Replacing the House Batteries -- Choices??

Feb 8, 2015
4
Beneteau Oceanis 393 Clipper Midland
I bit the bullet last year and switched over to LiFePo4 house batteries. I installed 800Ah (>700Ah usable) in the same space as my 450Ah (only 200Ah usable to keep from killing them) flooded cell bank had been. Firstly - it was very expensive. I had various reasons for doing this but essentially it boiled down to the following:
1) Efficiency is >98% (100Ah in means >98Ah out) - significantly reduces charge time compared to flooded (~60% efficient)
2) No need to top up daily or weekly significantly reducing engine run times. We all know the top 20% capacity of a flooded wet cell takes a LONG time to charge. LiFePo4 is linear.
3) much longer lifespan. 15-20 years using them daily vs. 5-6 years for flooded cells.
I am only a year into this but have been VERY happy with the choice. The payback will take 5-6 years however as I cruise past my next typical flooded cell replacement. Happy to share some of the experience with anyone considering this approach.
 
Mar 16, 2015
14
Hunter 310 Lake Norman
I have a Hunter 310 with the same set up. I have Trojan 145s 6v Golf Cart batteries, my first set lasted 9 years. I have refrigeration and top off the water every year. Works very for weekending. I was stay with what you have and agree the Costco batteries will have nearly the same power as yours when new.
 
Oct 24, 2014
9
Beneteau Oceanis 351 Baltimore, MD.
I have a 1988 Hunter 30-2 and for years we setup Solar on shore for several systems, all various, including my own... Long story short. When we bought the boat the previous owner had it wired WAY wrong and with flooded batteries. Flooded batteries GAS when charging. You don't want to breathe this in and it causes corrosion.
The 6V in question are good batteries but depending on your charging current you could have actually just drawn the water down too low and damaged them. Interstate are good and I've done a setup with those for a solar/grid charged battery reserve system for a home (Home is on grid until power is off, Solar and Grid keep batteries topped and cycle them). Flooded batts charge to 13.8v while AGM charge to 14.4v - another thing to keep in mind (you get slightly more watts out of the AGM - Volts X Amps = Watts). If your charging system is overcharging your batts you need to check the water regularly, like every month if not week.

I switched to AGM's, 5amp shore charge and 270w solar panels on the bimini (flexi panels) with an MPPT charge controller that monitors the batteries and my amp usage. We never plug into shore power. The solar can more than keep up and the batteries according to the MPPT (has a PC hookup for downloading usage) never dropped below 83% last summer. The AGM's I use are the UPG121000 which is a 12v 100Ahr batt and we have 4 on board. 3 on bank 1 and 1 on bank 2 but because the solar I have never once separated the bank. These batteries are not expensive at $190 each shipped but I've been using them for years and the oldest set runs my backup power at my house (3x100) and it's still in OK shape after 9 years (it has solar panels and three years ago we lost power for 5 days, the battery bank held it's own). AGM's can also be installed at any angle and typically last longer than flooded overall. How I was able to fit two extra under the rear berth.
 
Mar 13, 2016
9
Catalina 320 Tacoma
I'm in the process of upgrading my house bank as we type. I, too, found the 6v Interstate batteries at Costco, did a little research and decided to go with them. They are very good quality batteries and the best price by far in our area. They are wet cell batteries and this type does require frequent owner involvement with checking electrolyte level and doing a yearly equalization cycle, but if you are ok with doing this, they usually cost less than AGM or other "no maintenance" batteries.

I sail a 1993 Catalina 320 and did the load calculations and found that I use around 90 Amp hours a day when at anchor. This included refrigeration and my diesel heater. I have swapped out all lighting with LEDs, do not have an inverter or radar, so pretty basic DC needs. The four 6v batteries will give me 2 days at anchor and only draw down to 50% so I'm happy with that capacity. I cruse the Pacific NW so could stay in a marine each night if I want, but like to anchor out about half the time. With your last batteries lasting 6 years, it sounds like your charging system is probably working correctly, but you just need to check electrolyte levels more frequently. Good luck!
 
Sep 17, 2012
99
Morgan 383 Fairhaven, NY
Don't make it too complicated. If you can buy a pair of wet cell 6volt GC-2's or similar batteries at Costco or Sams Club for under $90 each just do it. Grab a gallon of distilled water on the way out. Just make sure you have a good 3 stage smart charger. You'll get another 6-8 years of weekending out of them. Bang for the buck can't be beat if they sit on charge with shore power all week.
If you're seriously cruising its a whole other ball of battery wax.
 
Feb 8, 2015
4
Beneteau Oceanis 393 Clipper Midland
If you're seriously cruising its a whole other ball of battery wax.
Absolutely this is true. Weekend sailing with the 6 volt battery setup works perfect, is low cost and can support a week or a month with good charging capabilities (and daily attention). Batteries get topped up and stay up during the week at dock. The setup with quality batteries like Trojan are have been the long term cruising standard for many years. I'm set up for long term cruising, hence my LiFePo4 setup. Overkill for most folks but very nice for long term cruising live aboard.
 
Sep 25, 2008
10
Catalina 36 MkII E. Greenwich, RI
"They were bone dry and when I filled them with distilled water they didn't hold a charge." Well, if the cases didn't leak and they were bone dry, you need to determine why, or keep a better watch on them.

I have 2 4Ds on my Catalina 36 MKII. Plenty of power for my needs. However, I'm installing solar this spring so I can run the refrigeration 24/7. One of the ways to cut back on power use is to change all your lighting to LED. I did that and it saves tons of power. Banggood.com is a terrific source. But I would definitely keep the present configuration.

Cheers

Bob
 
  • Like
Likes: xwiredtva
Jul 7, 2004
8,402
Hunter 30T Cheney, KS
"They were bone dry and when I filled them with distilled water they didn't hold a charge." Well, if the cases didn't leak and they were bone dry, you need to determine why, or keep a better watch on them.
good call. You don't want to install new batteries if you have something wrong with your charging system
 
Oct 24, 2014
9
Beneteau Oceanis 351 Baltimore, MD.
good call. You don't want to install new batteries if you have something wrong with your charging system
Agreed.
Or are unable to maintain them properly. Check the charging system, if it's a high amp charge then it's probably cooking the water off. If it's slow amp charge then it could be the alternator or the voltage is set too high on the controller.
 
  • Like
Likes: FastOlson
Aug 13, 2012
13
j boat j100 alamitos bay
Well I've been served well by Trojan T105 golf cart batteries (225AH). Why Golf Cart batteries? Consider how a golf cart runs... lots of bumps, deep discharge and recharge. Consider a boat...lots of movement, pounding, deep discharge and recharge. These can be found for around $125.
AGM batteries are popular because they need no maintenance, no topping up water. However, they are more critical on proper charging and should be fully re-charged every few cycles. In my current boat the batteries are all but in accessible so I have Lifeline AGM's. The Lifelines have a 5 year prorated warranty. But AGM's are much more expensive. I have used AGM batteries in other installations and found them more temperamental. The only reason I am using AGM's is the near impossibility of servicing the batteries in their existing location. If I could I would stick with 6v Golf Cart batteries.
Since you have received 6 years out of your current setup. I would continue with lead acid batteries. Personally, I would pay more for Trojan's because I know there quality, but if you're looking at interestate or costco. I would go with costco. Here are two articles from Practical Sailor http://www.practical-sailor.com/issues/32_3/features/Deep-Cycle-Battery-Test_5244-1.html and http://www.practical-sailor.com/blog/Gel-Versus-AGM-Batteries-for-Boats-11351-1.html Here is an article from West Marine on batteries https://www.westmarine.com/WestAdvisor/Selecting-a-Marine-Storage-Battery
 
Aug 3, 2014
65
Beneteau 343 San Francisco Bay
My recollection is that Maine Sail has the best info on batteries. One thing said is that there are almost no real deep-cycle batteries out there, other than golf-cart batteries. They can be huge and heavy, so shop around. Now, the charging system: if you have a dedicated engine battery, and two sets of house batteries, you need three battery switches (and of course at least one negative or ground switch). Furthermore, your onboard charger must have three separate charging outputs in this case, that is, you need a separate charging lug for each battery or set of batteries. If you do not have separate charger outputs for each battery, or battery sets (double 6-volts), the charger will not know how to do the correct charging, and battery life will be foreshortened (and indeed, all batteries could go "out" at nearly the same time, because of mis-charging). Finally, many or even most boats, do not isolate the batteries when they are switched On at the same time. If you do not have an elaborate isolation system, for instance, and you are charging with dockside 120v through your battery charger, and you have, again for instance, both house batteries switched On, it's possible that your charger is "seeing" both sets of house batteries at the same time, and cross-charging can occur; so dockside, just keep one house-battery set switched On at one time. Even under engine-charging conditions while underway, you could be cross-charging your house batteries if they are both switched On, but usually those engine charging times are not extensive, so not very worrisome. Hope this helps a bit.
 

tgrady

.
Nov 22, 2013
53
Hunter 33.5 North Vancouver
I bit the bullet last year and switched over to LiFePo4 house batteries. I installed 800Ah (>700Ah usable) in the same space as my 450Ah (only 200Ah usable to keep from killing them) flooded cell bank had been. Firstly - it was very expensive. I had various reasons for doing this but essentially it boiled down to the following:
1) Efficiency is >98% (100Ah in means >98Ah out) - significantly reduces charge time compared to flooded (~60% efficient)
2) No need to top up daily or weekly significantly reducing engine run times. We all know the top 20% capacity of a flooded wet cell takes a LONG time to charge. LiFePo4 is linear.
3) much longer lifespan. 15-20 years using them daily vs. 5-6 years for flooded cells.
I am only a year into this but have been VERY happy with the choice. The payback will take 5-6 years however as I cruise past my next typical flooded cell replacement. Happy to share some of the experience with anyone considering this approach.
Nice. Thought about those but went with Firefly (Carbon Matrix AGM). I did not like the idea of Lithium on the boat. It is hard to stop an exothermic reaction. But it is good to hear you like them.
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
They were bone dry and when I filled them with distilled water they didn't hold a charge.
This problem really needs to be addressed before new batteries are installed. Unfortunately there are a far too many crappy chargers out there that call themselves smart but are not. Six years is really less than reasonable life out of GC batteries for the described use. I suspect you have a charging issue..

I can't address all of misleading info in this thread, there's just too much of it. For your described use replacing four 6V GC2's with four more will be a reasonable swap out. The low Ah GC batteries are usually "consumer grade", some call them "condo cart" batteries, and generally lack the lab cycle performance of a 225Ah+ golf course grade battery. That said even a consumer grade GC battery is going to deliver better lab cycles than a flooded Group 24, 27 or 31 automotive cased battery.

Currently the best deal I know of runs through the end of Feb at Sam's Club. They have $25.00 off on the Duracell EGC2 230Ah 6V golf cart battery. This is a relabeled DEKA GC-15. They are on sale for $92.00 each at my local club. On a dollars to Ah's to cycles comparison it is really hard to beat a re-stickered DEKA GC-15 for $92.00....
 
Jun 19, 2004
512
Catalina 387 Hull # 24 Port Charlotte, Florida
I would go with what Maine Sail has stated at Sam's. Those are pretty comparable to the Trojan T 105 and cost less. I picked them up and yet couldn't get them to fit in my boat, so I had to opt for the T-105's that cost me more money. It was an height issue and the Trojans were a fraction of an inch shorter due to the post height.
 

patn44

.
Oct 3, 2008
15
Columbia , Catalina, Slipper 8.7 , 22, 17 Dog River, Mobile Bay
Have also experienced the 'death' of my two batteries with both having lost fluid. Was charging with a solar panel. Bought the boat in August, didn't check the batteries as they are in a nearly impossible location (plan to correct that). Did not know the age of the batteries. Found them dead and hauled them out. Fluid level was down by about 25%. Tried refilling and recharge but still found them "bad". Replaced with two new, one multipurpose and one deep cycle. New charger run off shore power.
Question: I would like to use the solar charger when sailing or at anchor. Can I connect the solar to the batteries while still running the AC shore charger? Must I disconnect the solar while using the AC charger?
 

patn44

.
Oct 3, 2008
15
Columbia , Catalina, Slipper 8.7 , 22, 17 Dog River, Mobile Bay
additionally, on my other boat, I found that when the fluid in the batteries is significantly depleted and the charger is continued, the batteries heat up dangerously and there is a potential for fire. Checking the fluid level is an absolute necessity.
 

Sumner

.
Jan 31, 2009
5,254
Macgregor & Endeavour 26S and 37 Utah's Canyon Country
If you are in an area with heavy golfing you should be able to find T-105's at a reasonable price. I got T-105's from a Batteries To Go near the boat yard in Florida for $93 (with trade-in) 2 years ago and I'm buying 4 soon and they are $103 now. There is another place in the area with similar pricing last time I checked,

Sumner
=============================================================================
1300 miles to The Bahamas and Back in the Mac...
Endeavour 37 Mods...

MacGregor 26-S Mods...http://purplesagetradingpost.com/sumner/endeavour-main/endeavour-index.html
Mac Trips to Utah, Idaho, Wyoming, Canada, Florida, Bahamas
 
Sep 22, 2014
9
Hunter 33 Parry Sound
I too switched to AGM (Grp 27s) and have 2 x 75 Watt solar panels. However, I am worried that my alternator is going to burn out as it gets smelly-hot when the motor is started after a night at anchor. I have no idea what to do about this and wish I had replaced with the same regular deep cycle lead acids
 
Mar 16, 2009
5
Hunter 35 Coconut Grove
I am a casual user and probably wouldn't be able to do the math even if I wanted to. I have the usual electrical equip for this type of boat-- standard small fridge, stereo, nav, cabin lighting. Nothing that draws too much power. I'll probably just replace what I have with the same since I'm too much of an electrical neophyte to be sure that if I go with 208 amp hours vs. 238 amp hours that I'll come up short just when I need power. Thanks.
Viamalu,

Do yourself a favor and bone up on 12v DC systems. The fact that your mentioned a fridge as something that doesn't draw to much power betrays your lack of knowledge. A fridge is one of the most, if not the most, power consuming thing on board. Even a small, energy efficient fridge running 24 hours in warm wx can easily discharge your house batteries and completely drain them within a couple days.

There are many sources out there that can give you an overview of how 12v systems work, and how to balance your system and maintain your batteries. Nigel Calder's excellent Boatowner's Mechanical and Electrical Manual will tell you most everything you need to know. Batteries will last a long time -- if you properly balance your system and maintain your batteries. However, if you discharge them deeply and often, don't recharge them properly, and don't refill with (the right kind of) water, you will be replacing them sooner rather than later. You'll save yourself lots of money and aggravation by learning how a 12v system works.

As others have pointed out, what you need depends on many variables. If you plan on running your fridge a lot (while not plugged in), and don't have a sophisticated charging system, you may need extra battery capacity. If you aren't planning on using the fridge off the grid, then you can probably do fine with the cheaper batteries. There really is no advantage to 6v over 12v batteries. The capacity of the battery is a function of the size of the lead plates in the cells. A 6v batter is just half of 12v battery. People buy 6v because they may (or may not) be less expensive per amp hour, or for size configurations.
 
Feb 26, 2004
22,760
Catalina 34 224 Maple Bay, BC, Canada
I can't address all of misleading info in this thread, there's just too much of it.
So true, I agree.

Perhaps this will help:

Electrical Systems 101 http://c34.org/bbs/index.php/topic,5977.0.html

I have no idea what to do about this and wish I had replaced with the same regular deep cycle lead acids
That's because AGMs accept a lot more current. You could add another battery to the bank to increase your capacity and reduce the depth of discharge.

There are a few AGM topics, prepared by Maine Sail, in the link above.