Using Pila charger for bare Li-ion

Miciobigio

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Hello,

i've just ordered a Pila charger and some Pila batts to use with my Aleph1 .

I have read in another 3D , that inside the Pila cells there is the circuit that prevent to drain the batt under 3 Volt ( or 3,2 V ) and this sounds fine to me; but it seems that that circuit take care also of the charge process stopping it at 4,15-4,2 volt.
If this is the case , why the Pila charger is so expensive ?
If this is the case i will not able to use the Pila charger to charge also my bare Li-ion /ubbthreads/images/graemlins/icon23.gif

Normally is the "intelligent charger" that know when to stop charging the cells !

Can someone confirm if the charge process is ended by the Pila cell or by the Pila charger ?

Thanks. /ubbthreads/images/graemlins/grin.gif
 

CM

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The cell terminates the charge so you can't charge bare cells with the Pila.
 

SilverFox

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Hello Miciobigio,

I can confirm that you can kill a bare cell in the Pila charger. Death comes by overcharging to a higher voltage than the cell can take.

I tried a bare cell and watched it closely. I got 3-4 cycles on it, then it died.

The Pila cells limit the voltage and properly terminate the charge. The general rule is Pila cells in a Pila charger.

Tom
 

wptski

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I've been charging Pila 168S in a Triton charger for some time. They probably have 3/4 cycles on them with no problems.

Nobody replied to my post about charging two at a time so I'm just about ready to try it myself! I'll try two in parallel. It would seem that the internal circuit would terminate each cell as it becomes fully charged but I'll keep a close eye on them for safety!
 

pyro

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don´t get a pila charger.
get onat that can handle barecells and charge the pilas with that too.
 

LitFuse

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I don't yet have any Pila cells, (soon to change with the arrival of the LionHeart) but below is a copy of another post a while back regarding a bare cell charger. I've been very pleased with it's performance. It will even run on 100-240V and 50/60Hz (with adaptor) and 12VDC. I plan on using it to charge the cells for my LionHeart too. I occasionally even use it to charge my camcorder batts! /ubbthreads/images/graemlins/smile.gif


I use a Lenmar MSC-1 for my bare Li-ions. I did have to "homebrew" the battery holder though. I just got an AA holder from RatShack, chopped it in half, stuck it down on one of the supplied charger plates with double sided tape, and soldered two wires. The whole thing took 10 minutes. This charger cuts out at 4.15V. It takes about 50 minutes to fully charge a 17670 cell. I use a one hour dial type mechanical timer as a safety.

I paid around $50 for mine about a year ago. You may find them cheaper now though. I have been extremely pleased with this charger. /ubbthreads/images/graemlins/smile.gif It even comes with a 12V plug for use in the car.

As I'm sure someone will say shortly, using bare Li-ion cells can be hazardous to your health. Be sure you are aware of the issues and take proper precautions. (or just use Pilas /ubbthreads/images/graemlins/smile.gif )


Peter



charger2.jpg


charger1.jpg
 

Miciobigio

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Thanks LitFuse , i'll let you know , but first i want to try using the Pila-system 168S-150S ( i ordered it today )then i'll decide to use that or to continue use my bare Li-ion.
For now i charge the Li-ion using a Bench-Power supply voltage and current regulated , i use 4,18 Volt and a max current of C , then when the current fall to C/20 i stop the charging process , but is boring ...

If the Pila will give me to short run-time i'll go back to the bare Li-ion and i'll send you a PM. /ubbthreads/images/graemlins/happy14.gif
 

CM

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[ QUOTE ]
wptski said:
I've been charging Pila 168S in a Triton charger for some time. They probably have 3/4 cycles on them with no problems.

Nobody replied to my post about charging two at a time so I'm just about ready to try it myself! I'll try two in parallel. It would seem that the internal circuit would terminate each cell as it becomes fully charged but I'll keep a close eye on them for safety!

[/ QUOTE ]

If the two cells are equal in charge state, they will charge but take twice as long to charge. If one cell is significantly more depleted than the other then it gets more complicated but I think it would be safe to charge them in parallel. However, would charge individually if possible.
 

wptski

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[ QUOTE ]
CM said:
[ QUOTE ]
wptski said:
I've been charging Pila 168S in a Triton charger for some time. They probably have 3/4 cycles on them with no problems.

Nobody replied to my post about charging two at a time so I'm just about ready to try it myself! I'll try two in parallel. It would seem that the internal circuit would terminate each cell as it becomes fully charged but I'll keep a close eye on them for safety!

[/ QUOTE ]

If the two cells are equal in charge state, they will charge but take twice as long to charge. If one cell is significantly more depleted than the other then it gets more complicated but I think it would be safe to charge them in parallel. However, would charge individually if possible.

[/ QUOTE ]
This would be true with a bare cell of any kind but since the Pila has it's own internal circuit to stop the charge, would it matter? I'm thinking that they both would charge and one reaches full so it cuts off while the other still charges to it's capacity. Just a theory! /ubbthreads/images/graemlins/grin.gif
 

CM

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That would be true regardless of whether the cell is protected or not. The pila charger charges at a fixed currrent and charging two cells (again, provided they are identical in charge state and capacity) in parallel will result in half the current to each cell and therefore twice the charge time. In reality, one cell will reach full charge faster since the cells will not be identical. If that's difficult to grasp, I present another analogy. It's like using a water hose with a 1 gallon per minute flow rate and filling a single 1 gallon bucket which would take one minute to fill, and then using the same hose with a diverter to fill two 1 gallon buckets which, if I had done my math right, would take two minutes to fill.

CM
 

PeLu

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When charging two cells in parallel they will be finished in less than twice the time, as only the constant current phase need twice as long.
Most of my cells are much less than half the time in this phase (when starting empty).

Anyway. When you have cells with very different charge state, the more discharged one may get too much current, especially whn the cell had a too deep discharge.
Do not forget that you have charge cells with a very low voltage with only C/20 or less until they reach 3V.
 

wptski

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[ QUOTE ]
CM said:
That would be true regardless of whether the cell is protected or not. The pila charger charges at a fixed currrent and charging two cells (again, provided they are identical in charge state and capacity) in parallel will result in half the current to each cell and therefore twice the charge time. In reality, one cell will reach full charge faster since the cells will not be identical. If that's difficult to grasp, I present another analogy. It's like using a water hose with a 1 gallon per minute flow rate and filling a single 1 gallon bucket which would take one minute to fill, and then using the same hose with a diverter to fill two 1 gallon buckets which, if I had done my math right, would take two minutes to fill.

CM

[/ QUOTE ]
CM:

I have no problem understanding that it takes more time to charge two batteries than one. I'm not using a Pila charger. I use a Triton that I can set the current and max time if desired.

Like you stated, the Pila charger is constant current. So what terminates the charge? The battery? It's been stated not to use a Pila charger on anything but a Pila battery.

Pelu:

The Triton was set for 500ma, so how is one battery going to draw too much current? The Triton whan set to 500ma starts at 100ma while it checks battery condition, it then increses in steps to max setting but whatever the program is, it'll drop to 400ma and so on. If watched, you'll see it go to zero current while it checks the battery voltage and then resume.

I may even take two Pila's that are not even close to being the same state of charge, connect a amp meter to each and monitor it, just to see what happens.
 

PeLu

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[ QUOTE ]
wptski said:
[The Triton was set for 500ma, so how is one battery going to draw too much current?

[/ QUOTE ]

Because one cell may 'charge' the other.
 

wptski

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[ QUOTE ]
PeLu said:
[ QUOTE ]
wptski said:
[The Triton was set for 500ma, so how is one battery going to draw too much current?

[/ QUOTE ]

Because one cell may 'charge' the other.

[/ QUOTE ]
Pelu:

It's been posted, maybe in another section/thread that as long as the cell is protected, it's not a problem.

I even posted that same question in a RC Forum and never got one hit. If it don't happen in the RC community, it doesn't happen at all. Those guys blow up batteries just for fun! They charge batteries in fireplaces, safes, brick barbecues, etc.
 

wptski

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I took two Pila 168S, one read 3.7V and the other 4.0V. Connected then in parallel to the Triton charger.

I set it to charge at 700ma and watched it for thirty minutes. Although it has a temperature probe, I checked it from time to time with a Fluke IR probe too. Barely got over toom temperature!

It wouldn't allow me to connect a meter is series to monitor current. I used a clamp type probe, the type that you connect to a DMM. I wasn't able to catch the point at which one ceased to charge. No excessive current was noticed. I have a idea on how I can monitor both cell's current at the same time!

It finished charging at 1078ma with one cell reading 4.15V and the other 4.16V.

They were brand new cells and this was the first charge.
 

PeLu

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[ QUOTE ]
wptski said:
It's been posted, maybe in another section/thread that as long as the cell is protected, it's not a problem.


[/ QUOTE ]
I've never seen a protected cell which also takes care for the charge current limit at low discharge (but I don't know too many), but on the other hand it is very unlikely that a protected cell gets dischrged too deep (only when stored at high temperatures).

[ QUOTE ]
I even posted that same question in a RC Forum and never got one hit. If it don't happen in the RC community, it doesn't happen at all.

[/ QUOTE ]

Thanks, this is a good evidence.
 

wptski

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PeLu:

I'll go by what's been posted about not using a Pila charger on bare Li-Ion batteries. That's suggesting that the charger has nothing to do with determining the point at which charging stops, so that being, it must be the battery.
 
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