Lithium Battery Upgrade

[edwardc]

The most cost effective batteries are golf cart batteries. Run the hell out of them, 80% discharge no problem, and when they croak get more for under $100 a battery. They will also survive gross abuse for a while, they are not easy to kill.

Joe,

I considered these in my early planning, based on other cruising friend's real world experience. In my case, the big drawback was that flooded lead acid (FLA) batteries only do well if you meticulously check and maintain the electrolyte levels. In my boat, the lead acid batteries are located in the very bottom of a large, deep sail locker in the cockpit. Getting to them requires emptying out most of the locker, and I just knew that I would be too lazy to do that annoying task as often as necessary. Thus, the "no maintenance" Gel Cells were a much better fit for me.

[Dave Neptune]

Edward, my AGM's (lead acid) were maintenance free. I replaced them when they were about 6 years old and installed by the PO. I replaced with the same and they were still going strong at 3 years. I ran my fridge & freezer 24/7 and often did not plug in the shore power at the slip as the solar kept things happy.

The AGM's can be drawn down a bit further than a straight L/A style and seem to have a longer life from what a lot of my "cruising buddy's" said they experienced. I too was considering the lith/Ion but could see no big gain with my needs.

Dave Neptune

[ndutton]

When changing battery chemistry take care to also provide the proper charging voltage and profile regardless of alternator, solar or shore charging. Many years ago I added an AGM without regard to charging profile and its performance was H-O-R-R-I-B-L-E.

Not the battery's fault though.

[W2ET]

I got about 6 years out of my AGM's as well, until I noticed that the charger was running continuously when shore power was connected. Then I noticed that the sides of the batteries were bulging out. That was it. Swapped them out for fresh AGM's. The second set was approaching 6 years also when the boat was sold.

Peter Kennedy at www.pkys.com had done the original install and used the apporpriate Balmar regulator in the project. The charger did have an AGM setting, which I used.

The selection of AGM's was all about "maintenance-free" and nothing else. I was not impressed with performance when drawn down a bit.

Bill

[edwardc]

Edward, my AGM's (lead acid) were maintenance free. I replaced them when they were about 6 years old and installed by the PO. I replaced with the same and they were still going strong at 3 years. I ran my fridge & freezer 24/7 and often did not plug in the shore power at the slip as the solar kept things happy.

The AGM's can be drawn down a bit further than a straight L/A style and seem to have a longer life from what a lot of my "cruising buddy's" said they experienced. I too was considering the lith/Ion but could see no big gain with my needs.

Dave Neptune

Agreed. Gels and AGMs are both Sealed Lead Acid (SLA) and maintenance free. I considered AGMs. They are cheaper and easier to source than Gels, but the boat came with Gels, and I didn't see enough advantage in switching to AGMs to justify it. I would still have similar cruising issues.

[joe_db]

Joe,

I considered these in my early planning, based on other cruising friend's real world experience. In my case, the big drawback was that flooded lead acid (FLA) batteries only do well if you meticulously check and maintain the electrolyte levels. In my boat, the lead acid batteries are located in the very bottom of a large, deep sail locker in the cockpit. Getting to them requires emptying out most of the locker, and I just knew that I would be too lazy to do that annoying task as often as necessary. Thus, the "no maintenance" Gel Cells were a much better fit for me.

I don't like wet cells, I am willing to pay the premium to not deal with water and acid.

[sastanley]

Hi, Shawn:

If planning an upgrade, your system raises some interesting questions.

Do you run the two alternators in parallel to combine their charging capacity?

Do you split them, with one feeding the starting battery and one feeding the house bank?

Do you just use one alternator to manage the charging requirement?

How is the system currently configured?

Hope all is well and that you are enjoying the new vessel.

Bill

Bill, Hi we are well and thanks, we are enjoying it.
Without getting too wordy:
I am not 100% sure how the boat is currently wired. I think I have some type of isolator that may charge either bank from either alternator, but I am not certain of this. The most recent PO just set both batt switches to "ALL", all the time. There are some variations on that theme I have tried, with inconclusive results, except I was unable to start one of the engines in some variation until switching back to ALL.
Another thing I noticed in some notes from 2 PO's ago:
I have a bank of (2) parallel Gr27 batteries for start.
I have a single Gr 27 battery for house.
I thought it was the other way around. Who would do that?
I need to spend an afternoon with no distractions and trace the 1-2-All switches, charge circuits, and diagram out the current set up. Not sure why this boat would have such a small house bank, and such a large start bank...once you get one engine going I would assume in a few minutes it could bring up a single start battery for use on the other motor.
Anyway, big changes in the batteries are a long way off for me..This is not a boat you spend endless days at anchor..zip to the next port and plug in the A/C!

[Sam]

I have mentioned this before but for the sake of new readers I'll mention it again. I live in Chicago with half year seasons at best. 1966 Morgan 34 is on mooring can with standard running lights, instruments etc and 55 amp alternator - nothing fancy. I switched to AGM years ago and have not looked back - currently have [2] identical Optima Blue top multi purpose for starting and house interchangeably - one from 2008 and other 2018, both work well and test out fine with volt meter and draw test. They are about 10 lbs lighter each than comparable lead acid and easier to handle. I do remove them during winter layup, store in a heated garage and periodically attach an AGM float maintainer. About 2 -3 times more expensive up front but sure seems better in the long run.

[southcoasting]

In last Winter’s big project for SV Nova Luna, I decided to make over the galley with new countertops, new sink, and add refrigeration. I decided to remove the old ice box on my Tartan 34 and make a new one in a new location with 4” insulation and a Nova Kool RT4 ice box. In this process, I had decided it was time to consider Lifepo4. I had been using 6 volt golf cart batteries that had to get replaced every 3-5 years and felt I needed more juice for my new refrigeration that I wanted to run full time. Since my boat stays in a mooring, I needed my system to be off grid capable…

I switched up my system to have one custom built 304 amp hour Lifepo4 house and one separate AGM battery as my starting battery. I bought my CATL cells as “grade B”. I attached a JK controller to them and installed a Renogy dcc50s DC to DC controller to handle my new 200 watts of solar power as well as the alternator charging.

In my one year of use I can say that my system works amazingly well. My one 304 ah battery stays topped up even with me running my fridge full time and there is a never a worry about starting engine as that battery stays seperate. The Renogy DC to DC controller simplifies everything for me so that the alternator charging to Lifepo4 won’t be an issue. Hope to get many years (20+) out of this Lifepo4 instead of having to change out batteries every 3-5 yrs…

[sastanley]

Wow...great report, SC. Glad it is working out.