallel. I THINK the right-hand pair are, but looking at the left-hand battery positive, the lead with the yellow label does not seem to connect to the other batteries, so this one might have originally been an engine start battery.

 

I just cannot see any interconnection of any of the 3 battery positive terminals.

The centre battery does have 5 cables on the negative terminal which is (at best) bad practice, and doesn't comply with the Boat Wiring specification requirements.

[Tony Brooks]

34 minutes ago, Alan de Enfield said:

 

I just cannot see any interconnection of any of the 3 battery positive terminals.

The centre battery does have 5 cables on the negative terminal which is (at best) bad practice, and doesn't comply with the Boat Wiring specification requirements.

 

Having another look, I think you are probably correct. It looks a mess.

Further looking shows the batteries are rated at 60ah and 540 A EN, so I suppose that is 540A CCA. To try to answer the original question, just one of those should start the OPs engine as long as it is kept adequately charged.

 

Further to Blackrose's post. I can see what looks like a substantial heat sink below the blue casing, so if it is a slit charge diode it is likely to be a passive one. That in turn means there is a very good chance that it is restricting the charging to all the batteries, however, this depends upon the type of alternator and how it and other charging components are wired.

[Tacet]

2 hours ago, Alan de Enfield said:

 

The centre battery does have 5 cables on the negative terminal which is (at best) bad practice, and doesn't comply with the Boat Wiring specification requirements.

Which are the Boat Wiring requirements not being complied with, please?

 

I fear you may be conflating a view on best practice with compliance and requirements.

[Tony Brooks]

50 minutes ago, Tacet said:

Which are the Boat Wiring requirements not being complied with, please?

 

I fear you may be conflating a view on best practice with compliance and requirements.

 

I think he is referring to the BMEA requirements and probably the ISOs. I think the BSS says something about that as well. So probably not a strict legal requirement, but something that should be adhered to. If the boat is within scope of the RCD/RCR then if it was questioned I think it would be difficult to justify it as being compliant.

[Alan de Enfield]

4 minutes ago, Tony Brooks said:

 

I think he is referring to the BMEA requirements and probably the ISOs. I think the BSS says something about that as well. So probably not a strict legal requirement, but something that should be adhered to. If the boat is within scope of the RCD/RCR then if it was questioned I think it would be difficult to justify it as being compliant.

 

As a lifeboat it would not have been built compliant with the RCD / RCR as they are not covered, however, if it was converted to a recreational boat (post 1998) is should have been surveyed and approved to the RCD requirements.

But, as with much of the waterways ...................  'should be' ............. is rarely applied.

[pedroinlondon]

19 hours ago, alan_fincher said:

Yes "cold cranking amps" (or "CCA") is what is most important for a starter battery.  Amp Hours (or "Ah") is far less relevant.

 

This is because you want it to supply very (very) big currents for a short period only, being quite different from a leisure battery which needs to be able  only to supply very much smaller currents, but continuously over a number of hours.

 

A starter battery ranging from (say) 700CCA to 900CCA should be far more than you need,

Thanks! That's the info I needed the most.

4 hours ago, Tony Brooks said:

 

Having another look, I think you are probably correct. It looks a mess.

Further looking shows the batteries are rated at 60ah and 540 A EN, so I suppose that is 540A CCA. To try to answer the original question, just one of those should start the OPs engine as long as it is kept adequately charged.

 

Further to Blackrose's post. I can see what looks like a substantial heat sink below the blue casing, so if it is a slit charge diode it is likely to be a passive one. That in turn means there is a very good chance that it is restricting the charging to all the batteries, however, this depends upon the type of alternator and how it and other charging components are wired.

Thanks Tony and Black Rose. For now I need to know what battery to purchase, I'll deal with the switches, charging options and regulation requirements next.

[Tony Brooks]

23 minutes ago, pedroinlondon said:

Thanks! That's the info I needed the most.

Thanks Tony and Black Rose. For now I need to know what battery to purchase, I'll deal with the switches, charging options and regulation requirements next.

 

The point that I think you may be missing is that unless you understand and monitor the battery charging you will destroy and expensive battery all but as fast as a cheap one. Unfortunately, we/I don't know if you do understand and monitor your battery charging so the only option is to advise you to buy an open, lead acid battery of the same size and terminal position as the ones you have now. This is so it fits into your existing battery cradle. If you buy a lead-carbon or AGM battery, it will cost more and may not last any longer.

 

As far as lead acid batteries are concerned, it is far easier for an ordinary boater to test open cell batteries for faults than any sealed battery, although sealed ones seem to be favoured by many boaters who have difficulty accessing their batteries, yours look easy to access.

 

I would not buy via either major online buying sites because you don't know who is doing the selling or if such technical data they supply is true. I used a specialist battery supplier with their own website. I think it was Advanced Battery Supplies, but there are others.

Edited April 17 by Tony Brooks

[Tacet]

2 hours ago, Tony Brooks said:

 

I think he is referring to the BMEA requirements and probably the ISOs. I think the BSS says something about that as well. So probably not a strict legal requirement, but something that should be adhered to. If the boat is within scope of the RCD/RCR then if it was questioned I think it would be difficult to justify it as being compliant.

If Alan is referring to the BMEA or ISO, then these are optional and it is inappropriate to claim (without being more specific) that the vessel is non- compliant with the Boat Wiring requirements.

2 hours ago, Alan de Enfield said:

 

As a lifeboat it would not have been built compliant with the RCD / RCR as they are not covered, however, if it was converted to a recreational boat (post 1998) is should have been surveyed and approved to the RCD requirements.

But, as with much of the waterways ...................  'should be' ............. is rarely applied.

Which of the RCD/RCR regulations (even assuming they apply) is not being met?

 

I think your view of best practice is being conflated with formal requirements.  Again.

[pedroinlondon]

20 hours ago, Tony Brooks said:

A run-of-the-mill wet 100Ah battery will have a Cold Cranking Amperage of around 700A or a marine cranking Amperage of around 800 amps. You must check that the case size fits your boat and that the terminals are in the same position as your existing setup.

 

A starting battery has a very easy life, so you don't really need anything fancy and expect 8 to 10 years out f a basic starting battery - unless you have poor charging.

 

So do I, which is why I think we need it clarified. If it is, so I suspect the lack of proper charging was the base cause.

Thanks Tony

All three batteries will be removed, so no much problem in fitting a new one in this space, regardeless of the terminal position.

As for charging it, I'll do that soon. These boats were on shore power all the time while on commission, but probably not after losing their jobs at sea.

[pedroinlondon]

20 hours ago, blackrose said:

Depending on how you're charging the batteries, another thing to consider might be whether you should match your domestic & start "battery types".

 

For example, if your domestic batteries are sealed maintenance-free and your start battery is open/flooded and you were charging both banks from a single battery charger on shore power, then you may well be overcharging or undercharging one or other bank during the absorption phase depending on what "battery type" you'd set on the charger. Although many battery chargers have multiple outputs for different battery banks, many chargers only have one "battery type" setting.

 

The same may be true for other charging sources such as solar controllers which charge a single bank but where a VSR has been used to connect a second bank.

I'm planning on having solar panels charging the starter and leisure batts separately, as in my previous boat. I think it works better that way.

3 hours ago, Tony Brooks said:

 

The point that I think you may be missing is that unless you understand and monitor the battery charging you will destroy and expensive battery all but as fast as a cheap one. Unfortunately, we/I don't know if you do understand and monitor your battery charging so the only option is to advise you to buy an open, lead acid battery of the same size and terminal position as the ones you have now. This is so it fits into your existing battery cradle. If you buy a lead-carbon or AGM battery, it will cost more and may not last any longer.

 

As far as lead acid batteries are concerned, it is far easier for an ordinary boater to test open cell batteries for faults than any sealed battery, although sealed ones seem to be favoured by many boaters who have difficulty accessing their batteries, yours look easy to access.

 

I would not buy via either major online buying sites because you don't know who is doing the selling or if such technical data they supply is true. I used a specialist battery supplier with their own website. I think it was Advanced Battery Supplies, but there are others.

I will have a dedicated solar panel and controller charging this battery, so it should be ok. On my previous boat I had that and the cheapo starter battery supplied by Collingwood lasted nearly 8 years.
Thanks for the advice on the type of battery. Access to this one is very easy and the leisure bank will be easy also.

[Tony Brooks]

15 minutes ago, pedroinlondon said:

I'm planning on having solar panels charging the starter and leisure batts separately, as in my previous boat. I think it works better that way.

 

FWIW I understand that you can use the load output on many solar controllers to charge the start battery. perhaps someone who has done this can confirm, deny or elucidate. That gives you more solar output to charge the domestic bank during the winter, because the start battery is only discharged by a very few Ah on each start's so is nearly always very well charged (providing the engine and battery are in good order). Otherwise, I think for a lot of the time you will be wasting potential solar output. The exceptionally easy life starter batteries have is why that cheapo battery lasted 8 years.

 

 

[ditchcrawler]

30 minutes ago, pedroinlondon said:

 . On my previous boat I had that and the cheapo starter battery supplied by Collingwood lasted nearly 8 years. 

My starter battery lasted that long and it sat all through Covid doing nothing.

[pedroinlondon]

I'm trying to find a starter battery of 700CCA or above with nut terminals but cannot...

I can only find with I think it's called "standard posts" which are smooth and unthreaded.

 

Can anyone confirm that the BBS rules require that the batteries are threaded and adaptors are not allowed, or was I wrongly advised?

 

Example: https://www.tayna.co.uk/car-batteries/yuasa/ybx5110/

[ditchcrawler]

4 minutes ago, pedroinlondon said:

I'm trying to find a starter battery of 700CCA or above with nut terminals but cannot...

I can only find with I think it's called "standard posts" which are smooth and unthreaded.

 

Can anyone confirm that the BBS rules require that the batteries are threaded and adaptors are not allowed, or was I wrongly advised?

 

Example: https://www.tayna.co.uk/car-batteries/yuasa/ybx5110/

I would suggest you are wrongly advised, what you can't use is these