# Opinion of best choice for marine conversion



## boekel (Nov 10, 2010)

What kind of boat is it?

Probably a forklift motor is good, as long as you have a low-rpm one.

We've converted a boat some time ago:
http://www.diyelectriccar.com/forums/showthread.php/boekels-boat-project-55318.html

A lot depends on:
the boat itself, can it handle weight (lead acid batteries or lithium), do you need constant power or only slow cruising and some extra power for maneuvering, expected use (range, charging) etc.


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## Kurtjfred (Mar 4, 2017)

Thanks for the Reply Boekl. 

It's 35 foot sailboat. I am removing over 350 lbs of engine and transmission

Putting in a large battery bank regardless of which engine is installed. diesel or electric Batteries are primarily for house bank use, lighting and electronics, with solar/wind charging and a 6kw generator as a backup and when desalinating water and running air compressor for filling scuba tanks. 

The motor needs are minimal HP and primarily short duration such as in anchorages, mooring or entering/exiting harbors and marinas. 

Safety reasons as fighting wind/current to get out or stay out of harms way is where the peak horse power/torque comes in to consideration. But just like flying small airplanes, planning and awareness can avoid that need. 


Pleasantly surprised to find lots of motors to chose from that meet the needs with a few suggestions in Private Messages. I take it vendors are not to be promoted on here. Wanting a direct drive was to keep the moving parts and maintenance less if possible. 

Would very much like to go with Lithium batteries but have yet to find anything close to the cost of AGM lead batteries


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## boekel (Nov 10, 2010)

second hand Tesla / Ampera battery modules aren't far from the price of good new AGM batteries...


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## nucleus (May 18, 2012)

There was a recent thread on sailboat conversions.

Beware LA AGM batteries, the specs are misleading. You lose so much capacity so fast that lithium are actually cheaper. Volt modules could be perfect for you.

Also, like I mentioned on the other thread, I would never use a brushed motor in a marine environment. You don't want sparks, and you don't want your commutator oxidizing. 

HPEVS will even build you a sealed motor if you want.

http://www.hpevs.com/hpevs-ac-elect...torcycles-mining-vehicles-hydraulic-pumps.htm


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## boekel (Nov 10, 2010)

our brushed motors have been under water at least 4 times (sometimes while running), are always in a damp environment and still do fine.

But...
it's primary use is on fresh water, no sea water involved.
it's an open boat (hence the flooding from time to time when the bilge-pump stops working)

don't know about the sparks, I'd assume the engine bay will be separated from the rest of the boat, and a gas leak detector is probably already there?

Just my 2ct


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## Kurtjfred (Mar 4, 2017)

Thanks for jumping in Nucleus.

Over the years I have met a few people in the Lead Acid battery industry and most will tell you its full of unscrupulous types. Entertaining to read the Trojan versus US Battery rivalry when they start bad mouthing each other.

I look at the users to get a better idea of what some of us were looking for when we put solar chargers and battery banks in our RVs and when living on 160 acres off the grid. Had 10 thousand pounds of scrap lead and even considered trying to build some homemade large stationary batteries ourselves. 

Built a few golf courses and saw firsthand what superintendents were using when maintaining fleets as well as a couple of friends who own and use lots of electric forklifts and tugs in their businesses. Heavy construction equipment fleet manager at my employer of 30 years added a little insight as well. Plenty of access to the real world results one can expect when comparing and I have decided to to go with the Northstar group 31 AGM instead of the Odyssey TPPL that the Coast Guard has had zero failures with. Northstar is using NEW lead, some refer to virgin lead and the bulk battery distributors in Northern California speak highly of them. 

As much as I would like to go with Lithium, I've spent too much time looking at inaccurate advertising and trying to find a trustworthy battery bank without spending 3 times what I can get the AGMs for. And I have met enough of the con artists selling salvaged as new. 

I would actually entertain building my own lithium battery if I felt I could get the information to teach myself and the cost savings would justify it. I love sweat equity.


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## Karter2 (Nov 17, 2011)

Do you actually have an idea of what capacity pack you will need/want.?
Whatever the requirements are, you cannot avoid the basic facts that a Lithium pack will take up half the space and weigh under half the weight of an AGM pack of similar useable capacity
Its also well known that lithium will outlast AGM by a factor of 2 at least.
Sadly, not all "Battery Specialist" sources are well informed about the pros and cons of various lithium options.
So yes, sourcing suitable packs is not as convenient as AGM, but there are definite advantages if you can benifit from them.
Volt or Leaf modules should be on your list of possibilities.


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## Kurtjfred (Mar 4, 2017)

Thanks for the input Karter 

Putting in a minimum of 9.6 kw and I am seriously considering doubling it 

Plenty of room and can easily accommodate the weight, I considered the lithium because the less bulk, the less modifications to accommodate But I will be doing some fiberglass and carpentry work regardless 

Spent most of my efforts trying to locate a trustworthy source for the Chevy Volt battery at a doable cost. 

Decided that if I take care of the AGMs, they will last long enough doing what I want from them for under 20 cents a watt. 


On a mission trying to find a good Smart charger for the AGMs now And that I will say I know little about. Programmable or off the shelf with enough current capacity and the correct voltage. In over my head a bit I think


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## boekel (Nov 10, 2010)

If you have space to put them...2v cells from a forklift can be very affordable, and better than any AGM...



















I purchased this 48v / 775Ah battery 3,5 years old, little used for just 750 euro's. It came from a broken forklift. Also purchased the motors...



















This is also going in a (small, 7m) boat, plenty power...


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## Karter2 (Nov 17, 2011)

1350 kg of battery is quite an addition to a 7 m boat !
...FYI , a comparable Li pack would be less than 300kg !


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## boekel (Nov 10, 2010)

Karter2 said:


> 1350 kg of battery is quite an addition to a 7 m boat !
> ...FYI , a comparable Li pack would be less than 300kg !


Yes sorry, motor is going into a 7m boat, not this battery 
together with 4 Tesla modules...

Some 7m boats wouldn't have a problem with 1350kg btw, another 7m boat I added an 800kg battery, whilst removing a 350kg diesel engine and 500kg of concrete ballast...

this is where the big battery is used:
http://boekel.nu/foto/16/2016-12boot/image107.htm


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