Electric Main Drive(s)

[Intentional Drifter]

OK, Rick, I'm a reasonably bright guy, and this is obviously your field of expertise and not mine, so...let me see if I'm understanding you and please correct me if I'm not.

Rather than letting the genset kick on at 80%, you're saying that a better point would be 50%. This is because we get more time motoring out of the batteries for the size of the battery bank. Would this remain true, though, given that these banks are being used for propulsion, where keeping voltage up may be more critical than than number of amps drawn? Or, do I have that wrong?

While I've got your attention, though, I'd appreciate your comments on another related matter: Lagoon is offering gels as an option to the wet cells. This is not a cheap option, and frankly, I'm skeptical. Part of me is concerned about the ability to replace them in some out-of-the-way place, but the other is economic. For a couple grand, I can check the water levels on a very regular basis!

Thanks for your input.

ID

[Rick]

Hummm! You have raised the questions which are VERY appropo! There has not been a history as quantifiable as the "wet" lead-acid" battery history yet as far as I have been able to determine with my relatively small sample experience, you will benefit from an increase in TRUE energy increase using either a gel-cell or high-quality AGM battery, either of which in general delivers more energy per pound or per cubic volume than wet-cell constructed lead-acid batteries. Notice that I have NOT concluded that the cost per lifetime cycle is better or not for these newer technology lead-acid batteries, like gel-cell and AGM.

HOWEVER, the data so far supports the idea that you will benefit from an increased energy optimization at a so-called 50% DOD for the newer battery types AND have a higher terminal voltage at the end of the so-called 50% DOD end point than what you would experience with wet cell lead-acid batteries. Now I have not answered your specific question regarding the end-point terminal voltage at a 50% DOD for wet batteries versus a 20% DOD.

I can calculate that for you if I know some specific internal resistance data for a specific battery type that you choose to compare with another battery type. Before doing that, however, realize that if you have ANY inclination to go with gel-cel or AGM batteries you will benefit from not only a higher terminal voltage at the 50% DOD point but from a lower internal cell resistance as well, which translates to an increased energy cyclical discharge/charge efficiency as well. These parameters are not well documented in the literature yet are known to exist.

Here is what we do know: There is only about a 15 year history of widely used AGM and gel-cell data and the summary is good when compared with wet cells, in general. Do NOT assume that any AGM will perform well, the particular brand is important.

Let us examine a "boundary value" regarding lead-acid technology applied to racing cars using electric motors. The "upper-end" of performers use Hawkins batteries which are VLRA type lead-acid batteries that can accept a 100% DOD with a recharge time on the order of 45 minutes! Because of the high energy density and high energy cyclical efficiency AND high terminal voltage under load AND low internal resistance the vehicles using these batteries beat the vehicles using other types of lead-acid batteries. Now the other end of a boundary value of utilization of lead-acid batteries might be a situation where a vessel only uses a battery to power an anchor light for 12 hours. One may determine that a sale-item wet battery may provide a higher economic solution over the lifetime yet one must realize that newer technology LED masthead lights having internal voltage regulators will yield an economic benifit if using virtually any non-wet lead-acid battery models. This WILL happen sooner, if not later.

[Rick]

Do not confuse Amp-hour efficiency with Amp-hour-Volt efficiency of a battery. Because of the internal resistance of ANY battery it is possible to have an Amp-hour effiency exceeding 100% due to the fact that the discharge voltage is ALWAYS lower than the charge voltage. Using true energy effiency: Amps-hours-Volts, a battery will NEVER exhibit more than 90 % or so efficiency in deep-discharge applications.

It is because of early lack of technology that most users of lead-acid batteries are confined to Amp-hour consumption and efficiency numbers in their "minds" in order to make some order of determinatino of qualilty with their products. With the advent of microprocessors battery monotors are able to measure TRUE ENERGY (Amps-Hours-Volts) as opposed to the old factor called "Amp-hours (translate: missing the Volts factor for true energy determination...an assumed "nominal" value of "12" is made). We now know that what was assumed in years prior to this new technology is not true when comparing true enery Amp-hours-Volts calculations.

[Wukong]

Looks like someone need to utilize the waste heat from the whispergen to power the Stirling engine.

[planetoftheapes]

Good Day,

I was wondering if anyone knows anything about Valence Li ion battries? Apparently, they are a direct replacement for conventional 12 volts, half the weight and twice the storage capacity, longer life span and therefore cost effective in the long run. They are also safe.

This could make a 420 motor for 8 hrs at the same weight as lead acid equipped, or of course, shed some serious pounds from the displacemnt at equal motoring time. Replace the generator with batteries as well and you could be energy independent. ?20 hrs of motoring with wind gens, solars, regen to top up batts. Yes you would always have to conserve energy.
The Fastcat 435 has them as an option.

Also, I ordered a 420 but still am blown away by the Sunreef 60/62. A true yacht that is 1.2 million high spec. What a ship! I've been told by people onboard an Atlantic crossing she sails very, very well. Unbelievable level of fit and finish. Apparently she recently won an ocean race with a top speed of 21 knots!

Is this too big for a family to circumnavigate on? Really, forget cost, which would you use to take your family around the world (420 vs SR 60 no other picks please)? I decided smaller would be less stress all around?
Also, we will test the technology thoroughly but for going off shore. No "I wouldn't go off shore with new technology" post please.

Enlighten me oh wise ones!

[Intentional Drifter]

Hi, Planet --

I've been wondering the same thing about the Valence batteries. I didn't know that African Cats was actually starting to use them, though. That's a good sign. Any idea about the cost? Certainly one of the advantages of the Li ion batteries is the ability to go to 80% DOD without harm, as well as much faster recharge time. Valence also says that their technology does not suffer from the safety problems that some others have had (doing extremely hot melt downs -- like the temperature of molten lava hot -- now, that would be tough on a battery box and think what it would do to the gelcoat!).

As to the Sunreefs, sure I can oh and ah over them, just like the Gunboats, but I don't let myself do anything more than that, as cost is an undeniable factor. So, I can't indulge myself in the pick, the answer is obvious.

ID

[Talbot]

I would be concerned about the cost of these Li-Ion batteries. There is even better new battery types available that are starting to be used in UUVs but are REALLY expensive.

Size of boat is a very personal thing. what is ideal for one is too big for another and too small for somebody else. Personally I reckon 40ft is about right - small enough to be able to get into most marinas, and big enough for most things you want to carry. sail sizes OK for short handed work.

[planetoftheapes]

Thanks guys,

I emailed Valence for a quote but no response. Given the cost of the 420, I don't see how a few thousand more for the Li batts would not be worth it, assuming they are as good as they claim. What are the better batteries out there? Are they safe for a boat at sea?

Is the choice between a Sunreef 62 and L420 really that easy? I've heard over and over, people on small boats (420 actually a pretty big boat) have more fun, big boat/big problems, huge anchors, alienate you from the locals, need crew...I cruised my Catalina 30 in 1996 to Cabo and felt a bigger boat would be a pain in the...
Latitude 38 mag says they wish their 60 ft. cat was smaller.

I will give this some more thought. Have not been on one yet. The visibility from the flybridge must be amazing. I am serious about a potential purchase. Yes, I will probably lose my 420 deposit-not a small sum. Just got a raise. The Gunboat 48 is the same price as the SR 62 (went aboard 48 in Annapolis) probably smaller inside than the 420. No contest for me between Gun 48 and SR 62. I would wager on the open ocean, the SR 62 would hold her own speed wise vs the 48 over a passage. The Gunboat 62, at 2.3 million, is really too expensive for me. My wife would divorce me.

Please more thoughts? Sorry, going off topic of electric drives.

[geoffgroves]

Here are the prices I got from Valence, at this stage I would suggest that they are too expensive for the mass market.

Term: Ex-China workshop in USD
U1-12RTL(24Ah): $360-$440
U1-12RT(40Ah): $515-$635
U24-12RT(100Ah): $1220-$1515
U27-12RT(130Ah): $1530-$1905

[Talbot]

If you think those are expensive, wait until you see the prices on the more exotic ones (IIRC Silver Zinc is now one recognised (and manufactured)type, but there are even more exotic ones being trialled)

[Intentional Drifter]

Thanks, Geoff. Those are some pretty high prices. No doubt they will come down over time. At this point, Lagoon is offering one option to the standard wet cells, that being gel cells. Whether AGMs will be offered is still unknown. Even with those choices, though, I look at weighing the options in the following way: (1) If a battery goes down, will I be able to easily replace it in, say the Rio Dulce? Or,some other remote place? (2) How much is it worth it to me not to have to check water levels? Right now, the option to replace both propulsion and house with gel cells costs an additional $3700. If someone were to pay me $100 to check the water levels on the batteries, it would take over 3 years of checking to make up the difference. At this time in my thinking, unless someone can point out some really powerful additional reason for going with the option, I'm thinking that with reasonable maintenance and good charging practices, I'll stick with the wet cells. (I'm open to being convinced otherwise, though. So, if you have those reasons, please post them.)

ID

[planetoftheapes]

ID,

Do you have the L420 options list? If so, could you please forward it to sotelojohn@hotmail.com or post here?
I was told it was not finalized.

AGM batts have many advantages over wet cell besides not filling with water.

[Brent Swain]

Has anyone considered a fuel cell, electric motor combination. I hear the price of fuel cells is dropping.

[Intentional Drifter]

There is the HaveBlue project, http://www.haveblue.com/about/index.htm that has a prototype boat. However, there has been very little news about it for the last year. I think we would all love to see something like this actually come to pass, but given the absence of news, I'm taking that to mean that they are likely having major problems. On the other hand, maybe they've gone into stealth mode in preparation of a major announcement. Unless you're an insider, though, how would you know?

ID

[planetoftheapes]

This is the quote they gave me?

U24 100Ah battery (Group 24 size) cost $2030 each.

Technology Comparison U1 U-Charge® System Performance Standard Lead-acid Saphion® Technology Improvement Operating Voltage 12V 12V Equivalent Capacity (Ah@ C/5) 45 27.2 65% Nominal Energy (Wh) 584 326 79% Cycle Life (80% DOD) 2000 300 666% Dimensions U1 U1 Equivalent Nominal Weight (kg) 7 11 36% Cost of Ownership 3.3 7.5 56%
Look at the cost of ownership. If ths is correct, these would be a far better choice given the weight savings and increased life.

Get rid of the generator. Replace its weight (and price) with additional Li batts, large bank of solars and two large wind generators. No maintanence, no fuel, maybe 20 hrs of motoring time. All at less total weight. That's for me!

You could have a small 6 hp diesel gen as emergency back-up!

Anyone know the total amp-hrs and peak current draw of standard battery banks?

Originally Posted by geoffgroves

Here are the prices I got from Valence, at this stage I would suggest that they are too expensive for the mass market.

Term: Ex-China workshop in USD
U1-12RTL(24Ah): $360-$440
U1-12RT(40Ah): $515-$635
U24-12RT(100Ah): $1220-$1515
U27-12RT(130Ah): $1530-$1905