PL 8 - Q and A section - How to Set up - Use etc,

[Burgerman]

I am trying to charge the fault cell. PL8 shows an error "SAFETY CODE 34: Wrong cell count" as the image below. It seems that's due to the cell's voltage is too low. Can I do anything to fix this error?

Yes. Connect a high cell as well. Once it starts charging, disconect it.
Or connect the low cell to a high cell, and leave it an hour. Then charge.

[snaker]

I tried to connect a cell that was actually 2.80V. PL8 works fine with this cell, after some minutes charging the voltage jumps to 3.20V.

[snaker]

BM, I do not want to connect the fault cell to higher voltage cells because I am afraid it could harm them. I intend to change the "low voltage restore" in the "Detection" tab from 2.55V down to 2.20V to charge just the fault cell. If PL8 still wont detect it, I will leave it alone and use the rest 16 healthy cells. Is there any problem if I set "low voltage restore" = 2.20V?

[expresso]

Good thing you got 16 good cells to use - always get extra cells for this very reason -

lowering the voltage restore down to even 2V - should be fine - i believe all thats doing is letting the PL 8 start a charge on a low Voltage cell -
which should jump start that cell -

does your charger allow you to lower it below 2.5V ?

[snaker]

It was my bad. 2.55V is the minimum value I can set. Maybe I will leave this low voltage cell alone and continue with the rest 16 cells. They are all ~2.80V.

[expresso]

why dont you try what BM said - connect that one low voltage cell with a good higher voltage cell - dont charge it - just leave them connected for a hour or more - then disconnect them again

it may bring the low cell up high enough for the charger to start charging it

try that- you may be able to get it up high enough past 2.55V - after a few hours - take the cells apart and check the low voltage cell - see what it reads -

if you need more time - leave them connected longer - and check again - till its high enough -

[snaker]

I am charging the rest 16 cells, it will take a week. Everything seems Ok till now. If all 16 cells will be successfully charged, I will ignore this fault cell, no need to fix it. If not I will try some fixes or order a replacement cell.

[expresso]

yes you can do that - but theres no harm to just connecting the bad cell with a good cell and leave it alone while your charging up the rest of them

then in the end you disconnect them and check the bad cell - it may be higher than 2.55V and may be able to charge it up - i wont use it either way - but just to get it going -

wont harm the other cell - just connect them together and leave them alone - you dont have to charge them this way - either way - what ever you like to do -

at least you got 16 good cells - all you need

[shirley_hkg]

Connecting a 2,2V cell to a 2.8V one won't do any harm . THEY ARE BOTH EMPTY .

You may get more than 1 bad cell with this lot , so don't dispose of any one too early .

For ease of mind , tap and go a dozen times when connecting them , before tightening up the connectors . .

[snaker]

I just finished charging the first cell. It looks good, 75Ah as claimed.

I will charge 16 cells that are actually 2.8V first. After that, I will deal with the fault cells.

Shirley, by your experience, are these cells fine if charged at 15A?

[snaker]

In the next days, I will leave my dad charge cells through PL8 base (not software). Does PL8 show a summary on its small screen after it finishes charging? I just want to note the charging time of each cell.

[shirley_hkg]

Shirley, by your experience, are these cells fine if charged at 15A?

That's fine .

However , its common sense to charge an empty cell SLOWLY .

Start with 2A , and resume to higher amp after 3.1V

[shirley_hkg]

Does PL8 show a summary on its small screen after it finishes charging? I just want to note the charging time of each cell.

YES ,it tells every thing BEFORE you press STOP .

PL8 only tells up to 99.99 Ah charged .

[Burgerman]

Didnt know that.

[shirley_hkg]

It has two digits only !

[Burgerman]

The point is a digit.

So instead of 99.99 Ah it can say:
100.0 Ah as its 5 digits still.
Or 999.0 Ah...
Or 99999 Ah even?

The Hyprion software was limited to 15 or 17 hours due to memory limitations. So you may be correct. It carried on and charged anyway. Not sure what the PL8 will do! Or the PC software.

[shirley_hkg]

When hits 100Ah , you will lose first 2 digits .

The mA is still counting , but it's meaningless already , itsn't it ?

CCS no problem but still limited to 16 hours ..

[Burgerman]

40A for 16 hours is 640Ah... Thats bigger than the fastest tesla! So no problems there.

If 100Ah gives 45 mile range approx, That would give us 290 miles range in a powerchair. Probably a little more.

[snaker]

My dad is trying to connect the low 2.2V cell to a 3.1V cell in parallel. Firstly, he connects 2 positive terminals. Everything is fine. Then he connects 2 negative terminals. He follows Shirley's advice, he only taps the wire's head to the negative terminal. We see sparks each time when the wire touches the negative terminal. After that we try to measure voltage and see the low cell's voltage increased a little (about 0.05V).

What should we do next? Lowering the high cell's voltage or continuing to tap the wire to the negative terminal till the low cell's voltage reaches 2.55V?

[shirley_hkg]

USE 2 long thin wires .

Keep tap and go till no spark and wires are not warm .

[Burgerman]

What shirley says. Or just keep tapping for a bit. Eventually thefuller cell will send itspower to the lower cell enough for the charger to start. The fact that theres a spark is a hopeful sign for that low cell. It means its not high resistance.

The reason it refuses to charge is that it can be dangerous to charge some lithium types if voltage has fallen too low. They are being safe. Anything from 2.9 to 3.0V or less is all basically empty... The charger wants to see 2.7V ideally, but will charge at a low rate .5A from 2.55V. At least it will with a cell node connection. It may need 2.7V without that.

[snaker]

My dad is making a long, thin cable. We will see if the low cell could survive.

I see PL8 takes very long time (about 1 hour) to charge the last 1Ah. E.g I set charge current at 15A, I see PL8 takes only 5 hours to charge a 75Ah cell nearly full (74Ah, 3.590V). Then it continues charging in 1 hour just to put 1Ah into the cell. Is there any setting to reduce that last 1 hour charging time? I mean PL8 no needs to charge full 75Ah, it can stop at 74Ah or when the voltage reaches 3.6V or it can continue charging but in a shorter time (i.e 15 minutes instead of 60 minutes).

[snaker]

We just connected 2 cells through a long, thin cable. No spark appears. After 10 minutes, the low cell's voltage jumps to 2.7V. Should I disconnect them or leave them connected in a while (e.g 1 hour)?

[shirley_hkg]

Leave them CONNECTED , and charge at 2A .

Till they are 3.2V , charge them at 15A .

[Burgerman]

He Leave both connected and charge slowly at 2 or 3A INITIALLY until about 3v. Then seperately charge each cell at 15A each.

[snaker]

The 2.2V cell survived
I charged it full, its charge result is the same as other healthy cells.

[Burgerman]

I suggest you monitor its voltage for a few days. All cells will fall to 3.4xx volts anyway. But if that one drops faster, or lower then you can be more worried!
Or do a DISCHARGE cycle, and read capacity in Ah.. See what it really is. Will take 7 hours.

Connect, choose discharge and wait... Then charge again later on.

[snaker]

After a week, I will discharge some cells (including the low voltage cell) to check their real capacity. I am charging cells in their first time. I see their input capacity is in range 76-78Ah. After a night, their voltage drops and stays at 3.4xx as expected.

[Gnomatic]

Glad your low cell survived, snaker.

Out of curiosity, how many Ah was returned?

[Burgerman]

I see their input capacity is in range 76-78Ah.

Meaning every one was fully discharged...