Help with rech. batteries and Nano charger

I've a question for you gurus: I've a couple of rech. Lithium batt. with no brand name, violet color, named LC16340 A700mAh 3.6v . How can I tell if they're protected or NOT?
Then: Nano charger. Who is the producer? Have you got its link so that I could have its specs?

TIA

Look for a protection circuit. Circuits I've seen were in the form of a disc on the negative terminal, and a strip of metal running along the length of the cell from the board to the positive terminal. The strip can be seen under the jacket.

If you don't see a circuit, assume it's unprotected.

I've never seen a protected 16430 with a capacity that high, so I'm guessing this one is unprotected

balazer said:

Look for a protection circuit. Circuits I've seen were in the form of a disc on the negative terminal, and a strip of metal running along the length of the cell from the board to the positive terminal. The strip can be seen under the jacket.

If you don't see a circuit, assume it's unprotected.

I've never seen a protected 16430 with a capacity that high, so I'm guessing this one is unprotected

Click to expand...

Thanks Balazer.
And what about the Nano charger. Have you got any info?

cheers

as AW or emilion about the nano charger.. i believe it's a china-produced low-end charger.. i haven't seen charging graphs... but i know that it trickle charges when it should shut off so it only gets a 'B' grade.. i want to take my nano chargers and upgrade the chip to the LT4054 charging chip.

telltales also for protected cells.. you can usually see the strip up the side that carries the current and on mine there is a black plastic ring around the positive nipple.

-awr

andrewwynn, thanks you

I should mention that i do use the nano 123 charger almost exclusively for charging my R123s.. just don't leave them on overnight.. i usually pull them of between 4.18 and 4.24V.

-awr

Interestingly, I need to leave my R123 in the nano charger overnight to get it to 4.17 volts. It's not that high when the light turns green.

it might take longer.. or possibly you may have pushed the battery a little hard and it won't hold more than 4.17... i've measured as high as 4.30 from a nano charger.. of course that is just one particular one that's been doing that i should compare to another.

-awr

balazer said:

Look for a protection circuit. Circuits I've seen were in the form of a disc on the negative terminal, and a strip of metal running along the length of the cell from the board to the positive terminal. The strip can be seen under the jacket.

If you don't see a circuit, assume it's unprotected.

I've never seen a protected 16430 with a capacity that high, so I'm guessing this one is unprotected

Click to expand...

I just received my DSD dual-charger and 2 protected 750mAh 16340s from Dae at qualitychinagoods. They have been working great although I have only managed to charge the cells to 4.09V (that could be because I stooped charging after 3 hrs). In fact, using these 2 cells, I managed to run a G90 (9V) bulb on my 6P for 35mins before the light started dimming noticeably.

if they are protected you don't have to worry about the charger over-charging.. let them charge longer and measure.. the % gained is not a lot from charging over 4.1V... in-fact many people prefer to charge to 4.1 or less because it tends to greatly increase the number of charge cycles you'll get out of the cells.

-awr

I don't think the nano charger will charge any cell past the voltage measured on the open terminals. On my Nano charger this voltage is 4.27 volts, and with a cell left in it overnight, it got of the charger at 4.27 volt, so that seems to be just fine. Yes, the green light comes on before it reaches terminal voltage (at about 4.10 volt on my Nano), but that is just to indicate that the cell is now useable. The Nano charger is quite a crude charger, and is probably made from a voltage source adjusted to 4.25-4.30 volts, delivering current through a limiting resistor. The current to the cell starts high and ends with nearly 0 mA if left in the charger. This charge curve is of course not the most time-efficient way to charge a Li-Ion cell (hence the Nanos relatively long charge time), but I think it's quite safe for the Li-Ion cells, and I can't se how it could overcharge it past 4.25-4.30 volts, which AFAIK is within safe limits.

Jan

what he said (i agree).

-awr

Regardless of what the Nano does normally, it has no failsafe. So when using unprotected cells there is some risk that it will burn your house down if you don't charge in a safe place.

'what he said' actually.. 'protected' can be just as hazardous.. there was a post of a major meltdown of a protected cell.. general rule of thumb.. keep insurance on your house... anything electrical can cause a fire is pretty much the rule.

the smaller cells like 600-700mAH and less are far less hazardous then the likes of 18650 simply because of the lower amount of stored energy.

-awr

Just wondering, why don't people seem as concerned about their Li-Ion cell phone batteries? Certianly they have protection circuitry, but their still Li-Ion cells.

If indeed the Nano works as I described (which I still think it does), it does just as good a job of protecting the cell (from overcharge), as a protection circuit built into the cell it self. They act in the same way - namely to cut off current to the cell, when the voltage has reached 4.25 volts. In fact, I would go so far as to say that the Nano is safer, because it is unlikely that the terminal voltage on the Nano should suddenly increase due to a fault, whereas with a charger system that relies on the built in protection circuit in the cells (like Pila for instance), the circuit in the cell could short out, and thereby allowing the charger to overcharge it.

Sean,
Exactly! - And their laptop, and their PDA and so on, not to mention power tools with Li-Ion technology.

Jan

At least they are less volatile than LiPos...

Better chargers and protection circuits have secondary protection mechanisms, like temperature.