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-   -   Battery Decision - Currently mixed age and AGM/Wet-Cell (http://www.cruisersforum.com/forums/f14/battery-decision-currently-mixed-age-and-agm-wet-cell-204525.html)

JoeDoc 19-07-2018 15:46

Battery Decision - Currently mixed age and AGM/Wet-Cell
 
Hi all,

I bought my first boat (2003 Beneteau Oceanis 331) in July of last year and have been slowly tackling the "Recommended Repairs" from my survey. I'm new to this so learning curve is steep (but fun!).

Coming to you guys for advice on one of these RR's. The engine battery on my boat is a 27 series AGM battery dated 2013. Apparently, the house battery went bad right before the survey so the previous owner installed a new West Marine Dual Purpose 1280 4D flooded cell battery right before the survey and sea trial.

My surveyor told me that "mixing battery technologies and ages is not recommended" and this is one of my Recommended Repairs (RR).

Over the course of the past year (I kept the boat in water all winter - keeping a close eye on her) the batteries have seemingly performed fine. I'm studying Nigel Calders book and starting to learn how they work....but my question to you guys is.....do I really have to ditch one of my batteries and spend more $$ to get a new one that is same age/tech? I will if I have to but I have a lot of projects in front of me and unfortunately not an unlimited budget :-).

Greatly appreciate your advice, as always. Thanks guys.

Joe
"Azimuth"
Annapolis, MD

smac999 19-07-2018 20:40

Re: Battery Decision - Currently mixed age and AGM/Wet-Cell
 
not really an issue with different banks.

batteries connected directly together in the same bank matter.

most boats would have multiple batteries in a house bank. all changed at same time.

if a single battery is effecting your budget.... you're probably going to be in trouble...

ranger42c 20-07-2018 03:48

Re: Battery Decision - Currently mixed age and AGM/Wet-Cell
 
Often you can find a charger setting that is compatible -- enough -- with both flooded and AGM batteries. Or with older chargers with no separate setting for AGMs, often the flooded setting is what they recommend for AGMs, too.

This is likely an "RR" that you can just address next time you need to replace a battery.

In the meantime, learn what bulk/absorption and float voltages each of your battery manufacturer recommends for that product... and then if your charger offers enough flexibility, pick a compromise profile that works for both together.

And service your flooded battery as necessary.

FWIW, I'd think the AGM is a decent choice for your starter battery... given that they don't self-discharge too much so you won't have to fool with it when (if) you winterize around here.

-Chris

JoeDoc 20-07-2018 04:59

Re: Battery Decision - Currently mixed age and AGM/Wet-Cell
 
Quote:

Originally Posted by smac999 (Post 2677360)
not really an issue with different banks.

batteries connected directly together in the same bank matter.

most boats would have multiple batteries in a house bank. all changed at same time.

Thank you, very helpful. I'm learning more about banks this AM and how they work. Appreciate the insight.

Quote:

Originally Posted by smac999 (Post 2677360)
if a single battery is effecting your budget.... you're probably going to be in trouble...

Nah, no trouble. Just trying to be smart about my spending and not be wasteful. Plenty of other boat things I could think of to spend $400 on.

JoeDoc 20-07-2018 05:23

Re: Battery Decision - Currently mixed age and AGM/Wet-Cell
 
Quote:

Originally Posted by ranger42c (Post 2677480)

In the meantime, learn what bulk/absorption and float voltages each of your battery manufacturer recommends for that product... and then if your charger offers enough flexibility, pick a compromise profile that works for both together.

-Chris

Chris, thanks a lot. That (and all of your advice) was really helpful. I will look at the mfg reco's for my batteries and settings for my charger this weekend and adjust accordingly.

I've been moving from system to system on my boat learning as much as I can and have been doing fine up until now. This is the first system that has given me pause (I don't have any real electrical background to speak of beyond a very basic understanding). I've decided to hire a professional to spend a few hours with me walking me through my batteries, charger and all the wiring so that I truly understand it all.

Thanks for giving me a great head start here though! Appreciate it, Chris.

Joe
"Azimuth"
Annapolis, MD

ranger42c 20-07-2018 08:32

Re: Battery Decision - Currently mixed age and AGM/Wet-Cell
 
Quote:

Originally Posted by JoeDoc (Post 2677538)
Thanks for giving me a great head start here though! Appreciate it, Chris.


Not to worry, Joe, enjoy your summer. Wave if you see us in the area. :)

-Chris

roland stockham 20-07-2018 12:58

Re: Battery Decision - Currently mixed age and AGM/Wet-Cell
 
Not a problem for the batteries because they are (or should be) totally separated. The problem is charging. A charger set to AGM will not fully charge deep cycle flooded cell because the voltage is to low but if you switch it to the flooded setting to properly charge the house bank you will cook the AGM. Incidentally batteries described as 'Duel Purpose' are usually just a heavy duty start battery not true deep cycle. What the previous owner did was fit a cheap battery for the sale! I would just run it assuming both are AGM's and look at it again in a couple of years when the house battery dies.

ranger42c 20-07-2018 13:13

Re: Battery Decision - Currently mixed age and AGM/Wet-Cell
 
Quote:

Originally Posted by roland stockham (Post 2677920)
A charger set to AGM will not fully charge deep cycle flooded cell because the voltage is to low but if you switch it to the flooded setting to properly charge the house bank you will cook the AGM.


Not always cast in concrete.

Some AGM settings on some chargers are higher or as high as the flooded setting. And the manufacturer's recommended bulk/absorption and float charges for some AGMs is higher than for another manufacture's recommended voltages for flooded.

Depends on exact battery and exact charger.

-Chris

JoeDoc 21-07-2018 09:47

Re: Battery Decision - Currently mixed age and AGM/Wet-Cell
 
Thanks again for all of the help and advice, guys. I'm enjoying this washout of a day here on the boat studying my electrical system.

So my boat has a Cruisair Sentry SM1220/2 battery charger. According to the manual - it does not have a selector device and can be used on lead acid, gel and lead calcium type batteries. Good to know. Boost is 14.3 and Float is 13.6 according to the label.

My 2013 starter battery is an Intimidator AGM 8A27M (92Ah)and my 2017 house battery is a West Marine Hybrid Dual Purpose 1280 MCA 4D(135 Ah) - which is a maintenance-free model.

I'm going to be installing a Battery Monitor this week (with the help of my mechanic friend) so it will be interesting to get better data than the batter condition meter on my panel.

Our longer-term goal is to eventually add some solar/wind for longer stays on the hook so this is all great to learn.

My education continues.....

Joe
"Azimuth"
Annapolis, MD


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