Planing CanView and BMS+ conversion with lithium

charger is payed for ;-)
3-4 days to get here

regarding my monitor the discharge of 1 cell one is the bent version i have made pictures of before
17:47 cell1 cell2
17:47 3,623 3,609 ( did not balance charge )
21:13 3,608 3,606
next day
22:22 3,608 3,604
08:00 3,598 3,598
12:29 3,598 3,598
1810 3,593 3.594
2333 3,588 3,594
next day
0900 3,588 3,59
it seems that the cell that was bent also charges higher and faster discharge.. if this is because it was bent... maybet the NANO part of it got mixedup when bent.

 

I would send it back if they can change the max voltage. 290v / 72cells = 4.02v which will kill a cell or two if your BMS fails.

 

they can not adjust it
they just sell a large order of preset chargers for thunderskys etc. they got in stock.
i will see what happens
the cells wil take in less amps when getting full so maybe the charger noticed this and go in to CV sooner
and if not i can always adjust it.

edit
the last 4 celllogs from the UK arived today!
now i have to wait for the balance boards i geuss tomorrow or 1 day after that
and the charger ending this week i think

 

Which balance board did you purchase?

 

Balancer 300mA für 1 Zelle LiFePo4 LiNANO® Lastmodul, Lipopower, LiNA

EDIT
and the boards have arived!:cheer2:
tomorrow or Friday the charger wil get here

EDIT

i tested one board and it got hot when i put more then 300mA into the cell the voltage go's up to over 3,7 volts
when i put less amps in ( 200mAmps ) the charger went up in voltage but the cell stayed at 3,69 volts so no overcharge ( max 3,8 )

edit
ok further testing

@ 0,1 amps 3,691
@ 0,2 amps 3,701
@ 0,3 amps xxxxx

so i have to set the charger to 0,1 amps charge and not higher.. because then i have a problem
3,691 is just within what i think is acceptable for me.
attached the curve of these bleeding boards
they are for cells with a max voltage of 4 volts but for top balance and some protection they are OK i think.

 

They are not too bad. They will burn off about 300mA when they reach 3.8v. According to the graph they start burning at 3.68v. My miniBMS generally start burning at around 3.5v. Along as you set your HVC to 3.8v it should be OK. You need to terminate charging as soon as any one of your cells reaches 3.8v.
Generally cells are fully charged when they have a resting voltage of 3.35v or higher. The difference between 3.68v and 3.35v is very little charge. So setting your HVC to 3.8v will maximize your top balancing at the end of charging. Your balancing boards are only designed to burn off charge at the end of charging and not at any other time and that is why they call it top balancing. After charging is terminated by your BMS HVC the boards will keep burning until cell voltages lower to 3.68v.

In your case the charging has to be terminated by your BMS HVC signal due to having a charger with a too high maximum voltage. Otherwise you may overcharge a cell. If you manage to get a charger with a maximum voltage setting of 3.65v x 72 cells = 262.5 v then your charger might go into CV mode if your battery pack is already well balanced and finish charging completely without being terminated by the BMS.

Most of my A123 cells were discharged to different levels so I had to manually charge some of them to bring them to a close voltage to the rest of the pack. But once your pack is close to being balanced the top balancing will become more accurate every time you charge. One cell was delivered with a discharge to 2.0v. almost empty.

 

i charged 2 cell yesterday using these boards at 22:12 finished
end voltage was 3,691 now the next day at 09:20 its 3,657 ( 5mv diff ) and 3,662 so i geuss they are steady
during that time the balance board where and still are connected.

 

There is a small amount of battery cell self discharge plus the balance board loading which would account for the 5mV difference. I assume that the charger is now disconnected.

 

yep
hope the charger gets here today
I do my first bench charge next week i hope..

edit

http://www.gebattery.com.cn/geb/EN/ProductList.asp?SortID=156&SortPath=0,133,156,

looking at this graph i would say out of gas mode would drop to 3 volts constant until empty?
did you also experience this?

 

i did a 1 amps current draw to see what happens

did not go down to 3volts with the cellog 8s logging i would have a nice log but now its hand manual logging ;-)

its seams to drop slower and slower.. at this rate a 10ah until 3volts.... i geuss when its dropping slower if i went on logging it would be higher then 10ah.
i hope!! 10 ah is low,., i would want to have 16ah - 3,6 to 3 volts.

 

at the moment i am a bit afriad that the charger that i am getting will get the voltage up to fast.
when i look at my RC charger that i use to test one cell it voltage gets up fast
and when i then stop charging the cell settles down to a wy to low voltage!
it did not get a lot of charge

i use the lipo 3,7 Nom. volts charge voltage to get past the 3,6 max of the lifepo4 max voltage setting this charger got ( its a imax B6 ) so i simulate the higher voltage the TC charger elcon 1500 will want to go to.
and the voltage go's up like crazy at 5 amps i have to stop because the bleeding board can ofcourse not handle 5 amps and the voltage go's up to 3,75 and higher..
when is stop these drop down fast also.. so i geuss they are not getting a high charge.

i am now discharging a cell to 3 volts with 1 amps what would take around 16 hours?

after that i will charge this cell back up using the 5 amps 3,7 volts setting and see if when these are depleted to 3 volts if they get up on voltage fast again or not..
i hope they dont because if they do then i think the CV voltage is way to high with 292 volts

 

UPDATE on the cell test

yesterday i put a 1 amps discharge on a fully charged cell.
i use a RC balance charger that also counts the mAmps and time.
i have it set at max 16ah pull and max down to 3,0 volts

it took 950,06 minutes for it to do a 16ah discharge and the end voltage was still at 3,202 volts....
so there is more! i will now again start to discharge from 3,202 ( i went up to 3,208 ) and see when it hits 3,0 and how many amps i got out of it by then.

edit
some link posted on the DIY ev forum

http://www.mpoweruk.com/lithium_failures.htm

EDIT
almost at 3,0 ( 3,041 ) volts
i desided to go to 2,9 because in my case ( 72 cells ) thats 210 volts ending voltage on the prius with the BMS+ ( or bms2 its the same )
i have taking out a extra 1,7ah at this point what would be a 17,7ah

so when charging to full +3,65 and down to 2,9 volts i get more then 17 maybe more then 18ah.
according to the A123 sheet the lowest voltage is 1,6... but that seems a bit to low and i can not go past the 2,9 volts because of the prius oem battery and DC system voltage of the prius.

EDIT
ok finished
2186ah more.
during al that time i got the cellog connected what is pulling total 15mAmps from this one cell ( 30 total ) so taking that into the current taken out of the battery

18,886 ( 16,7 first to 3,0 and 2186 second to 2,9 ) + ~282mAmps = ~19,168Ah. from this cell.
thats nice and i am not even down to its lowest capacity.
so a 80% DOD of ~16ah is easy to do and prolong battery life without losing the expected range....
just lets hope when the battery pack is completed i dont have any cells that are way below this.

i can not test al 72 cells this way.. it would take 16 x 72 hours or 20 days non stop discharging.

EDIT
voltage did get up a little to 2,905 after stopping the discharge
I start a charge now on this same cell to 3,6 volts
lets see how many Ah wil go in.
If that would be ~16ah i am happy ;-)

EDIT
mm strange i used like 80 watt out of the main ( power meter ) and put 15,5ah back into the cell but the cell voltage is art 3,368 volts.. i would expect it to be higher now.. well i have a cuttof set at 19,6ah then the charging will stop.
if the voltage is stil really low i will go on and charge some more ah into the cell.?!

EDIT
ok strange part 2....
when it reached 19,6ah it stopt like i wanted to but at tha point the cell voltages was 3,367 volts.
mains power that was used ~100watts it took 293,46 minutes to get there with a 5.0amps current that was going down the moment ( around 3 or so ) the charger stopped based on t he 19,6ah put into the cell.
i would expect the cell to be higher.. on the other hand.. maybe past 3,3-3,4 there is not a lot more to go into the cells? this would be the 80% soc ?

EDIT
ok from 3,367 to ~3,66 ( it rapedly settle at 3,558 ) it took only 1,611Ah. so i geuss thats the 80-90% part this was at 3,2 amps start current ( i set it to 5.0 but the charger noticed the celles would take no more then 3,2 so i geuss past the 85% point where t he current starts to drop )
after that i could do a charge with 100mA and it kept on charging ( stil doing now ) what would get it to 100% or so.

i am happy i think ;-)

this week i wil hope to test finish the housing so that i can put in the cells and do a benchcharge to see what the charger wil do.
after that i will really finisch the battery case and put it in side the car.
then i still have to place al the cabling the Ev200 contactors etc etc etc etc etc etc.... happy 2013 ;-)

 

nice
so you got like a 240mVolt diff at the end? ~3,09 - ~2,85 ? dont you think that big?

so the andersons did not get warm? your using the SB175 or SB50?

and you did this in out of gast mode?

having not 40ah but 20ah i would expect 50% of that so 22,5miles x 1,6 = 36km max.
thats nice.. and of course thats max situation i am hoping for a nice 20km or 12,5miles of range.

what was your ending voltage?
looking at the graph i would say somewhere 207?

 

anyone having problem charging these at sub zero? ( 0celsius and below )
now where having these freezing temp.. wel here in the EU ( maybe only planitair can answer this )
look at this tread about lifepo4 and charging when freezing
http://priuschat.com/forums/prius-phev-plug-in-modifications/96722-battery-crack.html
Post 6

 

This is where having a Lifepo4 battery made of five battery packs which can each be unplugged and removed is a good strategy for charging. Planetaire takes his five battery plugs inside where it is warmer and charges them overnight. Lithium has a problem with charging at below 10deg Celcius.

Maybe he even sleeps with them under an electric blanket on a really cold night.

 

o this is first time i read this here..i can not take my pack out.
what about mr plugin? not in a cold area?
so i can not charge my pack at current below 3 and freezing celsius.
i need to do a modification that i did not now about using heating pads or sometime like that.. o this is great...
this wil slow down my battery case building...
i wil place the elcon underneeth the cells? maybe that wil heat things up? in the spare tire section.
how warm does this thing get?
i also need to put in a temp sensor to prevent charging below 10celsius....

 

Not a real problem, capacity decreases at low temperatures. Not a problem where I am. This is where having a full spec sheet for A123 cells 20ah pouch cells would be handy. Normally You would expect a maker to include a SoC versus DegC graph.

 

Yes cells stay in my home when not driving. Now with outside temp like -8°C it is interesting. It is also interesting in order to reduce contact oxidation.

ound:

No electric blanket, but in winter the charger heat loss are inside my home. So they are not lost for everyone.

 

Hi Planetaire,

How warm is it inside your home? At 10 degC I would charge at at a low current level i.e. 2 amps. This is where having current control on your charger is handy.