Solar panel not gives it's max power - please help

[PNjunction]

Sorry - but this is so ridiculously UNSAFE that I think it borders on a troll. You didn't mention how you "matched" those cells when you made an array out of them. Did you get out your ZTS load tester?

Thinking and hoping won't bring back blown off fingers or a burned down house.

[billvon]

ok, it looks scary...
But I don't overcharge them or overheat them. I think in normal conditions it will not explode.

Here's what happens:

1) One cell gets a little higher in voltage. Not by much; just a little, due to manufacturing tolerances.
2) Let's say you are charging at 12.6 volts. That means each cell should get 4.2 volts; that is the max the cell can handle.
3) Since one cell is higher in voltage your actual voltages are 4.15 - 4.3 - 4.15 volts. The second cell is overcharged and is damaged just a bit.
4) You cycle it again. The damaged cell does not accept as much charge due to the damage.
5) Since one cell is damaged your actual voltages are 4.0 - 4.6 - 4.0 volts. The second cell is now seriously overcharged and is starting to plate out lithium.
6) The pack doesn't seem to be working as well - so you cycle it more often.
7) Now the voltages are 3.8 - 5 - 3.8. The lithium plating finally bridges the gap between the electrodes. All the energy of the pack is discharged through the lithium dendrite.
8) The aqueous electrolyte breaks down into a mixture of oxygen and flammable gas due to the heat. The dendrite vaporizes from the energy and a fire begins.
9) The fire heats the other cells; they release oxygen and flammable gases and the fire progresses.

This is what happened to older laptop batteries that tended to explode.

How do you avoid this? Via an external, pack-spanning protection/balancing circuit. Soldering a bunch of packs together does not get you that.

As I know, these batteries have a protect circuit. Hope it will help in normal use.

Not if you are just "soldering 20 bateries to 12V block."

[PNjunction]

Good stuff Billvon - although I can already see guys armed with a voltmeter reading between the lines trying to outsmart the safety concerns.

Ok, here is the thread recommended:

http://www.candlepowerforums.com/vb/showthread.php?294844-Charging-Lithium-Batteries%97rather-Balanced-and-in-Series-or-Parallel

Using only a voltmeter won't tell you about the *capacity* a cell has - and this has to be matched to the others. ZTS testers are commonly used. Charging is designed for the *lowest* capacity cell / bank. CRAP cells, mixed manufacturers, wrong voltage setpoints, despite a cell's supposed internal protections, etc can leave you without fingers or a house.

To the op: I BEG you to just get hold of a sealed lead-acid, and try this again. Preferably with a larger battery.

[MUHAMMAD FAIZAN]

Irradiance VS efficiency

Dear,
Please have a look at the post ,i have posted and give your precious comments.

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[SunEagle]

Dear,
Please have a look at the post ,i have posted and give your precious comments.

--- Mod Note: Are you referring to a post in another thread? If so, please provide a link.
It is not considered good behavior to try to drive traffic to your thread by seemingly irrelevant links in other threads.

Especially a thread that is 3 years old.