SCA16 wouldn't top off a 4.0Ah battery to 100%; a TCL6 did it right away

[COBill]

I have a SCA16 which is my preferred charger for the speed.

I had a 4.0Ah battery that was down to 60% so I popped it onto my SCA16 and it quickly charged it to 97%. I left it on the charger and it just stayed there, at 97%, for over an hour.

I took it off and popped it onto a TCL6, which got it up to 98%, 99% and then 100% within about 25 minutes.

Is my SCA16 broken, was this just one of those things, or won't a SCA16 take the batteries up to 100% like leaving them on the slower TCL chargers will?

 

[mino]

That is probably a question of newer /smarter/ firmware on the SCA16. Topping up a pack to 100% is WAY, WAY, worse for the pack than stopping just short of it. Especially if the pack was not fully discharged before that.

Secondly. With a faster charge the imbalances in the cells are more pronounced /the balancing circuit has a limited capacity/. A smart charger will stop charging earlier in such a scenario to ensure no individual cell is needlessly "tortured" by forcing a full charge for the pack.

What happened here, irrespective the specific cause, is the SCA was "lenient" on the pack while you effectively had the TCL force the pack to "take it"..

ADD:
IMO Festool is again doing the typical German mistake here. Being honest with the user instead of lying to him for his own good..
Had the pack reported /falsely/ that anything between say 95% and 100% is "100%", as many brands packs do, you would not be worried and all would be dandy for both your peace of mind and the pack's health.

 

[COBill]

Despite the common wisdom about batteries, that's simply not how I've ever used any of mine; I never let any of mine discharge below 75% no matter what the platform.

For my non-Festool tools, as soon as a battery drops to three of four LEDs, it goes on a charger, I check when using the tool and will swap in a battery that does show full LEDs.

Likewise, my phone goes on a charger whenever the battery drops to 99% or below, and I've always kept my phones on chargers at all times unless I am walking between chargers or am not near one. For example, when I arrive home, my phone comes off the car charger and goes on a home charger where it stays connected; when it's time to get in the car it gets disconnected from the home charger and gets connected to a car charger, and I keep the phone plugged in whenever using it.

(For that matter, I never let my gas tank get below ¾ tank, either.)

I charged this battery because I saw that it had dropped (what for me is) so far; normally they get charged when they drop much below 80%.

But I am willing to bet that you're right, the SCA stops charging at a lower "full" level, so I'll have to remember to use a TCL6 to top it off if I so desire in the future.

 

[onocoffee]

(For that matter, I never let my gas tank get below ¾ tank, either.)

My Gods, the Discipline!

There are stretches when I'm lucky to remember to fill it up to 3/4!

 

[Coen]

Despite the common wisdom about batteries, that's simply not how I've ever used any of mine; I never let any of mine discharge below 75% no matter what the platform.

Interesting. I have my Bosch 16A charger set to not charge above 80%

the balancing circuit has a limited capacity

Do the Festool packs even have a balancing circuit?

(For that matter, I never let my gas tank get below ¾ tank, either.)

Then you are the perfect candidate for a fully electric car, because beating the range of 1/4 gas tank is easy, lol. I drive it down to 60%, then I empty a 20L jerrycan into it, drive it down to 60% again, empty the 2nd jerrycan and then when it's at about 10% I visit the gas station and fill everything up. But the gas tank doesn't become smaller from being fully charged all the time like Lithium batteries do...

There are stretches when I'm lucky to remember to fill it up to 3/4!

Lol what? I never understood why people fill up to anything else than full.

 

[mino]

Interesting. I have my Bosch 16A charger set to not charge above 80%


Do the Festool packs even have a balancing circuit?


Then you are the perfect candidate for a fully electric car, because beating the range of 1/4 gas tank is easy, lol. I drive it down to 60%, then I empty a 20L jerrycan into it, drive it down to 60% again, empty the 2nd jerrycan and then when it's at about 10% I visit the gas station and fill everything up. But the gas tank doesn't become smaller from being fully charged all the time like Lithium batteries do...



Lol what? I never understood why people fill up to anything else than full.

Pretty sure they do.
At least the 5.2 packs do have one and I cannot imagine pulling up a 5-cell pack without a balancing circuit .. did not take apart a 4.0 pack though, so is indeed conjecture on my part.

What I would guess is happening here is the SCA16 charges fast .. the balancing circuit does not keep up .. the charger cuts it off based on the weakest cell as the pack "talks" with the charger it is full. Left alone, the pack would rebalance itself after some time, so that is not a concern. Then when a 97% charged pack is put in the SCA 16 again, it will refuse to initiate a charge cycle - it pointless to do so. The TCL 6 is an older model, likely unable read the pack status info .. so will merrily carry on topping up the pack as it has no way of knowing how/if the pack is full.

 

[Coen]

Are you sure? There is individual cell(pair) monitoring for sure, but balancing? Bosch doesn't have it either. It's one less thing to fail too.

Left alone, the pack would rebalance itself after some time,

Off the charger?

 

[COBill]

Then you are the perfect candidate for a fully electric car, because beating the range of 1/4 gas tank is easy, lol. I drive it down to 60%, then I empty a 20L jerrycan into it, drive it down to 60% again, empty the 2nd jerrycan and then when it's at about 10% I visit the gas station and fill everything up. But the gas tank doesn't become smaller from being fully charged all the time like Lithium batteries do...

Not so much; I would never go anywhere that didn't have a charger and would never start to drive anywhere if it wasn't at 100%.

Also not until you can recharge from 0 to 100% in under two minutes.