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Old 15-01-2013, 07:30   #1081
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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If you think lead acid batteries are unforgiving of mistake and neglect, we haven't seen anything yet. I know Prius owners that are having to by battery packs that cost over 1/3 the price they paid for the car, in less then 2 years.
First this is not LiFePO4 technology used in the Prius it is NiMH.. Second where are these Prius owners? Not in the Prius community forums bitching about it.

NO Prius owner is paying for a battery at 2 years. This is 100% misleading. A new battery pack from my dealer would run about $3054.46 installed however a salvage pack from a low mileage car can be purchased for $500.00.

If they had a failure of a pack in that time period Toyota is paying for it. These batteries have a 10 year 150k warranty. Considering I own a Prius, I like the technology and don't drive it to save the Earth, and am quite active in that community, the failures of battery packs are VERY, VERY rare even in Prius used as taxi's. There are LOTS of Prius out there with over 200k with the original pack.

Mine is a 2007 and has 122K +/- and the pack is as near perfect as can be. Even in the winter I am still averaging 46 - 49 MPG. Compared to my old vehicle I save about $3565.00 in fuel costs per year @ 4.00 per gallon. Even if my pack did fail, and I got a salvage pack, easy to do, I am still ahead by $3000.00 per year at $4.00 per gallon. 1/3 the cost of a new car???? This hyperbole is what all the non-Prius owners use to scare people with about hybrid technology..

My own Toyota dealer has had two - three failed packs and they all failed within the warranty period and were replaced 100% free of charge.

According to my service writer my dealer has more than 200 of these cars they service that are over 100k, including mine, and none have had a pack failure other than the 2-3 mentioned. People buy these to commute so they rack up mileage quickly compared to many other vehicles..

The Toyota warranty is 10 years 150k miles without pro-rata. Toyota puts their money where their mouth is on these packs. When was the last time you saw a gas engine with a 10 year 150k warranty?

Failed packs can happen, just like failed engines in gas cars, but it is rare.. Prius batteries are not suffering short life that I have seen nor heard of and my own is pushing 6 years and 122k.

Either way if or when I do kill my battery I will have a new one installed for about $500.00 (I would DIY the pack as it is not difficult and takes about 30 minutes.). By that point I will have saved over $10,000.00 in fuel costs so am still $9500.00 ahead of the game....

The REAL costs from my Toyota delaer for a factory new Prius traction pack is $3000.46 and .5 hours labor to install it. This amounts to $3054.46 to have Toyota install a brand new battery. Unless these cars are selling for $9000.00 new the cost of a Prius battery is NOT 1/3 the cost of a new car....
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Old 15-01-2013, 07:46   #1082
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

In my opinion, lithium phosphate batteries are ready for DIYers, but the charging systems to go with them are not as yet. Whether or not the charging systems will be available a year from now is something that I cannot predict.

Balancing is a nice optimization, but unbalanced LiFePO4 batteries are still vastly better than the best lead acid batteries.
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Old 15-01-2013, 08:43   #1083
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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I checked when I was using the jumper cables to short out a high cell, and if I remember around 2~3 milliohms.
Bob, 2-3mΩ is actually quite high, if you think about it. At 2mΩ per cell, the battery is at 8mΩ, so under a 1C (100 amp) load, the voltage drop is 800mV---0.8V---taking the pack down to a very noticeable 12.5V. That's quite a bit of sag.

Try repeating the test using a modest 3-10 amp load if you can. Bolt down the load leads to minimize contact resistance, and carefully measure the voltage on the copper and aluminum surfaces of the terminal, not the bolt.
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Old 15-01-2013, 08:56   #1084
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Re: the significant time it takes to do the initial bottom balance, I am heavily banking on the theory that once this is done---one time---the need to do it again, at sub-C levels, and with centered subcycling, will be never.

This being the case, I would much rather do the manual balance, than "invest" in a balancing circuit that ends up basically doing nothing.

On the other hand, if the cells are poorly matched to begin with, then any manual balance is just an exercise in futility, and you would probably want a balancer that does a top balance every cycle.
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Old 15-01-2013, 09:35   #1085
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Maybe a little history will shed some light on what seems to be becoming a debate. When the EV-1 first appeared 1996 with lead acid batteries, it managed around 80 miles for range. When the 2nd generation of EV-1s were released in 1999 they were sporting NiMH and range was 140 miles. When Detroit and Big Oil sued California on its 2% zero emissions mandate and won, GM collected all the EV-1s and crushed them. Standard Oil, fearing NiMH could put a dent in their business, bought the patents for NiMH on all cells larger than 10 a-hr. So now the largest cell available is a D flashlight cell at 10 a-hr. Even with these restraints Toyota has done quite well with the Prius. The oil companies never counted on lithium being able to be scaled up to the sizes we have now, and besides, even as wealthy as they are, they couldn't afford to pull and sit on lithium, as at the time there was a emerging laptop, cell phone industry.

Since known lithium reserves could only produce 23 million car size battery packs, we will be moving on to other chemistry combinations, too bad NiMH won't be one of them.
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Old 15-01-2013, 10:10   #1086
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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Since known lithium reserves could only produce 23 million car size battery packs
Not sure where you got that information from ?

A quick check of wikipedia : Lithium - Wikipedia, the free encyclopedia

Shows much higher numbers:

"1 billion 40 kWh Li-based EV batteries could be built with the currently estimated reserve base of lithium" based on this article:Green Car Congress: Study finds resource constraints should not be a limiting factor for large-scale EV battery production
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Old 15-01-2013, 10:27   #1087
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Those were old numbers that I crunched a long time ago.

SQM, FMC and Rockwood together control some 8 million tonnes of lithium, said Evans, roughly a quarter of the world's reserves.

Just one million tonnes of lithium is enough to produce 395 million units of Chevrolet's Volt electric car (16kWh) or 250 million units Nissan's Leaf (24 kWh), Evans said.


Since people want a electric car with a 300 mile range, then 2.6 billion of these 300 mile range cars on the known lithium reserves. Much better than my earlier projection, but still finite.

Where my mistake was is I knew we 32 million tons of known reserves, and I incorrectly assumed a ton of batteries was a ton of lithium, boy was I wrong.
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Old 15-01-2013, 11:41   #1088
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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Mine is a 2007 and has 122K +/- and the pack is as near perfect as can be. Even in the winter I am still averaging 46 - 49 MPG. Compared to my old vehicle I save about $3565.00 in fuel costs per year @ 4.00 per gallon. .
Hyperbole? I think you are guilty too. Arn't we all.

122000/6 = 20300 miles per year

A 28mpg car (something equivalent) would burn 726 gallons.
A Prius would burn (47.5 mpg) 428 gallons.

Savings = 298 gallons or $1192 at $4/gallon. From what I gather in my area, the avberage price of gasoline during the relavant period has been about $3.10/gallon, so an actual savings of $923. I drive less than tha, too, so my savings would be about $500/year. Though I like the Prius, there was a reason I bought a Subaru. Good in the snow and on the beach, too. I will certrainly look at them again when I need a new car; without the crazy primium they were easking at introduction, the value proposition should be better.

Yes, your old car was a pig, but that's neither here nor there in this sense.

-----

I'm watching this thread because as a multihul sailor, I would buy them for the weight savings alone. The $/pound proposition is certainly much better than carbon fiber!
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Old 15-01-2013, 12:26   #1089
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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Hyperbole? I think you are guilty too. Arn't we all.

122000/6 = 20300 miles per year

A 28mpg car (something equivalent) would burn 726 gallons.
A Prius would burn (47.5 mpg) 428 gallons.

Savings = 298 gallons or $1192 at $4/gallon. From what I gather in my area, the avberage price of gasoline during the relavant period has been about $3.10/gallon, so an actual savings of $923. I drive less than tha, too, so my savings would be about $500/year. Though I like the Prius, there was a reason I bought a Subaru. Good in the snow and on the beach, too. I will certrainly look at them again when I need a new car; without the crazy primium they were easking at introduction, the value proposition should be better.

Yes, your old car was a pig, but that's neither here nor there in this sense.

-----

I'm watching this thread because as a multihul sailor, I would buy them for the weight savings alone. The $/pound proposition is certainly much better than carbon fiber!
But I never said I bought the car new. I did not and never would but I do drive about 26k per year. The numbers were also based on our previous cars not a 28mpg sedan..

The Honda Pilot got about 18 MPG (now my wife's car). Just filled up the Prius this morning in Maine at $3.59 per gallon but my calculations that I had done were on $4.00, which is what it was averaging when I bought the Prius.. Did not feel like re-calculating because in Maine we've been hoovering high $3's low 4's for a couple of years.

Even at today's gas prices ($3.59):

Pilot = 26k @ 18mpg = 1444 gallons X $3.59 = $5185.00
Prius = 26k @ 47mpg = 553 gallons X $3.59 = $1985.00

I am still saving roughly 3k per year in gas costs over me driving the Pilot, I now do more miles than my wife.... My old Outback wagon averaged about 22mpg.

My absolute worst tank on the Prius was 43.7mpg (very cold and the heater was running the engine constantly) and the best has been 53.4 mpg.... The absolute best I ever did on the Pilot was 21.2mpg but she has been as low as 15.8 mpg.

That said I did a ton of research before buying a used Prius and so far it has paid off. Zero problems, zero fixes and $28.00 +/- fills the tank. The savings in gas compared to the Pilot have been great and very real. For me I just like the technology aspect of it and want to see how far I can get it to go mileage wise and longevity.

Now my wife wants one..... I need her Pilot some times and don't want to go back to three cars...... She took it to Boston yesterday, 262 miles, averaged 48.7 mpg and used about 5.3 gallons of gas.... Can't blame her for liking that..... Heck she got a free lunch out of it when compared to taking the Pilot....
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Old 15-01-2013, 12:57   #1090
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Replaced the 2X55 A/H AGM with a 24 A/H one one side & a 40 A/H on the other engine. The 24 A/H starts the 1GM with no problem but I try to ensure both are in parallel for starting to get a better life (start cycles). 24 A/H 3.6 kg 40 A/H 7 kg big weight savings Max has been 3 years out of the AGM.

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Old 15-01-2013, 14:12   #1091
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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But I never said I bought the car new. I did not and never would but I do drive about 26k per year. The numbers were also based on our previous cars not a 28mpg sedan.
I was just teasing.

My company supplies OEM coolants to a number of bus manufacturers, and quite a few of those are going to hybrid, not because of fashion but because of reduced operating cost. The Washington DC fleet has been almost all hybrid since 2005.

Metrobus (Washington, D.C.) - Wikipedia, the free encyclopedia

A funny thing about bus hybrids; they have to run larger supplemental cabin heaters because the engines don't produce much waste heat. But the stop and go city traffic is perfect for them.
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Old 15-01-2013, 14:38   #1092
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Well this thread has got a wee bit confusing, my decision now will be to NOT charge the Lithium's by the alternators on the main engines.

We will primarily use the 3 - 230 watt solar panels @ 36volts using the GSL MPPT60-2L Regulator which is purpose built for Lithium, we should peak at 50 amps for some hours in the areas we intend to cruise.

We will add a 240volt charger to cover shore and gen-set sources, this charger will also be dedicated to Lithium.

The main engine can charge the LA start batteries and Thruster bank.

Our batteries being new will have voltages very close, i have a cell logger(Junsie) and will order the hi/lo voltage switch as well.

I intend now to set it up simple under guidance from a few of the CF contributors. We shall then be able to gauge IF the system is suitable for someone that is not particularly electrically endowed... LOL!

Cheers, we shall see.
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Old 15-01-2013, 15:54   #1093
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On the other hand, if the cells are poorly matched to begin with, then any manual balance is just an exercise in futility, and you would probably want a balancer that does a top balance every cycle.
This is not true. If you top balance even unmatched cells equally to 3.6V, the capacity of the bank is restricted to the lowest capacity cell. So long as you never draw that lowest cell below its full capacity, lets say something like 2.8-2.9V, the subsequent charge cycle will return all cells to full charge equally.

Theory would tell us you could even mix a 200AH cell with a 400AH one and this would hold true. I'm not certain about that in the real world, but if you have 4 400 Ah cells with an actual capacity of 398, 402, 405, 410 Ah, while not matched, they will work fine together, the same as matched set, except the capacity of the bank is only 398Ah.

Balancing simply sets the SOC of each cell to some arbitrary point. Bottom balancing so they all go to 0% at the same time, top balancing so they all go to 100% at the same time. Once balanced, and kept within normal operating voltages, the relative SOC between the cells is very slow to change, if it changes at all. This is a distinctive characteristic of Li cells over time compared to other chemistries.

The question is exactly how perfect this theoretical characteristic is, and exactly how often a rebalance may be needed. But there are guys on this forum and homebuilt EV's that have demonstrated > 12 months, and some never needing to balance after the original installation.
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Old 15-01-2013, 16:27   #1094
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

I received the straps, bolts, and washers today, so I was finally able to do an accurate iinternal resistance test with tight connections. Using a 5.10A load across the bank, the voltage drop was 43mV. So the bank's internal resistance was 8.4mΩ, so the average cell was 2.1mΩ.

This is mildly disappointing, because this is over five times the resistance quoted by http://www.ev-power.eu/docs/pdf/Wins...Resistance.pdf and twice what I had hoped. I'm crossing my fingers that it'll improve after a few cycles---the cells may just be "rusty" from being unused for two years.

Internal resistance has very real ramifications on proper charging voltage as well as the alarm and disconnect voltages. It cannot be ignored if you plan to run any sizeable current.
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Old 15-01-2013, 16:38   #1095
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I received the straps, bolts, and washers today, so I was finally able to do an accurate iinternal resistance test with tight connections. Using a 5.10A load across the bank, the voltage drop was 43mV. So the bank's internal resistance was 8.4mΩ, so the average cell was 2.1mΩ.

This is mildly disappointing, because this is over five times the resistance quoted by http://www.ev-power.eu/docs/pdf/Wins...Resistance.pdf and twice what I had hoped. I'm crossing my fingers that it'll improve after a few cycles---the cells may just be "rusty" from being unused for two years.

Internal resistance has very real ramifications on proper charging voltage as well as the alarm and disconnect voltages. It cannot be ignored if you plan to run any sizeable current.
To get an accurate reading, you probably need to be in the flat part of the discharge curve? Say 3.2 to 3.3V per cell?

I did look for more exact numbers for you. 12.92 to 13.15V at the pack, switching from a 31A load to 150A charge on my bank, better than I remembered. But I have no idea how to translate that to internal resistance with 48 individual cells.
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