Sunday, May 31, 2020

Re: [electricboats] Looking to Purchase an Electric Boat

Winfield,  Is that your first or last name?  Anyway, I'll attach some photos of my boat.  It is not anybody's "stock" boat but it is built with known hardware.
Please ask me any questions.  There are two unique things about the boat/propulsion.
1.  There are two 82 lb. Motor Guide standard trolling motors mounted on custom steering bodies.
2.  One reason for twin OB's is the ability to turn by differential thrust.  This did not work as intended with two right hand props (standard Torquedo) .  A left hand matching prop was custom fabricated (scanned and 3D printed).  The boat will turn either direction 180 deg. within it's own length.  And BTW, I could be co-ersed into a Florida delivery.  Have several friends/family down there.
thanks,
Glenn Holland/NC

Sent: Thursday, May 21, 2020 4:16 AM
Subject: Re: [electricboats] Looking to Purchase an Electric Boat

Please also CC me photos
I live in SW Florida on Callosahatchie River on a 400 mile canal system 


On May 20, 2020, at 9:44 PM, Glenn Holland <gholland1@nc.rr.com> wrote:

What are your waters?  I have an electric propelled Redwing 18 Iaunch for sale..  If you give me an email, I've got plenty of photos.
Glenn Holland/NC
gholland1@nc.rr.com

-----------------------------------------

From: abners@iscselect.com
To: electricboats@groups.io
Cc:
Sent: Wednesday May 20 2020 9:34:12PM
Subject: [electricboats] Looking to Purchase an Electric Boat

Hi, does anyone have any suggestions on where I can buy a used GOOD QUALITY electric boat for a good price?
Also open to hearing offers.
Thanks

Re: [electricboats] Ten Socio-Emotional Benefits Of Sailing

Thanks, Jeff.

Just a heads up, the same original post (10 S-E Benefits...). hit another one of my boating groups today under the moniker “Queen Nanu“.  That group had questioned “Faith” after the “Heavy Weather....” post, it appears that there was a quick change in identity. 

So, if “Queen Nanu” is already here, you might want to moderate or remove that account too.

I agree with Larry that it is a shame that the interwebs have come to this.  I believe that our collective digital health relies on eternal vigilance, and we all play a part in that.

Click safely and carry on.
Eric
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Re: [electricboats] 39' sloop conversion

Matt,
Not so sure you would be satisfied with a 12kW system.  Staying at 48v is safer but you would be better served with a motor that more closely matched the design criteria of the boat builder.  Your original diesel was likely about 30-35hp and if you want similar performance a 20kW motor would be a better match.  This is what our computer model suggests:

38ft displacement sailboat (LOA 39ft – LWL 33ft (estimate) - displacement 18000lbs

  • Kts          Watt  (in calm seas)
  • 1.9         28
  • 2.3         48
  • 2.9         96
  • 3.7         192
  • 4.2         288
  • 4.7         384
  • 5.0         480
  • 5.6         672
  • 6.1         816
  • 6.6         10080  This is about the max performance of a 10kW motor - 90% of hull speed
  • 6.7         11040
  • 6.9         12000
  • 7.1         12960
  • 7.3         13920
  • 7.6         15840
  • Hull speed           7.70
Mike
Electric Yacht

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Re: [electricboats] Ten Socio-Emotional Benefits Of Sailing

Hi

I'm the 'owner' of the group.

This post and the person who posted it have been deleted.

Sorry it slipped through.

Jeff Butler
www.plugboats.com

> On May 31, 2020, at 7:45 AM, Larry Brown <elcapitanbrown@gmail.com> wrote:
>
> Anytime I see an outlier message like this that does not make sense that it would be posted to a forum I will not click on the link. Maybe it's software with "somewhat" relevance that can go to multiple groups that is harmless just to get followers. As more people get used to following where the software takes them, the more we suckers get used to it. When they have enough people suckered in the next link will spread malware and possibly one of these ransomware POS groups. I would stick to threads that at least match the subject. Unfortunately these hackers will get so good you won't be able to detect them. IE custom messages crafted for subjects that apply to the forum. Of course I'm highly unlikely to follow links anyway for this very reason. It's a bloody shame this is what the net turned into.
>> On May 30, 2020, at 11:16 AM, fred4936 via groups.io <fred4936=yahoo.com@groups.io> wrote:
>>
>
>
>


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Re: [electricboats] Ten Socio-Emotional Benefits Of Sailing

Anytime I see an outlier message like this that does not make sense that it would be posted to a forum I will not click on the link. Maybe it's software with "somewhat" relevance that can go to multiple groups that is harmless just to get followers. As more people get used to following where the software takes them, the more we suckers get used to it. When they have enough people suckered in the next link will spread malware and possibly one of these ransomware POS groups. I would stick to threads that at least match the subject. Unfortunately these hackers will get so good you won't be able to detect them. IE custom messages crafted for subjects that apply to the forum. Of course I'm highly unlikely to follow links anyway for this very reason. It's a bloody shame this is what the net turned into.
> On May 30, 2020, at 11:16 AM, fred4936 via groups.io <fred4936=yahoo.com@groups.io> wrote:
>

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Saturday, May 30, 2020

Re: [electricboats] Ten Socio-Emotional Benefits Of Sailing

Good article!

On Saturday, May 30, 2020, 06:21:17 AM EDT, Faith Banini via groups.io <faithbanini=yahoo.com@groups.io> wrote:


 
There's something about sailing that makes it quite unlike other sports. More than just skill and strategy, it teaches certain values that shape sailors into the unique athletes that they are.
 
Yet, we're often so focused on the physical aspects of sailing that we forget how much we stand to gain from the sport – both socially and emotionally. So here's a list of the top 10 socio-emotional benefits of sailing
 

Re: [electricboats] Ten Socio-Emotional Benefits Of Sailing

 I can’t see how long Faith has been a member, but her messages have hit many of the boat related groups that I belong to.  The groups are typically hit within a 5 minute window.  The other groups hit are not particularly electric boat related.

Since every one of her messages is just about the included link, as far as I can tell, this is just trolling for clicks.  It might be different if “she” gave any information about her interest in our group, or made a post that was relevant to one of our topics.

Fair winds,
Eric
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[electricboats] Ten Socio-Emotional Benefits Of Sailing

 
There’s something about sailing that makes it quite unlike other sports. More than just skill and strategy, it teaches certain values that shape sailors into the unique athletes that they are.
 
Yet, we’re often so focused on the physical aspects of sailing that we forget how much we stand to gain from the sport – both socially and emotionally. So here’s a list of the top 10 socio-emotional benefits of sailing
 
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Thursday, May 28, 2020

Re: [electricboats] Using online calculators - do they work?

Before I converted, I used http://www.psychosnail.com/boatspeed/boatspeedcalculator to get estimated power at a variety of speeds for my boat, and I looked at two other electric boats for which I had actual data (3 points for one boat and just one for the other). In those cases, the real life boats used 2-3 times less power than the calculator predicted. I applied that factor to the estimated power for my boat, and later took note of the power it really consumed at various speeds. I found the adjusted estimate to be quite good, though the actual was more impacted by speed than the estimate.

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Tuesday, May 26, 2020

Order Request....Trolling Motors






Dear Customer

My name is  Mr.Tom Rogers    and this order is an individual order and i like to make a purchase of a (Trolling Motors) and i will be more happy if you can email me with the size and Prices that you have for sale as well....Please let me know if you do accept credit card as a form of payment, and that will be pick up at your location..Hope to read back from you soon..

With kind regards
 Mr.Tom Rogers   

Monday, May 25, 2020

Re: [electricboats] Using online calculators - do they work?

Props,  several years ago I put the info for my boat in the Vic Prop calculator. 
For a 3 bladed prop it spit out 14×8.8. I put a used 3 bladed 14x10 on her, the 2 bladed 14×11 that came with her was trash.  Last season I went with a 4 bladed 12×12.5 meant for a wake board style boat. Looking at the Vic Prop recommendations to reduce diameter & increase pitch, I'm pretty spot on.  

Performance wise I feel the boat motors better with the smaller diameter prop. It has a ton of bite. Although I didn't pick up any additional speed at the same RPM's, the SOG remained the same
& my wattage dropped. Depending on conditions at 3-3.5 knots, 700 watts. Between 3.5 -4 knots, 1500 watts. I also would like to try out a larger prop, 15" diameter just to see the difference.  I'm retired now so pretty sure my wife would have an issue with that....

One major difference running the wake board prop, I do get regen at speeds over 4 knots. It's not much, 55-100 watts but if you were crossing an ocean it would help.  That's all I know 🤣



On Mon, May 25, 2020, 12:49 PM Eric via groups.io <ewdysar=yahoo.com@groups.io> wrote:
On Mon, May 25, 2020 at 06:29 AM, Larry Brown wrote:
I Wonder if we can use an adjustment formula to his calculator to get a better ballpark for our motors.  Even though he could not come up with reasoning for the discrepancy did he sound interested in it as a challenge or was he just dismissive of us being outliers that represent such a small minority that it's not worth his time to work on?  Or did he seem like the kind of guy that enjoys a challenge and may, at this moment, be tinkering around to examine it and give additional inputs that would accommodate electric propulsion.
The conversation was in 2011 and I haven't heard anything since, so I'm going to go with the "minority" perspective...

Eric

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Re: [electricboats] Time to re-power

Hi James, I've got the 2 powermax units now doing exactly that. 

And Eric, you are spot on. I had not really done the math to carry out the options. I think I need to work on other areas to gain some efficiency with what I have. If we trying to extend range or power up to make a bridge opening on the ICW, I need to just slow back down. We did just finish a cruise down the Florida keys and back, and all in all everything worked fine. 
Thanks guys. Cheers,
Ric
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[electricboats] Common Port or Separate Port BMS

I am converting my 24 volt solar powered boat over to LifePo4 from lead acid batteries. My bank today has a shunt in the negative and through my MPPT solar charger I can monitor power both in and out of the batteries. I only use an external charger at the end of the day so I am at no load condition.
If I switch to LifePo4 and add a BMS I have to make a decision whether to use a common port or a separate port BMS. I want the solar panels to still charge while I do have some load going such as putting along. I am thinking a common port solution would be best but does anyone have an opinion on this?

Thanks

Phil 

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Re: [electricboats] Using online calculators - do they work?

On Mon, May 25, 2020 at 06:29 AM, Larry Brown wrote:
I Wonder if we can use an adjustment formula to his calculator to get a better ballpark for our motors.  Even though he could not come up with reasoning for the discrepancy did he sound interested in it as a challenge or was he just dismissive of us being outliers that represent such a small minority that it’s not worth his time to work on?  Or did he seem like the kind of guy that enjoys a challenge and may, at this moment, be tinkering around to examine it and give additional inputs that would accommodate electric propulsion.
The conversation was in 2011 and I haven’t heard anything since, so I’m going to go with the “minority” perspective...

Eric
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Re: [electricboats] Time to re-power

On Mon, May 25, 2020 at 07:41 AM, Ric Sanders wrote:
I looked up the Elcon line. They want a 230 volt input. I’m trying to not have to rewire my existing generator to that voltage. 
Hi Ric,

To make sure that I’ve got this right, you’re looking for a charger that runs on 115VAC and outputs close to 100A of charging current for a 48V (nominal) DC battery bank.  Let’s do the math...

Charging voltages for a 48V battery run past 56V (above 58V for LiFePO4], but I’ll use 56V for now.  The charger manufacturers often use 66V as max output voltage for a “48V” charger.  100A x 56V is 5600W.  If we assume a 95% efficiency for the charger (most are not that efficient), then the charger needs an input of 6000W or more.  Assuming solid 115VAC input, you’ll need a circuit that supports a 52A load.  Since 115VAC circuits greater than 30A are pretty rare, I doubt that you’re going to find an off the shelf charger that meets your needs.  Most electrical engineers that need more than 3400W (30A@115VAC), go to 230VAC.

So given all that, you are probably stuck with two 50A 48v chargers, if you can find them, on independent 30A 115VAC circuits, if your generator will support them.  

Alternatively, all of the electric boats that I’m aware of that use high output generators to support their electric drives go with DC generators, rather than AC, e.g. the Lagoon/Solomon catamarans.  This eliminates the added components, wiring, and losses related to converting from DC to AC and back to DC and gives a more efficient serial hybrid mode like you have described.

Boats like mine are using their onboard chargers as emergency backups, using what is already there, to avoid installing specialized equipment to support a dedicated hybrid drive system.  And as I’ve stated before, I haven’t needed the serial hybrid capabilities in the 10 years since converting to electric.

Fair winds,
Eric
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Re: [electricboats] Time to re-power

FYI. Thundersky was sold to SinoPoly whose cells are readily available. And Winston, former owner of Thundersky now markets cells under his own name. 


On May 24, 2020, at 3:06 PM, Eric via groups.io <ewdysar=yahoo.com@groups.io> wrote:

Unfortunately, that isn't really an option.  I put this all together 10 years ago, and most of what I bought is no longer available.  Thundersky stopped making prismatic cells, but there are a number of other reputable manufacturers that still do, like CALB.  ElCon no longer makes the PFC 2000+ charger, although the still available PFC 2500 will produce almost 90% of the charge of the 2000+ when powered by 115V A/C.  The EVPower mini-BMS modules are no longer made, there were other manufacturer's versions, but even those may be gone now.  There are plenty of other BMS solutions, you pick the features and price that meet your needs.  But the E-xpert Pro HV monitor is still available, I saw a listing on amazon for about $250.  

You should also consider very heavy gauge cabling for your battery pack (see my photo album referenced in another post). I bought the cabling and hardware to make my own cables from genuinedealz.com, they've got great prices on marine quality wire.  I used 2/0 cable for all of my main current connections.  The bigger the wire, the lower the resistance (losses) over distance, and therefore, the greater efficiency of your system as a whole.

Fair winds,
Eric

PS, I didn't know anything about any of this when I started my project, and the help I got early on was limited.  But I figured out what my questions were, learned what I could here and from other groups; DIY electric car builders, boat builders, battery manufacturers, electrical engineers, etc. and figured out my own answers.  My credentials? I've got none, no college degree, just a smattering of practical experience in a wide variety of interests.  This is just a hobby for me.

On Sat, May 23, 2020 at 08:49 PM, fred jelich wrote:
How much to duplicate your setup? I don't know enough about it to try to build it myself.

On Sat, May 23, 2020, 2:31 AM Eric via groups.io <ewdysar=yahoo.com@groups.io> wrote:
Hey Fred,

Here's a post that I made a few years ago about my LiFePO4 battery bank:

01/26/17   #28070  

My battery pack is 16 Thundersky 160Ah cells in series with Mini-BMS modules from EV Works on each cell. My experience lines up with Jason's. Minimal draw over long storage periods. I have measured cell performance through annual controlled deep discharge and recharge cycles since the pack's installation in 2010. There has been minimal capacity degradation over the last six years, however, the cells are still outperforming their manufacturer's specs. I have adjusted my E-Xpert Pro battery monitor to account for my overall self-discharge rate, I believe that my present setting of 2.6%/month is very close. That rate includes the effects of the BMS cells.

I have stored my batteries starting at states from 100% down to 60%. As I stated earlier, the cells are still outperforming their stated specs. It does not appear that leaving them at 100% for months at a time has had any measurable effect. That said, maybe it has cost me something in cycle life. Since I am still under 100 cycles after six years, I doubt that I will get the chance to observe a small percentage reduction in the stated 2000+ cycle lifespan.

After owning this battery pack for 6 years, I am a solid proponent of the technology. Previously, the average lifespan of a lead acid battery in any intermittent duty has been something less than 3 years for me, in spite of my well intentioned, but apparently inadequate, attention to battery maintenance. This includes classic cars, utility vehicles and my boats.

I have found LiFePO4 cells to be lighter, smaller, take less attention, and safer than the various types of lead acid batteries (wet, AGM, gel). I have blown up a wet cell L/A battery with a trickle charger. This lead to extensive corrosive damage, luckily, the car and my garage did not catch fire. For me, the lithium cells have already proven to be cheaper, based on my personal history, I would be getting ready to buy my third set of lead acid batteries for my boat. That would offset any cost savings that I would have gotten during my initial install.

I purchased my cells and BMS in 2009 for just under $0.45/Wh, including shipping and taxes, which is still an excellent deal today for new, not used or reclaimed, product. So for those of you that are waiting for the prices to drop 20% in the year or so as promised by "experts", I can tell you that they were saying the same thing seven years ago. Maybe Tesla and cordless drill manufacturers are saving money, but those savings have never materialized for small volume, end user customers like us. That said, the prices have been stable while most things have been affected by inflation, so that is a net effect of getting relatively cheaper. Bottom line, other than your ability to afford the initial purchase, it is my belief that every other concern with LiFePO4 batteries that has been listed here recently, is really not an issue in the real world.

This is all based on my first hand experiences. Good luck with your decisions.

Eric
Marina del Rey, CA
1964 Cheoy Lee Bermuda 30, 5KW Propulsion Marine drive, 8KWh LiFePo4 battery pack.

Re: [electricboats] Time to re-power

One option you might consider is find a charger that does half the current you want and gang two of them together.  It may be easer to find two 50 amp chargers then one 100 amp charger.  Most chargers have no issues being run in parallel. 

On May 25, 2020, at 10:41 AM, Ric Sanders <rsandersemail@gmail.com> wrote:


I looked up the Elcon line. They want a 230 volt input. I'm trying to not have to rewire my existing generator to that voltage. 

I love the Victron line and use their charge controllers on our solar. I have a 2k inverter charger on our house system which is completely separate from the motor system so do not need another inverter. I've not found a Charger only yet to do what I desire and am still looking. I'm just beginning to get to where we can do some more extensive runs to find amp draw versus speed. With the limited ability we have to put power into the system, longer runs have so far been impractical.
Thanks guys
Ric


On Sat, May 23, 2020 at 3:26 PM Ric Sanders <rsandersemail@gmail.com> wrote:
Thank "Powermax" 48 volt 20 amp chargers powered from a 6KW 120 volt AC output generator set but I would really like to do is be able to put about 100 amps into the battery/motor circuit. 
Cheers,
Ric

Re: [electricboats] Time to re-power

I looked up the Elcon line. They want a 230 volt input. I'm trying to not have to rewire my existing generator to that voltage. 

I love the Victron line and use their charge controllers on our solar. I have a 2k inverter charger on our house system which is completely separate from the motor system so do not need another inverter. I've not found a Charger only yet to do what I desire and am still looking. I'm just beginning to get to where we can do some more extensive runs to find amp draw versus speed. With the limited ability we have to put power into the system, longer runs have so far been impractical.
Thanks guys
Ric


On Sat, May 23, 2020 at 3:26 PM Ric Sanders <rsandersemail@gmail.com> wrote:
Thank "Powermax" 48 volt 20 amp chargers powered from a 6KW 120 volt AC output generator set but I would really like to do is be able to put about 100 amps into the battery/motor circuit. 
Cheers,
Ric
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Re: [electricboats] Using online calculators - do they work?

This is brilliant, as far as I can tell.  :-). I Wonder if we can use an adjustment formula to his calculator to get a better ballpark for our motors.  Even though he could not come up with reasoning for the discrepancy did he sound interested in it as a challenge or was he just dismissive of us being outliers that represent such a small minority that it's not worth his time to work on?  Or did he seem like the kind of guy that enjoys a challenge and may, at this moment, be tinkering around to examine it and give additional inputs that would accommodate electric propulsion.

Although I've presented these questions, I know I'm an outlier in our group too because I have a trimaran which makes me even more of an odd bird.  So I wouldn't expect to get better than a ballpark of what my performance might be.

If money were no object I would buy a a series of variable pitch props at various sizes up to 18" max (my boat's limit) and run power, speed and draw tests through the water and provide data on each size at each speed for economy and emergency range at highest speed etc.  I would love to do it.  I wonder if we put together a fund between us to donate to the cause and approached some of the propellor manufacturers with variable pitch props to see if they would accept the money as "rental" for a range of props for this test.  I could run them and if we found a few more boats, catamarans and monohulls of a few sizes that could conduct the same tests.  We could ship them so they could come up with the raw data as well and generate purchase guides for the manufacturer's resource as well as our own.  I know it probably sounds crazy but it sure would be cool to get that data.

If anyone else would be interested in participating in such a thing, post away.  Who knows, maybe I could get a manufacturer to do it at no cost.  I would be surprised but you never know.  Some people love this stuff as much as we do.  For that matter, if anyone has any contacts for such a company that they think would be interested message me direct.  Our addresses are used in our email response addresses before the @ sign.

I admit this is probably a pie in the sky idea, but crazier things have happened.  Why not?

Thanks

Larry brown
S/V Trident

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On May 24, 2020, at 1:28 PM, Eric via groups.io <ewdysar=yahoo.com@groups.io> wrote:

Before I get to the calculators that are relevant to an electric boat conversion project, let's discuss the purpose of the calculators and how they work.

There are all sorts of calculators available, ones to plan retirement, manage our weight, make home improvements, etc. etc.  All of these calculators are based on known values and assumptions for the values that are not known, put into formulae that calculate the interaction of the data input and produce an answer to whatever question that we asked .  We use these calculators to predict future performance of a new system or changes to an existing system. This allows us to try different components or actions and see how those changes might influence the outcomes.  These calculators are limited by both the quality of the data, i.e. accuracy of the known data and validity of the assumed data, and the quality of the formulae in modeling results in the real world.

Simple calculators using only known data work very well, like converting standard measurements to metric, there are single constants and they always work.  Calculating miles per gallon is done with measured input, but the results are dependent on how accurate the distance (miles) or consumed resource (gallons of gas) are measured.  Estimating your retirement wealth 20 years in the future is harder, because the assumptions of available income, investment returns, and inflation are guesses at best.

We can validate how well a calculator works by checking the predictions against objective measurements of the system after implementation.  A 59" board will measure to 150cm every time (149.86cm to be more precise).  If my car gets 39.6mpg (2014 VW Jetta Sportwagen TDI) and I plan a trip of 500 miles, I should use 12.7 gallons.  But traffic, terrain, and how the car is loaded, influence the outcome, so the real answer might be +/- up to a gallon (36 to 42 mpg) and I would find that acceptable.  Alternatively, I could make assumptions about the additional influences and add them into the formulae in an effort to make the prediction more accurate, but at some point there are diminishing returns for the additional effort and complexity. 

Ok, so what about the calculators for our boat conversions?  They predict power needed, suggest components (like props) and predict performance of your completed project.  Some of these calculators are based on very complex models of hydrodynamics and some assumptions of how power is translated into movement.  These calculators work fairly well for their intended audience, boats being powered by internal combustion engines operation near 90% throttle (look, we've already made some specific assumptions).  And we know that they work fairly well by checking the predictions against the thousands of boats than meet that criteria.  We can tell if a boat is under-powered, and nobody is particularly concerned about an overpowered installation.  But even then, picking a propeller is still more of a fuzzy art, than a science, and dialing in a propeller selection when you don't have an identical example installation is still often trial and error.  Still, thousands of boats are re-powered with diesel or gasoline inboards and outboards every year and the owners are usually satisfied with the outcome, i.e. the resulting performance is close enough to the calculated predictions.

Unfortunately, these calculators don't work very well for our projects.  Most of these calculators today are based on the work of Dave Gerr who published "The Propeller Handbook" almost 20 years ago.  It is an excellent reference and many of the guidelines and suggestions are as true for us as other boats.  But, in my experience, the "power needed" predictions are not even close for our use case.  In the case of the Vicprop calculator, it predicts that my boat needs 15hp at the propeller to motor at 6kts, and that 7hp will only push the boat to 4.5kts.  You can see my measured performance results in other posts.  The energy used is measured as it comes out of the batteries, before any losses in the cabling, controller, motor, gearbox, or bearings, therefore, the power available at the propeller must be less than the power coming out of the batteries.  Let's check the predictions against my measurements.  I'll be using the simple conversion of 1hp = 746W to translate between the two values.

my boat at 6 kts:
prediction: 15hp (11,190W) at the prop
measured: 7hp (5200W) at the batteries
result: calculator predicted 115% more power needed and any losses between my batteries and propeller makes that worse.

My boat at 4.5 kts:
prediction: 7hp (5200W) at the prop
measured: 2.1hp (1600W) at the batteries
result: calculator predicted 225% more power needed and again, my system losses would make the error greater.

We can see that as we slow down, the calculators get more inaccurate.  I did have a conversation with Dave Gerr about these discrepancies, and he and I agreed that his formulae work for what they are intended for, and that they appear to not work for for our specific use case.  We did not come to any conclusions about the cause of these discrepancies or adjustments to make for our use case.  

I know that in this age of information, we want straightforward answers to what seem like straightforward questions.  But, recognize that we are outliers in the world of naval architecture and marine engineering.  For some of it, we're on our own.  Which is why we're in this group, right?  We're breaking new ground together.  Which is why I believe it is so important to go beyond "it works!" or "I'm happy" and really measure our results, share those findings and work together to figure this all out.

Whew! that was more than I had intended...

Fair winds,
Eric

Sunday, May 24, 2020

Re: [electricboats] Time to re-power

Unfortunately, that isn’t really an option.  I put this all together 10 years ago, and most of what I bought is no longer available.  Thundersky stopped making prismatic cells, but there are a number of other reputable manufacturers that still do, like CALB.  ElCon no longer makes the PFC 2000+ charger, although the still available PFC 2500 will produce almost 90% of the charge of the 2000+ when powered by 115V A/C.  The EVPower mini-BMS modules are no longer made, there were other manufacturer’s versions, but even those may be gone now.  There are plenty of other BMS solutions, you pick the features and price that meet your needs.  But the E-xpert Pro HV monitor is still available, I saw a listing on amazon for about $250.  

You should also consider very heavy gauge cabling for your battery pack (see my photo album referenced in another post). I bought the cabling and hardware to make my own cables from genuinedealz.com, they’ve got great prices on marine quality wire.  I used 2/0 cable for all of my main current connections.  The bigger the wire, the lower the resistance (losses) over distance, and therefore, the greater efficiency of your system as a whole.

Fair winds,
Eric

PS, I didn’t know anything about any of this when I started my project, and the help I got early on was limited.  But I figured out what my questions were, learned what I could here and from other groups; DIY electric car builders, boat builders, battery manufacturers, electrical engineers, etc. and figured out my own answers.  My credentials? I’ve got none, no college degree, just a smattering of practical experience in a wide variety of interests.  This is just a hobby for me.

On Sat, May 23, 2020 at 08:49 PM, fred jelich wrote:
How much to duplicate your setup? I don't know enough about it to try to build it myself.

On Sat, May 23, 2020, 2:31 AM Eric via groups.io <ewdysar=yahoo.com@groups.io> wrote:
Hey Fred,

Here's a post that I made a few years ago about my LiFePO4 battery bank:

01/26/17   #28070  

My battery pack is 16 Thundersky 160Ah cells in series with Mini-BMS modules from EV Works on each cell. My experience lines up with Jason's. Minimal draw over long storage periods. I have measured cell performance through annual controlled deep discharge and recharge cycles since the pack's installation in 2010. There has been minimal capacity degradation over the last six years, however, the cells are still outperforming their manufacturer's specs. I have adjusted my E-Xpert Pro battery monitor to account for my overall self-discharge rate, I believe that my present setting of 2.6%/month is very close. That rate includes the effects of the BMS cells.

I have stored my batteries starting at states from 100% down to 60%. As I stated earlier, the cells are still outperforming their stated specs. It does not appear that leaving them at 100% for months at a time has had any measurable effect. That said, maybe it has cost me something in cycle life. Since I am still under 100 cycles after six years, I doubt that I will get the chance to observe a small percentage reduction in the stated 2000+ cycle lifespan.

After owning this battery pack for 6 years, I am a solid proponent of the technology. Previously, the average lifespan of a lead acid battery in any intermittent duty has been something less than 3 years for me, in spite of my well intentioned, but apparently inadequate, attention to battery maintenance. This includes classic cars, utility vehicles and my boats.

I have found LiFePO4 cells to be lighter, smaller, take less attention, and safer than the various types of lead acid batteries (wet, AGM, gel). I have blown up a wet cell L/A battery with a trickle charger. This lead to extensive corrosive damage, luckily, the car and my garage did not catch fire. For me, the lithium cells have already proven to be cheaper, based on my personal history, I would be getting ready to buy my third set of lead acid batteries for my boat. That would offset any cost savings that I would have gotten during my initial install.

I purchased my cells and BMS in 2009 for just under $0.45/Wh, including shipping and taxes, which is still an excellent deal today for new, not used or reclaimed, product. So for those of you that are waiting for the prices to drop 20% in the year or so as promised by "experts", I can tell you that they were saying the same thing seven years ago. Maybe Tesla and cordless drill manufacturers are saving money, but those savings have never materialized for small volume, end user customers like us. That said, the prices have been stable while most things have been affected by inflation, so that is a net effect of getting relatively cheaper. Bottom line, other than your ability to afford the initial purchase, it is my belief that every other concern with LiFePO4 batteries that has been listed here recently, is really not an issue in the real world.

This is all based on my first hand experiences. Good luck with your decisions.

Eric
Marina del Rey, CA
1964 Cheoy Lee Bermuda 30, 5KW Propulsion Marine drive, 8KWh LiFePo4 battery pack.
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