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"two Optima marine AGM units the following week. I hope they live up to their price... "


I always wonder about that as well, Chris.

We had the Optima AGM's and the tech recommended the Trojans. At $200 a piece they better be worth it.

http://www.trojanbattery.com/pdf/datash ... Sheets.pdf

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Re the Optima, I did notice their profile is a tad shorter (less tall) that the Deka units. To use the standard battery tray hold-downs, I had to turn the top bar over and tighten with the fasteners rubbing. No big deal, just not as designed.
Question for this using AGM's, do you find you need to re-charge in the spring or just get in and go? Probably depends on temps, condition left and any residual drain.
Thanks,
Chris

TwoBurgers wrote: Sun Sep 10, 2017 1:42 pm Re the Optima, I did notice their profile is a tad shorter (less tall) that the Deka units. To use the standard battery tray hold-downs, I had to turn the top bar over and tighten with the fasteners rubbing. No big deal, just not as designed.
Question for this using AGM's, do you find you need to re-charge in the spring or just get in and go? Probably depends on temps, condition left and any residual drain.
Thanks,
Chris

I would trickle charge all winter. I have one charger and just switch each battery every month. The optima should last a long time if u take care of it (well after 5 years)

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Just purchased a battery jump pack on Amazon. These are great insurance against dead batteries on the water.
Also use it to electrically lift our engine hatch so we can pull the batteries out for the winter.

I will say, these jump packs have really gotten smaller since I've owned my last boat a few years ago. Picked up the NOCO Genius Boost HD GB70 2000 Amp 12V UltraSafe Lithium Jump Starter model to crank 8 liter engines (or diesels).
https://www.amazon.com/gp/product/B016U ... UTF8&psc=1

She's a beast.

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AsLan7 wrote: Thu Oct 12, 2017 7:58 pm .
Just purchased a battery jump pack on Amazon. These are great insurance against dead batteries on the water.
Also use it to electrically lift our engine hatch so we can pull the batteries out for the winter.

I will say, these jump packs have really gotten smaller since I've owned my last boat a few years ago. Picked up the NOCO Genius Boost HD GB70 2000 Amp 12V UltraSafe Lithium Jump Starter model to crank 8 liter engines (or diesels).
https://www.amazon.com/gp/product/B016U ... UTF8&psc=1

She's a beast.

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That's the same unit I bought for our techs at work. They work great. We have a couple of them.

Great minds think alike BBp!

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

Bfun220 wrote: Thu Oct 12, 2017 11:08 pm 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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I would start to drink first.

Yep I'm loving the new fangled switch!

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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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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.

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.

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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!

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.