Looking for someone who has Lithium Iron Phosphate battery systems knowledge

ajbelcher · February 2015

Looking for someone who has Lithium Iron Phosphate battery systems knowledge - I have some questions regarding the charge controllers which have been built in to some systems I came across - From looking at them they appear to be hooked up in series of 40 batteries for 144 volts per layer and there are 4 layers each charge controller board controls 8 batteries per layer so there are 5 boards per layer - wondering if the layers could be split to give me 48v - I have pictures will pm them if you contact me -

BB. · February 2015

Sounds like an opportunity for folks that want to get into LiFePO4 batteries without spending an arm and a leg.

Let us know how this works out.

-Bill

ajbelcher · February 2015

Looks like it should be able to be turned into 10 160ah 48v strings if anybody has some insight as to how the charge controllers work - as LiFePO4 batteries are not the usual batteries I deal with - and anyone interested and has information that is helpful Id be happy to make some available at a great price - these are all new sealed setups never installed before the company went under

westbranch · February 2015

Al, to start off what brand are they?

LiFePo4 batteries are ~ 3.25V per cell, vs AGMs at 2V so 8 cells for 24V, etc

here is one example should give you some basic info

18 Kwhr Energy Storage System - Lithium batteries 24 Volts connected in series. Pack Voltage Nominal 24 VDC; Pack Voltage Peak 32 VDC; Cycle life 3000 Cycles; Five year prorated warranty. Includes Battery Management system, cell monitoring of temperature and voltage control. Includes fuse and contactor [ battery disconnect]. Works seamlessly with most leading solar charge controllers and inverters. Max Charge voltage not to exceed 28.8 VDC. Cell balancing at .75 amps.

Nominal Capacity : 18 Kwhr
Battery Type : Lithium Iron Phosphate
Battery Voltage : 24 Volt DC
Operating Voltage: 24 Vdc to 30 Vdc
Cycle Life 3000 Cycles
Charge Voltage: 28.0 Vdc Bulk Charge | 28.8 Vdc Absorption Charge | 26.5 Vdc Float Charge
Discharge Voltage: 24 Vdc Max
Max Discharge Current : 350 amps at 80% DOD | 500 Amps at 50% DOD
Max Charge Current : 300 Amps
Operating Temperature -45 deg C to 65 Deg C
Warranty : 5 Years Prorated
Dimensions : 27.5 X 25.6 X 15.35 inches ( L X W X H)
Weight: 450 lbs

hth

ajbelcher · February 2015

My biggest question remaining is the circuit boards which I believe are charge controller/cell balancing controllers - each set of 8 batteries has a wire that goes to the positive and negative terminal of each battery that goes to a parallel port on the board - to the best of my understanding this should be used to balance the charge between the cells it is hooked up to - currently there are 40 batteries hooked up in series on each layer then the 4 layers are hooked up in parallel - if we were to change it to 16 batteries in series and 10 of those cells in parallel will the balancers still work or are they only designed to work at the voltage that the batteries were in the original set up

BB. · February 2015

What brand/model of balancers are you looking at?

-Bill

Blackcherry04 · February 2015

So, if you have 40 @ 3.2 v cells you'll have 10 batteries @ 12 v , and 160 amps hrs each. If your doing 48 V it's going to take 4 of your 12v batteries per string with 2 left over.

Blackcherry04 · February 2015

ajbelcher wrote: »

The standard for these batteries is 8 batteries to make a 24v "cell" in other applications these are 160 batteries in 4 strings of 40 in parallel -The plan is to change this to 10 strings for 51.2 volts well within confines to a standard "48v" string for charging and inverting purposes

the balancers are built in to the case that holds all 160 batteries - attached pictures

Thats doable, first I saw 160 batteries mentioned. 2 strings would make a nice bank.

ajbelcher · February 2015

Thinking most wont need more than one due to the much higher acceptable depth of discharge on LiFePO4 one bank as pictured above should be the equivalent of 2-3 strings of 48v 1600ah lead acid or am i missing something in thinking that - I know you get as many as 8000 cycles if you dont discharge past a certain point and are rated for 3000 cycles at full discharge - we will be trying hooking one up to a system in the next few weeks - after which if all goes well I have a few extras available

Blackcherry04 · February 2015

ajbelcher wrote: »

Thinking most wont need more than one due to the much higher acceptable depth of discharge on LiFePO4 one bank as pictured above should be the equivalent of 2-3 strings of 48v 1600ah lead acid or am i missing something in thinking that - I know you get as many as 8000 cycles if you dont discharge past a certain point and are rated for 3000 cycles at full discharge - we will be trying hooking one up to a system in the next few weeks - after which if all goes well I have a few extras available

One string of 16 cells is only 160 amp hrs @ 48 v.

ajbelcher · February 2015

I meant the entire case which has 10 strings of 16 cells for 48v at 1600ah

Blackcherry04 · February 2015

ajbelcher wrote: »

I meant the entire case which has 10 strings of 16 cells for 48v at 1600ah

Yeah, that would be huge bank. I am not in to them, but it would be nice for someone that was. The BMS is hard to know , usually the controller is set to the pack voltage and the cell boards are 3.2 v and operate individually on the cheap systems and report to the BMS, but who knows on that one.

ajbelcher · February 2015

I guess we will find out when we hook them up - original wholesale price on the bank was 50,000 were designed to go into a solar co op housing development that never materialized - so i have access to a bunch of them at a fraction of the original cost - and a list of people interested if we can get them working in a system

westbranch · February 2015

I was wondering if they used each layer which would be a ~120V set

Blackcherry04 · February 2015

ajbelcher wrote: »

I guess we will find out when we hook them up - original wholesale price on the bank was 50,000 were designed to go into a solar co op housing development that never materialized - so i have access to a bunch of them at a fraction of the original cost - and a list of people interested if we can get them working in a system

One thing about those is the cells are large enough to have lot's of amp hrs without having a gillion connections. Just the cells alone would be in the $30,000 range and that whole setup reeks of quality.

Post back and let us know how it goes.

ajbelcher · February 2015

that is my original guess if by design 120vdc to 120vac is not a difficult conversion but with most solar people on 48v 0r 24v systems trying to figure out if they can simply be reconfigured to put in those applications

Blackcherry04 · February 2015

ajbelcher wrote: »

that is my original guess if by design 120vdc to 120vac is not a difficult conversion but with most solar people on 48v 0r 24v systems trying to figure out if they can simply be reconfigured to put in those applications

They can be used, not a doubt. You just have to decide how you want to sell them and what quantities.

ajbelcher · February 2015

If we can get them working they definitely would be an impressive bank - well designed in a nice neat package - retail was to be int the $70,000 range - am hoping it works in which case i might be splitting a few banks for those who do not need that much power - and cost would be half what the batteries alone would cost you - this will be a one time deal have a limited number available and plenty of interest if I can show one working in a system - and a whole lot easier than trying to get equivalent lead acids into a space as the whole thing weighs 2000# a whole lot less than 13,000# for two 1600ah 48v lead acid strings and should outlast them by many years

eric1565 · March 2015

Can anybody give me names of inverters that work with Lithium Ion batteries? I have some tesla modules (22.2V Nominal, and they swing from 15V dead to 25.2 volts, but all the inverters I have seen only work with Pb voltages. I am also going to have solar cells, and I also want the inverter to charge the batteries when usage is low. Each module is about 5.3 KwH. Any ideas on MFG's that will work? I don't know what voltage I will run, but I have about 12 modules, so I can do a different voltages to optomize the set up. Never done this before, any help would be appreciated.

westbranch · March 2015

welcome, I think the only way, with those voltages, you can use them is with a 24 volt inverter and set your BMS LVD to kick in before you get to the lower 'knee'. OR rearrange the cells to fit into 'normal ' inverter set points.. either 12 or 24V or ? They are just a bit too odd to make work without a lot of fiddling, IMO...

mike95490 · March 2015

Exactly, you are starting just below the 24V inverter ranges, and not much is going to help. If you get another pack, the XW series manages about 45-67V range, that's what I'm doing with my NiFe pack

BB. · March 2015

You might try contacting our host Northern Arizona Wind & Sun and check with them:

http://www.solar-electric.com/inverters-controllers-accessories/inverters/exsiwain.html

Exeltech are a high quality inverter and it seems like they may be able to do some semi-custom configurations.

-Bill

eric1565 · March 2015

BB. wrote: »

You might try contacting our host Northern Arizona Wind & Sun and check with them:

http://www.solar-electric.com/inverters-controllers-accessories/inverters/exsiwain.html

Exeltech are a high quality inverter and it seems like they may be able to do some semi-custom configurations.

-Bill

Thanks. We can run the modules in series to get different voltages;

e.g. we can use:

17.4 min voltage, 24.9 max voltage

34.8 min voltage, 49.8 max voltage

52.2 min voltage, 74.7 max voltage

69.6 min voltage, 99.6 max voltage

It would be ideal to be able to adjust min and max voltage, and perhaps max charging current.

Also needs to have lithium ion charging profile, which is super simple - CC/CV. Just don't want to charge them like lead acid.

westbranch · March 2015

Charging those cells is no problem as the CC can handle the output range needed by those cells. The problem remains, and it is getting the power out of them in a voltage range that the inverter will handle be it a 'nominal' 12/24/48 volt system you decide on using. Yes?

I just looked at Cotek power supplies but the only go to 500W, BUT they have a 15V model http://www.cotek.com.tw/pro371680.html, you might want to contact them...

eric1565 · March 2015

westbranch wrote: »

Charging those cells is no problem as the CC can handle the output range needed by those cells. The problem remains, and it is getting the power out of them in a voltage range that the inverter will handle be it a 'nominal' 12/24/48 volt system you decide on using. Yes?

I just looked at Cotek power supplies but the only go to 500W, BUT they have a 15V model http://www.cotek.com.tw/pro371680.html, you might want to contact them...

See my ideal voltage ranges above. They are slightly flexible, of course.
Don't need to go all the way to 15V per module, 18V would be just fine. (or 36V, 54V, etc)

\edit: made a new thread here. sorry for hijack.

Looking for someone who has Lithium Iron Phosphate battery systems knowledge

Comments

Categories