Trying not to over think a basic charging system

[john61ct]

Originally Posted by EmPrep

...while keeping in mind that we're not talking 100% accuracy here....what's wrong with three of these as idiot lights (bells) to KISS and protect the batteries? https://12vtechnology.com/products/1...e-boat-monitor
I'd muffle the alarm but what's not to like if you simply want to know that you're getting close or already there?

You only need that if you don't want the better accuracy of a proper SoC meter.

And only one if you combine banks as I (very strongly) advise.

And make sure the alarm trigger V is user adjustable, ideally .0X resolution.

[john61ct]

Originally Posted by EmPrep

Welllll...i just replied with the answer that you're after and 'wrote' evidently too long/timed out/lost the entire post while signing back in.

All to common, nature of HTTP editors.

Write in a local editor, then copy / paste into the forum editor so minimum time held open.

No idea what the pitchforks stuff is about.

Top quality lead batts are a tiny fraction of the price here in the US than anywhere else on earth afaict.

The founding research by Enersys wrt their TPPL AGM was funded by the military.

As is most progress in the battery market afaik.

[EmPrep]

Originally Posted by john61ct

Please call them VSRs or combiners so people realize just bog-standard functionality, treat "integrator" as a branding thing.

And yes you're set on them, so no point discussing that further, do keep us posted as they perform over the years.

I'm old and have troubles. I tend to call things what the manufacturer calls them and even worse explain why I like them as the story unfolds. I suck at storytelling too.

Originally Posted by john61ct

...Again, forget CCA, completely irrelevant once you get into 200+A deep cycle batts of any type..."

CCA s are important to me. My hydraulics won't work without them. I am hoping that either my other two 12 volts (CCAs known) or my (2) 6 volts (unknown) will keep me from hanging up in the air somewhere/unable to move should my primary battery fail.

Originally Posted by john61ct

Probably already posted:
The best battery value by far is Duracell (actually Deka/East Penn) FLA deep cycle golf cart batteries, 2x6V, around $200 per 200+AH @12V pair from BatteriesPlus or Sam's Club. Deka labeled same batts also sold at Lowes.

...already posted and already purchased (see previous posts)

Originally Posted by john61ct

"..So wait until you can measure the draw before buying the batts..."

We had no choice but to configure, purchase and (hopefully soon) send all of our equipment to the electrical/hydro/leg installer. Spring 'up north' is a busy season and any 'ciphering' had better start before the first boat shows start or timely work is rarely done. My question involving 6V golf car battery CCAs was the last piece of the puzzle.
By the way, did I mention that this simpler than pie system coupled with say an even simpler timer for the charger (if you're not a big believer in 24/7/365 float charging) is 'the bees knees' for not overthinking basic boat power?

Sincere thanks for all of your help and everybody else's in this hopefully informative thread.

[john61ct]

Originally Posted by EmPrep

CCA s are important to me.

You misunderstand.

My point is there is no accurate way to get a number from some conversion formula.

The CCAs will be **so high** from a large deep cycle bank

**that** is what makes them irrelevant for this use case.

[john61ct]

Found an old note from Maine Sail, just as one data point, not saying anything can be extrapolated between the two measures.

> Odyssey TPPL AGM yesterday. It is rated as a 100Ah battery and it delivered just 84.67 Ah's. It is also factory rated at 1150 CCA and it still delivers a 1415 CCA reading on the capacitance tester despite being down over 15 Ah's.

If you really want the CCA number for your bank, try contacting Deka / EPM East Penn tech support (888) 844-7704

[sailingharry]

I've read through this thread, and you have a simple use-case that is ripe for a simple answer. As I read it, you have a smallish outboard with moderate electrical demands being used for day-cruises and plugged in to shore power whenever not in use. This does not demand a blue-water solution! My thoughts:
* Use FLA batteries. They are a great value, and will meet your needs with no issues. Do not use multiple chemistries, because when your ACR (or integrator, or multi-bank charger) is connected, they are all banked together and get the same charge profile.
* Use a quality 3-stage shore power charger. Anything less is not suitable for 24/7 connection.
* Use the smallest charger you can get. Given your battery bank, even a 20A charger will have you fully 100% recharged overnight (well, 90% overnight -- the last 10% will take another day regardless of charger).
* Use any ACR you can find. The "brains" don't matter much, and since it only closes when you are charging, the current draw is really irrelevant too.
* Combine your non-starting batteries to the biggest you can afford (space, dollars, motivation), in one bank. A pair of golf cart batteries are 225AH, and will power most cruising sailboats with refrigeration and lighting for an easy 24 hours. Your needs are probably much less. Four batteries would be insanely powerful.
* Your "start" battery doesn't need to be very large or special. A nice Group 24 or so would be plenty.
* Not sure what your hydraulics draw, but a pair of golf cart batteries (CCA not listed) will easily start my diesel inboard engine even when 50% discharged -- that is a 100A draw.
* Your outboard alternator is nice, sure, but really irrelevant. It won't run long enough or put out enough power to have much impact. It's also a "dumb" alternator that probably isn't adjustable -- making FLA batteries a good call (FLA are very tolerant of bad charging practices).
* So, material list -- 2 golf cart batteries, one Group 24, an ACR/integrator, and one single-bank 20A smart charger.
* HIGHLY RECOMMEND fusing the batteries with Blue Seas MRBF (terminal mounted fuses).

Hook it up and go fishing!

[john61ct]

My understanding is the electricity is not for cranking needs only.

But powering the hydraulics themselves, in a system for lifting the whole boat itself up out of the water.

Like a portable lifting dock that is built into the boat.

So lots more Ah needed in a short time, nothing to do with "blue water" needs.

Probably more than a windlass, more like a land vehicle recovery winching system.

So yes, deep cycling **and** massive high amp rates required for at least several minutes at a time. Far from the OP's concept of "fairly low loads"

As I mentioned, getting those actual measurements is needed before further progress can be made recommending what batt type and how large a bank will optimize for long-term running costs.

I reco'd those Odyssey TPPL AGM in the meantime because the OP implies they may want to stick to a smaller bank, say under 400Ah.

[carlwk3c]

Originally Posted by wtmf

why had no one invented a keel with battery space?

Because it would be below the bilge and easily flooded, killing your batteries and your entire electrical system.
Batteries and electrical connections don’t like being submerged. They should always be located at a level that your bilge pump(s) would keep dry in all but the late stages of an outright sinking.