Lithium batteries on trailer sailors?

[Ziradog]

So, does it make any sense to put a LiFePO4 batteries on a small boat with a simple elctrical system like most trailer sailers have?  The main advantages seem to be weight and the ability to discharge more deeply and more times than AGM or flooded batteries.  The downsides are much higher initial cost & the need for new/different charging systems.  A regular Group 24 flooded battery lasts me about 4 - 5 days without doing anything special, and that is with running a CPAP all night.  Should I be looking at lithium?

[Riley Smith]

If your present battery does what you need, is there a reason to change? A long time ago when I had electrons on the boat, I ALSO had a bum neck that gave me all manner of grief if I even LOOKED at that lead acid battery. For me that would be the main factor- weight. But weight in a sailboat is sometimes an advantage and can be used to enhance stability. Your call. With my battery aboard I didn't need crew (ballast). I don't know that I'd change for the sake of changing because that would also probably mean upgrading the charger. More $$$$.(Don't know your exact set-up but guessing). Unless charge time is a factor or some other facet that isn't coming to mind right now.

[Wolverine]

2 years ago I needed to replace my old group 27 wet cell battery. I purchased a cheap $135 lithium from Amazon, a lithium charge controller, and a 50 watt solar panel. I have gone on several extended cruises, 4-5 weeks, and never ran out of power. All interior and exterior lights are LEDs, I run 2 cheap isolating fans at night, and I have a 12v "computer" fan for ventilation that runs 24/7/365. The boat is in the water all year with no electricity, hence the solar. How long will the cheap battery last? Only time will tell.

[Riley Smith]

I'll have to admit that I'd love to have a good battery. The old lead-acid died a horrible death getting me back to the ramp after almost being swept to sea. No wind or I would have sailed. And one of those fold-up solar arrays too, although that would most likely not see much use considering almost all of the time on the water is day-sailing for a couple of hours. The boat stays inside so that would be no use. Still, it would be nice to have some power on occasion. Summer is coming and I've considered sailing at night to avoid that laser in the sky. And besides, I know where some lights are where the fish slam the bait. I could see one of those LED arrays they put on trucks 

[pgandw]

I switched to a cheapie 160AH LiFePO4 battery ($220 from Amazon) on my camper 2 years ago, replacing a pair of GC-2s that would no longer hold a charge. Cost was less than a replacement pair of GC-2s, and I have more usable battery capacity. My shoulders and back have thanked me any time the battery needs to be removed. And I lost 80lbs of tongue weight, too.

My 19ft Mariner has no electrical system. But I did switch to an electric outboard, and my shoulders and back were REALLY appreciative. Next step is put in a simple electrical system with a LiFePO4 battery - probably a 200AH if I can fit it. I can use the battery to recharge the outboard battery, and to run my CPAP for a few nights of anchoring out. A 100 watt portable solar panel will probably not keep the battery full on a multi-day cruise, but it will certainly help.

You can now buy a 150AH Bluetooth LiFePO4 battery for less than $250, and a very capable 20A LiFePO4 charger for another $60. No worries about acid spills, or adding water, or leaving at a partial charge. Life is better with these batteries.

I became a convert when the price came down to present pricing.

Fred W
Stuart (ODay) Mariner 19 Sweet P

[Ziradog]

@Wolverine, could you do the same with your old group 27 battery?  Other than the 24/7/365 fan, our electrical budgets look fairly similar.

@pgtandw, I use solar to keep my battery charged.  I don't have an electric outboard.  I don't pull the batteries out of my boat until they die (usually) so the weight isn't an issue.  Using your figures, add ~$125 for a solar charger, total $435.  That's about 3 of my current battery.

Certainly more power (longer to discharge) would be nice but I rarely have a problem now so I'm not sure I want to spend the extra $$$.

[Wolverine]

I don't really need 200ah of battery. I had the space from the 2 wet cells and at $105, I thought, what the heck. The solar panel cost $95 and with the controller your estimate is accurate. The weight and increased charging cycles is what convinced me to spend the money. It was a test to see if I should convert my Orion to lithium.

If I was only day sailing, or occasionally overnighting, I wouldn't have spent the money. However, I take several 2-4 week sails every year. When I'm out, the VHF is always on because it has an emergency weather alert. The chartplotter is always on because I use the anchor alarm at night. The depth meter is always on for the shallow water alarm. Those anre a constant draw.  Add the 2 oscillating fans and anchor light at night.
Charging my phone. A 12v vacuum. As stated already, the 12v computer fan.

I've noticed a trend of removing the propane stove/oven and installing electric in a lot of boats here. They must use a lot of amps.

[GWB]

If you need to replace your current battery, it's a hands down "yes".  The lithiums now are so cheap, they are practically the same price as lead acids.  If your current battery fills your needs, then stick with it until it needs replacing. 

When you do replace your battery and if you stick to the same amp hour value, you will double your capacity as the lithium has more usable capacity than lead acid for a given ah. I upgraded my camper battery from a 100 ah lead acid to a 300 ah lithium. I 6Xed my capacity for almost the same sized battery.  The only added consideration is the charge profile.  You may need to reconfigure your charge controller or replace it.  I don't know what you are running, but maybe it would allow for running a 12v fridge. Think, ice cubes for boat drinks. 😃

I have a 100ah lead in my boat that runs a chart plotter, lights(led) and the fridge.  (and fans)(and charging devices) It doesn't make it through the night sometimes before the fridge shuts down for low volts and the chartplotter is also a huge draw so I only run it when I want the navigational assistance. 100 watts solar btw. 

I am eager to upgrade.  A lithium 100 would most likely do it, but a 300ah battery would be the cats meow. Standing by on that for now due to cost.

Best of luck in your choice.

GB