Headway 38120s overcharge !!!???

[IRON DOG]

Hi , I got a headway pack maid of 24 series 2 parallel (a38120se) lifepo4 cells .

Yesterday , i got my new adjustable charger , its a Mastech dc powersupply HY10010EX .

I put the charger on the pack whitout the BMS at 87.6 volts ( 3.65 v for 24 series ) .

The charge was looking good , start at 6.5 amp and slowly going down .

6 amps , 5 , 4 ..... 1.5 and then noise " tock , tock " comming from the pack

Unplugged the charger right away and check all my cells .... OH NOOOO .

4 of them are f..k , i check the voltage on those ( 0.597 v )( 0.274 v )( 0.004 v )( 0.001 v )

I try to charge them individually , nothing work still the same , I gess i overcharge them :x

I try to charge the pack whit the BMS , the charger wont start .

(1) I never gona charge whitout the BMS again

(2) I need a good BMS whit leds for this pack

(3) Can i do someting before puting them on shelf , reminding me how dumm i can be ?

(4) I probally gona need to buy some new ones , where ???

 

[sangesf]

After I get my headways, I'll let you know how many I have left over.
(yes, they will be 31280S')

 

[Pure]

For cells

http://www.evassemble.com/index.php?main_page=product_info&cPath=2&products_id=18

For the best BMS option out there.

http://endless-sphere.com/forums/viewtopic.php?f=14&t=26554
http://endless-sphere.com/forums/viewtopic.php?f=14&t=30021

 

[dnmun]

why didn't you monitor the cell voltages while charging if you had no BMS? you have to push voltage well over 4.2V to totally kill them, imho. i did that to one cell with a 5V cell phone charger

 

[IRON DOG]

why didn't you monitor the cell voltages while charging if you had no BMS?

Because it is my first project , my first unfinish electric machine , my first but not my last mistake .

I guess " I have to pay to know " :?

 

[999zip999]

This a expenisive hobby for all of us.

 

[veloman]

Ugh, I just overcharged my headway 38120p (power 8ah version) to 4.18v each, again. I didn't notice any ill effects the first time I did it, months ago.

But for tonight, the bike sleeps outside.

Does anyone know how bad (or not so bad) is it to have them near 4.2v?

They are sitting at 3.38v after running up and down the street.

Such a stupid move to charge with an SLA charger that goes too high for pack. 99.9% of the time I remember to watch it and unplug well before full. I guess I got comfy because lifepo4 is safer. I would never do that with li-ion and won't continue with lifepo4.