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Old 20-05-2010, 17:11   #16
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The PDF opens fine tonight here too.

So you're setting 14.4 as full? Adustable to 14.6 or you disagree about charging them up that high?
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Old 20-05-2010, 17:18   #17
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The PDF opens fine tonight here too.

So you're setting 14.4 as full? Adustable to 14.6 or you disagree about charging them up that high?
Actually the battery is full at 14.0V . Anything above 14V is just a surface charge and BMS uses it to balance the cells. You can charge to 15.2V without damaging the battery, but there is simply no point of doing it, since its all a surface charge after 14V.

For example, if you keep charging at 0.1C after 14V the voltage will rise so fast, there will be about 2 minutes between 14V and 15V, so what does that give you? 0.003 AH? Surface charge disappears almost immediately once the load is put on the battery and it runs between 13.2V and 12.8V for almost entire time.
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Old 20-05-2010, 17:39   #18
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"Some of us just like to be on the leading edge and see the future, while others will stick to what worked before until its all gone"

That's a bit inaccurate. Some of us stick with what's proven, until new and better technology matures, gaining the inevitable benefits that come with time (cost, reliability, serviceability, performance...)

And while it may be true that today's LFP is more expensive but lasts longer, remember that like every technology the costs will likely decrease over time, so you may come out ahead buying lead batteries today; by the time they need replacement, the LFP's will be that much cheaper.

But for the benefit of all of us, I hope there's enough bleeding edge types to lead the charge and get us all to a lead-free future!
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Old 20-05-2010, 17:56   #19
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"Some of us just like to be on the leading edge and see the future, while others will stick to what worked before until its all gone"

That's a bit inaccurate. Some of us stick with what's proven, until new and better technology matures, gaining the inevitable benefits that come with time (cost, reliability, serviceability, performance...)
I can see how my statement might have been interpreted as inaccurate, but that is not how it was meant. I meant it the same way you did.

However, maturity of any product or technology is in the eye of the beholder. LFP cells existed 5 years ago, but weren't readily available for an average buyer. Even today you can't buy them from many established battery retailers, and those where you can buy them keep the price at high premium because they can get away with it. However, cells that I buy are priced at the best level, direct from the factory, with minimum overhead. LFP demand is growing much faster than supply, so the common thought that it will get cheaper doesn't seem to hold. Eventually, years from now, supply will meet demand and price will level, but it won't be much lower than today, since battery cost is factored over its lifetime, longer lasting battery is always more expensive. Don't think of battery cost in $/AH or $/WH, think of it as $/WH/cycle life, that is how market prices any battery and when looked that way LFP costs less than Lead, so there is no incentive for it to be even cheaper until market saturates, but that is long time from now, in this energy hungry world.
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Old 20-05-2010, 19:07   #20
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BTW I think what you're doing is cool, and I'm looking forward to more updates as you move forward.

"Even today you can't buy them from many established battery retailers, and those where you can buy them keep the price at high premium"

The ubiquity of lead batteries is likely an important factor for cruisers wandering into out of the way places....I hope LFP's become widely available.

As for cost, I know little to nothing about the battery industry, but what technology doesn't follow Moore's law? Researching price trends lead me to this from Deutsche Bank:

The firm notes the average lithium-ion cell price in 2009 has been $650 per kwh, but claims automakers are already seeing bids for $450 per kwh from battery companies for delivery contracts in the 2011/2012 timeframe.
Furthermore, they predict an additional 25% decline in price over the next 5 years and a 50% decline over the next 10 years along with a doubling of performance over the next 7 years.

Or consider solar panels – demand for them has remained high right? “The prices for high power band (>125 watts) solar modules has dropped from around $27/Wp in 1982 to around $4/Wp today."


Maybe I'm just hoping they get cheaper...

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Old 21-05-2010, 15:02   #21
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"As for cost, I know little to nothing about the battery industry, but what technology doesn't follow Moore's law?"
Actually, the battery industry does not follow Moore's law. Batteries, regardless of technology and adjusted dollar values, haven't gotten significantly better or cheaper in the past hundred years. Lithium technology has spiked that in the last decade or two, but nowhere near the kind of huge changes that Moore's Law would call for.
The big joke as always been that the next big shift in battery technology would be here in five years...since the 1930s. Five years. And it always is just five more years away.
If lithium-something doubles power density, that's great. If it does so at double or triple cost...it will never get outside a niche.
I'm still waiting for the grapefruit sized home nuke that Reddy Kilowatt promised me in the early 60's! It's just five years away...since the 60's.
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Old 04-06-2010, 20:46   #22
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While I am finishing up BMS-in-a-box solution, which will be completed in a few days, I have posted LFP-in-a-box unit for sale in Classifieds section.

http://www.cruisersforum.com/forums/...bms-41683.html

This is limited time offer only in Tampa Bay area, the system is half the price of competition, because I need the funds to invest in further BMS production.
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Old 05-06-2010, 04:45   #23
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Quote:
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I can see how my statement might have been interpreted as inaccurate, but that is not how it was meant. I meant it the same way you did.

However, maturity of any product or technology is in the eye of the beholder. LFP cells existed 5 years ago, but weren't readily available for an average buyer. Even today you can't buy them from many established battery retailers, and those where you can buy them keep the price at high premium because they can get away with it. However, cells that I buy are priced at the best level, direct from the factory, with minimum overhead. LFP demand is growing much faster than supply, so the common thought that it will get cheaper doesn't seem to hold. Eventually, years from now, supply will meet demand and price will level, but it won't be much lower than today, since battery cost is factored over its lifetime, longer lasting battery is always more expensive. Don't think of battery cost in $/AH or $/WH, think of it as $/WH/cycle life, that is how market prices any battery and when looked that way LFP costs less than Lead, so there is no incentive for it to be even cheaper until market saturates, but that is long time from now, in this energy hungry world.
So true...to truly compare the actual costs for LiFePO4 you need to look at it over time and $/WH/cycles ratios.

Great info on this thread. I don't get to check in that often as I'm traveling a lot and doing system installations. Just back from Spain putting in a custom lithium system with both house and starting batteries, the charging setup for both, overcharge/discharge/alternator protection, monitoring, etc. Very happy customers.

But I want to say that what you are doing is great. There are different levels of solutions for this world and the more people working on it the better. Yes, the systems like I just did are expensive. However as more of them happen and alternatives develop we will all be able to enjoy a new generation of energy storage and use.

Hopefully all this is a part of really changing our world and our future. Energy efficiency in all forms is so important in the big picture, and I'm very happy to be involved in this stuff!

Bruce
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Old 05-06-2010, 05:03   #24
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So true...to truly compare the actual costs for LiFePO4 you need to look at it over time and $/WH/cycles ratios.

Great info on this thread. I don't get to check in that often as I'm traveling a lot and doing system installations. Just back from Spain putting in a custom lithium system with both house and starting batteries, the charging setup for both, overcharge/discharge/alternator protection, monitoring, etc. Very happy customers.

Bruce
Please share the details of your installation in Spain in the LiFePO4 boat thread. I would love to hear all the details of your project as I am sure many others would. Some photos would be great also.

I would like to hear specific details with regard to charging/discharging and alternator protection.
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Old 05-06-2010, 05:45   #25
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Well...sorry to say that I'm not yet allowed to discuss very much with this particular project, or even the name of the boat. Hopefully they will let me soon. They don't want the competition to know their exact set-up. DEFINITELY no photos allowed.

However, I can say the main house bank is a standard Genasun 200Ah x 24V system. The alt. reg. is also Genasun, as is the starting battery charger. While I can't give the whole configuration on this boat, of course I can design/suggest systems for particular applications.

It won't be long before systems like these are well-known, but in order to get these jobs one has to make agreements...;-)

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Old 05-06-2010, 05:50   #26
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Originally Posted by RunningFish View Post
"Some of us just like to be on the leading edge and see the future, while others will stick to what worked before until its all gone"

That's a bit inaccurate. Some of us stick with what's proven, until new and better technology matures, gaining the inevitable benefits that come with time (cost, reliability, serviceability, performance...)

And while it may be true that today's LFP is more expensive but lasts longer, remember that like every technology the costs will likely decrease over time, so you may come out ahead buying lead batteries today; by the time they need replacement, the LFP's will be that much cheaper.

But for the benefit of all of us, I hope there's enough bleeding edge types to lead the charge and get us all to a lead-free future!
Well, if we figure Lifepo batteries have twice the usable capacity of lead-acid, then these units cost $2500/200/2 or $62 per amp/h of lead-acid equivalent. That's not two or three times as expensive, it's 30x more expensive than a good deep cycle lead-acid.

I have no doubt that the price will come down radically, especially if electric cars catch on. Until then, I'll keep using lead-acid; can't justify a 3000% price penalty when lead-acid works reasonably well.

By the way, advocates of Lifepo often argue that longer life justifies the price difference. IT does not. Their analyses are flawed by the assumption that money has no time value. In other words, these analyses fail to take into account that a dollar spent five years from now to replace a lead-acid battery is not equal to a dollar spent today.
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Old 05-06-2010, 06:10   #27
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As I read throu what the BMS in-a-box will do, I dont see that it fills the need of a cruiser..
And undrestand, Im not knocking what you're doing, but please describe the the actuall use of the product for the intended use on a boat in real cruising situations..
Not on a boat for weekend use now and then, or a vacation trip to the islands for a week off work, but real life cruising..
While cruising, the "house bank" is your onboard sorce for "PG&E" or "Ma-Bell" and provides not only the lights and electronic sorce, but is your power for your workshop, your inverter system, and all other systems on the boat....
If the wife is watching a move while doing the dishes, and I make a trip to the bathroom, its not an uncommon event in a house, but in a boat the same process is using power for the TV and DVD player, the inverter is on, and while she is doing the dishes, the fresh water pump is kicking on and off, and I just closed the door on the head, and in a few seconds the "Electro San" kicks on and I'm using a second pump to wash my hands.. enough stress on the unit, not yet as a friend is calling on the SSB and I pick up the reciever to yell back...
Ive just taken that 200 AH battery and sucked the crud out of it, and I'm really not interested in visual or autable noises going on.. I just want the system to work...
At the present, we have 10 each lifeline 4ds and and they are spread out throuout the boat.. Another 2 each group 27s for the starter bank..
I might be a little on the edge of what is needed for cruising but the future of house banks for cruisers needs to be of almost "Unlimmited" power sorce. a bank that will not only put out the power but will recieve it by way of solor or wind to charge it back up and do it fast..
Show me a system that will maintain my boat in a stand alone system, off the grid and I'll be the first person in line to buy one.
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Old 05-06-2010, 23:53   #28
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I might be a little on the edge of what is needed for cruising but the future of house banks for cruisers needs to be of almost "Unlimmited" power sorce. a bank that will not only put out the power but will recieve it by way of solor or wind to charge it back up and do it fast..
Show me a system that will maintain my boat in a stand alone system, off the grid and I'll be the first person in line to buy one.
But that is the great advantage of using LiFePO4 batteries- their fast charging characteristics.
The batteries will "receive" the power as fast as you can deliver it no matter if it is supplied by genset, solar or wind power. The limiting factor is the charging source and not the level of charging current which the batteries can safely accept.

Last week a boat builder interstate launched his cat "Exhale". He only has a small LiFePO4 bank which is basically just for getting him out of his mooring.
The batteries are only 60Ah in capacity (2x 30Ah) with plans to add to battery capacity in the near future. The generator supplier was doing genset testing on the boat last week and couldn't believe his eyes when he was charging the batteries after discharge and his ammeter was showing a charging current of 114amps! I think most people will agree that to pump 114amps into a 60Ah battery is seriously fast charging. The batteries were reported as being fully charged by the time the boat returned to its mooring 22 minuted later.
Try doing that with any lead acid / AGM battery and see how your battery likes it.
So the batteries could accept all that the generator could put out (plus considerably more) which is a good example to show that the limitation on charging speed is not with the batteries but rather with the size of the generator, number of solar panels and output capacity of your wind generator.

So the difference here is that where you would normally have a huge lead acid battery bank to supply all your "energy hungry" electrical equipment, instead you have have a much smaller LiFePO4 battery bank weighing a third of the lead batteries and when you are out at sea they can be fully recharged in well under half an hour by a short run of the generator. You do not suffer the limitation of trickle charging as you do with lead acid batteries which necessitates having to use a much larger battery bank.

So when you talk of the requirement of an "unlimited power source" for a cruiser your limitation is the size of the diesel tank, number of solar panels or capacity of wind generators aboard your boat rather than any limitation imposed by the lithium battery.
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Old 06-06-2010, 06:50   #29
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I think a lot of folks have gotten used to the huge Ah numbers required to run their stuff with lead batteries. "Bigger is better" has definitely been a valid concept for a long time. It takes a while to accept the "smaller" Ah bank(s) you can use with lithium.
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Old 06-06-2010, 14:35   #30
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I guess after the first million electric cars are sold (zzzz) we'll see some slightly used Li-whatever battery packs available from the junk yards, and then there will be an affordable Li-whatever battery source for sailors who can't justify a tenfold expense for them.

Another five years maybe?
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