MARINE BATTERIES

They'll happily cook both types. At least historically mine have, before I 'fixed' them. Which is why I don't think there is much point (IMHO) in buying 'marine' batteries - they may be more heavily constructed, but methinks that would only matter if you were constantly getting the pounding that the F1 boats (or Brendan) gets.

Of course, the counter argument is that I've just spent £400 to save a set of £200 batteries, so my payback is a good 4 years...
 
Just replaced all three AC Delco Truck batteries on ours a couple of weeks back, after exactly 10 years of service. One is still good (the dedicated starboard engine starting one, which isn't wired in to the charger, so only ever charged by the alternators), so brought it home and umm err....... still trying to find a good use for it.
 
Nope, I think I'm completely right. 10 1.2V 2.4Ah batteries in series gives 12V 24Ah. Parallel up 5 of these 10 cell sets and you get 12V 120Ah. Amps don't care about series/parallel.
 
Its best not to buy on price. i.e. cheap! and as a rule of thumb, the heavier the battery the better it is, of course it does have to fit into your battery case/space etc. I always use wet cell batteries as they tend to last longer and have a bit more oomph than their newer designed counterparts!

Barry
 
I disagree. It would be great if connecting in series gave you both an increase in voltage and capacity, but unfortunately it wont. 10 1.2V 2.4Ah batteries in series will give you 12V and 2.4Ah, in parallel they will give 1.2V and 24Ah. The product of voltage and capacity is the energy stored in the batteries which is constant for a given set of batteries. Increasing the voltage of the system will reduce capacity and vice versa.
 
He's right. The key is energy: 1 volt is the same as 1 Joule (energy) per Coulomb (charge). One Coulomb is the same as 1 Amp flowing for 1 second.

So we can write:

1 V = 1 J / (1 A x 1 s), or

1 J = 1 V x 1 A x 1 s

3600 J = 1 V x 1 Ah

so a 1.2 V 2.4Ah battery stores 1.2 x 2.4 x 3600 = 10,368 Joules of energy.

10 of them store 103,680 Joules, whereas a 12 V 24 Ah battery stores 12 x 24 x 3600 = 1,036,800 Joules
 
sorry, but you ain't right at all. put say three cells in series, each with 2.4AH capacity. Now I say you'll get a bank with 3.6Volts, and a capacity of 2.4AH. You reckon it'd have 7.2AH.

But each cell can produce nominally 2.4Amps for an hour, so taking the lower figure, it's easy to see where the total capacity of 2.4AH comes from, yes? . each cell produces 2.4Amps, which passes through the other two cells The cells are in series, you'd need 7.2AH cells to get a 3.6V, 7.2AH bank.

You can add up the voltages, by wacking em in series..... you can do the same to capacity, or AH, by connecting em in parallel - but you can't have both at once. Shame tho /forums/images/graemlins/smile.gif
 
Which will teach me not to post after being down at the pub. On both Monday and Tuesday.

Stupid boy, and sorry to Ken Taylor, who gave me an A+ for the applied electricity part of my degree course.
 
[ QUOTE ]
Which will teach me not to post after being down at the pub. On both Monday and Tuesday.

Stupid boy, and sorry to Ken Taylor, who gave me an A+ for the applied electricity part of my degree course.

[/ QUOTE ]

Don't worry. I was lost the moment Wiggo mentioned his mate Joules.

XX Sandy.
 
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