Anyone replaced diesel with electric propulsion? If so have you found an economical supplier of quality lithium batteries?
Almost. I do realise you mean for main propulsion, but.... I replaced the old but reliable petrol outboard with a 55lb thrust electric motor for the dinghy. Seems to be about the same as a 2.5hp.
One of the best things ive done - no fuel, no mixing oil, no storage problems (battery or motor), weighs less, and much easier for the kids.
I just ordered some cells from these guys.sibeile.en.alibaba.com/productgrouplist-818674255-2/prismatic.html?spm=a2700.shop_pl.41413.43.274c1a06tfV33Y&filterSimilar=true&filter=null
Are you going to group the cells together in a battery box with a control module and what are you going to drive with them?
setting them up as a 24v battery bank, 8 x 280a/h cells with bms. Going in my son's boat as a house power bank.
Select to expand quoteBedford81 said..
setting them up as a 24v battery bank, 8 x 280a/h cells with bms. Going in my son's boat as a house power bank.
Near as I can tell and I'm happy to be corrected, 1 litre of diesel provides 40Mj so if I burn that in an hour it equates to 5kwh at a presumed efficiency of 50%.
A 12V 100Ah battery will provide 1.2kwh at 90%
SO 400Ah of battery provide roughly same power as a litre of diesel?
I would be taking a good long hard look at electric, but not for another few years.
I don't like the cost of materials in lIthium and the reliance on the obligatory BMS but the next generation stuff everyone is working on looks mighty impressive. We have electric cars to thank for that as they increase in popularity.
Solid State batteries, Lithium sulphur, carbon nanotube, cobalt free lithium... (insert favourite new tech here) ...the differences in charge time and capacity are pretty impressive.
IBM, Panasonic, NEC...the money going into R&D is staggering. Lots of spin off benefits for us grotty yachties coming, but as they say in the classics..watch this space.
I've been looking at building an electric putt putt ( or whatever you would call an electric 18' open boat that's good for about 6kts ? ) batteries are the main draw back, increased range = weight & $.
Select to expand quotewoko said..
I've been looking at building an electric putt putt ( or whatever you would call an electric 18' open boat that's good for about 6kts ? ) batteries are the main draw back, increased range = weight & $.
Maybe golf cart batteries...
Not propulsion but... In 2018 I bought 2 x 120AH Full River AGM batteries, 36kg each battery as house batteries. I was never really impressed with their performance. I recently changed to 2 x 100AH Li batteries, 11kg each. Remarkable improvement in performance with a significant weight reduction.
At this point in the game the idea of converting from oil burning engines in boats or cars is just political correct, virtue signalling crap.
The practicality of it is just not there at the moment.
Oh, all I need is to be able to get the yacht on and off the berth/mooring, for the rest of the time I will sail the boat.
Yeah sure. Best of luck with that idea. It might work if you never leave the harbour and just do weekend racing.
Do the maths. What is heavier, a bank of batteries that will give you 500 miles range, or an engine that burns 2 lires/hour at 5 knots which requires you start with 200 litres of fuel which weighs 200 kg.
Get real.
Select to expand quotecisco said..
At this point in the game.....
The practicality of it is just not there at moment.
I think I might have to agree with you there..
I have literally just hopped out of a mates brand new hybrid Toyota Rav 4, having discussed the fuel consumption/last refuel date v price and watching the fang dangled display on the function display... I was not impressed, compared to my wife's diesel burning Hyundai ix35....
Revisiting this topic because I still have a drip from my diesel, so am weighing up options.
Just spoke to Brent at Eco Boats, who gave me what seemed to be an honest opinion; diesel wins for steaming, but electric keeps the ladies happy.
Some quick numbers ...
I have a Cavalier 28, and I don't want to be underpowered, so a good solution would be the Bellmarine DriveMaster Ecoline 6.0 kW 48 V starting at (will not be less than) $8990.
However, the fun starts with the battery. If I want to steam for 3 hours, I will need 3 x 6.0 = 18 kWHr of power. Convert that to AH = kWHr * 1000 / V = 18.0 * 1000 / 48 = 375AH. The nearest, single unit I can find on the interweb is 48V 400AH for US$13,500 or about $17500 (not including shipping).
So, the motor plus battery is adding up to, say $25K to $30K. Even if I halved that, I would find it hard to justify.
Sorry Arch, but your calculations do not include a charging system to handle dead flat batteries..
I would suggest a diesel driven generator.
So you could motor along smoothly and quietly for 3 hours, then anchor and run the diesel to charge up your batteries.
If you are not in a place where you can anchor, just casually drift along. (Err, sorry to bother you skipper, but are they breakers just over there?)
I think Bukh make a nice little diesel engine that you could use to power the generator.
Gary
A mate of mine converted his 38ft dinghy (4 tonnes) to electric about five years ago, he used a 5kW motor from an old electric vehicle and has 9.6 kWh of gel batteries (4 off 200Ah) which give about 2 hours runtime @ 4 knots (50% DOD). I keep telling him, he would get an extra hour run time if he converted to a modern brushless motor.
I believe he spent about $2700 for the batteries and vehicle. He also has a 2000W genset on board which will give about 2 knots when connected to the motor.
There are much cheaper alternatives to the Ecoboat option, a 10kW motor kit with controller, display and wiring harnesses costs about $2800 in Australia, but you would have to DIY belt drive reduction gearbox between the motor and drive shaft. (I think his pulleys, belt and thrust bearing was under $100). He built the mounting frame out of mild steel.
As for the battery sizing you would only draw 6kw if you are trying to drive the boat above hull speed, there are numerous spreadsheet apps available on the net that can estimate the battery size based on your range requirements and hull shape. Remember that the slower speed the less drag, thus longer range.
Note: I also have a Bukh, which takes a fair amount time in maintenance and money keeping going, so I have done a fair amount of research on this idea.
Select to expand quoteRamona said..
Fix the leak.
Yes, definitely the preferred outcome.
Select to expand quotegarymalmgren said..
Sorry Arch, but your calculations do not include a charging system to handle dead flat batteries..
I would suggest a diesel driven generator.
So you could motor along smoothly and quietly for 3 hours, then anchor and run the diesel to charge up your batteries.
If you are not in a place where you can anchor, just casually drift along. (Err, sorry to bother you skipper, but are they breakers just over there?)
I think Bukh make a nice little diesel engine that you could use to power the generator.
Gary
Gary,
I hear you. I needed to run the numbers as a "what if" scenario. I did a little more research on a new Diesel today. Interesting that a new electric motor costs as much as a new diesel (say, $9K to 10K for a 10 to 14 HP unit, plus or minus a K). However, the cost of the battery is huge. And you have to add in more stuff, as you point out, like a Diesel Generator, which you could easily replace with a Diesel Engine, but that would put you right back where you started.
Martin
Brent from EcoBoat gave me a sanity check on my cost estimates for a battery, suggesting $800 to $1200 per kWh. For 18 kWh (3 hours steaming at 6 kW) the cost of the battery is about $14K to $22K, so my earlier internet estimate of $18K was sane.
I'm going to fix that leak.
I find it fascinating that Achernar in his first post recommended 'SAILING UMA' to watch and despite all the incipient enthusiasm in his second and third post decidedly voted for diesel power.
I thought, you are a new convert! 
Sailing Uma, of which I am a great fan of, is a long and quite interesting series running for at least the last five years. Their motto is "DON'T BUY A COUCH!"
Dan and Kika started in the States with an old and neglected 1972 Pearson 36 and while sailing around the world they gradually refurbished the boat with a lots of elbow grease employing the latest technology, among many other things a full electric conversion which recently got updated.
Their gradual, relentless work and dedication to s a i l i n g is not just way beyond anything available on utube today but the detailed no-nonsense explanations and open, friendly way of conducting their business is something, imo, nobody equalled, yet.
They are in Norway at the moment and there is a unique quality to their posts, THEY NEVER EVER MENTIONED THE CHINEESE VIRUS YET, EVER! Despite sailing all the way through the States, Canada, Europe last year.
If they deserve a medal for their efforts I am sure they deserve a crown for keeping their posts virus-hysteria-free!
The s a i l i n g part is the crux of the matter. One who is in a hurry might be pressed by time to get there or back quickly but a sailor who is following the wind and not the clock would not have such considerations and is perfectly well served by a clean electric propulsion system which does not have to cost an arm and a leg.
I must regretfully disagree with Cisco on this matter keeping in mind that our mind set is quite different, I got all the time in the world so I could sail everywhere, on and off my moring as well (having the engine started but disengaged, just in case, thou). The lame quip about the ladies wishes is just...hmm......lame. Strewth!
I appreciate the concerne of costs and weight issues, however, imo, the greatest hindrance is the initial apprehension of this new technology.
Accepting the inevitable, electric propulsion does not only need a bit of money and effort but more of a paradigm shift in our way of thinking.
SG I'm sure there's a battery revolution around the corner, and our cars will lead the way, with fast charging stations regularly spaced around the country. But On a vessel ?genny back up ? Mariner recharge? Or Hopping big solar array? And no doubt the return of the old days of clawing off a lee shore
SirG, I don't have an ideological position on electric v diesel. I would love to have an electric, but the dollars are prohibitive, especially for the battery. Alternatively, I would love to have a leak-free, non-smelly, non-grimy diesel (to keep the ladies happy). Woko and others have pointed out the "lee shore" scenario. That, and the happy-ladies-scenario, are real factors in my decision-making process.
I posted the Uma link as a direct answer to the OP question. I fully admire what Dan and Kika have done, but it has taken them many years of full-time commitment and the accumulation of much DIY expertise, which I don't have.
Working the numbers was a reality-check, which has persuaded me to continue to try to fix my leaking diesel motor. If electric had a comparable dollar-cost to diesel, I'd seriously consider it.
As an aside, I wonder how well elec controllers, motor windings & general connections will play out maintenance wise ? ive just replaced a start capacitor on a single phase AC motor, it was easy to diagnose the problem as it had a major melt down, do big DC motors have similar weak links ?
Select to expand quoteRubikRedDog said..
Near as I can tell and I'm happy to be corrected, 1 litre of diesel provides 40Mj so if I burn that in an hour it equates to 5kwh at a presumed efficiency of 50%.
A 12V 100Ah battery will provide 1.2kwh at 90%
SO 400Ah of battery provide roughly same power as a litre of diesel?
Very nicely done - neat and simple calc to give you a handle on the problem (provided those efficiency estimates are good).
Though perhaps the 400Ah battery is a little generous, given that it would likely not cycle 0%-100% but at best 10%-90% state of charge. And with your 90% efficiency (also generous?) we will end up with more than 400Ah required.
Here's an interesting case history of a new build of an electric-powered, marina-based 44 foot day-sailer in San Francisco.
brooklinboatyard.com/from-the-shop-floor-march-2021-the-all-electric-taylor-44/
Select to expand quoteKarsten said..RubikRedDog said..
Near as I can tell and I'm happy to be corrected, 1 litre of diesel provides 40Mj so if I burn that in an hour it equates to 5kwh at a presumed efficiency of 50%.
A 12V 100Ah battery will provide 1.2kwh at 90%
SO 400Ah of battery provide roughly same power as a litre of diesel?
Very nicely done - neat and simple calc to give you a handle on the problem (provided those efficiency estimates are good).
Though perhaps the 400Ah battery is a little generous, given that it would likely not cycle 0%-100% but at best 10%-90% state of charge. And with your 90% efficiency (also generous?) we will end up with more than 400Ah required.
Maybe not generous but rather underdone for AGM batteries.
12V 100AH AGM battery will likely deliver only 60% of its rated AH if you want it to be cycled and have a reasonable lifetime. The implications are quite severe. You will only get 720kwh from the 100AH AGM battery. So maybe 7 AGM 100AH batteries required to match the 1 litre of Diesel.
The math "A 12V 100Ah battery will provide 1.2kwh at 90%" will however work for LiFePo batteries. 90% depth of discharge is repeatably achievable.
I hope the math is correct :-)
So if you assemble your own lithium phosphate batteries they can be quite economical. I received the following reply from an eBay supplier today.
"Hi mate,
Thanks for your message. Your requirements sounds like a big project. So to output 10kw at 48v, we'd looking at 10000/48 roughly 210A current output. As currently most high output bms is 200A, some are 250A, both are just barely over your current draw. And considering it's used on motors which might draw a higher current depending on the load. So I'd recommend building 2x 48 volt 270ah bank and put them in parallel, each 48v 270ah bank will be equipped with a 200a bms, this way the system (2x banks in parallel) will have a output capacity of 48v x 400A roughly19 kw, and with your 10kw motor, it'll work just all right, with some slack for the peak high current.
And to build that bank, each 48v 270A bank will require 16x these cells, so 2 of such banks will require 32x these cells. I don't have current stock of the 48v 16s bms as I rarely come across such requirements, but I can source in daly 16s 200A smart model if you do need them, I'm on contract with Daly and I can get their bms in maximal a week if you confirm you need them.
In regard to the size, each cell is 205 x 175 x 75, so the final size will depend on how you arrange them, e.g. if you put them one hard against each other it'll be 205 x 175 x 1200, that's a narrow and long array of them, or you can put them to 4 x 4 blocks. So I don't think there is a readily case to just accomodate them. My experience the best way is just to make sure they are clamped together and bolted down security, then you can custom made a box using plywood or acrylic sheet, or even without a box and have them exposed as long as they are in a safe environment.
I can do a bulk price for these. So for the battery, the best price I can do is $1.05 per ah, i.e. $283 each cells, so for 32 cells in total that would be $9050, plus actual shipping. The BMS I can source in and sell you at my cost at whatever its cost worths.
Let me know what's your plan.
Regards, Tim"
Kinda late to the discussion I know but if anyone wants some information on the physical aspects of a diesel to electric conversion Tim Lackey has done a couple including one recently. Good dissertation with pictures on the process he followed, mounting the engine, building and fitting the battery boxes, adding in the wiring and control systems, etc. See lackeysailing.com , Lyra is the latest conversion.
