Lithium Iron Phosphate Batteries; LFP; LiFePO4 discussions

Re: Lithium Iron Phosphate Batteries; LFP; LiFePO4 discussions

RCinFLA wrote: »

Four pack versus 12v AGM, about twice the price ($500-$540 for 100 A-H)

Its not really fair to compare a AGM battery to a LFP Battery. They are different in so many ways.

100Ah AGM battery can only provide you 30 amp hours if you want it to last 3000 cycles.

100Ah LFP Battery can provide you 80 Amp Hours every day for 3000 cycles.


The 100AGM battery really only gives you 30 Amp Hours every day if your trying to get a long life out of your battery.

So yea LFP is double the price but it's also more than double the battery.

LFP - 80 Amp Hours a day x 3000 days gives you = 240,000 Amp Hours
AGM -30 Amp Hours a day x 3000 days gives you = 90,000 Amp Hours

The LFP Battery Pack will Provide you with 150,000 More Amp Hours before it starts providing you with 80% of its rated capacity.

The numbers only get better if you discharge less than 80% DOD everyday.

70% DOD Daily = 70 AH per day x 5000 Days = 350,000 Amp Hours
AGM -20 Amp Hours a day x 5000 days gives you = 100,000 Amp Hours

LFP Gives you 250,000 More Amp Hours than AGM Batteries

The difference is amazing and its not really fair to compare LFP to AGM, or AGM to LFP.

Re: Lithium Iron Phosphate Batteries; LFP; LiFePO4 discussions

RCinFLA wrote: »

5000days/365 = 13.7 years! Do you really think they will last that long?

Accelerated discharge/charge test cycling does not necessarily expose all failure and aging modes. I do agree you can get more usuable A-H per cycle. Longevity remains to be proven.

I was only comparing price. I am not convinced of a price to payback advantage at their current pricing. One story from the web I came across had 20% of the batteries received failing within a short time. With an unproven track record it is a lot of money to put on the line. If the price ratio was 1.1 to 1.5X I would take the risk.

Yea I think its possible that they could last that long or longer if treated correctly.

I'm looking for data that proves the manufacturer life cycle ratings wrong too though but have not come up with much on this yet. So until I do find some good data proving the cycle test wrong I'm going to keep my mind open about whats possible.

For the regular Solar House Setup you can use Lead Acid or LFP, either way will work but for Portable Type Systems the lead acid batteries are not even something we consider because of all the benefits LFP Gives us vs AGM.

Re: Lithium Iron Phosphate Batteries; LFP; LiFePO4 discussions

Hey All,

I have read this thread with great interest. I have also seen that video where an EV guy complains about a failure rate of 20% and that he cannot get any satisfaction from Thundersky. Here is the link to the video:

http://www.youtube.com/watch?v=FB1iKYgKSqo

RWB,

in your experience have you had any failures or any need to claim on warranty or know of anyone first hand that have attemped a warranty claim. In terms of warranty issues does one have to deal directly with the manufacturer in China or the agent in the US. What does the warranty cover anyway. I am almost sold on this battery tech except that I have seen no details or mentioned on warranty. I dont think is should be an issue since the battery is so " GREAT" the manufacturer should have minimum warranty issues all the more reason to give a "GREAT" warranty.

Cheers...
Damani

Re: Lithium Iron Phosphate Batteries; LFP; LiFePO4 discussions

Looks to me like the LFYP vs FLA is very competitive an an amp hour basis!

24 L16RE-B's = 2220 ah @ 24v 555 ah @ 25% DOD = $7390 (NAWS)
16 400 ah LFYP = 800 ah @ 24v 560 ah @ 70% DOD = $7280 (Includes Shunts $400)

8-10 years FLA vs 13+ years FLYP; Lighter Weight; No Watering; Little Degradation if left at 50% DOD...

With only a 3% loss per month this may be a "long" term storage solution!?
800 ah hours in June would give you 799.82 ah in December

Beginning to look like a no brainier to me..... only one last question; warranty? If I mess up and kill a FLA there is a pro rated warranty... What if I kill a FLYP? More yard art?

Re: Lithium Iron Phosphate Batteries; LFP; LiFePO4 discussions

From EV guys' experience the warranty is almost not existant. Stated warranty is one year. If you buy from a US distributor you may get the one year warranty. If you buy directly from China, go through the freight clearing process, you likely will get no warranty because you are not big enough for manufacturer to pay attention to. If you are General Motors things are different.

As to paralleling, the EV guys are doing this. There is a lot of monitoring of cells to keep tabs on conditions. They are drawing 2C and 3C discharges in some cases so are hard on cells. They are putting together >15 kWH battery packs.

I read that China and a place in East Europe are the two primary world sources of Lithium raw material.

Probably in a few years, when EV's and hybrids are using large quantity of these batteries, things should get better.

Re: Lithium Iron Phosphate Batteries; LFP; LiFePO4 discussions

Chuck46 wrote: »

Mike I do wish passive solar would work but it doesnt yet.





Major forgot, I am not sure what is ment by 2C or 3C can yoou give a brief explination?

2) 2c or 3C C= Capacity A 50 AH Capacity battery 2C = 100Amps 3C = 150A

1) Let's find a way to make solar heating for the critter tank work. For the same size collector, heat is several times more efficient. If you had just a couple hours of sun a day, a collector, and an intermediate/storage tank, a passive thermosiphon would work. A day without sun, you have to burn generator fuel, only if it gets way below freezing. What about a simple sky cover, that prevents the tank from radiating it's heat out to the stars at night? (thats a way ancients made ice, shallow open trays at night, open to the sky)

Is much water consumed at night, can it drain into an insulated tank? or a demand waterer fed from an insulated tank. Propane heater ? change out a 30gal propane tank weekly?

Re: Lithium Iron Phosphate Batteries; LFP; LiFePO4 discussions

Dapdan wrote: »

Hey All,

I have read this thread with great interest. I have also seen that video where an EV guy complains about a failure rate of 20% and that he cannot get any satisfaction from Thundersky. Here is the link to the video:

http://www.youtube.com/watch?v=FB1iKYgKSqo

RWB,

in your experience have you had any failures or any need to claim on warranty or know of anyone first hand that have attemped a warranty claim. In terms of warranty issues does one have to deal directly with the manufacturer in China or the agent in the US. What does the warranty cover anyway. I am almost sold on this battery tech except that I have seen no details or mentioned on warranty. I dont think is should be an issue since the battery is so " GREAT" the manufacturer should have minimum warranty issues all the more reason to give a "GREAT" warranty.

Cheers...
Damani

Yes I have had 1 Cell from a 40AH Battery Pack that went bad on me. The Battery pack had been sitting in a hard case by its self for 6 months or so while I forgot about it. I have no idea what the SOC was on the battery before it was thrown into the hard case for 6 months or longer. I do know that when I pulled it out I could see that the Balancing Module was not lit up green like the others so I tested it and it was for sure a dead cell.

I called my US Supplier and they told me to send it in and they would verify the serial number and that it came from them and then send me a replacement. They honor the 1 year warranty.

You guys probably do not know this but there is actually a Factory Producing ThunderSky LFP Battery Cells in the USA..................But the cost per cell is double what it cost if they come out of China

And that 1 Cell that went bad is the only cell out of 80 Different Thunder Sky Cells, and I left it sitting for half a year without any protections or knowing the SOC before forgetting about it. I'll get it replaced for free, not big deal.

Its funny because the Lead Acid Batteries seem to be the batteries that are going bad on us all the time. My partner has thrown away 15 quality Hawker Odyssey AGM Batteries and other brands over the last year because they go bad if you store them for very long, and he charged them once every Month or so but it still did not help.

I bet there are alot of lead acid batteries out there that never meet their rated output and life cycles.

Re: Lithium Iron Phosphate Batteries; LFP; LiFePO4 discussions

rwb,
from you,
"My partner has thrown away 15 quality Hawker Odyssey AGM Batteries and other brands over the last year because they go bad if you store them for very long, and he charged them once every Month or so but it still did not help."

forgive my sidestepping here, but somehow this does not sound right as agms do not lose that much of their power during shelving as you are indicating. i have recently, as an experiment, left my sunxtender sit with no loads or float charge for a month just to see the result. the voltage hardly dropped at all and was brought back up in no time. i believe the measured resultant voltage was about 12.7v (exact reading i don't recall) and usually my rest voltage is in the range of 12.8-12.85v. it used to be about .05v higher for the rest voltage, but i'm not going to complain about a battery that is going to be 7 this year. knowing this i suspect there's more to the story as to why your partner is "throwing away" batteries. what of the warranties on those batteries if it's applicable?

Re: Lithium Iron Phosphate Batteries; LFP; LiFePO4 discussions

jeffkruse wrote: »

I have a question, with a Xantrex 4548 and an XW charge controller how many cells would be needed? The XW only goes to 64V for charging. Is the input voltage wide enough for the 4548 to work with these cells. At 64V what would be the SOC?

16 cell in series for 48v system. 3.2vdc nominal per cell X 16 = 51.2 vdc.

Set bulk at 57.6v, float at 56.0v to 54.5v. I would set low battery cutoff on inverter at 45.0v to 48.0v depending on you max load expectation and A-H ratings of batteries.

Re: Lithium Iron Phosphate Batteries; LFP; LiFePO4 discussions

I posted this on the Outback Forum four days ago... no response yet?!

I am considering a "24v" LiFeYPO4 Battery bank. These battery's typically have a BMS (battery Management System) across each 3.2v cell. This BMS is a 600mA shunt that shunts across the terminals when the cell reaches 3.65v. My question is; with the bulk, absorb & float voltages set at 29v (8x3.65v) how will a my MX60 & FX80 chargers react when a cell tops off and the shunt closes to limit overcharging?

Perhaps, I can get an understanding here... as I understand it, charge controllers are designed for LA batteries... as they get full the resistance increases, with a LFP and a BMS, as it tops off the shunt will close lowering the resistance (?). Wouldn't the controller misinterpret this and up the amps?

Re: Lithium Iron Phosphate Batteries; LFP; LiFePO4 discussions

the 600mA is a concern for me too... the second BMS looks like it would (may) be short lived what with open circuts...

I have the potential of putting 108 amps to the bank on a clear day... if I limit the voltage to say 27 volts and only go for 90% SOC, one cell may top off and then those shunts will go off like popcorn! LOL

Re: Lithium Iron Phosphate Batteries; LFP; LiFePO4 discussions

John, its not the float cycle that really concerns me but bulk & absorb... BTW I'm looking at 700ah cells, 400ah min. two banks 24v 700 ah, perhaps 48v bank (s)

does that "well design charger" also include an 80amp solar charge controller?

Just asking here.. I don't know.

Re: Lithium Iron Phosphate Batteries; LFP; LiFePO4 discussions

john p,

How is that daisy-chained "signal wire" used? I read on the Thudersky site that it interfaces with their BMS which, apparently, is used to control a charger. But do you know how does it? In other words, what kind of information or control signal goes through that daisy chain?

Kamala

Re: Lithium Iron Phosphate Batteries; LFP; LiFePO4 discussions

Audredger to be 100% honest im not sure but fairly sure they are 2x400ah batts in one case. I do know the extra terminals are not for battery management

Kamila the signal wire only transmits a voltage signal to a battery management controler. which strictly is not a true battery management controller as all it does is show on a display or LEDs an over or undercharged cell or complete battery , it can then control a relay to turn off the battery charger if fully charged or turn of some device using the battery power if the battery/ies are to far discharged.
you need the individual cell levellers to ballance the cells.
600ma ones ok up to 200ahr but you really need 1.5a ones of you using cells from 400ah to 1000 ah

To further explain about cell charging . you have to think more along the lines the battery charger is only putting out a"big" charge when the battery is "empty" as it approaches "full" the charge is tiny and the first ones to reach "full" just need to drop tiny amounts of charge so the others can catch up.. But the thing to remember is the cell differences when nearly "full" is very small usually something like this best one 3.65 worst one 3.52 or something like that . that is why 600ma is adequate.. and you not going to get"controllers popping like pop corn. I have measured a 48v chain and only found about .12 difference on average between all. dont lose sleep about it but do use ballancing modules if you can redilly get 1.5a ones use them

Re: Lithium Iron Phosphate Batteries; LFP; LiFePO4 discussions

It looked to me like two +'s on one side and two -'s on the other... figured it was to handle the amperage.. may just stick with 400's or 700's
Thanks