Author Topic: Iron Edison Lithium Iron Phosphate Batteries  (Read 216 times)

WindFarmer

  • Newby
  • *
  • Posts: 39
Iron Edison Lithium Iron Phosphate Batteries
« on: October 30, 2017, 05:31:09 PM »
Greetings
A longtime customer of mine has ordered a 360 Amp Hour Iron Edison lithium iron phosphate battery set. The batteries have not arrived yet but the wheels are turning in my head on how to set up the charge controllers.
We will have one Classic 200 for the PV side and also new Classic 250 that is being installed as we speak. The Classic 250 came with the Bergey XL1 wind turbine.
I was told by Iron Edison that the Classic will work to charge their lithium batteries. For our 48V configuration they recommend 54.6 for the bulk/absorb voltage @ 1 hour and a float voltage of 53.8.
Could someone that has set up these type of lithium batteries or any type lithium give me an education on what to program differently when coupled to a lithium vs the L-16’s I will be pulling out?......
Thanks for the help in advance.
Marc

Westbranch

  • Hero Member
  • *****
  • Posts: 2532
  • Building System (sort of) 1 weekend at a time
Re: Iron Edison Lithium Iron Phosphate Batteries
« Reply #1 on: October 30, 2017, 05:44:19 PM »
Marc, you have the only 2 numbers you need, Absorb 54.6 and Float 53.8 and set the Absorb time limit to 1 hour.
KID FW1811 560W >C&D 24V 900Ah AGM
CL150 29032 V.2126-NW2097-GP2133 175A E-Panel WBjr, 3Px4s 140W > 24V 900Ah AGM,
2 Cisco WRT54GL i/c DD-WRT Rtr, NetGr DS104Hub Hughes 1100 Sat. Modem
Cotek ST1500 Inv  want a 24V  ROSIE Inverter
OmniCharge3024  Eu1/2/3000iGens
West Chilcotin 1680+W to come

ClassicCrazy

  • Hero Member
  • *****
  • Posts: 1476
Re: Iron Edison Lithium Iron Phosphate Batteries
« Reply #2 on: October 30, 2017, 10:34:19 PM »
Unless they changed from a few years ago I believe that the Iron Edison lithium packs use Calb Batteries. So if you do some research on here you can search for Calb on the forums here and you will find lots of info .

I think a lot of it really depends on what they are using for BMS system .
Those setpoints they gave you sound close to bottom balancing . I have 16 Calb 100 AH cells in series for 48v . I run them up to 56v and set ending amps for 5 amps . Then it drops down to float at 54 volts. But I am doing bottom balancing with no BMS and had the prepare the batteries by draining them all out to same empty voltage. At 56v that is about 80% capacity I believe and it stays away from the point where cells can over volt if they are out of balance at the top. That is the theory anyway .

Usually a top balancing lithium system is 3.65 v  ( LiFePO4 ) full per cell or around 58 v for the 16 cell pack. At that point the charger cuts down the current and lets the BMS fine tune balance each cell.

So not sure if Iron Edison is still using Calb cells or something else and what exactly their charging scheme is - maybe they are doing a type of bottom balancing too . Although maybe they only have 15 cells ? that would put the top at 54.7 v  ( 15 x 3.65 = 74.75)

http://www.calbusainc.com/additional-information/

Larry
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie

AndyH

  • Newby
  • *
  • Posts: 2
Re: Iron Edison Lithium Iron Phosphate Batteries
« Reply #3 on: October 31, 2017, 05:18:52 PM »
LiFePO4 uses the first two stages of charging only - CC then CV.  There should be no float, and the charger should never go into balance.  Once lithium chemistry cells are full, adding more energy drives the cell voltage up rapidly and will damage the cells.  Similarly, they should never be allowed to discharge below 2.5V per cell for the calb/thundersky/etc. large format prismatic cells.

There's no such thing as 'bottom balancing' and a lithium pack should always be fitted with a BMS that at the very least cuts the load whenever any cell reaches 2.5V and stops the charge input when cells reach about 3.65V...3.60V is better.  No two cells are 100% identical - each has a different 'internal resistance' and that value will change as the cell ages - and it'll change quickly if a cell is overcharged or over-discharged.  The weak cell will always hit low voltage first under load, and will hit high voltage first when charging.

Most BMSs switch in a resistor to keep high cells from being overcharged.  It's important that the charge current is kept low once the charger switches from constant current to constant voltage for the 'absorption' phase.  For example, if the BMS can only convert 1/2W of energy to heat, pushing 1W into the cells can push a cell's voltage over the set point.  Many of the BMSs will terminate charging as soon as the first cell reaches the high voltage cut-off.  That keeps the pack from overcharging, but never allows balancing.  If only 70 or 80% of ultimate pack capacity is used, though, it shouldn't affect pack performance much as most of the energy in LiFePO4 is stored in the 'middle' 80%, and they prefer to be kept there rather than constantly topped off like lead/acid.

WindFarmer - since LiFePO4 carries most of its energy 'in the middle' and only a few percent is stored above 3.6 and below maybe 2.8, they work well as lead/acid replacements.  If the rest of the equipment can handle the voltages, a nominal 48V LiFePO4 pack can run between 57.6V (3.6V per cell) and 40V (2.5V per cell low voltage cut-off).  Staying between those values should provide about 3000 full cycles - narrowing to 54.6V is about 3.4V per cell and is maybe 70% capacity.  Ultimate/never exceed voltages for LiFePO4 are in the 2.1V and 4.2V range - so the MidNite recommendations are very safe and very conservative.  Double check the response of the charge controllers - it's possible that setting a float voltage below the end of the CC/CV voltage doesn't allow float to start - that's a good thing and should work fine.

Andy
(I used to assemble LiFePO4 battery packs for electric bicycles and motorcycles, worked on an analog BMS project, and built prototype packs for a TTXGP motorcycle team.)
« Last Edit: October 31, 2017, 05:28:55 PM by AndyH »

ClassicCrazy

  • Hero Member
  • *****
  • Posts: 1476
Re: Iron Edison Lithium Iron Phosphate Batteries
« Reply #4 on: October 31, 2017, 07:49:01 PM »
Thanks for the info Andy .
Are there any BMS that you can recommend for Calb batteries that will accomplish what you are talked about ?

Larry
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie

AndyH

  • Newby
  • *
  • Posts: 2
Re: Iron Edison Lithium Iron Phosphate Batteries
« Reply #5 on: November 01, 2017, 10:02:41 AM »
Thanks for the info Andy .
Are there any BMS that you can recommend for Calb batteries that will accomplish what you are talked about ?

Larry
Glad to help, Larry.   I shut my business down about 5 years ago and haven't kept up with the BMS market so can't recommend a commercial unit.

If you're in a DIY frame of mind, this open source analog BMS shows how relatively simple the high voltage and low voltage protection can be.  I use this for all of my lithium packs, from LiFePo4 and LiPo pouches for portable ham gear to my 24V off-grid LiFePO4 pack.  https://endless-sphere.com/forums/viewtopic.php?f=14&t=26554   I don't have it signaling my Classic 150 yet, however, and don't recommend manually managing a lithium pack.

At a bare minimum, choose something that absolutely won't let any single cell discharge below 2.5V or be charged above 2.65V and you're golden. 
« Last Edit: November 01, 2017, 09:48:44 PM by AndyH »

ClassicCrazy

  • Hero Member
  • *****
  • Posts: 1476
Re: Iron Edison Lithium Iron Phosphate Batteries
« Reply #6 on: November 01, 2017, 11:45:24 AM »
Andy -
I have a crudely constructed Headway 48v 10 AH lithium ( came that way from China )  poorly mounted and bouncing around on my ebike for 5 years - amazing it gave me so much use despite all the odds against it . But after some of the screws came loose and another time balance wires from the BMS broke I learned a few lessons - especially after the 2 amp charger failed and I tried using something different and found out the limits of BMS balancing - ha ha - finally got it going again . But 10,000 miles not too shabby all considering and it still goes though with a few cell swaps here and there.

My 100 AH Calb 48v set was to give me some experience and I made some mistakes - the first of which was not getting something to protect the pack from going below 40v - no matter what - something unexpected always happens . I think I caught a totally drained pack in time because the pack still has been chugging away .  Sometimes best way to really learn is from problems - though in this case it can be expensive mistakes !

I will check out the link you sent. 

Larry
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie

WindFarmer

  • Newby
  • *
  • Posts: 39
Re: Iron Edison Lithium Iron Phosphate Batteries
« Reply #7 on: November 02, 2017, 03:57:01 PM »
Larry and Andy
Thank you for the information. I will read it more in depth over the next few days. Talk to you soon.
Marc

WindFarmer

  • Newby
  • *
  • Posts: 39
Re: Iron Edison Lithium Iron Phosphate Batteries
« Reply #8 on: November 16, 2017, 04:45:53 PM »
Andy
Great information.
How do you think the Temperature Compensation should be set on our Classics and the Magnum 4448 PAE I/C? Is a Battery Temp Sensor needed at all?
Thanks for the help.
Marc 

mike90045

  • Hero Member
  • *****
  • Posts: 564
    • The Ranch (via facebook re-direct)
Re: Iron Edison Lithium Iron Phosphate Batteries
« Reply #9 on: November 17, 2017, 06:43:59 PM »
A warning about using balance boards in a large system .   Don't   
Charging a pack at 40 Amps, what sort of balance board can handle that?  Most are rated for much less.  if you find them, good for you - but I'm not holding my breath.   Even if you assume final charge stage is 5 amps, a 1A balance board is still leaving 4A going into the full cell
 And then you have to consider the failure rate of the plethora of wires, parts and such.   A factory designed EV, battery and BMS is vastly different than what a consumer can purchase.


There IS such a thing as bottom balance, but you have to be sure to cease charging when the the pack reaches the the proper FULL voltage, and use a LVD to insure you don't overdischarge.

Several good discussions about  it if you google search for
"bottom balance" site:solarpaneltalk.com

Top balance has pro/con. So does Bottom balance  don't discount one till you understand both enough to decide for yourself.
« Last Edit: November 17, 2017, 06:54:00 PM by mike90045 »
http://tinyurl.com/LMR-Solar

Classic 200| 2Kw PV, 160Voc | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph )| Listeroid 6/1, st5 gen head | XW6048 inverter/chgr | midnight ePanel & 4 SPDs | 48V, 800A NiFe battery bank | MS-TS-MPPT60 w/3Kw PV