Power Made Easy

This was an interesting article on electrical power from Slow Boat. I thought it was well written.

This person is using Lithium batteries, which mean many many boat dollars??

Power Made Easy – Slowboat

I believe he made several posts here on his experiences. Look for posts by kev_rm.

Thanks. That is a big big upgrade.....

Here's the previous thread

Hey all. Thought I'd post a link to the earlier thread talking about our lithium setup in case you had trouble finding it. (Kevin's TF handle is tfmkevin.)

http://www.trawlerforum.com/forums/s4/board-power-made-easy-28564.html

Cheers! -Laura

Well, lithium is expensive, yes. But to do a realistic total cost-of-ownership comparison with AGM batteries...

Lithium costs - in round figures today - $1K per 100Ah at 12.8V. Assuming lithium provides 80% usable capacity without damage, that's $1K for 80Ah usable. $12.50 per usable 12V Ah

AGM costs - (again round figures) $750 for 220Ah at 12V. Assuming AGM is 50% usable capacity without damage, that gives us $750 for 110Ah usable. $6.82 per usable 12V Ah

So - for usable capacity, that makes lithium about twice as expensive as AGM.

Lithium has (depending on whose data you believe) 2x-10x the lifespan of AGMs (number of charge/discharge cycles, etc) So - that makes total cost of ownership roughly the same for lithium (if you take 2x) or better for lithium if you take a higher multiplier.

Caveats:
- If you don't keep/use the boat long enough to wear out a set of AGMs, the longer life of lithiums is irrelevant.
- Charging lithiums is easier on your generator (lets you charge at higher charge rates, so running the generator shorter times at higher loads) so that might also save some money long term.
- Lithiums are smaller, lighter, deliver higher max current, charge faster, have a much flatter voltage curve (easier on all the DC motors on your boat), and make you better looking. At least one of those may not be true.
- Lithiums require reprogramming your charging equipment, and some equipment may not work correctly with them.
- Lithiums are still new technology in the boating world, so we may find issues down the road. (Down the channel?)

Kevin

tfmkevin said:

AGM costs - (again round figures) $750 for 220Ah at 12V. Assuming AGM is 50% usable capacity without damage, that gives us $750 for 110Ah usable. $6.82 per usable 12V Ah

So - for usable capacity, that makes lithium about twice as expensive as agm

Click to expand...

The 220's I am using cost $295 us and Australia is renowned for being expensive.

https://www.baintech.com.au/busines...v-220ah-agm-battery?search=battery&Itemid=427


Weight is irrelivant for us at least.
So much so that the old dead batts are still below And will remain there.

Simi 60 said:

The 220's I am using cost $295 us and Australia is renowned for being expensive.

https://www.baintech.com.au/busines...v-220ah-agm-battery?search=battery&Itemid=427


Weight is irrelivant for us at least.
So much so that the old dead batts are still below And will remain there.

Click to expand...

Yep, I was going based on Lifeline 6V GPL-4CTs (2x6V=12V)
https://www.amazon.com/Lifeline-Marine-AGM-Battery-GPL-4CT/dp/B0029XJ1U6

$399US each on Amazon - so closer to $800 for 12Vx220Ah.

Thanks for responding Kevin. Been burning up my day reading your blog, Ford Terror is on my list for next summer! I am just down river from you in Longview......

Two Sam's Club Duracell golf cart batteries cost $230 and provide 230 AHs at 12V and are some of the cheapest $/AH you can find- 1/3 the cost of the AGMs in the example above.

Simple to charge- almost any charger will work. Simple to maintain- I check water every 3 mo, I add water about twice each year. SOC can be quickly measured with a hygrometer accurately.

Lithium batteries have their place in life where weight and size matters, like an electric car or a cell phone. But in a boat where they are down low in the bilge and at least in my boat where I have room for four, they work fine for me.

David

tfmkevin said:

AGM costs - (again round figures) $750 for 220Ah at 12V. Assuming AGM is 50% usable capacity without damage, that gives us $750 for 110Ah usable. $6.82 per usable 12V Ah

Click to expand...

not sure where those numbers are coming from, but flooded is ~ $220

Lithium is effectively a luxury product and has almost no install base in mobile and/or off grid.

Edit: ya what david said

Amazing how much the price of lithium batteries is starting to come down, and their use outside of electronics. I was shopping for a new battery for my motorcycle today, and found that there are now lithium replacements for just about double the cost of the AGM I have currently. I went with AGM becuase we may sell the bike in the spring, but I was surprised to see them as an option.