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Battery discharge/charge cycles question.


tosher

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Hi all. I am looking to replace my dying 12 year old services batteries with 3 new Varta LFD 230AH sealed lead acid batteries. The spec for these seems ok but shows the max number of cycles down to 50% state of discharge as 200 which seems a little low.  My question is ------ In our normal cruising mode the batteries never fall below 75% so does that mean that the number of cycles would increase to 400?    My reason for choosing the Varta ones is that they are a direct replacement size wise for my old Elecsols so no alterations to wiring or fittings will be required.   Many thanks.

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45 minutes ago, tosher said:

so does that mean that the number of cycles would increase to 400?

Probably quite a bit more than 400. The curve is not a straight line. The only way to know would be to get hold of the data sheet for those batteries (or ask Varta). 

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If you have managed your Elecsols so well that they have done 12 years, you will have no problems with the Vartas.

Most Elecsols died in short order no matter how well they were treated. The best I ever achieved was 6 years and that was when on a land line for extended periods.

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33 minutes ago, Jen-in-Wellies said:

That's what log graph paper is for.

Or you can fit @WotEver  line or curve you like. (see what I did there?)

Jen

Do not try and bend the curve, that's impossible. Instead, only try to realize the truth...there is no curve. Then you will see it is not the curve that bends, it is only yourself.

29 minutes ago, Boater Sam said:

If you have managed your Elecsols so well that they have done 12 years, you will have no problems with the Vartas.

Indeed. 12 years impressed the hell out of me. 

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7 minutes ago, tosher said:

Thanks for all your replies and the answer to my question, I feel more comfortable about the Varta batteries now and will probably go down that route. Thanks again.

Hope to see you in another 12 years then... when the advice might be something different! :D

 

(12 years? You ought to be running a battery masterclass!) ;)

 

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2 hours ago, Sea Dog said:

Hope to see you in another 12 years then... when the advice might be something different! :D

 

(12 years? You ought to be running a battery masterclass!) ;)

 

They have been flat as a phart for the last ten years they just dont use the boat much ;)

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If anyone is interested --- I have two engine driven alternators 110A & 75A charging my 3 x Elecsol 270AH batteries via a Sterling Alternator-to-Battery charger. All fitted when the boat was built 12 years ago. We are out in the boat for about 4 or 5 months throughout the year and normally cruise for about 3 or 4 hours per day moving most days with the occasional day off. The batteries usually fall to about to 90% after an overnight stop and maybe down to 80% after a day without running the engine. These values have reduced considerably in recent months and the volts drop under load as the batteries die. Most days when cruising the batteries are recharged to 100%.

When we are not cruising the boat is left unattended in a marina with all electrics switched off.  In the summer months I leave the shore power lead unplugged to prevent any chance of galvanic corrosion but in the winter months I plug in the shore power and leave a battery charger on.  I have a Smart Gauge which I think is the main reason for my batteries lasting so long as it gives a very good indication of the state of  charge of the batteries. I always try to keep them as near to 100% charged as possible but other than that I just keep them clean, well watered with the odd bit of maintenance.  At present the engine running hours are approaching 5000hrs.   

Sorry if I have bored you!!!!

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4 minutes ago, tosher said:

If anyone is interested --- I have two engine driven alternators 110A & 75A charging my 3 x Elecsol 270AH batteries via a Sterling Alternator-to-Battery charger. All fitted when the boat was built 12 years ago. We are out in the boat for about 4 or 5 months throughout the year and normally cruise for about 3 or 4 hours per day moving most days with the occasional day off. The batteries usually fall to about to 90% after an overnight stop and maybe down to 80% after a day without running the engine. These values have reduced considerably in recent months and the volts drop under load as the batteries die. Most days when cruising the batteries are recharged to 100%.

When we are not cruising the boat is left unattended in a marina with all electrics switched off.  In the summer months I leave the shore power lead unplugged to prevent any chance of galvanic corrosion but in the winter months I plug in the shore power and leave a battery charger on.  I have a Smart Gauge which I think is the main reason for my batteries lasting so long as it gives a very good indication of the state of  charge of the batteries. I always try to keep them as near to 100% charged as possible but other than that I just keep them clean, well watered with the odd bit of maintenance.  At present the engine running hours are approaching 5000hrs.   

Sorry if I have bored you!!!!

Not at all boring. Peoples first hand experience with batteries is probably thee most discussed items on a boat along with toilets!! Every little bit of info helps.

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3 minutes ago, mrsmelly said:

Not at all boring. Peoples first hand experience with batteries is probably thee most discussed items on a boat along with toilets!! Every little bit of info helps.

Strangely enough, smell is very important to both, as I discovered when a battery went down and Hydrogen Sulphide permeated the boat!  ?

 

George

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2 hours ago, blackrose said:

Yes it sounds contradictory but a plot on a graph resembling a straight line is also known as a linear curve.

You learn something every day - I'd always thought a curve (by definition) was not straight but now I know better.

 

I'll save that away for a suitable time - say when Mrs 1st Ade tells me to slow down, the road curves ahead...

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