18volt drill -charge-inverter

Lon nan Gruagach

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Shouldnt be too heavy, but check if your inverter is pure or modified sine wave and if the charger is ok with it.

Virtually all electrical equipment has its power requirements written on it, Voltage, frequency and either power(Watts) or current(Amps)
 

Kelpie

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I tried my 150w cheapie inverter and whilst my Makita 18v charger would power up, it would shut down as soon as I tried charging a battery. Turns out the charger requires 240w minimum.
The question is, can I use a cheap modified sine wave inverter, or do I need to go for a pure sine wave? The Makita kit was very pricey so I don't want to sink the ship for a ha'pny of tar...
 

BobnLesley

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Ours charged for years off a cheap and cheerful 300 watt inverter from Maplins, or as an alternative:
When our drill battery eventually died after about six years (perhaps through using a cheap & cheerful inverter?) I removed the battery and connected a twin-core wire to the terminals using crimped spade connectors and crocodile clips at the other end, thereby powering the drill directly from the 12-volt house batteries; powered this way it worked perfectly other than spinning noticeably slower, which made it brilliant for drilling stainless steel.
 

William_H

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Ours charged for years off a cheap and cheerful 300 watt inverter from Maplins, or as an alternative:
When our drill battery eventually died after about six years (perhaps through using a cheap & cheerful inverter?) I removed the battery and connected a twin-core wire to the terminals using crimped spade connectors and crocodile clips at the other end, thereby powering the drill directly from the 12-volt house batteries; powered this way it worked perfectly other than spinning noticeably slower, which made it brilliant for drilling stainless steel.

It is very unlikely the inverter caused the failure of the drill batteries. Time and use kills them. However for NIMh or Nicad batteries one of the killers is when you squeeze the last bit out of the batteries. ie the drill starts to run slow so draws more current from the batteries. One cell usually drops to zero volts first then the current through it tends to try to charge the cell in reverse. This causes dendrites to grow in the cell so that it eventually appears as a short circuit even for charging. So then the charger sees a lower voltage battery and tries to charge after it is fully charged or charges with too much current either of which will overheat the batteries drying them out. a new set of batteries from China are not that dear. Often fitted are 4/5 sub C size if batteries are in the handle or sub C if in a detachable pack. I don't know if it will help but I have just replace the 6 cells in an old battery drill. Works great now. I have wired diodes across each cell to hopefully bypass this reverse charging thing. I guess I will never know if it works however the last lot of batterie sin this drill did not last long. I may have overcharged them however. (got wam) good luck olewill
 

Beyondhelp

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I tried my 150w cheapie inverter and whilst my Makita 18v charger would power up, it would shut down as soon as I tried charging a battery. Turns out the charger requires 240w minimum.
The question is, can I use a cheap modified sine wave inverter, or do I need to go for a pure sine wave? The Makita kit was very pricey so I don't want to sink the ship for a ha'pny of tar...

Most chargers are switch mode, and thus work PERFECTLY FINE with modified square wave inverters. TBH I've used modified sine inverters for 10+ years and found very few things that wouldn't run on them.
 

rogerthebodger

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GHA

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My idea is to used one of these from 12vcd to give 20vdc and use a 10ohm resistor in series with the battery as poster by william_H in my other thread
If you dig around on ebay there are constant current / constant voltage boost converters around, so no need to bother with a resister to limit the load, just dial in the max current & max voltage. Ebay does everything :cool:
 
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