Is my battery dead ? Can I revive it ? Cells only have 10 cycles

I thought I had done everything right ! I left the battery sit at 36 V for winter. When I go to check on the battery since sun came back I was at only 2,35 volt… Each cells are wether at 0 v or 0,35 v

There’s nothing I can do right ? Like all those brand new 30Q cells must go to trash ? IMG_20190218_113543

Was it connected to voltage meter / vesc/ antispark? Mines been sitting in my closet just chilling for the last 5 months… Nothing has happened :thinking:

Lithium based batteries do not get damaged solely from being over discharged.

What will kill a lithium cell is pulling reasonable amounts of power at low voltages. When this happens the electrolyte will “offgas” and build up pressure within the cell. This is what causes prismatic cells to puff. Internal resistance will increase as voltage drops, and any drawn power will cause electrolyte decomposition.

Luckily for you, these cells were not under load at such a low voltage. They simply discharged VERY slowly. This probably did not damage them.

Do NOT try to power anything with them, as this could cause instant permanent damage.

You can likely recover these cells. You’ll need a non-standard charger like a bench power supply that can do CCCV.

Set the voltage to your max pack voltage, and limit the current to 0.25 - 0.5A. The lower you set this, the higher the likelyhood of recovery and the slower the pack will charge. You can do the math regarding how long it would take to charge (5Ah pack at 0.5A would take 10 hours, etc)

You also have the option of charging each P group individually by using the same current settings but setting your voltage to 4.2V. I would highly recommend this over charging the whole pack at once as your series groups are likely out of wack.

Did you say some are at 0V and some are at 2.35?

If they are actually at 0V then those P groups are toast. And you won’t be able to replace them with new cells as the new cells wouldn’t match well with the other recovered ones.

I’m hoping the 0V was just a measurement error. Could you give a detailed list of all the P group voltages?

If the cells are seriously that out of wack, then your BMS is probably what caused it and is toasted.

9 Likes

They just need a little nap :smiley:

pfFhISq

5 Likes

Thanks for the reply guys.

To clarify : the whole pack is at 2,40 v Each P group is between 0,34 and 0,45 V

The only charger I have are regular ones, and a 4S lipo charger… What should I buy to restore this battery ? All the cells are brand new it would be a shame not to try to revive them.

The battery was sitting with just an antispark plugged into it… maybe that’s the culprit

2 Likes

What I would do is to try to charge each individual group separately with some power supply with limiting resistor in between. Take any 5V power supply (like USB power supply) and add a resistor in between say 50ohms will max pass 100milliAmps, Add a mutimeter to check the voltage that it will never exceed 4.2V in a cell. When you have reach say 3.7Volts, you can start charging the next group untill all groups are 3.7Volts. Then you can start charging the pack normally. Some chargers refuse to charge empty cells.

IMG_20190218_154518 I have tried with my lipo charger… No luck it says low voltage and won’t charge @TowerCrisis BMS is charge only

Whole pack voltage : 3,30v at charge port and 4,14 v at output P1 - : 00,28 v P2: 00,28v P3: 0,28v P4: 00,44v P5: 00,45v P6:00,46v P7:00,47v P8:00,48v P9:00,48v P10 +: 00,48v

use nihm to boost up the voltage than use lipo mode to charge to full,

5 Likes

I have tried and I can charge with nihm charging at 0.1 V and voltage instantly raised at 1,23 v for P1

than use nicd and try again or increase the amps but dont do it for too long.

youve gotta be fast

as soon as the group hits 3v switch to lipo immedieatly

I dont mean to be rude Alan but are you sure you can give advice about this kind of thing? I dont want this to result in an even more broken pack

1 Like

Yeah I have to be fast before the voltage drops again ? I am currently charging P1 at 0,2 amps to avoid any stress on the cells. P1 went from 0,28 to 1,79 v in a few minutes of charging

yeah the voltage drops really fast, the nicd part is used to trick the charger.

yes defiantly, i trust myself, but i usually do it on my trusty icharger 1010b+

^revived a lot of dead laptop cells

2 Likes

ah ok, lol

good luck esker :frowning: seems like antisparks are becoming a winter parasite for esk8 :rofl:

Yeah I was so joyful at the idea of riding this board again ! I guess I have to stick with my other builds for now. I already see myself spend the week looking at this charger, hoping I won’t have to build a new battery :confused:

Do you have a lab bench power supply? if so reviving can be much easier…

2 Likes

I wish I had, I want to buy one since months but never took the plunge. Now I regret hahah

1 Like

BTW do you have a good one not too expensive to recommend ?

cant recommend one, as my i charger does the trick most of the time.

you know you can charge at higher amps for shorter periods right (chances are that will boost the voltage up higher and faster)

^not recommend

and why not take the pack apart and do each cell individually? chances are one or two cells are damaged.