More batteries.

Steve Dion · Sep 1, 2011

Ed: I have had very good success with Gel batteries too. One of the down sides that I see with the 6 volts occurs if your bank only has 2 batteries. If one of those batteries goes south you no longer have a house bank. If you have 2 12 volt batteries in the bank and one goes bad, you still have a 12 v (albeit smaller) bank.

My original set of Gels on my H'31 lasted for 10.5 years. I am currently into 5+ years on this set on my Hunter 36.

For me personally the ease of care (none) makes them high on my list and I will probably continue to use either Gel or AGM technology in the future.

Lifeline now makes a 150 amp AGM that has similar measurements to a Group 31 but is a couple of inches taller. The only issue with these happens to be the weight (near 100#).

Stu Jackson · Sep 1, 2011

Ed, given the technology, not much really has changed, other than AGMs.

Anyone, I say anyone, who is considering AGMs should really read Maine Sail's excellent discussion. (Ed, you know where to find it, right?) They are simply NOT the solution for everyone.

Putting aside AGMs, we still have wet cell, gel or 6V.

Steve discussed the 2 battery 6V solution very well. Not, IMHO, as solution. 4 6V definitely a winner for battery longevity and bang for bucks in ah and space.

Gels for the lack of maintenance issues for sure. Wet cells for simplicity and lowest first cost.

That said, here's what i did this year: I had 3 wet cells, 130 ah each, 390 ah house bank. I went through the same reasoning: gels, great but more expensive (had them on a previous boat and loved 'em), but my boat has EXCELLENT access to my four batteries. If you have lousy access, gels are a great answer.

The extra 450-390 ah just wasn't worth it for me to reconfigure the battery spaces on my boat. I personally didn't mind the extra wiring, simple for me.

So, I went and bought straight replacement wet cells.

Then I "Broke IN my New Batteries" and they work just fine.

http://c34.org/bbs/index.php/topic,6353.0.html

Your boat, your choice, but I would be very very careful in going the AGM route.

Benny17441 · Sep 1, 2011

That Optima ad is just partly true. Yes you can get the same number of capacity amps from two 6V batteries as you can get from a pair of 12V but how about the number of cycles and the cost factors. The 6V batteries are larger and heavier because their lead plates are larger and heavier and these plates as they wear down will largedly determine the longevity of the battery. Needless to say a pair of 6V cannot provide the redundancy that a pair of 12V can. With today's portable generators and hardwired inboard chargers the need for large battery banks is no longer what it was.

Stu Jackson · Sep 1, 2011

Ed, that's a good one, but this is the one about AGMs:

http://forums.sbo.sailboatowners.com/showthread.php?t=124973

Stu Jackson · Sep 1, 2011

Benny17441 said:
With today's portable generators and hardwired inboard chargers the need for large battery banks is no longer what it was.

I disagree. I don't have a generator and most likely never will.

I feel the two best things one can do for their boat is to enlarge the house battery bank as much as possible and to buy a battery monitor. Not necessarily in that order.

I like to anchor out and don't like noise.

It all depends on how you use your boat.

If you're a marina hopper, it doesn't matter.

If you like to anchor out and you have a fridge, around 400ah is a good two days and maybe more without running any kind of engine. Not including solar (or wind), of course.

Your boat, your choice.

sailaway78 · Sep 1, 2011

Battery Tender

With the battery tenders now available, the ease of access no longer needs to be part of the equation. I recently installed on after reading some comments here. Makes filling all batteries a simple two minute exercise. So, for a little over a hundred bucks, you can eliminate this argument. So for me, 450ah of wet cell golf carts is the way to go. 300 watts of solar, and a 400watt air-x lets me go nearly indefinately without running any kind of gen set. A few simple squeezes of the bulb on the battery tender lets me keep water levels good at all times.

Maine Sail · Sep 1, 2011

Ed Schenck said:
There have been several posts recently(and forever) on the subject of batteries and chargers. Almost everyone who has them laud their 6v golf cart batteries in series. Is it just cost per amp-hour?

No but that is a GOOD part of it. 6V batteries are taller & have thicker plates than a comparable case size 12V and will almost always outlast any 12V battery in cycle life. The taller case makes for more area at the bottom for shedded sulfation particulate to build up and not interfere as soon with the plates. The positive plate thickness is also considerably thicker which is what yields long life and true deep cycle capability. A GC2 6V is roughly the size of a group 24 12V yet has only three cells vs. six cells. This means the plates are MUCH thicker. 2 12V group 24 batteries will give you about 130-140 Ah's and 2 6V GC2 batteries will yield about 215 - 230 Ah's.

Ed Schenck said:
I found this, is it just sales hype?: http://www.1st-optima-batteries.com/faq17.html

Poorly written garbage.

Ed Schenck said:
It seems like a waste of space, wire, and connections to get 225 aH. Four six years I had three house Gels which performed flawlessy. Then before my 2007 departure for Florida I replaced with four AGMs. Probably stupid since the Gels showed no sign of weakening.

Actually you'll be hard pressed to find any pair of 12V batteries than can compete capacity/space wise with 6V batteries.

GEL Cells are perhaps the longest lasting batteries out there but also the easiest to ruin. If treated well they can go 8-10 years. If 6V wet cells are treated well they can also go 8-10 years.

Ed Schenck said:
Now four big Trojan golf cart batteries, flooded, will cost about $540. and provide 450 amp-hours.

You DO NOT need to spend the gourmet pricing for Trojan's to get decent quality in a 6V battery. The 6V GC2 case size is about the most competitive battery market out there and brands like Crown, Superior, East Penn/DEKA & US Battery all make top quality 6V batteries. The US Battery products I feel beat Trojan at this point in time.

Ed Schenck said:
And more deep cycles?

Compared to a 12V battery, yes.

Ed Schenck said:
Four AGM, group 27, 100ah Trojans will set you back $900. But for many years of maintenance free battery life and less space and weight. I know we have visited this many times. Maybe things have changed?

Trojan would be about the last AGM I'd buy. Sam's Club now sells the DEKA/East Penn 6V is wet or AGM as well as 12V. The group 31 AGM at our locals Sam's Club is $166.00 and is the IDENTICAL battery West Marine sells. With batteries lead is what you're paying for. Heavier batteries in "general" last longer. If you want to do extended cruising I would suggest going GEL cell (with PROPER charging) or wet not AGM.

I can buy 460 Ah's of 6V GC2 batts (DEKA/East Penn) at Sam's Club for under $300.00. The Trojan's are stretching it to be worth $5.00 more per batt in "quality" over the DEKA's yet based on your numbers you're looking at a $60.00 premium PER BATTERY to pay for a burgundy case and a Trojan label....... Trojan's used to cost about $5.00 - $8.00 more per battery now it's more like $45.00 - $70.00 more and that is just completely ridiculous.

Stu Jackson · Sep 1, 2011

Can we (you?) move this great discussion???

...to Musing with Maine Sail? Too good in content to not have there for reference in the future.

Benny17441 · Sep 2, 2011

Do not overlook replacement availability. If you are on a trip and one battery fails you could probably find a 12V wet cell battery almost anywhere. Looking for AGMs or Gels may require you to look further and farther.

Stu Jackson · Sep 2, 2011

Very, very good point, Benny.

Benny17441 · Sep 2, 2011

Stu, it's your right to disagree and I just wish we had your generally cool climate and cold Pacific waters. Our use of gas powered electrical generators stems from our oppressive high temperatures and high levels of humidity here in the Gulf of Mexico. The rest is a proggresion, as long as we are using our genrators to run A/C we might as well recharge the batteries and as long as we can maintain fresh batteries there is no need lug around, provide space, pay for nor maintain a large battery bank. Now I'll grant you that in the winter time when some days do not require the use of A/C that we do not have the size of bank to support our needs without the generator but those days are relatively few in comparison. We do run the generator less on cool days and it may not be at night.

Stu Jackson · Sep 2, 2011

Understood, good explanation. You may recall that I did say "It all depends on how you use your boat" and simply gave my experience.