Saving weight

[Aussiesuede]

Originally Posted by Nordic cat

Any reccomendations, or things to look out for?

During the recharge of lithiums in general? The Valence Lithium phosphates are as safe as Lithium can possibly be because the phosphate used would suffocate a fire. With a non-polymer lithium ion there is no way to suffocate the fire, and that's why they have absolutely no place on a boat. But these Lithium Phosphates are actually safer than lead acid in regards to an uncontrolled fire. The problem is if you mischarge them, they'll be completely ruined (no room for error). If you mischarge lead acid, you can destroy cells, but you'll not usually lose the entire battery in one instance, but rather simply degrade it's performance and shorten it's life. With lithium, it's a one time deal. Short out the charge cycle and the battery is toast. But it's impossible for the lithium chargers to actually cause this circumstance. Either they charge correctly, of not at all, as they are completely regulated by a computer circuit with shutoff as the only option to mischarge. So in this regard, the Litium system is truly an install and forget system.

It's like with every thing; There are pros and cons. Unless your primary goal is weight savings and increased capacity -(and you've the stomach for the cost) then it's not yet a battery platform for the masses. But if you're designing an 'Electric', or hybrid platform, then they definitely are worth the look.

[Roy M]

When I built my Searunner, over thirty years ago, it weighed more than it does today, thanks to modern stuff. I traded the Volvo MD2B diesel for a Yanmar 3GM30F and saved over 200 pounds. Going to high-test anchor chain helped me to cut some more. Etc., etc. Jim Brown kept repeating the mantra of GO LIGHTER, to his builders. I have been reducing weight in everything I can as the years go by. Today, unloaded for cruising, yet carrying all my tools and junk, I'm riding at my design waterline. I can't wait to see the difference made when I pull out my old centerboard and replace it with a composite version. Then, there's the removal and replacement of my floorboards with foam/fiberglass and aluminum stringers. The test version was fifteen pounds lighter. My hard dodger will weigh about fifty, as will the Kantola hard dinghy I am about to start building. Someone once told me that a rough gauge to set my cruising waterline was 1" per thousand pounds of payload. It seems correct. I can substitute another case of peanut butter for every floorboard I replace.

[fastcat435]

[QUOTE=BigCat;193363]

Originally Posted by Aussiesuede

The Valence Batteries Gideon referenced are currently the best choice imo and they are Lithium Phosphate Polymer. There are benefits to using Lithium Magnesium Polymer in a larger custom battery bank (ie, full electric instead of hybrid) but the phosphate's are better in the smaller form factors we're accustomed to. The best of the standard form factor magnesium's I've found are the 'Torqueedo's' . The real benefit to magnesium vs phosphate is they don't 'self discharge' when not used. Sit em for a year unused and the power that remains stored is above 90%.

torqeedo: Produktbeschreibung


So, in Torqueedo batteries, apparently, you are limited to a maximum of 332 amp hours at 24 volts for a cost of $2,800, if I correctly understand this link: Torqeedo POWER 26-77 UI BATTERY AND ACCESSORIES (207-2203)

I haven't come upon any pricing for Valence batteries. Where do you buy them?

We purchase them directly from Valence since we purchase many units at a time
The present cost is around USD 1950 each for the type U 27 with 1.6 Kw usable energy for each at a weight of 18.6 kilo or 40 LBS

Greetings
Gideon

[colemj]

Originally Posted by ldrhawke

WEIGHT SAVINGS
NO to yourself as your loading a 6 month supply of beer and liquor onboard.

That's just crazy talk.

Originally Posted by ldrhawke

WEIGHT SAVINGS
NOto you wife...

Doesn't matter what you fill in after that start - not gonna happen.

[fastcat435]

Originally Posted by colemj

That's just crazy talk.


Doesn't matter what you fill in after that start - not gonna happen.

The nice part of saving weight is that you can have beer , wine 2 girlfriends and many more on board if you want and if your wife will allow you !!!

[BigCat]

Originally Posted by Aussiesuede

Yep, they do require a special lithium charger. Use a 'regular' charger and sit back for an impressive fireworks show...

As far as alternators go, pretty much every one uses externally regulated chargers now for the house batteries, anyway. These are electronic devices that let you set the desired voltage, etc. In my build, I am going to leave on the standard alternators and use them for the starting batteries. I will bolt on high capacity externally regulated alternators for the house batteries, in a completely separate system that has 24 volts. The starting battery systems will be 12 volt because that's what the electronic systems that govern modern diesels use. See:
http://www.defender.com/product.jsp?path=-1|328|6421&id=104488

[ldrhawke]

Like most topics, there are different outlooks........IMHO AGMs have more positives than flooded, gel, or lithium.

But that is just my opinion, but it based on reading the following reviews and users opinions.

Comparing Marine Batteries

[BigCat]

Originally Posted by ldrhawke

Like most topics, there are different outlooks........IMHO AGMs have more positives than flooded, gel, or lithium.

But that is just my opinion, but it based on reading the following reviews and users opinions.

Comparing Marine Batteries

I had been planning on using AGMs before Lifeline came out with the 'memory' issue. Their warranty now requires that you fully charge your battery each and every time you charge it. Not something you want to do on a sailboat, unless you use a generator for charging, IMHO. I am planning on using additional engine large case high amp alternators to charge my house bank.

[ldrhawke]

Originally Posted by BigCat

I had been planning on using AGMs before Lifeline came out with the 'memory' issue. Their warranty now requires that you fully charge your battery each and every time you charge it. Not something you want to do on a sailboat, unless you use a generator for charging, IMHO. I am planning on using additional engine large case high amp alternators to charge my house bank.

As I understand it, with AGM's you don't need to overcharge, like wet cells which you over charge 140% to get a full charge. With 95% efficiency AGM's suck up most of what you give them and take a charge faster because of it. This also makes you solar cells much more effective it helping to keep AGMs fully charged.

I just put 3 AGM 31's on my boat as house batteries. I decided to go with Sears DieHards, in large part because of the no hassle "Satisfaction Guaranteed" From past issues with Sears products I know when pushed they always stand by their Guarantee.

They are made a military battery mfg. Exceed Lifeline specs cold cranking and reserve, are about 6 lbs heavier which is why they have a little more output, and the case and terminals are a better design.

And being of Scottish decent, I picked them up at the store with no shipping cost for only $239.99 each.

[ldrhawke]

Originally Posted by fastcat435

The nice part of saving weight is that you can have beer , wine 2 girlfriends and many more on board if you want and if your wife will allow you !!!

All depends on how much they weigh................. May have to ask the wife to stay home......That's if I still had one.....

[BigCat]

Lifeline Batteries - Marine & RV Deep Cycle Batteries says, "For maximum battery life, a battery must be recharged to 100% capacity. Recharging less than 100% may result in premature battery failure. Lifeline batteries are not covered under warranty if they are not recharged properly. For more information, please refer to our warranty policy." Lifeline batteries seem to be the most widely distributed AGM marine batteries.

[fastcat435]

Originally Posted by ldrhawke

All depends on how much they weigh................. May have to ask the wife to stay home......That's if I still had one.....

My wife is very liberal but I am not sure she is that Liberal to stay home ( she loves sailing ) and give the fun to other girls

Regarding battery's we are looking at the new Nickel Metal Hydride battery's for our Green Motion propulsion system and will test these later this year on a sailing catamaran.
We could achieve weight savings of 500 LBS over AGM battery's with the same usable capacity.

Anybody interested in the outcome of these test can write me for a end report.

Greetings

Gideon

[ldrhawke]

Like everything they have certain limitations, cycle life is not good.

The nickel-metal-hydride battery

Research on the nickel-metal-hydride system started in the 1970s as a means of storing hydrogen for the nickel hydrogen battery. Today, nickel hydrogen is used mainly for satellite applications. nickel hydrogen batteries are bulky, require high-pressure steel canisters and cost thousands of dollars per cell.

In the early experimental days of nickel-metal hydride, the metal hydride alloys were unstable in the cell environment and the desired performance characteristics could not be achieved. As a result, the development of nickel-metal hydride slowed down. New hydride alloys were developed in the 1980s that were stable enough for use in a cell. Since then, nickel-metal hydride has steadily improved.

The success of nickel-metal hydride has been driven by high energy density and the use of environmentally friendly metals. The modern nickel-metal hydride offers up to 40% higher energy density compared to the standard nickel-cadmium. There is potential for yet higher capacities, but not without some negative side effects.

Nickel-metal hydride is less durable than nickel-cadmium. Cycling under heavy load and storage at high temperature reduces the service life. nickel-metal hydride suffers from high self-discharge, which is higher than that of nickel-cadmium.

Nickel-metal hydride has been replacing nickel-cadmium in markets such as wireless communications and mobile computing. Experts agree that nickel-metal hydride has greatly improved over the years, but limitations remain. Most shortcomings are native to the nickel-based technology and are shared with nickel-cadmium. It is widely accepted that nickel-metal hydride is an interim step to lithium-based battery technology.

Advantages

30-40% higher capacity than standard nickel-cadmium. Nickel-metal-hydride has potential for yet higher energy densities.
Less prone to memory than nickel-cadmium - fewer exercise cycles are required.
Simple storage and transportation - transport is not subject to regulatory control.
Environmentally friendly - contains only mild toxins; profitable for recycling.

Limitations


Limited service life - the performance starts to deteriorate after 200-300 cycles if repeatedly deeply cycled.
Relatively short storage of three years. Cool temperature and a partial charge slows aging.
Limited discharge current - although nickel-metal-hydride is capable of delivering high discharge currents, heavy load reduces the battery's cycle life.
More complex charge algorithm needed - nickel-metal-hydride generates more heat during charge and requires slightly longer charge times than nickel-cadmium. Trickle charge settings are critical because the battery cannot absorb overcharge.
High self-discharge - typically 50% higher than nickel-cadmium.
Performance degrades if stored at elevated temperatures - nickel-metal-hydride should be stored in a cool place at 40% state-of-charge.
High maintenance - nickel-metal hydride requires regular full discharge to prevent crystalline formation. nickel-cadmium should be exercised once a month, nickel-metal-hydride once in every 3 months.

[Aussiesuede]

I'd consider nickel-metal-hydride's for a house bank, but not for propulsion needs. You'll discover early on the heat issues associated with high discharge rates. Hydrides get VERY hot @ high discharge rates and will need to be cooled down somehow, and that generally requires energy of some sort. Also, cell damage during the charging cycles (which is very easy to occur) shortens an already short life cycle considerably.

Gideon, out of curiosity, what is the proposed bank size/voltage for the Green Motion?

[fastcat435]

Originally Posted by Aussiesuede

I'd consider nickel-metal-hydride's for a house bank, but not for propulsion needs. You'll discover early on the heat issues associated with high discharge rates. Hydrides get VERY hot @ high discharge rates and will need to be cooled down somehow, and that generally requires energy of some sort. Also, cell damage during the charging cycles (which is very easy to occur) shortens an already short life cycle considerably.

Gideon, out of curiosity, what is the proposed bank size/voltage for the Green Motion?

Good Morning

we are installing 16 Kw usable power in Green Motion , enough for 2 hours at 8 Kw or 3 hours 5 kw consumption
with 8 Kw we can run the boat 7 knots
with 5 Kw we can run the boat 6 knots of speed without starting the generator.
The company we are working with has given us a estimate on life cycles of 2000 with discharge levels to 80 % and if that is the case we are very happy with it.
For the service side we are using another 6 Kw usable power and that should be plenty
given the fact that we also have 1200 of solar panels on the boat and 1 or 2 wind generators with 100 to 500 watt of hourly power .

Greetings

Gideon