Makita Li Ion voltage question

[trout]

I know some of you have been using the Makita lxt battery packs and that the cells are very robust .
my question is when I have been using my drill and the battery has drained to the point when it stops working the pack reads about 14 volts.
it is an 18 volt 3000mah pack by the way .

I am also using these batterys for my bike lights with the drivers from Taskled these allow a cut off at a preset voltage to protect the batterys from over discharge , so what do you think would be the correct voltage
for me to set my driver to for this low voltage setting ,

it can also be set for half drained and to flash a warning also what voltage would be half drained.

thanks

 

[dat2zip]

I believe there are 5 li-ion batteries in the pack. Standard Li-ion batteries hot off the charger are 4.2V and drop to 3.8V shortly after using them. Also, 14V is around 2.8V and the pack may have electronics in it for low voltage cutoff which would be around the 2.8V/cell range.

I would set the low battery status around 2.9V/cell ( 14.5V) or higher depending on when you want status.

I have measured these off the charger at 21V or so which equates to exactly 4.2V/cell.

Wayne

 

[trout]

Thanks Wayne
I am running 4 cree Q5 s and the bflex goes out of regulation at about 15 volts and the lights dim , so that gives me a low warning

I just need to do a run test to see how long I have left before darkness to get home in ,

 

[LuxLuthor]

An important question is whether this pack is using Lithium Cobalt (old Li-Ion technology) at 3.7V nominal, or the new A123 Nano Lithium Iron Phosphate 3.3V nominal per cell that are in many Dewalt power tools. The two have very different performance and management guidelines.

 

[trout]

An important question is whether this pack is using Lithium Cobalt (old Li-Ion technology) at 3.7V nominal, or the new A123 Nano Lithium Iron Phosphate 3.3V nominal per cell that are in many Dewalt power tools. The two have very different performance and management guidelines.

just when I thought I had the answer
then another variable rears up . how do I tell what is in there.
the makita drill was advertised as the nano tech batteries.

they charge in 22 mins from empty and just keep going untill the drill wont turn anymore . I quess this is not a good thing to do and should charge before the drill dies.

assuming they are the nano lith ones what would you suggest for warning and cutoff voltages please.

cheers Chris

 

[ledaholic]

The LXT series of tools have the low voltage cutoff devices built in the tool itself. They are also adjustable. I discovered this when I modified my LXT light.

 

[Alan B]

This is an old thread, but just for completeness I'll add that the Makita packs are reportedly Lithium Manganese (LiMn) type cells. These have voltages similar to the Lithium Cobalt cells (4.2V max) but deliver high currents which is appropriate for their application.

I've been researching this again lately and it seems that the lithium tool batteries are either Lithium Iron or Lithium Manganese due to their high current capacity. Very few use Lithium Iron battery technology probably due to the lawsuits still going on after years of litigation. Only DeWalt/Black and Decker seem to have Lithium Iron type tool batteries. All the rest seem to be LiMn.