Batteries

[AsLan7]

Great minds think alike BBp!

[Bfun220]

Umm, if I ever start to think like BB I'll seek professional help and medication. Not necessarily in that order.

[AsLan7]

Umm, if I ever start to think like BB I'll seek professional help and medication. Not necessarily in that order.

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[Big Block Power]

I would start to drink first.

[Southernboatman]

Yep I'm loving the new fangled switch!

[AsLan7]

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Since it is storage time, the batteries have been pulled and have been replaced with Dehumidifier tablets and Air Freshener. Man those Trojan's (batteries ) are heavy!

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[thunder550]

I'm running a pair of the Walmart EverStart 1000MCA batteries. I read someone's rule of thumb regarding the dual battery switch...they use switch position 1 on odd-numbered days, and 2 on even, and only use the All position when neither battery individually has enough juice to crank the engine. So I've been following that.

[Driller]

One thing about batteries that I have learned from owning a golf cart. The further you discharge them, the shorter the life. That's why I always use a battery charger and keep my batteries fully charged. It is not as simple as "they always start the boat", that may be true, but that doesn't mean their life has not been shortened considerably.

My golf cart batteries are 8 years old. Trojans. I plug them in after every run. Keep the charger cord hanging right next to where I park. They are still going strong.

See representative chart below - likely you're manufacture has a similar chart for your particular battery. They all look the same. The further you discharge a battery and re-charge, the shorter the life of the battery.

You almost triple the cycles by only discharging to 40% capacity. Biggest bang for the buck is trying to never pull them down past 20% discharge, but we all know that is not possible when we're at anchor cranking the stereo.

My 2-cents.

[AsLan7]

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Hey driller. Great Chart.

Question:

Let's say you accidentally left something on which discharged your new battery ONE time so it's now dead. You place a charger on it. Get it back to 100%. So based upon that chart, because of that ONE time....your battery went from roughly 3,800 "cycles to failure" --- to now 500 "cycles to failure". Correct??

If so...Wow.
That's a costly mistake. One just lost 3,300 cycles!

[Driller]

No, I don’t think that is correct. I believe it is representative if you consistently drained the battery to full discharge every time. Then you would only be able to do that ~500 times.

The chart is really only representative for a particular battery. The point is, the curve is not linear. Pulling the battery down to full discharge takes a toll on them. So if you had a choice to have the stereo on one battery for 2 hrs and the other for 2hrs it is better than pulling down one battery for 4 hrs. Assuming your boat will still crank.

[Bfun220]

No, I don’t think that is correct. I believe it is representative if you consistently drained the battery to full discharge every time. Then you would only be able to do that ~500 times.

The chart is really only representative for a particular battery. The point is, the curve is not linear. Pulling the battery down to full discharge takes a toll on them. So if you had a choice to have the stereo on one battery for 2 hrs and the other for 2hrs it is better than pulling down one battery for 4 hrs. Assuming your boat will still crank.

Or use a deep cycle battery for your house battery.

[AsLan7]

No, I don’t think that is correct. I believe it is representative if you consistently drained the battery to full discharge every time. Then you would only be able to do that ~500 times.

The chart is really only representative for a particular battery. The point is, the curve is not linear. Pulling the battery down to full discharge takes a toll on them. So if you had a choice to have the stereo on one battery for 2 hrs and the other for 2hrs it is better than pulling down one battery for 4 hrs. Assuming your boat will still crank.

Ok...thanks. That makes more sense. Great post.

[Driller]

No, I don’t think that is correct. I believe it is representative if you consistently drained the battery to full discharge every time. Then you would only be able to do that ~500 times.

The chart is really only representative for a particular battery. The point is, the curve is not linear. Pulling the battery down to full discharge takes a toll on them. So if you had a choice to have the stereo on one battery for 2 hrs and the other for 2hrs it is better than pulling down one battery for 4 hrs. Assuming your boat will still crank.

Or use a deep cycle battery for your house battery.

Curves are simular for deep cycles, it just takes longer to take them down to 100% drained. But you are correct, a deep cycle is much better .

[AsLan7]

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Curves are simular for deep cycles, it just takes longer to take them down to 100% drained. But you are correct, a deep cycle is much better .

We use two deep cycle batteries. Always heard to use one cranking battery and one deep cycle battery in a boat but we have never had any issues using two deep cycles over the last 15 years.

[Bfun220]

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Curves are simular for deep cycles, it just takes longer to take them down to 100% drained. But you are correct, a deep cycle is much better .

We use two deep cycle batteries. Always heard to use one cranking battery and one deep cycle battery in a boat but we have never had any issues using two deep cycles over the last 15 years.

When it's time to replace mine I'll go with deep cycle. They have heavier plates which is why thier better.