Electric 22 feet speedboat from 1957

Hi guys,

I am brand new on the forum so don't shoot me down right away.
I have started a project (around one year ago) of completly restouring a wooden (mahogany laminated and oak framed) speedboat of 22 feet in lengt which ways in at about 200 kgs.
This restauration is still in progress and will be for at least one more year, from my electrical education i have picked up quite the intrance to the battery propelled systems especially the one in RC cars, Now i am a bit older i've started this project. as they say boys dont grow up only their toys get bigger... ps: and i am only 20 who knows what the future has in store

The boat was powered before by a single 50 hp 2 stroke outboard engine, this will be changed to a fully electric propulsion plant.
The plan now is to use a ME 1616 22 KW continous PMAC motor in combination with a secvon gen4 size 6 (80V) 550 A max below a link to the motor. This motor will be installed on a mercury 50hp 2stroke outboard from the 70's just because i love the look of them, and for the looks there has to be a outboard behind the boat. since you may already have guessed it is the intention to make this a planing speed boat im not really intrested in the exact amount of knots just want to get up and stay on a plane with ease.

https://eveurope.eu/en/product/me1616-pmac-engine-water-cooled-22-kwatt/

The battery to power the system will be completly self made from 18650 lion cells nominal voltage 3,7V in a configuration of 28S 60P (i like the challenge and i know i will be spot welding more than 3000 times
For now i have the idea to use the panasonic ncr18650pf 2900 mah cells. around 1700 of them to get about 18KW hrs of battery pack. The battery will be heated by trace wiring or atleast thats the idea and i have not yet come up with a idea to make it water cooled, but i am sure some ideas will popup in the future or if some one has an good idea or has seen a good idea for this elswhere let me know.

I already have the controller, and in about one month i will buy the motor. (if you guys pursway me not otherwise)
The BMS is in progress of being made, ive already got one that will do 32S 300 amps but the 300 ams is factory rated so i might an additional board of diodes to handle the power or install better ones than the factory ones.
Since i have taken note that is is quite hard to program a secvon i am thinking about going to a shop to let the controller and motor be programmed, actually i like to do it my self but i have no DVT and DCF and no XIATT etc so it will be cheaper to outsource it. for the ones wondering, i bought the controller blank from ebay so no help from any supplier etc.

for all who will say it will cost me allot of $ and is is more economical to use a gas powered engine... YES I KNOW it is not about the money and no i am not someone with allot of bucks, just working class. it is either this hobby or a psychiatrist :wink: where the money goes to.

I will try to post some pictures later (first have to figure out how )

In this post i will put updates of my progress and if you have any suggestions and or questions please ask them.

I think youre asking for too many amps from an 18650pf. 550amps from 60p is about 9amps/cell. and that wouldn't be a quick burst. from the boat sitting still how long would it take to get on plane?

im no expert but it would really suck to spend all that money on batteries and time doing spotwelds then have the pack fail in a very short time period.

theres probably better cells at the same price that you could use.

The controller can handle max 550A at 118V battery voltage but i will never reach the 550 amps. at least i hope so!
the motor will be 22kw nominal so that would mean with a pack voltage of 100v a draw of 220 amps resulting in 3,7 amps per cell. which is a little over 1c.

i think that when staying on a plane the draw will be around 12-15 Kw or 150 amps or 2,5 amps per cell.
The planning now is to make the battery modulair and easy to remove also adding additional cell will be possible.
The hull shot time is expected to be around 20 seconds.
Recently i have restoured a flying finn bayfinn (for lakes) which is a 17 ft wooden boat but weighs the same as my 22ft speedboat (when it will be finished). behind the bayfinn there is a 9.9 hp yamaha and is will just get on to a nice plane with one person.

do you have any suggestions about other cell that may be interesting for me, i have been reading the lion cell aging post by docware if found this quite intresting.

Here are some pictures of the hull just so you can get an idea 8)

That boat would look much cleaner with an inboard motor set up 8)

the pf lifecycled at 4amp discharge has 2500mah after 300 cycles on the spec sheet, sounds good to me. that boats going to float like a cork bobber. are you going to have to some sort of gear like a 2to1 or just play with different props

For now i have the idea to use the panasonic ncr18650pf 2900 mah cells. around 1700 of them to get about 18KW hrs of battery pack.

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Have you considered using a salvaged car battery? The 2013 leaf has a 21kwh battery. Some already have cooling solutions.

That boat would look much cleaner with an inboard motor set up

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I disagree with you on that one, it is the intention to keep the boat as original as possible.
When going for an inboard the weight will become problematic, i will need an prop and rudder going through the hull which the hull
really is not made for (overlapping mahogany planks of 5 mm thick bonded by a few thousand copper ribbets).
An ''ugly'' box in the middle of the boat is not my taste, less is more :wink:

the pf lifecycled at 4amp discharge has 2500mah after 300 cycles on the spec sheet, sounds good to me. that boats going to float like a cork bobber. are you going to have to some sort of gear like a 2to1 or just play with different props

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the outboard i intend to use already has a 2/1 ratio (normal lower end for an outboard), the electric motor has a top speed of 6000 rpm where the gas engine that was supposed to power the prop had 5500 so i will be already in the right direction. later i will change the prop for a new one probably with a higher pitch as well.

Have you considered using a salvaged car battery? The 2013 leaf has a 21kwh battery. Some already have cooling solutions.

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I have tough about some Tesla cells but my bank account is disagreeing on that...
The problem that i have with the leaf packs is that they are way to heavy for me i would like to stay under 100 KG for the whole pack. i see on the interwebs that a leaf pack weighs in at 650 lbs or +- 325 Kg :? thats just to much for this little boat

This is one of my other boats that i have restored, the one of the lake type and a completely different hull type.
The pics from b4 are the rough shape of the boat below you can find how it will turn out (except for the electrical part 8) )

Btw this project will become way more sexier i am sure of it.

https://barqo.co/en/boat-rental/flying-finn-classic-boat-met-cabriokap-en-dektent-klassieke-sloep-summertime-1957

You have some nice projects 8)

A whole Leaf battery may be too large/heavy but it is made of many individual 60Ah modules. You can use as many as you like. There are similar sized cells available from other cars. Electric car cells tend to be large, capable of relatively high discharge and have long life. The price can also be good for used cells. Instead of thousands of spot welds and custom battery casing you can bolt together 10/20/30 large, strong modules.

Just an idea to consider

Thanks Punx0r!

I am looking into using some cells from an electric car, the ones around me (the Netherlands) are at the same price level of new cells so than id rather make my own. maybe something affordable pops up.

, yes,.. do not underestimate the work, time, cost, effort, etc,...involved in assembling a 1700 cell battery pack.
I suspect the probability of a few problems occurring are not insignificant.
Much simpler to repurpose a professionally built EV pack,..in particular a small pack from a PHEV pack of 10-12 kWk such as fitted to the Outlander , Prius PHEV, and various other similar vehicles.
They have prismatic Panasonic cells with screw terminals that can be reconfigured for voltage/ah preferences.
For example..
[youtube]Gf9fDbwF1K0[/youtube]

The Smart four-two EV battery might also be usable and might be more available in or around NL. I agree the price for used batteries needs to be sensible and shouldn't cost the same as new 18650 cells. Perhaps try German ebay?

For a boat you could also consider a LiFePo4 battery pack. It is heavier than 18650 LiIon but easier to build a pack. And safer with much longer life.
https://www.ev-power.eu/Winston-40Ah-200Ah/

There's a topic somewhere on the forum about used EV batteries and their specs. I would definitely be looking at those vs. a gigantic 18650 build. Leaf modules are very easy to work with and readily available. Chevy volt cells are probably the next most available. Build what you need using the modules/cells.

SlowCo said:

For a boat you could also consider a LiFePo4 battery pack. It is heavier than 18650 LiIon but easier to build a pack.

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"easier" depends on what cells you use; easier than 18650 certainly.

but leaf ev modules and eig nmc cells, among others, are at least as easy, perhaps even easier, to build packs from, than those winston/calb/thundersky/etc modules.

do not underestimate the work, time, cost, effort, etc,...involved in assembling a 1700 cell battery pack

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Well yes... you are totally right, the hours are not worth the costs.
I have done some comparising between all the different battery systems that i can use for my ''little'' project.
The outcome is that i have change my mind on the 18650 project, instead i will go for Lifepo4.
In about 2 weeks i will place a order for 64 Lifepo4 cells with a capacity of 150 amps each comming at a whopping weight of 3kg each. (weight is most important 2nd is the ''safety'' part)

The configuration will probably be something like 26S 2P resulting in a weight of +- 150kg. The battery capacity will be around 25kw.
The ones that i have left will be used for upcomming projects and/or sold. price tag of the cells --> a little over 6000 euro incl shipping.


Anybody intrested in a li-on bms 300amps 32S
If i remember correct Lifepo4 charging is also CC-CV correct?

A used 20KW car battery would go for around 3500-4000 euro than id rather buy them brand spanking new.
Now on the hunt for a lifepo4 bms capable of 300 amps+ and prefferably 32S. i maybe go to 32S2P but i want to first get the whole thing floating and do some test runs with the weights of the battery pack, motor and boat handeling etc...

I'll try to upload some screenshots of my excell comparison sheets that i've used to determine my choise.

Here they are:

*just one note, all of the cell prices are incl tax and removal supplements if i would have bought these they total price you see would go down with about 25% (this depends of each cell).
Only the Lifepo4 costs are what they as they are stated.

Quintino said:

Anybody intrested in a li-on bms 300amps 32S
<snip>
Now on the hunt for a lifepo4 bms capable of 300 amps+ and prefferably 32S.

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if your previous pack design was to be 32s, with li-ion, it would have been 118.4v nominal, since they're usually 3.7v average.

to get the same nominal voltage (so your controller gets the correct voltage for it, and the motor will still be able to spin as fast to give you the thrust you're after) with lifepo4, you must use at least 37s, since they're only 3.2v average.

37s will also have around the same peak voltage, at 135v (3.65v/cell), vs the li-ion at 134.4v (4.2v/cell), so you can use the same charger, if it's slighly adjustable.


however...in your first post you say it's going to be 28s li-ion, which is 103.6v nominal, and 117.6v full.

lifepo4, for the same basic nominal and full, would be 32s for 102.4v and 116.8v.

Quintino said:

In about 2 weeks i will place a order for 64 Lifepo4 cells with a capacity of 150 amps each

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capacity is not measured in amps. it's amp-hours (ah). it is an extremely important difference, that could make or break your project if you don't understand it and watch out for it in the cell specs.

amps (a) is capability, not capacity.

a cell can have a capacity of 150ah, but be unable to deliver even 100a (amps). amp capability depends on it's c-rate, which gives the amps (a) by using the ah x the c-rate, usually listed as 0.5c, or 2c, or some number like that. if they are 2c cells, then a 150ah cell can provide 300a. if they are 0.5c cells, then a 150ah cell can provide 75a.

The battery capacity will be around 25kw.

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again, capacity is not measured in kw, but in kwh.

kw is capability, not capacity. keep this in mind when looking at cell specs so you don't end up with a pack that can't deliver what you need (be that enough watts for the max power your system needs, or enough watt-hours for the range you need).

Quintino said:

I have done some comparising between all the different battery systems that i can use for my ''little'' project.
The outcome is that i have change my mind on the 18650 project, instead i will go for Lifepo4.

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you don't say which specific cells you're going to use, but since lifepo4 comes in 18650 format as well as several others (just like the other chemistries do), i'm assuming you're probably going to use a form of large-capacity prismatic or pouch cell to end up using fewer cells for the same capacity and capability pack you'd've built from the li-ion 18650 cells.

so some general advice:

pouch cells of any chemistry (including those encased in plastic bricks) generally require compression placed evenly over their largest surfaces. without this they may swell up during use, and cause internal damage to themselves, or even rip the pouches off the electrical connections (or tear the pouches open). so design your battery casing with this in mind. there should be a psi or kg/m2 spec in the spec sheet for the cells, to know how much compression to go for.


some of these large-format cells have bolt-on terminals, making interconnection easy. some of them just have tabs, which means coming up with a connection system. if yours are the latter type, there are a number of threads that explore these.


regarding bms, you don't have to use a bms capable of the current you're after. you can simply use a small one and then build a circuit driven from the fet gate circuitry on the bms to operate a contactor. it might be a little more complex to design and build, but it might be cheaper, depending on the contactor cost, since the bms is likely to be significantly cheaper and smaller.

You are right, to ease you mind all the differences regarding the capacity capability c-rate etc... are well known to me. I am not really known to my spell corrections so please excuse me 8)

If you go to my lifepo4 pdf you will see a comparison between cylindrical cells and prismatic cells, you assumed right that I will be using prismatic cells. I am quite sure that there aren't even cylindrical cells of 150 amp... Hours

To come back on your calculations about voltages - - > if I recall correct I stated in my opening post that I've already got a bms capable of 32s and 300amps. I also stated that I was thinking of making a pack with 28s which would result in 117,2 volts using lion but I do not like the aging of the cells at 100%soc so I would only charge them up till 4.1 per cell resulting in 114.8 volts.

I have the borgwarner gen4 size 6 80volt controller which can handle a voltage of up to 118v. I only wanted to be on the top part of my voltage capabilities due to less amps going through the wires, less thicker wires less heat losses etc etc.

Now i have decided to go for PRISMATIC lifepo4 cells which have a capacity of 150amp/h at 3.2v (nominal) I will make a pack of 26s2p due to the c-rate of the cells (continuous 1 and for 300 sec 2)
I also do not want to ask to mutch of the cells that's why the 2 parralel and I want to pull just under 300 amps. Why only 26S you ask? Well due to the weight problem I'd rather have some thicker wires (75mm3) running through the boat than a additional 12 cells resulting in another 40 kg. If I need the capacity I will enlarger the pack but first I want to test the systems.

FYI for the sevcon/borwargner the max is 550 amps so when I have a battery pack voltage of 83.2V nominal with a capacity of 300 amp/h I can provide 24,96 kwh to my motor continuous (which is only capable of 22kw continuous)

Thanks for the tip about the BMS, the cells in question have bolt on connections to make installation easier.

If you find some type mistakes in this message please consider that it is written on a small phone :wink:

how many kw was needed to keep on plane?
please reply to evboats@yahoo.com

Timf1981 said:

how many kw was needed to keep on plane?
please reply to evboats@yahoo.com

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Why should he reply to that email address? Much better to share the answer here so others can also read it. That's what a forum is for :wink: