winston/thundersag voltage

nechaus

100 kW
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Oct 11, 2011
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Brisbane > AUSTRALIA
Can someone explain to me why the information is saying 4 volts per cell?
have i been charging these cells wrong for the past 2 years?
was under the impression of 3.65 volts max, i always did that with headways and got correct capacity, never bothered testing capacity with the thundersag because always had more than enough
http://en.winston-battery.com/index.php/products/power-battery/item/wb-lp12v40ah?category_id=176

even charts show upto 16 volts?


and then this 4.5 volts?
http://en.winston-battery.com/index.php/products/power-battery/item/ts-lthp250aha?category_id=203
 
i think these have Yttrium as the rare earth metal used in the lifepo4 matrix. i had heard of using 3.9V as charging voltage but never thought it was 4.5V so if you can find out anything from the company it would be useful to know.

i looked at the factory pictures. they show the different manufacturing locations in factory and in the last one there is a guy standing at the end of the conveyor with those big 200Ah cells rolling off the formation charge line and he is stacking them on a pallet beside him.

the entire scene is so immaculate and clean, you would think it had been cleaned up and prepped for a press photo.

but if you look closely you can see a 30Ah prismatic cell under the leg of that conveyor. as though when they cleaned up someone just kicked one of the loose prismatics laying around on the floor next to his station under the conveyor and nobody noticed it when they took the picture. you can see the end of sticking out from underneath.
 
the Yttrium substitutes for the iron in the crystalline matrix. Li Y(x) Fe(1-x) PO4 instead of lifepo4 stoichiometry.maybe they have raised the amount of Yttrium present and that allowed them to raise the charge voltage from their previous composition and previous 3.9V charging voltage.
 
Mmaybe its an "anti-sag" additive ? !...god knows they need it !.
But seriously , there have been some changes as several other companies have increased their charge voltages for lipo also ?.
HK and other LiPo suppliers all have a range of "HV" cells and packs that they recommend to charge to 4.35 v and a nominal of 3.8 v.
http://www.hobbyking.com/hobbyking/store/__51499__Turnigy_Bolt_2400mAh_3S_11_4V_65_130C_High_Voltage_Lipoly_Pack.html
 
This isn't new, I actually remember my friend saying this because we had x4 20ah thundersag 12v series packs on an ebike about 3 or 4 years ago or when ever I first really got into ebikes.. at that stage it just went over my head and i followed the charger settings


I was more concerned I was missing out on some capacity, If i had the time atm, Id do some charge and discharge graphs..
but then again all my thundersky cells are OLD! so pointless
 
dnmun said:
the entire scene is so immaculate and clean, you would think it had been cleaned up and prepped for a press photo.

but if you look closely you can see a 30Ah prismatic cell under the leg of that conveyor. as though when they cleaned up someone just kicked one of the loose prismatics laying around on the floor next to his station under the conveyor and nobody noticed it when they took the picture. you can see the end of sticking out from underneath.


LOL! Good eye mate! That tool is the laser marker, and if everything goes well, it prints a barcode that ties it to it's formation capacity/Ri data collected from formation. They almost instantly burn intricate patterns into almost anything, I sent my phone through one for fun and it nearly hit the lens of my phones camera, and did manage to burn right into the clear plastic of the LED flash.
 
Maybe it's holding up the machine? ;)

Anyway, can be assume 4.5V for a thundersag cell is a mistake or daydreaming? Considering that the best 18650 cells are good for no more than 4.35V due to electrolyte breakdown.
 
Punx0r said:
Maybe it's holding up the machine? ;)

Anyway, can be assume 4.5V for a thundersag cell is a mistake or daydreaming? Considering that the best 18650 cells are good for no more than 4.35V due to electrolyte breakdown.


4.5v would likely be a typo of 3.5V. The capacity difference in charging to 4.5V vs 3.5V would almost nothing, but at 4.5V my guess is you can fill that cell with gas until venting in perhaps under a day.
 
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