Advice needed from Gibbo ( or anyone who knows)

[Phil Ambrose]

My starter battery needs replacing, it was on the boat when we bought her 8 years ago. Now the question is should I replace it with like for like ie. a 110a/h is there any benefit from this or can I save a bob or two and say fit a 85a/h

My domestic bank is 7 X 110a/h

Any comments would be appreciated

[Justme]

How big is the engine?

 

Starting power is not measured in ah but CCA (cold cranking amps if I remember right)

[Guest]

I don't claim to be an expert on batteries (or anything else), but common sense tells me that if the particular battery that you have has worked without fault for a number of years, then a like for like replacement would seem reasonable. I have found "truck"starter batteries to be reasonably priced on the whole.

[alan_fincher]

Surely with a starter battery any quoted Amp Hour rating is largely an irrelevance ?

 

A starter has to deliver very large currents for (hopefully) seconds at a time, and hopefully seconds don't even turn into minutes.

 

An Amp Hour rating relates to discharging batteries at a very much slower rate than this.

 

What is important is the batteries ability to deliver the large currents, I believe, and that is not necessarily very related to "Amp Hours".

 

The type of engine you have is also of relevance. A vintage one will generally draw far bigger currents on the starter, (unless decompressed), than a modern one, and hence may need a beefier starter.

 

A truck starter battery (of any type) will start most modern narrowboat engines, generally.

[soldthehouse]

Justme is correct ratings are normally on the label and give AH and CCA... CCA650 and above gives a healthy performance. I think Mr Catchpole gave a goodlink in another postto battery performance

Edited October 5, 2009 by soldthehouse

[nb Innisfree]

I thought leisure batteries were starter batteries with handles?, if so just use a 110ah leisure, £70. They claim to be ok for leisure and starting so that surely must confirm it + you could interchange with domestic bank if you so desired

[Phil Ambrose]

Thanks for the input chaps, food for thought, will probably just stick another 110a/h in as Inisfree points out if push came to shove it's interchangable

[Nickhlx]

Thanks for the input chaps, food for thought, will probably just stick another 110a/h in as Inisfree points out if push came to shove it's interchangable

 

 

Hi Phil,

 

I think what it also confirms is that the voltage from the charging alternator is just right for longevity of the battery - so what is / was it ?

 

I would guess 13.8 to 14.3....

 

Nick

[Phil Ambrose]

Hi Phil,

 

I think what it also confirms is that the voltage from the charging alternator is just right for longevity of the battery - so what is / was it ?

 

I would guess 13.8 to 14.3....

 

Nick

 

With my charging set up of 5 X 100watt solar panels and/or 4 stage charger and/or alternator through a Sterling Battery to Battery charger I can get domestics upto 14.8 but starter battery struggles to get to 13.8

 

Phil

[Nickhlx]

With my charging set up of 5 X 100watt solar panels and/or 4 stage charger and/or alternator through a Sterling Battery to Battery charger I can get domestics upto 14.8 but starter battery struggles to get to 13.8

 

Phil

 

That seems to suggest / confirm that for longevity of a battery, 13.8 volts or so is good .. The downside is that at that voltage it would take a long time for a battery (bank) to reach full charge from a low state of charge. It works for the starter battery as it is working almost all the time at 100% SOC and not being overcharged. So a reasonable compromise for selecting a charging voltage if it is an option ( either from time constraints or from being able to program in to the charging device) is not much above 13.8 volts - say 14.0 to 14.2 Volts.. Higher charging voltages will get more charge in, in the time available, at the expense of longevity of the battery (or bank).

 

I will check mine at the next opportunity, just out of interest ...

 

Thanks,

 

Nick

Edited October 6, 2009 by Nickhlx