Bought a new boat that needs new agms?

[LifePart2]

I totally disagree with a64pilot: Lithium is definitely the way to go. So many advantages with no real downside. About the same price as good quality AGMs. A little bit more complicated to set up, but really not very difficult to do. Once they are installed you will love how quickly they charge up with solar input.

Here is exactly how to set it up:

LIFE: Part 2: Lithium Batteries – best thing since sliced bread

Fair winds!

[john61ct]

Originally Posted by LifePart2

I totally disagree with a64pilot: Lithium is definitely the way to go. So many advantages with no real downside. About the same price as good quality AGMs

What continent are you referencing? Certainly not true in NA, LFP is easily 4-6x pricier with the control gear. High risk of not getting ROI, single unexpected failure can instantly render the LFP bank scrap, while payback starts at maybe 20 years?

[CarinaPDX]

My first battery banks were 3x Rolls FLA group 30H. They worked well, and even in the tropics I only had to add about a cup of water (total for all three) every month - a minor inconvenience. Without smart regulators I would expect more water consumption and shorter life, so regardless of which batteries you buy invest in a quality charger, alternator regulator, and solar/wind regulators. The main disadvantage to FLA is the higher internal resistance, which results in longer charge times and voltage sag during heavy loads (lots of fun when the GPS resets when the engine is started).

IIRC I have since had three sets of Sonnenschein gel batteries (DF180). Although they have significantly lower capacity than the (larger) previous batteries, the faster charge rate and the stiffer voltage under load were worth it. There have been a lot of low quality gel batteries on the market; Sonnenschein were the first to master gel manufacturing, and East Penn (Deka) are also constructed with this technology - the only two worth buying. I have had long battery life, and certainly haven't heard of any issues with charging to less than 100%. I have mostly just let the engine, solar and wind do their thing and would typically run the engine for charging at anchor once a week for an hour or so to top off.

I need to replace now, and just this week was looking into AGMs. Lifeline does stand out, and especially because I can get about 50% more AH than the current gels in the same space. The Deka gels would be in-between for capacity. I have also had Fullriver AGMs recommended to me - they are a major player in the AGM market, and are available at a lower price. I am a bit concerned about the finicky charging needs though. I have no problem with the charge settings, but having to run the engine to top the batteries every couple of days seems a bit much. I guess I am not seeing the attraction versus gels other than more AHs.

Thoughts?

Greg

[john61ct]

If you're set up for and comfortable managing GEL, stick to them.

If NA, Deka's are OK, lots cheaper than Sonnenschein.

[CarinaPDX]

If I stay with gels, which is increasingly likely, I will use Deka group 31 batteries. I am trying to finish my engine install this winter and will be running new cabling so now is the time to convert to BCI group 31 from the iso size.

[john61ct]

Any new box IMO should be designed to fit a variety of sizes. I would always want to be able to revert to standard FLA in a pinch,

$200 per 200+AH @12V pair for Deka GC 6V FLA in the US, or Trojan T-105, available worldwide

There are ways to deal with that V sag issue, starting with separating House with a Blue Sea switch incorporating Starter Isolation feature.

[CarinaPDX]

Originally Posted by john61ct

There are ways to deal with that V sag issue, starting with separating House with a Blue Sea switch incorporating Starter Isolation feature.

That was just one example - using an SSB at full power or bringing up the chain can also be problematic. Separating is only part of the solution. Of course if the batteries are topped up then no probem; it is only an issue when the batteries are lower (e.g. after a few days at anchor and one wants to get going). Most of the time it is not an issue. Keep in mind that Carina is a small boat with small banks and a big electrical system


Greg

[john61ct]

Yes more AH is the fundamental cure.

LFP would solve it without that too, more compact and light weight.

But pricey.

[LifePart2]

We bought our LiFePO4 at https://www.ev-power.eu/Winston-40Ah...55a080805rqmb6 when we were in Italy.

300Ah was about the same price as 600Ahr of AGM's. Of course you can get simple lead batteries for much less. Then we installed a simple battery management system as described in my ebook.

Lasts for at least 10 years, and probably more. No sudden failure unless you overcharge them or over discharge them. They don't like that and are less tolerant than Lead for that. But it is simple to set up a system that prevents that. We have had them for 3 years already and love them.

I get no commission and have no benefit from recommending them, so if you prefer Lead, go for it!