Are Lithium batteries becoming realistic?

[Colvic Watson]

We have a bank of lead acid batteries totalling 420AH and that gives us a realistic actual bank of 190AH - based on a cruising lifestyle where we'll not get past 90% charge except with a marina shorepower stay and never dropping below 50% so that we don't quickly knacker the batts.

Based on about £120 each that means the cost per usable AH is £2.52. Then factor in the short life expectancy of 5 years, the huge weight and the long charge time. Lithium batteries are now easily available in sizes of 90AH and the cost is £675 each. Two of those gives me the same battery capacity, they weigh a tiny fraction so they can be put almost anywhere, last longer and are much quicker to charge. The AH cost is £7.50 or about three times the cost of lead acid - in other words the numbers are getting closer - what other issues are there?

 

[northwind]

Ask Boeing...

http://en.wikipedia.org/wiki/Boeing_787_Dreamliner_battery_problems

 

[sarabande]

water. Lithium doesn't like it.


I spent a merry day on the M5 some time ago managing the emergency services response to a lithium battery fire in a batch of ex helicopter batteries from Yeovilton. It took a lot of persuading to stop the FB using hose reels.


They are a serious, very serious, fire hazard unless managed in a very technical way. I'd stick with familiar lead-acid, or AGM technology, and look at options for maximising your present battery-charging regime. You are unlikely to have the storage space or electrical capacity constraints which can justify lithium.

 

[KellysEye]

They have also caught fire in phones and computers. Fires are rare but I wouldn't risk them on a boat.

 

[Greenheart]

How many electric cars are on our roads today? I thought they used lithium cells, without incident. Aren't there various types of lithium battery, with differing degrees of volatility?

 

[Colvic Watson]

Indeed - and water is as likely to get in a car as in a sealed compartment on a boat.

 

[Greenheart]

So...does that show that Lithium batteries are a good evolution, or not?

Lighter weight of batteries would really open the door, assuming they're not actually dangerous or astronomically costly.

 

[maxi77]

water. Lithium doesn't like it.


I spent a merry day on the M5 some time ago managing the emergency services response to a lithium battery fire in a batch of ex helicopter batteries from Yeovilton. It took a lot of persuading to stop the FB using hose reels.


They are a serious, very serious, fire hazard unless managed in a very technical way. I'd stick with familiar lead-acid, or AGM technology, and look at options for maximising your present battery-charging regime. You are unlikely to have the storage space or electrical capacity constraints which can justify lithium.

So you think Lead-acid batteries are safe. If they were invented today the H&S rules for their use would be horrific I suspect. The basic problem is that stored energy always wants to get out and punishes misuse.

 

[Twister_Ken]

Lighter weight of batteries would really open the door, assuming they're not actually dangerous or astronomically costly.

Considering your average upper class yot drags around several tons of lead in the keel, while a working class one makes do with an equivalent weight of cast iron, a bit less battery weight, low down, is hardly going to open any doors.

 

[Blueboatman]

In one of my -very few- forays into actually asking a question lol on here , I pondered this some 4 years ago.. IIRC fuel cells looked 'better' then and were being used offshore racing..

The big unknown seems to be, how long do you get before you do actually kill a Li-based battery? They don't like cold, and I have yet to get 5 years from one in power tools. At 1-2.5a/h capacity they get very hot too at fast one hour charging speeds.
How would that be in a boats bilges?
Any golf cart Li technology in use?

Do phone batteries go 5 years, which are theoretically quite high end things? Mine don't, and it is recommended they be flattened regularly too..

BUT, to be able to discharge to nothing instead of fussing at a lead acid80%, joy of joys.. I would expect the USA to be ahead in the specific sailing application because of their larger industrial sourcing..Anyone?

Our charging systems seem up to the clever job, just drive everything through a 12-240v pure sign wave inverter and an 'as supplied' charger to ensure regulated charging I guess..

 

[Greenheart]

Considering your average upper class yot drags around several tons of lead in the keel, while a working class one makes do with an equivalent weight of cast iron, a bit less battery weight, low down, is hardly going to open any doors.

Not sure if the class-system enters the question, Ken...I was thinking if weight permitted, lots of 20-25ft yachts could carry as much power as only far bigger ones presently can.

 

[Robg71]

Not all lithium batteries are equal
I am assuming as you stated you were looking at 90ah batteries, your looking at Victron
They are lithium iron.
Boeings undoing was lithium polymer, along with sonylaptops.

10 or 15 years ago,i first started using lithium batteries in small rc model flying.
Instead of ic engines, these batteries, and three phase motors were showing up, with massive current discharge capacity, in short times. I could happily pull 40 amps plus burst out of a 2ah battery They were asounding.
The technology has moved on, and anything that can pack the amount of power in to such a small space is going to have some down side. Its how you manage it. You dont seem to mind producing hydrogen gas in your engine bays these days charging lead acidbatteries.
Its how its risks are mitigated....
Correct battery monitoring is critical...

 

[Colvic Watson]

Further searching shows that a direct import from China is half the AH/£ cost I'd estimated. I like the idea of having a single 60AH Lithium battery and running everything from that with a 75AH lead acid in reserve. That 60H Li-ion is equivalent to about 200AH of lead acid lumps. One thing that would concern me is the solar panels, they couldn't go straight in, a lead acid lump is very tolerant.

 

[northwind]

Not sure if the class-system enters the question, Ken...I was thinking if weight permitted, lots of 20-25ft yachts could carry as much power as only far bigger ones presently can.

But how much power do you actually need on a small boat?

LEDs have made the biggest difference to power requirements, meaning the amount of power actually needed is much smaller.

 

[David2452]

Considering your average upper class yot drags around several tons of lead in the keel, while a working class one makes do with an equivalent weight of cast iron, a bit less battery weight, low down, is hardly going to open any doors.

Oranges are not the only fruit, also yachts are not the only boat.

 

[Robg71]

Check out the victron website, it has some very good white papers and philosophy's for onboard power generation...
Bearing in mind they are also selling the stuff....

 

[ip485]

FWIW I think too much emphasis can be placed on batteries. My sailing vessel is reasonably large, reasonably power hungry, and the battery bank quite sizable - at 800ah. However while extended cruising - a couple of weeks off the grid anyway, even with that capacity it surprised me how easy it was to find the batteries frequently depleted (well moving well towards 50% anyway). I thought a Genset was the answer and with 8Kwh available being off the gird was only a flick of a switch to being back on it - but the Genset is reasonably noisy and surprisingly slow at bring the batteries back up. We are accustom to plugging into the mains and overnight silently, slowly and without knowing the charge comes back. So I have been fortunate enough to be able to install 660 watts of solar panels in two panels on an arch. I wondered whether it would be enough. Well I am delighted to say it seems to be the perfect solution. While sailing during the day the power drain comes from being lazy and using the autohelm almost all the time, the fridge and freezer and the navionics. These run the batteries hard. The solar array even in British conditions on a miserable day at this time of year keeps up with the demand so you go into the evening with close to 100% capacity. Sailing or at anchor a reasonable in road is made during the hours of darkness but probably a bit of motoring deals with that at night if underway, or the usage goes down at anchor, and the solar array quickly recovers the batteries in the morning. So a good solar array will "save" the batteries and enable you to work with traditional batteries and maintain a high level of charge for most of the day. Importantly it all happens silently and constantly in the same way as being on grid.

So the point of the post is whatever your battery arsenal I think the key is how you intend to keep them topped up and so far I have been amazed and pleasantly surprised if you give careful thought to a solar solution just how effective this can be - that is where I'd spend my money rather than on Lithium batteries.

 

[Greenheart]

But how much power do you actually need on a small boat? LEDs have made the biggest difference to power requirements, meaning the amount of power actually needed is much smaller.

LEDs certainly are great...I was reading earlier about the dim recesses of an engine-room that is now made bright by having one of those cheap strips of LEDs round all the corners.

As to how much power is really needed, the answer must certainly be almost nil...but as long as there are powered conveniences that forty-footers enjoy, their denial to 20-footers must relate to the unavailability of sufficient power, largely as a result of lead-acid batteries' massive weight.

I'm still fascinated by electric auxiliaries. I hold out hopes for diesel-electric propulsion in sailing boats - I reckon diesel experts will agree that many sailors' brief use of their engines while getting out of the marina, is not good for the unit's long-term health; but if you had 10kw to play with for fifteen or twenty minutes, you could get off the mooring without starting the diesel. I don't pretend to have worked out any solution to the problems involved, but undoubtedly weight was one of them, and lithium ion cells could be an answer.

 

[Buck Turgidson]

It's an interesting question as to how much battery capacity a small boat needs. I note that the minitransats are limited to 200ah but sailed 2000+ nm last year. To my mind the solution isn't capacity on a small boat but rather generation. An ideal combination of solar + wind+ water turbine should negate the need for a large battery capacity and this along with an onboard fuel based generator whether that be engine driven, genset or a fuel cell should give even a small boat a very long autonomous endurance.

 

[Redshank Evo26]

It's an interesting question as to how much battery capacity a small boat needs. I note that the minitransats are limited to 200ah but sailed 2000+ nm last year. To my mind the solution isn't capacity on a small boat but rather generation. An ideal combination of solar + wind+ water turbine should negate the need for a large battery capacity and this along with an onboard fuel based generator whether that be engine driven, genset or a fuel cell should give even a small boat a very long autonomous endurance.

My boat has a 45ah car battery and a small (18" x 10"') solar panel through a controller to charge it, Outboard motor with no charge coil. That is enough to run the instruments once a week for a couple of hours and having fitted an LED tri colour and LED interior lighting pretty much as many lights as you want! I did have a solar panel connected without a control box previously, but that cream crackerd the battery in 2 years. The only concession I make is to use the hand held VHF most of the time and not to leave to garmin fish finder on all the time as that does seem quite power hungry.