LiFePO4 gives $21k Return

NorthernFocus

NorthernFocus

Well-known member
Joined
Jun 29, 2014
Messages
1,424
Location
Alaska
Website
www.northernfocusphotography.com
Fluid Motion Model
R-25 Classic
Hull Identification Number
FMLT25910808
Vessel Name
Divine Focus
I've now made a couple of cruises with the new battery. It's performing as hoped with no dedicated thruster battery. So I started wondering whether the up front investment pencils out.

The manufacturer claims the battery is good for 6000 charge cycles. I never trust such claims so half it. That's 3000 cycles. At the end of a week on the water it shows two charge cycles. We average 8 weeks on the water every summer so that's16 cycles per year. 3000/16 works out to 187 years. Historically I've averaged $125/yr on batteries for house and thruster banks. 187 x 125 = $23,375 saved less the $2k invested in the LiFePO4 and charger. That's a net return of $21,375. Now I just have to update my will.
 
Ha this is funny!
It’s like me trying to justify the value of all the seafood we catch vs store bought.
But I think the lithium upgrade wins compared to seafood vs fuel cost. But then again we always have the freshest best seafood on the table. Plus we have the memory / stories about each catch we make. Priceless
 
Mike and Sarah said:
Ha this is funny!
It’s like me trying to justify the value of all the seafood we catch vs store bought...
Click to expand...
Typically when we invite friends to dinner we serve halibut and spotted shrimp. It's not the cheap $25/lb stuff from the market. It's the $200/lb stuff we catch ourselves.
 
NorthernFocus said:
I've now made a couple of cruises with the new battery. It's performing as hoped with no dedicated thruster battery. So I started wondering whether the up front investment pencils out.

The manufacturer claims the battery is good for 6000 charge cycles. I never trust such claims so half it. That's 3000 cycles. At the end of a week on the water it shows two charge cycles. We average 8 weeks on the water every summer so that's16 cycles per year. 3000/16 works out to 187 years. Historically I've averaged $125/yr on batteries for house and thruster banks. 187 x 125 = $23,375 saved less the $2k invested in the LiFePO4 and charger. That's a net return of $21,375. Now I just have to update my will.
Click to expand...

My first set of AGM's lasted me 90 days. My second set, I got a little over 14 months. Converting to LFP therefore has saved my boating as I couldn't afford to replace my batteries that often, year over year. Not to mention the health care costs associated with moving those heavy lead based batteries in and out of the boat so often.
 
Submariner said:
My first set of AGM's lasted me 90 days. My second set, I got a little over 14 months. Converting to LFP therefore has saved my boating as I couldn't afford to replace my batteries that often, year over year. Not to mention the health care costs associated with moving those heavy lead based batteries in and out of the boat so often.
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Wow Martin! Your experience with the your AGMs sucks. No wonder you changed to LFP.
As a counterpoint, over the past 11 seasons with the R-25 Classic and now with our C-28, I have averaged over 4 years of use out of every single AGM battery before replacement. The replacements were solely due to preventive maintenance, not because of battery failure. I have never had a AGM failure in my boats.
That said, I buy the best AGMs I can get and they are not cheap. But still far cheaper than LFP batteries.
 
scross said:
Wow Martin! Your experience with the your AGMs sucks. No wonder you changed to LFP.
As a counterpoint, over the past 11 seasons with the R-25 Classic and now with our C-28, I have averaged over 4 years of use out of every single AGM battery before replacement. The replacements were solely due to preventive maintenance, not because of battery failure. I have never had a AGM failure in my boats.
That said, I buy the best AGMs I can get and they are not cheap. But still far cheaper than LFP batteries.
Click to expand...

My hat's off to you... 4 years on AGM batteries... I can't relate, not even sure I can imagine what that's like. Everybody boats different. For us, power is everything, and the more the better. Solar is mission-critical onboard as it provides about 80% of all the power we consume. (420 watts of solar, 320ah of LFP)

Since I converted Channel Surfing to LFP in February 2022, we have not had a single electrical issue on the boat. We run our inverter daily, water heater, microwave, coffee machine. I can pull 150 amps at 12volt DC to power the coffee maker. We've ran the coffee maker with only 25% SOC. Voltage will hit 11.7volts, which causes the inverter to beep (low voltage warning is 11.8 volts). If voltage were to hit 11.5, the inverter would shut off, but we've never had that happen.

I spent $7k for parts, and about 50 hours of my own labor to convert Channel Surfing to LFP. It was a lot of work and was worth every cent and hour spent.

IMG_8835.PNG
 
Submariner said:
My hat's off to you... 4 years on AGM batteries... I can't relate, not even sure I can imagine what that's like. Everybody boats different. For us, power is everything, and the more the better. Solar is mission-critical onboard as it provides about 80% of all the power we consume. (420 watts of solar, 320ah of LFP)

Since I converted Channel Surfing to LFP in February 2022, we have not had a single electrical issue on the boat. We run our inverter daily, water heater, microwave, coffee machine. I can pull 150 amps at 12volt DC to power the coffee maker. We've ran the coffee maker with only 25% SOC. Voltage will hit 11.7volts, which causes the inverter to beep (low voltage warning is 11.8 volts). If voltage were to hit 11.5, the inverter would shut off, but we've never had that happen.

I spent $7k for parts, and about 50 hours of my own labor to convert Channel Surfing to LFP. It was a lot of work and was worth every cent and hour spent.

View attachment 27757
Click to expand...
We do multi week cruising like you do. Not to Alaska though! We just never use the inverter. Oh I test it for a minute every other year or so to see if it still works but that’s it. We live very comfortably in our 12 volt world. Even in marinas with shore power we only hook up to 120 volts about 1/2 the time. The only 120 volt thing we have on board is the microwave and it’s not used much even when on shore power….
 
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Submariner said:
My hat's off to you... 4 years on AGM batteries... I can't relate, not even sure I can imagine what that's like. Everybody boats different. For us, power is everything, and the more the better. Solar is mission-critical onboard as it provides about 80% of all the power we consume. (420 watts of solar, 320ah of LFP)

Since I converted Channel Surfing to LFP in February 2022, we have not had a single electrical issue on the boat. We run our inverter daily, water heater, microwave, coffee machine. I can pull 150 amps at 12volt DC to power the coffee maker. We've ran the coffee maker with only 25% SOC. Voltage will hit 11.7volts, which causes the inverter to beep (low voltage warning is 11.8 volts). If voltage were to hit 11.5, the inverter would shut off, but we've never had that happen.

I spent $7k for parts, and about 50 hours of my own labor to convert Channel Surfing to LFP. It was a lot of work and was worth every cent and hour spent.

View attachment 27757
Click to expand...
Sounds like the battery that you need is called a generator 😕
 
scross said:
Wow Martin! Your experience with the your AGMs sucks. No wonder you changed to LFP.
As a counterpoint, over the past 11 seasons with the R-25 Classic and now with our C-28, I have averaged over 4 years of use out of every single AGM battery before replacement. The replacements were solely due to preventive maintenance, not because of battery failure. I have never had a AGM failure in my boats.
That said, I buy the best AGMs I can get and they are not cheap. But still far cheaper than LFP batteries.
Click to expand...
"Deep cycle" batteries and AGM are little more than marketing schemes by the battery manufacturers. Which worked. They've sold millions of them to replace the ones that people ruin by using them exactly as they're advertised to be used. Every lead/acid battery whether deep cycle or not begins to "sulfate" when it drops to 12.3 volts. So basically if you actually use what labeled as a deep cycle battery as advertised you're killing it every time you draw it down into "deep cycle" territory. AGM is essentially the same chemistry as flooded cell and suffers the same issues. It dies a little bit every time it's drawn down to fully utilize its name plate amp hours. If lead acid/AGM batteries are used in a manner to optimize their life they are basically half the advertised capacity(in Ah).

I've only made two one week trips so far with the LFP battery and as far as I'm concerned it has already proven that it's worth the money. Simply the piece of mind of knowing how much capacity that I have left and that always being way more than necessary is worth it. Not to mention shedding 160 lbs of lead.

And no, if you do the math the AGMs are not cheaper in the long run than the LFP.
 
NorthernFocus said:
"Deep cycle" batteries and AGM are little more than marketing schemes by the battery manufacturers. Which worked. They've sold millions of them to replace the ones that people ruin by using them exactly as they're advertised to be used. Every lead/acid battery whether deep cycle or not begins to "sulfate" when it drops to 12.3 volts. So basically if you actually use what labeled as a deep cycle battery as advertised you're killing it every time you draw it down into "deep cycle" territory. AGM is essentially the same chemistry as flooded cell and suffers the same issues. It dies a little bit every time it's drawn down to fully utilize its name plate amp hours. If lead acid/AGM batteries are used in a manner to optimize their life they are basically half the advertised capacity(in Ah).

I've only made two one week trips so far with the LFP battery and as far as I'm concerned it has already proven that it's worth the money. Simply the piece of mind of knowing how much capacity that I have left and that always being way more than necessary is worth it. Not to mention shedding 160 lbs of lead.

And no, if you do the math the AGMs are not cheaper in the long run than the LFP.
Click to expand...
Dan, Agree with what you are saying. I do spend time every morning and evening monitoring my house bank SOC. My AGMs only get 1/2 the draw of the LFPs. In 11 years while cruising and when stored on the trailer my house batteries have never been drawn down below 45% SOC or 11.0 volts.
In short term of 11 years on my two boats I have replaced 9 AGMs at a total cost of under $2500. In the short run of 11 years, I do believe that AGMs have been more cost effective than a LFP conversion when paired with a robust solar system and conservative energy consumption practices. Using Martin’s expense of $7k per boat converting from AGM to LFPs on both boats that cost total would have been $14,000.
We don’t use the inverter because we really don’t need a microwave oven, coffee maker, satellite internet, television or other power hungry devices while cruising. For us those things are the antithesis of why we are cruising. And we don’t plan on keeping our boat for another 187 years.
I understand that not everyone wants to be as conservative as I am with energy consumption. LFPs are a great solution for those folks.
 
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