Originally Posted by Brewgyver
So, are you considering putting an E-Semi truck drive battery in a boat
Ha! We read the same news articles!
No, but I am trying to wrap my head
around the relationships and equivalencies.
My boat is long and thin, has a 10.1 knot hull speed
, carries 250 gallons of diesel
, 350 gallons of water
maker). I've installed 1.08 kW of solar panels
on the arch, and have room for another 1 kW, maybe 2 kW more.
I'm looking at buying
Victron 250/100 because my current
Victron controller limits output to my old lead acid battery bank of about 1,250 Ah to 700 watts. It's a silly purchase
, what I have handles all of my electrical
needs and I've not used the gen set in years, but the larger MPPT
controller might come in handy during periods of intermittant sun or if a back-up controller was needed.
A friend and I just built a dinghy
and I was considering electric
motors. But the best 10 horse were stupid expensive, and the batteries … same. So I stuck with my old Yamaha 15 horse two cycle. Though I don't like gasoline, it always starts and I do like its power to weight ratio. But I learned that a 10 hp motor
is about 7.5 kW.
My 30 year-old Yanmar
81 horse 4jh-dte has started to make a rhythmic squeak, probably nothing big but needs attention more expert than me. As I was looking into repair
, friend I built dinghy
with, and who had just replaced (with very little help) the Volvo
in his C&C
40 with a 4 cylinder Yanmar
said, "before you put a lot of money
into that old engine
, the new ones are smoother, cleaner and a lot better."
Which caused me to cycle back to wondering how much electric motor
I would need to replace the Yanmar, and how much battery I would need to replace the diesel
, with no loss in performance.
80 horsepower nominal = about 60 kW, though I throttle back to 80 percent. One gallon of diesel provides about 55 hp-h, I burn about 1.8 gals per hour at a water speed of around 8 knots.
I have 1,750 pounds of diesel fuel
weight I could use for batteries (ignoring what's needed for my Dickenson heater), plus probably another 1,750 pounds of water weight capacity I could use if I installed a water maker, plus replacing 500 pounds of lead acids with Li-??, plus replacing the weight of the diesel engine
, plus the weight of the gen set … It seemed doable, if one only looks at the numbers.
But it's an old boat and I'm an old man. I doubt there's enough left in either of us for a project
of this magnitude, and not nearly enough in the bank for the probable cost.
battery pack set my brain back into gear
, so I thought I'd clarify the equivalence of kWh to Ah. It's more than you wanted to know, but thank you for asking. You've helped clarify my thoughts.