Unrelated to lasers.. still powa!

OK, so I have a battery question about Li-ions.
I have a battery pack with a charger, from a makita 10.8v (this one Makita LCT204W 10.8v Cordless 2 Piece Drill Driver + Impact Driver Kit + 2 Lithium Battery 1.3ah : Tooled-Up.com).
The batteries in the unit are dead; they are SE US18650VT (second line T C112VSL19J) models. This pack contains 3 18650's in series through a charge controller, and the pack is rated at (3.6 x 3= 10.8v) 1300mAh, my question is this: When plugged into a charger will the charger aim to reach the optimal voltage (4.2v for li-ions?) after a preprogrammed mAh has been reached (which would at best render the batteries unusable after one or two charges, at worst cause a discharge meltdown/explosion/really bad shit) OR
The voltage is not reached until the battery is full, and only the voltage affects charge time directly, current is not monitored by the charger at all. I have been searching for an answer to this question for weeks lol, please help as it directly influences rebuilding all battery packs with product specific chargers. Thanks, and have some cake.:bday:
Basically can I stick some li-ions with a higher mAh rating into the pack and get longer out of it? Providing they have the same discharge rating.

Okay. Easy example :
We don't care about the brand.
Take 3 identical accumulator with nominal voltage 3,6V. (Battery 10,8V in total)
Your charger's load voltage must be 10,8V +5%<x<+15%
So 12,4V is the maximum you should take.
Your charger max current should be 1/10 of battery's capacity.
If it is 1500mAh, then take a 150mA max current. If you choose more, battery could overheat.
Let's say you took a 12V 100mA charger.
1500mAh/100mA = 15h for full charge. The voltage of your battery should be like 11V instead of 10,8, but it's normal. If you are not sure of the load state of the battery when you connect it the first time to the charger, then check it (for example it will be at 9,9V). Stop it at 11V, this mean it will be charged. Don't let it more than 15h, it could overheat.

I stick some li-ions with a higher mAh rating into the pack and get longer out of it?
=> Yes. If a laser diode requires 200mA and your battery is 1600mAh, you can use them 8hours. If it is 3600, you can use it 16hours.
But the more capacity they have, bigger they are.

the optimal voltage (4.2v for li-ions?)
=> No. 3,7 or 3,8 max cause nominal is 3,6.

And yes, in Li-ion battery voltage is proportional to load.

Aurelienbis said:

=> Yes. If a laser diode requires 200mA and your battery is 1600mAh, you can use them 8hours. If it is 3600, you can use it 16hours.
But the more capacity they have, bigger they are.

Click to expand...

Ok, ty for the time, but thats secondary school stuff .
Li-ions are a bit more fickle in the charge process and I was wondering if the charger is specific to the 3x 3.6v in series @1300mAh or if it is safe to put say 2000mAh 18650's, not what the outcome would be if the battery pack did not explode in a fireball of metal shards and burning lithium. :wave:
I have read people swapping notebook battery cells for higher mAh rated ones, but others say no... confusion.

Edit: just reread your 1st post, I will check the charger, i think it is maybe 12v

Yes you can charge 2Ah with the 1,3Ah you used. Charge time will just be longer.
I said max current should be 1/10 of capacity. Sometimes it is 1/1 and there is no problem if accumulators are good. Just check your charger. What's voltage and max current ?

Customer Image Gallery for Makita DC10WA 10.8v Li-ion Charger
is the back shot of the charger, has a range of output 7.2-10.8v 2.4-1.6A, it is a "quick" charger, so really pumps the amps in there lol and due to the nature of the battery use I would have to get some high discharge (>10C rating iirc) batteries.

Well... If your 1300mAh didn't explode, why would 2000mAh do ?
It's ok. Just don't let the charge last too long, but the charger should stop himself when load is complete.

Call it paranoia on my part lol, after the "safety" of Nimh etc batteries and my own experience of "ok mind the -ve terminal on that pack... ow shit spark.." and then seeing/hearing of home made packs exploding.. safety first lol.
I get the whole protection circuits and how they work with smart chargers but big brands are notorious for cutting corners to make a part manufacturer specific. ty for the info, gonna try it with some bigger cells cus lord if i can find those exact ones.
I dont suppose u know what the second line of digits on the battery means do u?
ty

Uh, most everything that guy is saying is wrong.

It is quite obvious he hasn't worked with Li-ions before because he doesn't even know their voltage. Do not take his advice.

Li-ions are 4.2v at full charge. Definitely do not just hook em to a 12v 100ma wall wart and wait for 15 hours. That's a very bad idea. If you could guarantee it was exactly 12v it wouldn't be extremely dangerous, but most "12v" sources are more like 13-15v. Li-ions need a current controlled charge which will stop when they reach 4.2v.

If the batteries were the only thing wrong with your drill (the charger didn't malfunction causing the batteries to die did it?) you will be able to replace them just fine. Either use some IMRs or some of the new 3000 or 3100mah sanyos. I'm sure the 1300mah original batteries were IMRs so if you got standard Li-ions at 2000mah they would have much higher internal resistance and probably get pretty hot at the current the drill runs. Higher capacity doesn't always equal higher discharge current, internal resistance plays a big role there.

The batteries died cus of a 20foot drop off some scaffolding, bent a battery casing.

benmwv said:

Uh, most everything that guy is saying is wrong.

It is quite obvious he hasn't worked with Li-ions before because he doesn't even know their voltage. Do not take his advice.

Click to expand...

Seriously ? Nominal voltage isn't 3,6V (or 3,7 depending on the accumulator quality) ? Are you kidding me ?

benmwv said:

Li-ions are 4.2v at full charge. Definitely do not just hook em to a 12v 100ma wall wart and wait for 15 hours. That's a very bad idea. If you could guarantee it was exactly 12v it wouldn't be extremely dangerous, but most "12v" sources are more like 13-15v. Li-ions need a current controlled charge which will stop when they reach 4.2v.

Click to expand...

When I say 12V, it means 12V on a voltmeter.
You are right, the load voltage is 4,2V. When I make my own chargers I use +5<x<+15% as you have seen, and +15% is exactly 4,13V. Getting a little lower isn't dangerous, don't you think ?


I am really wrong is the load current which shouldn't be so slow. And getting the battery at 11V instead of 12,6 won't make any danger too (even is they are not fully charged). But saying most everything is said is wrong is a bit too much.

Aurelienbis said:

Okay. Easy example :
We don't care about the brand.
Take 3 identical accumulator with nominal voltage 3,6V. (Battery 10,8V in total)
Your charger's load voltage must be 10,8V +5%<x<+15%
So 12,4V is the maximum you should take.
Your charger max current should be 1/10 of battery's capacity.
If it is 1500mAh, then take a 150mA max current. If you choose more, battery could overheat.
Let's say you took a 12V 100mA charger.
1500mAh/100mA = 15h for full charge. The voltage of your battery should be like 11V instead of 10,8, but it's normal. If you are not sure of the load state of the battery when you connect it the first time to the charger, then check it (for example it will be at 9,9V). Stop it at 11V, this mean it will be charged. Don't let it more than 15h, it could overheat.

Click to expand...

Aurelienbis said:

Seriously ? Nominal voltage isn't 3,6V (or 3,7 depending on the accumulator quality) ? Are you kidding me ?



When I say 12V, it means 12V on a voltmeter.
You are right, the load voltage is 4,2V. When I make my own chargers I use +5<x<+15% as you have seen, and +15% is exactly 4,13V. Getting a little lower isn't dangerous, don't you think ?


I am really wrong is the load current which shouldn't be so slow. And getting the battery at 11V instead of 12,6 won't make any danger too (even is they are not fully charged). But saying most everything is said is wrong is a bit too much.

Click to expand...

You seem to be spreading disinformation to members...

The Nominal Voltage for a Li-Ion Battery mentioned in the OP
is 3.6V...
The Fully Charged Voltage of the same Li-Ion Battery is 4.2V...

A recommended and safe charger will charge that battery to
4.2V and stop charging.

Recommending to charge Li-Ion batteries with 12 Volts is just
irresponsible...

I suggest you do some research and reading on the charging
characteristics of Li-Ion batteries before sharing your vast
knowledge....


Jerry

You can contact us at any time on our Website: J.BAUER Electronics

You misunderstand what I said.
I said : 3,6V is nominal voltage and I thought 3,8 should be max which in fact is 4,2.
12V was for a battery of 3 accumulator.
Of course, a single accumulator shouldn't be charged with 12V, which is dangerous.

You're putting the wrong kind of cells in that pack. You need IMR cells with low internal resistance capable of supplying tens of amps.

I can't seem to find a datasheet, but then again, I'm not looking too hard. I believe these particular cells are capable of at least 15A current draw. I'd avoid pulling that much from a standard icr.

BShanahan14rulz is correct.

The original cells are low capacity because they are designed for very high current draw.

To substitute high capacity cells may not be the best idea.

2C is the maximum safe draw for most high capacity #18650 cells (2 x 3100ma=6.2 amps).

You would probably exceed that (twice Capacity) rating with the tool.

There is only one way to check and that is careful measurement of the maximum current with the new cells fully charged.

The charger must also be checked to insure it is regulated & does not exceed 12.6 VDC when the cells are fully charged.

LarryDFW

BShanahan14rulz said:

I can't seem to find a datasheet, but then again, I'm not looking too hard. I believe these particular cells are capable of at least 15A current draw. I'd avoid pulling that much from a standard icr.

Click to expand...

I have lol, very fin hard lol, if u could have a quick look that would be epic.
I had a feeling the max draw maybe a problem, gonna have to use top quality cells at around the same mAh.

edit: think I got something: similar cells (top codde is the same) Max. Discharge Current: 15000mA(ambient temperature 25℃), so yeah 15A.
http://www.keeppower.com.cn/?MainID=4&ID=57&Language=en