Hobby charger: never charge a protected battery

[Aquanaut]

My hobby charger manual says never to charge or discharge a Li-ion battery fitted with an integral protection circuit. Why is this a limitation? Maybe they only mean series connected packs?

 

[kramer5150]

??? thats strange, what hobby charger are you using?

 

[45/70]

My Dynam DC6 manual says the same thing. I think it is likely just for liability reasons. As flaky as the protection circuits are on most cells, they are just covering their a$$ in case a protection circuit fails.

Dave

 

[LuxLuthor]

I charge my protected cells all the time with several of my hobby chargers.

 

[DimeRazorback]

I use protected cells with mine, nil issues so far :)

 

[pae77]

I use protected cells with mine, nil issues so far :)

Same here.

 

[Battery Guy]

My hobby charger manual says never to charge or discharge a Li-ion battery fitted with an integral protection circuit. Why is this a limitation? Maybe they only mean series connected packs?

I think that they are trying to say "don't use this hobby charger to charge your laptop".

My guess is that they are referring to OEM type lithium-ion cells and batteries. Common examples being cell phone batteries, laptop batteries, camera and camcorder batteries, etc.

Cheers,
BG

 

[alpg88]

i think, the reason why they say so is cuz charger will not "see" the battery , but the pcb.

 

[Aquanaut]

i think, the reason why they say so is cuz charger will not "see" the battery , but the pcb.

If the pcb cuts off the charging voltage at 4.0V, and the charger cuts off at 4.2V, would there be a conflict that could cause problems? Would the charger "try harder" to up the battery voltage?

I am referring to an Imax B6 Ultimate charger:
http://www.skyrc.us/indexhome.htm#/product/Charger/b6200/

 

[TranceAddict]

it will be ok if you only charge a single cell, just be careful with the charging current, set not too high to avoid tripping the protection circuit. When charging multiple cells in series hobby charger will actually output high voltage to counter the voltage drop between each cells, but the first few cells in series might get significantly higher voltage if the balancing leads aren't connected, doing so might trip some pcb which has overvoltage protection, while some might work.
avoid charging protected cells in series with hobby charger, for it may behave undesirably.

 

[Al Combs]

If you had a bunch of them in series with no balancing taps, eventually the protection circuit on the one with the highest level of charge would trip and leave the weaker ones half charged. Not so much a safety disclaimer as a preemptive answer to it doesn't work.

 

[Aquanaut]

So, to confirm, with balancing taps in place, there should be no problem charging protected batteries in series. Correct?

 

[PapaLumen]

Hmm interesting thread as i am just about to pull the trigger on a hobby charger for charging my dozen protected 18650's. I was intending to use balance leads, probably charging 4 at a time.

Would be interested to hear of any actual problems people have had charging protected li-ions in series with a hobby charger, with or without balance leads.

:popcorn:

 

[KiwiMark]

If the pcb cuts off the charging voltage at 4.0V, and the charger cuts off at 4.2V, would there be a conflict that could cause problems? Would the charger "try harder" to up the battery voltage?http://www.skyrc.us/indexhome.htm#/product/Charger/b6200/

No, I don't think you would get anything other than 'connection lost' type error.

 

[KiwiMark]

So, to confirm, with balancing taps in place, there should be no problem charging protected batteries in series. Correct?

I would think that there would be no issue whatsoever. I would also think using balancing taps for charging unprotected Li-ion cells in series would be a good idea.

I've never noticed any difference charging protected vs unprotected cells with my hobby chargers or my cradle chargers.

 

[A380]

By now I'm charging up to 4 protected cells in series with balance port with no problem.

 

[45/70]

It shouldn't make any difference whether the cell(s) are protected, or not. With a hobby charger, if the cells are hooked up properly, the cell can't possibly be subjected to a voltage higher than 4.20 Volts. That's one of the main advantages of using a hobby charger.

If you attempt to charge Li-Ion cells in series, without balancing leads, you're screwing up anyway :poof:, as this will subject cells to voltages higher than 4.20 Volts. This should never be done! :caution: This is improper use of the charger. The balancing leads are there for a purpose, not just a handy option. They have to be used when charging Li-Ion cells in series. :caution:Don't charge Li-Ion cells in series without attaching the balancing leads!:caution:

Dave

 

[Aquanaut]

Comments appreciated. Thanks.

It didn't occur to me that if the protection trips, I would just get a "no circuit". Of course, that makes sense.

 

[Al Combs]

I would also think using balancing taps for charging unprotected Li-ion cells in series would be a good idea.

Hmm, good point. I was thinking in terms of protected because that's what the OP said he was using. But to charge unprotected cells in series without balancing leads is definitely a safety hazard.

 

[45/70]

Hmm, good point. I was thinking in terms of protected because that's what the OP said he was using. But to charge unprotected cells in series without balancing leads is definitely a safety hazard.

Even if you charge protected cells without balancing leads, the cells will not be evenly charged (balanced), as the balancing feature of the charger cannot distribute current to the individual cells, as is needed to accomplish this. Charging protected cells without balancing taps attached, may not cause an explosion or anything while charging the cells, if the protection circuits work properly, and that is a big if, but the cells will not be evenly charged. Now if you attempt to use cells charged in this way (without balancing) in a series application, there is a risk of explosion, as it is possible that the cells could be in radically different states of charge. :poof:

Again always use balancing leads when charging Li-Ion cells in series. They should never be charged in series without balancing. Balance charging Li-Ion cells in series is not an option, it is mandatory.

Dave