Can Makita LXT fast charger charge multiple cells at once?

[fitek]

Hi folks, now that I have 12 of the 18v LXT packs, I have a problem since I have only one charger. I am looking into getting another, but that still means having to swap batteries 6 times into the charger.

So... does anyone know if I can just attach some wires to the charger and charge, say, two packs at once? 3? 4?

Alternatively, should I start contemplating using another charger to do most of the charging, and then balance/top off using the stock charger?

 

[Ypedal]

Hmm.. i have 2 used makita chargers i'd give you a good deal on !! :wink:

Are the packs stock with original BMS etc ?

 

[fitek]

The packs are entirely stock. I used the docks sold online by a guy I know here locally so no mods required to extract energy, I just screwed the docks to a piece of acrylic and bolted the resulting packs to my bike frame. I started with just 4 batteries which was totally manageable (20 minute charge time for each). 12... well that will take some patience. Also the bike looks like Pancho Villa with a LXT bullet belt around its waist.

 

[Doctorbass]

yes you can.. but each charger will charge same number of s cells.. the number of parallel cell to the pack with the BMS can be infinite.. the charger have a current control so that will just take more time as you multiply the parallel cells to the pack on the charger.

summary: One normal stock pack on will keep his the BMS and the rest of the battery need to be paralleled on this pack (every parallel cell group together) not only the 0V and the +18V... but every link between series cells need to be connected to the rest of the packs in parallel.

Doc

 

[fitek]

Ok, thanks guys. I will probably rewire my two larger battery blocks so all cells are in parallel. Then it will be easy to connect both in parallel to the charger and in series on the bike.

Does anyone have a dead LXT shell that can be plugged into the charger?

 

[Jonathan]

fitek,

I have couple LXT shell available. They're yours if you pick them up b4 xmas.

 

[fitek]

I wired one of Jonathan's shells up to a pack that is 4 18v LXTs in parallel. I just soldered a wire to the each of the terminals on the PCB in the shell. However the charger flashes that the battery is bad after about two minutes.

Do I need to somehow disable the BMS board to get this to work?

 

[dimitrib90]

I wired one of Jonathan's shells up to a pack that is 4 18v LXTs in parallel. I just soldered a wire to the each of the terminals on the PCB in the shell. However the charger flashes that the battery is bad after about two minutes.

Do I need to somehow disable the BMS board to get this to work?

Thats weird. These batteries have no BMS. It must have something to do with charger.

 

[Doctorbass]

Konion cells of the LXT are great!... BUT THE CHARGER THAT USE NO BMS IS COMPLETLY DIFFERENT!!

The charger use a complex timing of detection of different parameters like temp rise, voltage rise and current rise when the battery is connected to determine it state.

I have the 3 different charger that makita sale for these battery.. and i never succeded to use them with rebuilt battery..

It seems that the temp sensor of the pcb in the battery is the key... the way it detect the temp variation would activate the charger or not... I know that these charger use a fan that blow inside the battery and that the circulation of the air flow affect the temp reading quickly when it start.. and the timing of detection of that temp rise is very precise....so if you remove the shell of the battery.. the air flow take more time to affect the sensor and the charger will detect that something is wrong... I know that konions cells are very sensityve to heat and that affect their calandar life.. so the perfect air circulation on the shell is needed.. so the detectin of that is very critical...

I simulated different conditions to try to activate it without any succes... i feel that it also "remember" if that timing have been changed and wont restart after that ...

The best way to use this charger is to use a fully fonctionnal battery (without the led blink problem) and to connect wires on the cells that will goes to the external pack to be charged.. then to reassemble the shell with these wires that goes out by some holes in it... that should work..


Doc

 

[fitek]

Thanks DoctorBass. I think I will open up a couple of the working batteries and solder wires to them. I guess that is also helpful because I won't have to carry an extra shell around. I don't have much cargo space.

I have ridden the bike 43 miles in the past couple weeks, charging is such a pain though hehe.