Makita Battery powered Boom Box

[marty]

Cut the bottom off Makita BML185 18V LXT Flashlight.


Got a Altec Lansing iMT800 Boom Box. Want to power this with 18V Makita power tool batteries.


View attachment 3

Boom box is normally powered with this power supply or 8, D cell batteries.


PROBLEM Makita battery drains too low and turns to trash. Won't charge any more. Yellow death light on charger.

Tried using this circuit board from the old flashlight as a low voltage cut off.

Did something very wrong with the first one and voltage drops to 0 as soon as a load is hooked to it. Bought a second one. Tested with the flashlight bulb [XPR 18V 0.6A] It works fine. Tested with the boom box. It don't work. Suspect that boom box is drawing too many Amps? Measure amps with the battery connected to boom box (no LVC). Meter jumps around allot. Goes up to around 1 Amp for a second when I turn the volume all the way up.

Makita 18V 3.0Ah Lithium Ion batteries have 10 cells in them, 2 parallel 5 series. Voltage when fully charged is about 20V

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The 18650V are used in:
-The BL1830 makita pack of 18V 3.0Ah
-The BionX electric bike battery of 24V and 37V 9.6Ah

The 18650VT are used in:
-The BL1815 makita pack of 18V 1.5Ah ( but they have 1.3Ah real)
-The Bosh 36V slim and fatpack


Here are their specs:

18650V: ( the most popular for ebikes)
( same as the Sanyo’s UR18650W)

-Voltage range: 3.0 to 4.2V
-Nominal voltage 3.7V
-Capacity: 1500mAh(10C) to 1600mAh(1C)
-Max Discharge C rate: 10C ( 15-16A)
-Max Charge C-rate: 1.5 to 2C depending on the cooling
-Cycle life: 700 cycles to 75% initial capacity ( from BMZ manufacture)
-Cycle life claimed by Makita: 1200 cycles
-Internal resistance 30miliohm per cells
-Released in 2005... still existing in 2011



18650VT:

-Voltage range: 3.0 to 4.1 or 4.2V
-Nominal voltage 3.76V
-Capacity: 1030mAh(10C), 1080mAh, ( 1C) to 1300mAh(0.1C)
-Max Discharge C rate: 15C ( 17-20A)... and 30A for 30 sec
-Max Charge C-rate: 3C depending on the cooling
-Cycle life: 500 cycles to 90% of initial capacity, at 2A discharge ( from BMZ manufacture)
-Cycle life claimed by Makita: 1200 cycles
-Internal resistance :initial is 25 miliohm ( 26-28 miliohm of used cells)
-Gravimetric energy94 Wh/kg
-Released in 2005... still existing in 2011

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Doctorbass say "Voltage range: 3.0 to 4.2V" per cell so 5 x 3V = 15V, I am guessing that the low voltage cut off should shut off the boom box when the batteries voltage goes down to about 16.5 volts.

Where can I find a low voltage cut off that will work with 18V Makita batteries and this boom box?

 

[TroySmith80]

Hi Marty, i want to do something similar, did you ever figure this out?

 

[marty]

When I was poking around with the volt meter I thought I might have heard a real quiet seeeeeet. After that the iPod stopped charging.

why does stopped have two p's
https://www.google.com/webhp?hl=en#hl=en&q=why+does+stopped+have+two+p%27s

Took the boom box all apart. Found a little do-dad on the circuit board that cooked. Might still have all the parts in a box?

Bought this - Makita LXRM03

 

[Punx0r]