Lithium Batteries (for the rest of us)

[senormechanico]

200 aH lithium bank is the "everything" source on our boat.
They don't even blink no matter what the load.
Watermaker performs better too.

[campr]

So I'm thinking of getting into this LiFePo thing, but I'd like to go cook on electricity and be 'green' about it, so no engine runs during the day if at all possible. Could it be possible to do the heating via electricity? What would one use? A heat pump? Resistive heating? Use the sea to initially heat up the air to make the difference smaller?

The boat is currently equipped with a small windmill generator. It produces around 150W at 20kn. Obviously I will also have to get some solar panels to augment this power, but I have a couple of questions about this LiPo lark:

1. Obviously, I need to do a calculation of the electricity needs, but will the LiPo be able to handle current requirements of heating and cooking (~ 3kW)? Do I need to go to 24V systems to keep the current down and the cables a manageable size?

2. Currently the batteries are stored in the engine compartment. Will the batteries be able to take this kind of heat punishment, and what will it do to their life-span?

3. What sort of over-capacity should be included to account for spells of weather without sun or wind? We will be doing a trip around the world via cape horn and the cape of good hope. Staying in the trade-wind belt as much as we can.

4. Is this actually feasible, or is it crazy?

5. If the diesel-engine ever breaks unrepairibly and I need to re-engine I would like to go electric. I've got a 40ft 9ton Moody (primrose), with a 38bhp (47bhp for short periods of time) thornycroft engine. What sort of electric motor would I need, and above all, what kind of battery pack would I need to be able to putter in and out of harbour?

As you can see, I'm hoping to replace the Diesel elements in the boat, but need a little guidance on what the capabilities of LiPo are.

[skipmac]

So I'm thinking of getting into this LiFePo thing, but I'd like to go cook on electricity and be 'green' about it, so no engine runs during the day if at all possible. Could it be possible to do the heating via electricity? What would one use? A heat pump? Resistive heating? Use the sea to initially heat up the air to make the difference smaller?

Heating as in heat up food to cook it or are you referring to heating the boat in cold weather with electric as well as cooking with electric?

Either or both will use very large amount of electric power. Possible, yes. Practical and cost effective, probably no.

The boat is currently equipped with a small windmill generator. It produces around 150W at 20kn. Obviously I will also have to get some solar panels to augment this power, but I have a couple of questions about this LiPo lark:

1. Obviously, I need to do a calculation of the electricity needs, but will the LiPo be able to handle current requirements of heating and cooking (~ 3kW)? Do I need to go to 24V systems to keep the current down and the cables a manageable size?

With enough batteries and proper wiring you can distribute as much power as you like. Just have to size the system to meet the power requirements.

2. Currently the batteries are stored in the engine compartment. Will the batteries be able to take this kind of heat punishment, and what will it do to their life-span?

Wait for one of the LiFePo experts to comment on this.

3. What sort of over-capacity should be included to account for spells of weather without sun or wind? We will be doing a trip around the world via cape horn and the cape of good hope. Staying in the trade-wind belt as much as we can.

4. Is this actually feasible, or is it crazy?

To heat and cook with battery power on top of your other electric needs is probably closer to crazy than feasible. To have enough battery capacity for this you would need a huge battery bank and a huge charging system to run it. If you plan to do this without running the engine or a generator you would have to turn your whole boat in a solar panel and install wind generators at every corner.

Here's one very basic example. Details simplified and conversion efficiencies, power factors etc ignored for now. If you used one small electric heater, say 1500 Watts. At 12V that would use 3000 amp hours in a day. Yes an electric space heater is not the most efficient but other more efficient heating by electric to heat a 40' boat would use at least this much or more.

5. If the diesel-engine ever breaks unrepairibly and I need to re-engine I would like to go electric. I've got a 40ft 9ton Moody (primrose), with a 38bhp (47bhp for short periods of time) thornycroft engine. What sort of electric motor would I need, and above all, what kind of battery pack would I need to be able to putter in and out of harbour?

38 HP is about 50 KW. Even if you allow for efficiencies and higher torque at low rpm for electric and go for a smaller electric I know of no commercial system of that size. So first you would have to design and build your own system. If you want nothing more than to motor for 30-60 mins in and out of a harbor then maybe 1000-2000 amp hours worth of batteries will work.

As you can see, I'm hoping to replace the Diesel elements in the boat, but need a little guidance on what the capabilities of LiPo are.

You could do all the above but be prepared to shell out many, many thousands of dollars and install so many batteries you will have to move your water line up several inches.

[campr]

Yes, I see your main point, replacing Diesel by electric is going to break the bank (and possibly the boat). 38bhp is ~ 28Kw (it's divide, not multiply). Plus you'de be saving the losses from the gearbox (~30%), so ~20Kw should be OK for most situations.

The reason for doing the cooking electrically is the fact that the gas bottles are difficult to fill from country-country as the fittings and/or testing requirements change Also, carrying an extra type of combustible (fuel) is just a pain. Diesel cookers are just plain expensive, and can only be used for cooking. The electricity can be used for other things (tools, compressors etc etc).

Using a heatpump is like a reverse air conditioning, it removes energy from the outside and moves it into the boat. It can be up to 7x as efficient as direct resistor heating (space heater).

Covering the boat in solar panels has been done, although it's quite revolutionary (and therefore expensive). And also not really feasible for a sail boat, because you need to be able to walk on deck to change sails.

Sounds like it's just too much trouble and too expensive to do at the moment. Maybe in 40 years every boat will have it due to the high cost of Diesel.

[skipmac]

Yes, I see your main point, replacing Diesel by electric is going to break the bank (and possibly the boat). 38bhp is ~ 28Kw (it's divide, not multiply). '

Correct. Have done the calculations for my boat but was trying to do work emails and math at the same time. Guess I'm getting too old to multi-task. And even at 28 KW there's still no commercially made system that I know of that is close to that power. If I recall, 12 KW is the largest I've seen.

Plus you'de be saving the losses from the gearbox (~30%), so ~20Kw should be OK for most situations.

Not just the gearbox but parasitic loads from the alternator, water pumps, etc. But I think 30% is on the high side but then you can factor in the higher torque for electric VS diesel at low speeds.


The reason for doing the cooking electrically is the fact that the gas bottles are difficult to fill from country-country as the fittings and/or testing requirements change

It is a problem. Am planning to cruise EU in a couple of years and have already found out what a pain the different fittings can be. But not insurmountable. I think outside Europe you will run into fewer variations and just a couple of adapters will get you by most places.

Electric cooking, no matter what technology will draw a lot of power. True it will be relatively short time but on top of all the other draws it will add up.

Also, carrying an extra type of combustible (fuel) is just a pain. Diesel cookers are just plain expensive, and can only be used for cooking. The electricity can be used for other things (tools, compressors etc etc).

AC is handy. I have a 2 KW inverter and a 2 KW Honda generator. Don't leave home without it.


Using a heatpump is like a reverse air conditioning, it removes energy from the outside and moves it into the boat. It can be up to 7x as efficient as direct resistor heating (space heater).

Know all about heat pumps. The point is up to 7X as efficient. The colder it gets the more difficult it will be to extract heat from environment. MY parents have a heat pump in their house and below 0 C the efficiency drops dramatically. The power draw jumps plus they have to use supplemental heat. Also, you are running a compressor to run a heat pump and that is going to draw some significant power even in mild conditions.


Covering the boat in solar panels has been done, although it's quite revolutionary (and therefore expensive). And also not really feasible for a sail boat, because you need to be able to walk on deck to change sails.

Sounds like it's just too much trouble and too expensive to do at the moment. Maybe in 40 years every boat will have it due to the high cost of Diesel

Believe me, I would really like to go electric but I came to the same conclusion and draw some criticism from some of the go electric crowd because of it. The biggest objection I have not found any solution to is range. If you will motor more than an hour or three then you will either need huge solar or a generator. Add the gennie and you are right back with running a diesel engine.

[skipmac]

Originally Posted by campr

Maybe in 40 years every boat will have it due to the high cost of Diesel.

One additional comment. No matter what the cost of diesel there is no technology even on the horizon that I know of that gives you portable energy content per weight/volume that you get from petroleum products. Maybe fuel cells for electricity but they still require some kind of fuel.

Know of no technology that will move solar up to the 80-90% efficiency that could dramatically increase power generation per area.

Know of no battery or capacitive storage system that is imminent that will cut battery size/weight by a factor sufficient to give 200-400 mile range under power for a cruising size sailboat.

So for now, electric is a great solution for boats up to +/- 35' that only need enough range to get from the dock to the channel or similar.

[roetter]

Filling Propane
Propane is a little more difficult in Europe, but it can be found. With the proper regulator you can also use Butane, which is more common in Europe.

I bought a European Propane bottle plus the rubber hose connector for their BBQs. I cut the European hose and my NA hose and connected with a simple hose fitting and clamps. I than placed the full bottle upside down with a small hoist and 'decanted' into my NA bottles no problem. Did that for 10 months.


heating
LiFePo batteries can easily supply 1C of current. For 3kW you would need about 230A at 13V to drive the inverter. No problem at all, as you want much more in capacity. I am installing 1400Ah (2x700Ah) LiFePo in my boat next month, plus 1800W of solar. No generator for full time live aboard with water maker, lots of refrigeration, and a 'this is NOT camping' mindset.

I would go for a Diesel heater like Espar for going Cape Horn. If you like to heat just once in a while then go for a heat pump heater like a reversible AC and keep it to a small living space. With good covers you can easily sleep in a 5C (40F) environment.

Good luck. Sounds ambitious, but that is the fun.

[campr]

Thinking of going for 400Ah or 700Ah, with a 123bms system to keep it all balanced. Charging will be done by ~ 400Wp on-deck solar cells and a 200Wp windmill. Chances are we'll add another windmill (higher capacity) and possibly some more solar cells. That should enable us to cook electrically on board (~1000-2000Wh per day) on an induction cooker. Hopefully it will also provide electricity for the fridge 800wh(?) and other lower-consumption items like the navigation computer and depth-sounder.

Maybe even two windmills will be needed to cover our power-needs around cape-horn (where I expect little sun but lots of wind.)

Maybe a prop-shaft driven generator would also be a boon, while underway. I hear some guy in Germany re-wound his car-dynamo to make it generate more power at lower revs.

[Colin A]

There are a few companies out there selling large Electric drive systems.
Elco being one of the more well known names
Quote Request | Elco Motor Yachts

I was also wondering if anyone had looked into Super B batteries, they appear to be another company trying to offer a more bolt in solution.

Super B | Super B

There is a distributor in Florida for them they are expensive but not quite as bad as the Mastervolt or Genesuns.

[skipmac]

Originally Posted by Colin A

There are a few companies out there selling large Electric drive systems.
Elco being one of the more well known names
Quote Request | Elco Motor Yachts

I was also wondering if anyone had looked into Super B batteries, they appear to be another company trying to offer a more bolt in solution.

Super B | Super B

There is a distributor in Florida for them they are expensive but not quite as bad as the Mastervolt or Genesuns.

Hi Colin,

Thanks for the link to the Elco motors. That's one I had not found in previous research. HOWEVER, they suggest their EP-7000 as a replacement for diesel motors of 45-85 HP. List price for the package $15,995.

On top of that I would need to spend more thousands on batteries and if I wanted a cruising range of more than a couple of hours a diesel genset.

So bottom line, my conclusions from previous research on costs to replace a diesel engine with electric with comparable power and range will cost about triple the price of a new diesel engine.

What I can't understand is why these systems cost so much. I looked into commercial grade, constant duty rated motors and they sell for a fraction of that. My wife has a Prius hybrid that has a 60 HP electric motor. I checked with Toyota and a new electric motor would be less than $1000. For about $20,000 you can buy a bass model Prius brand new with gas engine, electric motor, hybrid control system plus air conditioning and seating for 5. So how come a marine electric drive and controller costs almost as much as a whole car?

If because the motor is "marine" grade then sell me the industrial motor for $1000 and I'll buy 3 or 4 of them and swap out if the old one gets rusty.

Sorry, rant now over.

[senormechanico]

The answer is "M & M".

Marine and Medical.

[I.Grind]

Originally Posted by Colin A

There are a few companies out there selling large Electric drive systems. Elco being one of the more well known names Quote Request | Elco Motor Yachts I was also wondering if anyone had looked into Super B batteries, they appear to be another company trying to offer a more bolt in solution. Super B | Super B There is a distributor in Florida for them they are expensive but not quite as bad as the Mastervolt or Genesuns.

I see you also received your free edition of Electric and Hybrid Marine magazine. Battery porn, I love it!

[CharlieJ]

Disclosure: I am a partner in Clean eMarine-Americas; a provider of engineered electric propulsion systems.

Regarding shifting propulsion from ICE to electric; the general rule of thumb is that an electric drive with properly sized prop, will be about 1/3 the hp of the ICE it replaces. IAW; a 12kW electric system replaces an ICE in the 30-40hp range.

We will be introducing a 22kW system (replaces 62-75hp ICE) in the near future.

[campr]

There is one advantage of electric over diesel that seems to be forgotten often.

I can't take a refinery & drilling rig on the boat, but I can take solar cells and windmills.

So for long-term long-distance cruising I prefer and energy source which can replenish itself. Even if the replenishing sources are a bit bulky.

[skipmac]

Originally Posted by campr

There is one advantage of electric over diesel that seems to be forgotten often.

I can't take a refinery & drilling rig on the boat, but I can take solar cells and windmills.

So for long-term long-distance cruising I prefer and energy source which can replenish itself. Even if the replenishing sources are a bit bulky.

But how will you replenish your batteries when they get old and die? You can't take a lead mine or a lithium mine with you.

Seriously, the ability to "refill your tanks" with solar is one of the many reasons I would like to go solar but until the issue of cruising range is addressed I see significant limitations for a cruising boat.

So how do you plan to address cruising range for long distance cruising?