Makita 14 volt LI ION Battery

[barry wilkins]

Hi I have cut open this battery because it will not hold any charge.There are four connections, +, -, TH, DISS.
It contains 12 1.2 volt cells ,20K thermistor ,and a thermal cut out switch.
I have ordered 4 x 3.7 volt 4.5A cells on ebay ,I just hope I can squeeze them into the case .

Barry Wilkins

[tom66]

Re: Makita 14 volt LI ION Battery

18650 cells? You probably got 0.47Ah, not 4.7Ah cells. Don't expect the full capacity out of them!

[sam_sam_sam]

Re: Makita 14 volt LI ION Battery

There are four connections, +, -, TH, DISS.
It contains 12 1.2 volt cells ,20K thermistor ,and a thermal cut out switch.

Barry Wilkins

You may have bought the wrong Batteries you need to buy LI ION Battery that has the protection board built in to them like this one
http://www.ebay.com/itm/NEW-2X-Panas...-/330634383068

[budm]

Re: Makita 14 volt LI ION Battery

"It contains 12 1.2 volt cells" if they are 1.2V cell, it will not be LiIon, more like NMHi

[kc8adu]

Re: Makita 14 volt LI ION Battery

you MUST have a protection/balancing board!
and yes there are 4500mah cells...in 26650!
i have some "kingkong" 26650 here that are to spec and then some.
but ebay is a minefield of garbage batteries.

[domas]

Re: Makita 14 volt LI ION Battery

Well balancing is not always a big deal, might cause problems, might not.
But voltage is.

Well, 12 * 1.2V is 14.4V.. (nominal)
For Li-ion 4* 3,7V it is 14.8V (nominal)

Fully charged nimh 12*1,5V (please correct me if i am wrong regarding 1,5V/cell) = 18V, so they will probably be charged at close voltage to 18V

For Li-ion 18V means 18/4=4.5V/cell

kaboooom

[domas]

Re: Makita 14 volt LI ION Battery

http://www.candlepowerforums.com/vb/...f-NiMh-batteri

well it depends on charging method. Or are you using another, non-nimh charger?

[Kiriakos GR]

Re: Makita 14 volt LI ION Battery

Possibly you do not care if your cordless tool would have power just for few minutes and look as a toy.
Yes those NICD cells they come for a price, and with out spending 40-60$ you can not properly rebuild the power pack ( battery).

[tom66]

Re: Makita 14 volt LI ION Battery

Yes, and you CANNOT, absolutely CANNOT charge a lithium ion or lithium polymer battery with a ni-cad or ni-mh charger. This is how you start a fire. Lithium ion/polymer is 4.25V absolute maximum, 4.2V recommended limit. Even at 4.35V the cell already starts bloating and failure via flames has a high probably. And, as you approach the peak voltage, the current falls off, which will allow a non-voltage-limited supply to exceed the crucial threshold voltage.

[kc8adu]

Re: Makita 14 volt LI ION Battery

some of the newer cells terminate at 4.35.
but absolutely you must have a proper charger.
i have a friend with the imfamous makita li-ion packs with the drop dead and wont charge bug.looks like the too smart charger will get gutted and leads from the charging/balancing contacts brought out to a hobby charger.batteries are still in good shape according to my tests.

[Kiriakos GR]

Re: Makita 14 volt LI ION Battery

Yes, and you CANNOT, absolutely CANNOT charge a lithium ion or lithium polymer battery with a ni-cad or ni-mh charger.

Hey Tom I need some extra info about your Warning, can you explain how in Earth or any other planet is possible one NIMH or NICAD 1.5V charger to blow away one 3.7V battery ?

But wait a minute we have a more serious problem, the one who started the topic he is imagining that he is going to solve his problem with his own technological idea.

He does not ask for any help, and so what we are doing in this topic?
Killing time ??

[domas]

Re: Makita 14 volt LI ION Battery

Hey Tom I need some extra info about your Warning, can you explain how in Earth or any other planet is possible one NIMH or NICAD 1.5V charger to blow away one 3.7V battery ?

But wait a minute we have a more serious problem, the one who started the topic he is imagining that he is going to solve his problem with his own technological idea.

He does not ask for any help, and so what we are doing in this topic?
Killing time ??

tom66 was referring to the situation of using 4 li ions instead of 12 nimh in series..

I did the math in post #6

[Kiriakos GR]

Re: Makita 14 volt LI ION Battery

tom66 was referring to the situation of using 4 li ions instead of 12 nimh in series..

I did the math in post #6

Yes you did the math and the one who started the topic he wrote in the title LI ION and what he dissembled were NICAD or NIMH.

And about Tom we love to play with our wooden swords from time to time. LOL

[tom66]

Re: Makita 14 volt LI ION Battery

Hey Tom I need some extra info about your Warning, can you explain how in Earth or any other planet is possible one NIMH or NICAD 1.5V charger to blow away one 3.7V battery ?

A user above was talking about using four Li-Ion or Li-Poly cells in place of 12 NiMH or NiCad cells. Using the same charger with such a set up would present a risk of fire. Do you think I joke about with lithium batteries? They are very dangerous. Not to be messed with.

Perhaps you need one to catch fire before you learn your lesson from messing around with them.

[luke10050]

Re: Makita 14 volt LI ION Battery

A user above was talking about using four Li-Ion or Li-Poly cells in place of 12 NiMH or NiCad cells. Using the same charger with such a set up would present a risk of fire. Do you think I joke about with lithium batteries? They are very dangerous. Not to be messed with.

Perhaps you need one to catch fire before you learn your lesson from messing around with them.

yeah nobody seems to realise but me that they all carry small explosive devices in their pockets *not products* (read. phones)

[Kiriakos GR]

Re: Makita 14 volt LI ION Battery

It is not wise to use a generic risk assessment for every LI ION no matter when it was made OR the chemistry which were used OR the size OR the application which this cell it is designed to serve.

Even if you set water on fire it will start boiling.

Modern LI ION for phones using plain Nylon as material for their outside packaging.
The old days they were in metal cage.

Practically the use of LI ION in cordless tools it the MOST stupid choice, but mostly because their CUT-OFF voltage which will stop the tool from functioning.
With NI-CAD you may continue to do some work until you use even the last drop of energy in them.

Cordless tools power-pack DOES NOT offer proper ventilation (cooling) for the Cells, therefore the designer of those power packs is primarily the fool of the village, but even so he did use a thermal cut out switch.

The true question here is ARE YOU TRAINED TO REBUILD YOUR OWN BATTERY PACK ?
YES? NO ? MAYBE ?

The 95% of the people are incapable to make one properly assembled battery pack.
They do not have even basic materials as for example isolating paper with special properties against catching fire and waterproof so to not be destroyed by battery liquids leakage.

Because of this special paper the serious made NI-CAD THEY COME WITH IT as standard.
The heat shrink NYLON is for batteries for TOYS.

Yes there is much more in all of this and you possibly discover them in the next years of your life.

[tom66]

Re: Makita 14 volt LI ION Battery

I'm not sure if you are agreeing or disagreeing with my assessment that replacing the nickel-chemistry cells with lithium-chemistry cells is a bad idea.

In general ni-cad and ni-mh have many problems but they are extremely safe. In the worst case a ni-mh may bulge and leak, but even that is rare. The main risk is NiMH/NiCd can deliver extremely high currents, which could cause an external fire. Whereas a lithium battery, if improperly managed, can start a fire on its own, with no external short circuit, if it is abused or punctured.

Now, modern phones use a safer lithium polymer (flat cell; lithium ion is round cell) type chemistry which is fairly resistant to puncture damage. (Not all lithium polymer are the same.) It will usually get hot and smoke if damaged. The phone's charging circuit manages the charge voltage, current and temperature; many batteries also contain an over-voltage cut off to prevent catastrophic fires occurring. There have been incidents where these protections have failed: as documented in these MacBook and iPod events.

However, the same does NOT apply to your average 18650 cell you buy on eBay! Most of these cells do not have any form of protection circuit which will prevent the cell voltage from being exceeded. Those which do are the exception and not the rule. In addition the somewhat safer chemistry typically used in a mobile phone is more expensive, and has a lower overall capacity, as such it is not found in most 18650 cells.

In short, don't fuck around with a LiPo or LiIon or you WILL regret it.

[barry wilkins]

Re: Makita 14 volt LI ION Battery update

Hi I have cut open this battery because it will not hold any charge.There are four connections, +, -, TH, DISS.
It contains 12 1.2 volt cells ,20K thermistor ,and a thermal cut out switch.
I have ordered 4 x 3.7 volt 4.5A cells on ebay ,I just hope I can squeeze them into the case .

Barry Wilkins

Regarding the cells actually fitted ,the battery case definitely says its Li Ion battery ,but i was surprised when I opened the battery up ,12 cells of 1.2 volts each, made me think they were actually Ni Cd.
The 20K thermistor changes its value as the battery heats up ,and I presume this controls the charger to prevent overheating of the cells as it was cemented to the pack.
The thermal cut out switch operates at a set temperature and goes open circuit to switch off the charger.
The batteries I ordered are definitely marked 3.7 Volts 4500mA which is greater than the battery was originally. I don't think there will be any overheating problems with the two safety components inside the battery pack.

Barry Wilkins

[tom66]

Re: Makita 14 volt LI ION Battery

It's your risk. The problem with lithium ion batteries is once they start overheating, they can go, well, thermonuclear. It's called thermal runaway and can be quite explosive and flammable. Thermal cut off doesn't matter, it's too late. It would seem that the battery may have been replaced with a fake / cheap one? A Li-Ion charger could just about charge Ni-Cad batteries, though it would lead to them failing quicker. Hopefully the charger you have is actually a Li-Ion charger not a Ni-Cad one too.

You will not be able to acquire real 3.7V 4.5Ah/4500mAh cells in the 18650 cell format. It's simply impossible. Panasonic, a company that makes real Li-Ion batteries, just hit 3.4Ah in a single cell -- an impressive achievement. Did you order any one on here marked UltraFire?

http://www.ebay.co.uk/sch/i.html?_tr...at=0&_from=R40

In which case you may want to see this chart:
http://lygte-info.dk/review/batterie...mary%20UK.html

which shows a more realistic capacity of below 2000mAh even under light loads. Under heavy loads, it's even worse. Note how the good brands (LG Chem, Panasonic, Sanyo, Samsung) top out around the 2500~3500mAh mark, and to do so, they've invested billions in research, development and facilities to make these cells. You think some dodgy Chinese battery manufacturer has hit 4500mAh?

[Kiriakos GR]

Re: Makita 14 volt LI ION Battery

Barry one picture it is worth more than 1000 words.

Basically in this thread there are present some knowledgeable people with different start points, which care to assist you with some worthy feedback.

Use us if you care for a second opinion of some value, but gives us pictures.
We do not even know if what ever you are holding there is an Genuine MAKITA battery.