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

[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...

[snaker]

Glad your low cell survived, snaker.

Out of curiosity, how many Ah was returned?

I charged it in 2 stages. Firstly, I charged it from 2.7V to 3.2V at 2A => 3Ah returned. Then I charged it full at 12.5A => 73.5Ah returned. So total Ah is 76.5Ah.

[shirley_hkg]

After a night, their voltage drops and stays at 3.4xx as expected.

It seems they are of VERY good quality .

[Gnomatic]

Glad your low cell survived, snaker.

Out of curiosity, how many Ah was returned?

I charged it in 2 stages. Firstly, I charged it from 2.7V to 3.2V at 2A => 3Ah returned. Then I charged it full at 12.5A => 73.5Ah returned. So total Ah is 76.5Ah.

Thanks. So that REALLY discharged cell is still full capacity. Excellent!

[Burgerman]

Not nesassarily. What you replace isnt the cell capacity. A high resistance cell will waste energy as it is charged so more goes back.

Te actual capacity is measured on discharge testing. The difference is the efficiency.

[snaker]

I finished full charging all cells and step into the discharge stage. As I remember, when I clicked on Start button I saw the "n CYCLE" option. Now the "n CYCLE" option disappears as the image below. Does it depend on presets? How to get it back?

PL8.png (10.5 KiB) Viewed 11284 times

[Burgerman]

You dont really want it back. Actually I only ever used it on metal hydride.

But:

[c500user]

I plan to buy a PL8 but just saw that the dual version is on special and only $30 dearer.
http://www.store.revolectrix.com/Produc ... l-PowerLab

Any reason not to buy the dual version?

[shirley_hkg]

Check out page 15 of this thread .

[c500user]

Check out page 15 of this thread .

Thanks, I missed that. Shame it is not identical as 2 PL8's.

[Burgerman]

One big issue is that I cannot send you a properly configured preset with extended and corrected parameters. So it will give a few errors periodically.