"carbon foam batteries"

BrentB":1q8ptxzd said:
I don’t but received email from Fisheries Supply about them
Click to expand...

Ditto. That's why I started looking. Pricey, $486 for a group 31, but...
 
Ben Ellison put the Firefly Carbon Foam batteries in his test boat "Gizmo" almost 2 years ago: See Here If you are interested read down thru all of the comments, which go to Jan. 2018.

So where do these belong in the C Dory? They weight about the same as same size "Sam's Club" DuraCell AGM group 31 (75#, same foot print), and the Carbon Foam cost is $486 plus tax and shipping (?)... The Sam's club are $180 (slightly up from when I bought mine 4 years ago). The Firefly cost almost 3x as much.
Now, I don't discharge my AGM's much more than 50%--and they are still going strong. I might be able to eliminate one of the AGM's and still have almost the same usable power...but how long will it really take to recharge?

Despite what the video guy says, here is what Bruce Schwab who engineers and sells these batteries says about cycles and depth of discharge:
50% DOD ~3600 cycles 80% DOD ~1000 cycles This means that in fact you get 3.6x the longevity of the battery if you only discharge it to 50% SOC, or 12.2 volts as I am doing with my AGM's now!

I don't really see much advantage for our little boats. A Lithium ion battery with 100 amp hours is just about $1000. Its weight is 29# a little less than 1/3 the weight of the Carbon foam or the Lead Acid AGM. There is substantial weight savings. But does the Li ion battery really last a long time if it is fully discharged. At first the hype was they can be fully discharged with no damage. Time has proven that wrong. They should be periodically taken down to 10% SOC, but the greatest longevity is still not discharging over 70%. Yes they last longer than AGM, have greater capacity, weigh less, but at 5x the price!
 
https://deepcyclebatterystore.com/wp-co ... -specs.pdf

As you can see, at least according to the mfg., the life of the battery ranges from 500 (full discharge) to 3,000 (20% discharge) cycles and this is just a standard old lead acid golf cart battery. Without the trip out west (4 months each) I am guessing even 500 cycles would be enough for 5 years but I am not trusting enough of these specs to actually drain the battery 100% - they don't mention the loss of capacity if you do that.

Trouble is, a couple these Crown CR-260s are over $500 and, if you can really get a full discharge over 2,000 cycles with a lithium ion (if you believe the mfg), a little over twice the price doesn't seem so bad. It doesn't seem good enough to actually do anything, but if our batteries were bad, it would be VERY tempting (double our capacity - maybe we could leave the freezer on all night).

John[/img]
 
If the cost were down, I would make the switch in an instant.

I put a lithium ion battery in my offroad motorcycle after the standard battery left me stranded. Its been 3 years, and months will go by without starting this bike. It holds a full charge for what seems like indefinitely. I've been very impressed with the performance, and at a fraction of the weight. The cost difference was more, but it wasn't the kind of investment it would be for the boat.
 
JOHN C":5dkr74ek said:
https://deepcyclebatterystore.com/wp-content/uploads/2016/12/Crown-CR-260-specs.pdf

As you can see, at least according to the mfg., the life of the battery ranges from 500 (full discharge) to 3,000 (20% discharge) cycles and this is just a standard old lead acid golf cart battery. Without the trip out west (4 months each) I am guessing even 500 cycles would be enough for 5 years but I am not trusting enough of these specs to actually drain the battery 100% - they don't mention the loss of capacity if you do that.

Trouble is, a couple these Crown CR-260s are over $500 and, if you can really get a full discharge over 2,000 cycles with a lithium ion (if you believe the mfg), a little over twice the price doesn't seem so bad. It doesn't seem good enough to actually do anything, but if our batteries were bad, it would be VERY tempting (double our capacity - maybe we could leave the freezer on all night).

John[/img]
Click to expand...

Yes, these are just standard high end golf cart deep cycle--and slightly higher capacity than the Trojan's usually used in multiple applications. But they are dong some funny stuff: They give 50% DOD as 1.94 volts per cell or 11.64 volts for the 6 cells. In most books, 50% discharge is 12.2 volts stead state. I am not sure how they are measuring this but assume that it is an amp-meter, with a cut off of 10.5 volts...way below where many of our "12 volt" appliances function well. For example my refrigerators will cut off at 11.5 volts --(adjustable in some). We also have to realize that end volts for battery discharge is steady state--which means no draw or current addition for at least 2 hours. Voltage will go lower when the appliance is actually running. Also the resistance of wiring, will drop the perceived voltage at the device.

I found them for $200 each--still higher than the well regarded Trojans or the Sam's Club by East. Penn.
 
Check out Kevin Morris’ article on SLOWBOAT about lithium batteries. Interesting.
 
Gene, Thanks for the referral to the blog on Li ion batteries. The article I read was written in 2016. Today the company he linked to is selling Victron Energy Li ion batteries. The basic wiring, gauges etc are $1500. Each bank of 300 amp hours is $3700. Thus the complete system would be $8900 for 600 amp hours. He also paid $400 for each of the golf carts. You can buy the Trojan AGM 220 amp GC for about $255, or a Deka 448 amp hour lead acid L 16 battery for about $160 (or $320 for 2, more capacity than he had with the AGM--most folks get as much as 10 years out of these very heavy duty commercial batteries--the heavy part is why they are not good for c Dorys). There are cheaper resources, and you can come in for a little under $1000 for 100 amp hours--but that does not include all of the monitors, and safety devices which should be part of a system.

Another thought was that he was running the inverter to heat water, yet running the engine 4 hours a day to keep up with his battery charging needs as he cruised. We always heated the hot water with the diesel main engine as a byproduct of waste heat. Also since he apparently cruises the PNW, many diesel hydronic heaters have a provision to heat the hot water tank. The water heating was one of his main demands (as well as household refrigeration). The refrigeration has other more efficient ways to handle it--at a lesser cost--Holding plates with compressor off the engine, 110V or 12 v compressors.

One of the RV folks ran his entire system off Li Ion Batteries for a number of years--he did it as an experiment with a battery manufacturer. The manufacture re-balanced his battery pack cells each year. This gave the best performance. [/u]
 
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