need help wiring headway 38120S 10ah lifepo4 cells

hello all,

Hope you are well. I am admittedly new and dumb at this. I need help wiring (and then properly charging) 16 headway 38120S 10ah lifepo4 cells to be 35ah or better, ultimately to power a 12 volt boat trolling motor (which is 62lb thrust)

I sound like i know more than i do but the story is:

1) What i built before to power things:
8 cell pack of headway 38120S 10ah lifepo4's, with a 50 watt solar panel to charge it when not in use. Also has a solar charge controller to manage that. (The final product is basically like this:

or http://laserhacker.com/?p=92). It worked well but had no stamina compared to the interstate 35Ah deep cycle battery (DCM0035 agm deep cycle: https://www.amazon.com/gp/product/B005CLPOQM/ref=oh_aui_search_detailpage?ie=UTF8&psc=1) that i am now trying to replace with these headway lifepo4 cells.

2) What I am trying to build now:
Just want to upgrade the above to be 35Ah or better. To match the deep cycle, was told i needed to increase the Ah and add 8 more batteries to arrive at 16 total headway 38120S 10ah lifepos cells for a 40Ah battery pack.

3) What i want to power with new battery pack: 62lb thrust electric trolling motor, DC 12V
http://newportvessels.com/electric-trolling-motor-62lb-thrust-saltwater-l-series/

4) problem A:
I need to know how to connect the cells (as my attempts have not done what i wanted.) i can put 4 cells in series and get 12 volts. But i need to add the 12 or 14 remaining cells i have to get 35Ah or more but keep it all at 12 volts to hopefully get the stamina of the interstate 35Ah battery. And i want the batteries in more of a cube shape rather than a long line of batteries of course.

5) big problem B:
i got the new Lifepo4 cells. But I likely ruined some or most of them since i was trying to charge them all, and i wired them all up as parallel and attached a standard agm/6/12v battery charger to charge them. (This is the charger: Schumacher SC-1200A-CA SpeedCharge 12Amp 6/12V Fully Automatic Battery Charger at: https://www.amazon.com/gp/product/B000BQSIWK/ref=oh_aui_search_detailpage?ie=UTF8&psc=1).
Now i have 4 of the cells that still show 3.3 or so volts with a multimeter, 4 or 5 of those cells that show anywhere from 2.0 and 2.6v, and the rest of them seem to show between .500mv and like 1.8v.

6) how many of those cells are not ruined and how many are not ruined and recoverable ?

7) if any are recoverable, how?

8) guess there is something about balancing the cell? Not sure how or why. My previous 8 cell build did fine and I never balanced it and it charged with the solar panel.

Then once and if i have to get new replacement cells, how to wire it up, as described in #4 above.

MANY THANKS in advance with any insight you can share.


Other info Fwiw
https://m.youtube.com/watch?v=erS3b22FgmU

Lifepo4 cell info is pasted at this symbol §§§§§ below, or visit here: http://www.evassemble.com/index.php?main_page=product_info&products_id=18

--------------------------
§§§§§
Model: Headway 38120S 10ah cell

Type

38120S

chemical composition

LiFePO4

Nominal Capacity

10Ah

Charging voltage

3.65V

Nominal Voltage

3.2V

Cut-off Discharge Voltage

2.0V

Charging Method

CC/CV

Maximum Discharge Current(continuable)

100A

Maximum Charge Current(continuable)

50A

Cycle Life

1500cycles 1C 100%DOD

2000cycles 1C 80%DOD

Work temperature

Charge -10℃?~ 45℃

Discharge -20℃?~ 65℃

Energy Density

105 Wh/Kg

Initial Internal Impedance

<4mΩ

Dimension(mm)

Diameter

38mm

Length

120mm(152 with screw)

Weight(g)

360

Dimensions of 38120S holder:80x40mm
38120S,38120HP,38140S use same #38 holder
?Shipment can be issue out on 1-3 days after Payment

--------------------------
****
62lb Thrust Newport Vessels Trolling Motor
Shaft Length 40 Inch Adjustable
Volt 12-Volt
Max Amp Draw 58 Amps
Battery
(not included) 12-Volt Deep Cycle or Marine
Circuit Breaker
(not included) 60 Amp Manual Reset
Compatibility Saltwater/Freshwater
Mount Type Durable Nylon Transom Mount
Handle Standard
Speeds 5 Forward & 3 Reverse Speeds
Battery Meter 10 Point Battery Meter
Max Vessel Size 10.5ft-12ft
Motor Weight 23lbs
Shipping Weight 25lbs
Shipping
Dimensions 55" x 20" x 6"
Included Propeller 3 Blade Large Prop
Motor Material Stainless Steel Hardware for
Saltwater
Shaft Material Fiberglass Composite
Max Speed
on 7.5ft Boat 11.19mph
Warranty 1 Year Limited Warranty

++++++++++++++++++++++++++++++++

You wire them 4s4p for an equivalent 12.8V nominal battery pack. You should either use a 4s 60A minimum bms for them or charge them with a balance charger. Don't run the pack below 10.5V. Or 2.5V per cell assuming you want it to last. A 4s4p pack should run 58A fine. If they are out of balance now, you should balance them all to ~3.2V each before assembly. Although this is fro lipo, it applies to lifepo4 too.
http://scriptasylum.com/rc_speed/lipo.html

thanks wesnewell! forgive my ignorance of many of the things you suggested, so here I go with Qs:

You wire them 4s4p for an equivalent 12.8V nominal battery pack.

Click to expand...

sorry, don’t understand 4s4p...so this means wire them with cells that are placed 4 to a row by 4 columns, for 16 total?

charge them with a balance charger.

Click to expand...

where is the best place to get one, amazon or battery space? so many choices there...do I need one to charge just one headway cell at a time or 4 at a time or what? Rather have one with a screen that shows me some numbers. (I know this must sound so elementary to you. sorry)
one of these?
https://www.amazon.com/dp/B0178I2CAM?psc=1
http://www.tenergy.com/01321?sc=59&category=37996
http://www.ebay.com/itm/like/222353609189?lpid=82&chn=ps&ul_noapp=true

Don't run the pack below 10.5V. Or 2.5V per cell assuming you want it to last.

Click to expand...

so for the cells that my multimeter is showing at 2.7 or below, some are like .134mv, what to do about or with those?

A 4s4p pack should run 58A fine. If they are out of balance now, you should balance them all to ~3.2V each before assembly.

Click to expand...

and balance them to 3.2v would be done one battery at a time using one of the battery balancers above, or similar, right?

Although this is fro lipo, it applies to lifepo4 too.
http://scriptasylum.com/rc_speed/lipo.html

Click to expand...

heading over to read this right now.

thanks in advance, very much wesnewell!

alrighty thanks for the link, so 4s4P was not an option, just 4s3p, but I added a row so this is what I would want, right? ツ
http://clients.misenheimer.com/v/AxU9UyCKjvA9moEz3ndy

and so now just to figure out which type of balance charger and to also figure out if I ruined some or all of my cells. maybe the balance charger will reflect that or help me resurrect them?

thank you!

I charge all cells to same voltage. Yes all the same.like 3.4volt. Even better to parallel of cells togethere and charge to 3.4 volt.
Do not put on a higher voltage charger then 3.6volt the max... Please do not make fire.

Be sure the cells you parallel are at or very close in voltage before you wire them together!!!

I would say the cells below 2v are bad, even the ones below 2.5v are questionable.

The charger you showed will work but many others. You will beed balance wires off the batteries to connect to the balance port on the charger, as well the power leads.

Dan

markmm said:

5) big problem B:
i got the new Lifepo4 cells. But I likely ruined some or most of them since i was trying to charge them all, and i wired them all up as parallel and attached a standard agm/6/12v battery charger to charge them. (This is the charger: Schumacher SC-1200A-CA SpeedCharge 12Amp 6/12V Fully Automatic Battery Charger at: https://www.amazon.com/gp/product/B000BQSIWK/ref=oh_aui_search_detailpage?ie=UTF8&psc=1).
Now i have 4 of the cells that still show 3.3 or so volts with a multimeter, 4 or 5 of those cells that show anywhere from 2.0 and 2.6v, and the rest of them seem to show between .500mv and like 1.8v.

Click to expand...

If they were all in parallel, then all were charged to the same too-high voltage (whatever that charger was able to push them to), and possibly at too high a current. Most of it depends on exactly how that charger does things, because it is a "smart" charger, just not meant for this type or voltage of battery.



I would recommend not using any of the cells that were charged with that charger, because you won't know what could go wrong until it does.

It is likely that all the cells are damaged, but in what way or if they are now fire hazards, you would only know by using them (preferably in a controlled environment). Sometimes a cell that has been damaged by overcharging might fall down to it's correct voltage, but be unable to supply current at it's original rate, or hold it's original capacity. Sometimes it's damaged in a way that leaves it "leaky" so that it loses charge all teh time--when such a cell is paralleled with other charged cells, it then drains them, too. Sometimes it's damaged in a way that leaves it vulnerable to an internal short during charge or discharge, and while that might not have enough energy in just one cell to heat it enough to the point of fire, if there are enough other cells paralleled with it, and the internal short is fast enough, it can then heat it to the point of fire.


It is possible nothing at all will happen, and that all those cells above 3v are fine. It just isn't all that likely.

thank you DanD214, 999zip999, amberwolf and wesnewall,

good info and I appreciate you taking the time to help me out with your counsel. very kind and I appreciate it.

so more Qs if you are inclined:

1) for the good cells, to get them to the same voltage, which 'balance charger' (preferably with a display screen) would be best, and do I do that 1 cell at a time or up tto 4 at t time depending on the charger type? is this a good one? (imax mini b6:
https://www.amazon.com/gp/product/B00L5YBJI2/ref=ox_sc_act_title_4?ie=UTF8&psc=1&smid=A2P1F0527LD7PL)

2) a lot of the Balance Chargersay they charge LiPo/LiIon/LiFe but do not list "lifepo4" - specifically. it will still work?

3) so I just dont have any way to see if all the cells are damaged? can the balance charger tell me that? if my multimeter says this or that cell is below 2.5v or 2v then I just give up on it? (where does one take them to recycle/dispose of them?) arg, the $$$$!

4) where do you order your lifepo4 cells from? china for about $19 each and 4 weeks to get? or is there a better way?

THANK YOU!

Mark where are you located ? Life is lifepo4 same. Any cell any one should not go above 3.7v - 3.5v is best.on the low side 2.5volt witch is the same as Zero voltage. Don't go above or below.

Thanks 999zip999, I am located in Georgia, USA.

Here are my main remaining dilemmas. I really appreciate everyone that has chimed in. Learned a lot so far, for sure.

1) for the good cells, to get them to the same voltage, which 'balance charger': is this a good one?
(imax mini b6:https://www.amazon.com/gp/product/B00L5 ... F0527LD7PL)

2) so I just dont have any way to see if all the cells are damaged? can the balance charger tell me that? if my multimeter says this or that cell is below 2.5v or 2v then I just give up on it? (where does one take them to recycle/dispose of them?) arg, the $$$$!

3) where do y'all order your new lifepo4 cells from? china for about $19 each and 4 weeks to get? or is there a better way?

THANKS!

Thanks Matador. While i dont think i understood most of it, I am learning and appreciate you sharing the balancing info!

I'd even be careful joining LiFePo4 cells that are 100mV apart. 3.2 to 3.3V represents a considerable portion of their total energy for instance. I'd aim for closer to 10mV.

markmm said:

Thanks Matador. While i dont think i understood most of it, I am learning and appreciate you sharing the balancing info!

Click to expand...

I also recently questionned myself on the subjects recently : https://endless-sphere.com/forums/viewtopic.php?f=14&t=86547

Is there a way to check if a cell is damaged ????

Well there are indirect ways to know if a cell is damaged :

1 . MEASURE CAPACITY Let's say a cell is rated to give 10 Ah while drained at 2amps from 3.6 volts to 2.5volts.... using your Imax B6 in discharge mode, you shoud measure close to 10000 mAh (10Ah) of capacity.... If you get a lot less (eg 6 Ah or 60% of the original capacity), then the cell has been damaged badly.

2. MESURE ABILITY TO HOLD SAME VOLTAGE FOR A LONG RESTING PERIOD : If you charge a cell to top voltage it is rated for... i.e : 3,60V for a LiFe(PO4), but it leaks voltage for no reason even if you dont use it, it might be a bad cell that has developed a short.... the short will act as a heat element.... dissipating precious energy stored to wasted heat.... discharging the cell, and dragging down other parraled cells with it... sometimes to the point of overdischarging and damaging other otherwise good cell with it

3. MEASURE SALVAGE VOLTAGE : LiFePO4 is one of the "safest" lithium chemistry for fire hasards and explosion. But as a rule of thumb, if a cell has been discharged to a voltage that is below the minimum rated voltage (consult headway manufacture datasheet for your type of cell, such as http://www.litrade.de/pub/HeadWay%20LiFePO4%2038120__%20Specifications1.pdf ) then it has undergone chemical deterioration and will never perform as it should have. It migh be dangerous to force a charge on an overdischarged cell as it may overheat and trigger a sort of chain reaction, culminating in thermal runaway (cell venting or exploding if it has no pressure release valve). Dont use overdischared cells. Same foes for overchared cells.

4. MEASURE THE INTERNAL RESISTANCE: this one is for more advanced users... and generally requires special equipement.... There are Impedance meters that measure cells resistance with high frequency AC current. You can also mesure the IR using DC current measurements and a set of resistors and easy physic formulas like in this video :

[youtube]3OEJ6eok-Zs[/youtube]

Let's say headway says its cells has around 5 milliohms impedance (AC resistance) and you measure 50 milliohms with your meter.... than the cell is going or has gone bad... higher resistance means the cell will not be able to deliver as high of a current without heating (and thus degrading even furthermore) a lot... thats bad.
If you dont have a impedance meter.... use the method in the video to caculate DC internal resistance..... Maybe the headeway would be aroud 10 to 15 milliohm DC resistance brand new.... if you get 500, than your cell is clearly ruined.... higher resistance correlates with voltage sag under load.... following the formula delta V = R x I.

I'm personnally in the process of testing and caracterising used 18650 cells from makita tool paks to make an ebike battery... for inspiration, here are my results until now :View attachment Makita VTC4 cells from doctorbass.xlsx

But even all these methode, sometimes you just wont know if cell will have a reduced life from not yet revealed damage.... the 4 test i talk about are not infaillible, but should give you a food idea, especially if you combine them togeother...
Sometimes I wish I had an X-ray machine or a high resolution CAT-Scan... to diagnose my cells.... to expensive though

All these test can help you finding the bad cells but it will not garantee that all cells left that passed these tests are 100 % good cells... although it increases your chances. Hope this helps.

In regards to charger, The imax B6 is only a 50W charger. Your 40ah battery pack is 512wh, so it will take ~10 hours to fully charge the pack (512/50). If you want to charge it in 5 hours, you need a 100W charger, etc.

Markm hard to say what is a safe low voltage it could be different on headways and or A123 or cheap Chinese Lifepo4. A slow discharge over months is different than putting a 12-volt charger on a 3.5 volt cell and ends up at 2 volts. The second scenario sounds a lot more dangerous to me.

thanks wesnewell, Matador and 99zip999,

really, really appreciate the help. so much to learn. great to have peeps like you with the mad skilz!

Matador, that list of tests for what shape my cells are in, that is awesome. I did go ahead, not knowing any better, and ordered a "Genuine SKYRC iMAX B6AC V2 Dual Power (6Amps,50Watts) LiPo,LiHV,LiIon,LiFe,NiCd,NiMH,Pb Lead Acid AC/DC Professional RC Balancing Battery Charger & Discharger (Version 2) w/ Micro USB Port by SkyRC" So hopefully that thing wil help me test them.

so if it takes a long time to test them since it is only 50W (whatever that means!), well, then it takes a long time.

best test the cells independently? guess I would need to do them 1 by 1, correct? not screwed into one another like in series.

so I think my plan is this, again, not knowing any better but gleaning the good info from y'all:

1) test each cell with the new battery balancing charger. somehow determine which ones are good, using Matador's damage tests and the charger's screen, hoping they are or will get to 3.2V. (38120 3.2V 10Ah headway Lifepo4 battery Cell). is a digital multimeter too crude of a tool for this, for a 'second opinion?'

2) if they do not get to and stay (when not in use) at (*EXACTLY*?) 3.2V, I guess they are bad and I throw them out/recycle

3) the ones that are good, I make sure they are all at 3.2V ("balance them"?) and then I wire them like this: 4s4p
http://clients.misenheimer.com/v/AxU9UyCKjvA9moEz3ndy

4) lastly, I order new 3.2V 10Ah headway Lifepo4 cells to get back up to 16 total cells that will give me 40Ah, I think. I have bought them various places but where do you buy them?

thanks x 101010101010

hey everyone, would love to get this last bit of feedback from y'all's vast experience and kindness! I need to determine which of my cells are good and how to use a balancing wire.

A) I got this charger: Original SKYRC iMAX B6AC Version 2 Digital. I
- do I connect 2 batteries at a time or more?
- I connect the positive to the positive and the neg to the neg of course, and it will discharge.

BUT to charge, do I need to also add an addl balance wire? (it complains that there is not balance connection found)

Exactly where do I add the balance wire, both on the charging unit and to the cells?

B) if they do not get to and stay (when not in use) at (*EXACTLY*?) 3.2V, I guess they are bad and I throw them out/recycle?

4) where do you buy your 38120S 10ah lifepo4 cells from?

THANK YOU!


LiFePo4 Headway Cells

Balance wires hook up the same on all battery types. And this is how.
http://scriptasylum.com/rc_speed/lipo.html
The plug plugs into the balance port of the charger. It's a jst-xh port, so you need a jst-xh single plug.
Don't make this hard. It's simple.
https://www.youtube.com/results?search_query=how+to+parallel+charge+

thanks wesnewell
-so basically plug the wire with the jst-xh end into the port on the balance charger;
-then take the (2) negative wires coming from other end of the jst and also connect them to the negative ends to EACH of the TWO (or more) batteries
-then take the 1 positive wire coming from other end of the jst and also connect it to the ONE positive end of the battery.

should I connect them in series, I suppose (end to end)

how many 38120S 10Ah cells should I connect and do the above to? (2, 3, 10, etc.)

wil more than 1 battery balance if more that 1 is attached? or do I need to do that 1 by 1?

some of those links you sent talk about charging in parallel but I think I heard you should charge in series or is that not right?

thank you again.

Read this.
https://endless-sphere.com/forums/viewtopic.php?f=14&t=39666

alrighty, doing that next, thx

Hello, I have sixteen of these: 38120S 10Ah Headway Energy Cells, wired to be a 12v40aH cell. (Pls see uploaded pic). Am using it to power a 12V, 62lb thrust trolling motor and a fishifinder. (I did all the balancing before assembling into the final cell). i am using a solar charge controller (tried pwm and mppt) to charge and recharge/maintain.

Setup works fine but i have 3 questions:

1. What should the "full" charge of this cell be? Right now it is staying at 13.2.V. (Showing on solar charge controller and on standalone multimeter. Should it be higher, lower? (Perhaps I am just used to my lead acid battery's full charge being between 13.7 and 14.2V)

2. Running the trolling motor for roughly 2 hours (at highest speed) expired the cell, much shorter than I thought.

3. When solar is not avail, I dont think i can use a standard 12V smart car charger to charge the battery properly, right? But can i use this other brand smarter charger, since it has various features for lifepo4 battery:

http://amzn.to/2rtcCCt
CHEERSON Original SKYRC iMAX B6AC Version 2 Digital LiPo LiIon LiFe NiMH NiCd 2S 3S 4S 5S 6S RC Battery Balance Charger and Discharger with DC PC USB Port Temperature Port

**Thank you very much in advance.**. And happy Day of the Dad to whom it applies.

Mark

Typical charge voltage for LiFePO4 is 3.65v/cell, so 14.6v for your 4s pack. At a lower voltage, it will charge to a point, but you will not get full capacity. Try increasing your voltage.