# Inverters are they fine to use for charging



## zappy (Mar 6, 2009)

cordless batteries?Any damage they might cause?


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## TOOL_5150 (Aug 27, 2007)

zappy said:


> cordless batteries?Any damage they might cause?


Yeah, their totally fine, especially if it produces a modified sine wave. OTOH, I just use a car charger for my batteries when there is no AC avalible. Its really good for when you had too much to drink the night before and come home and forget to charge your batteries - you just charge them on the way to the site. Seems to charge even faster than the AC chargers.

But thats never happened to me before :no:

~Matt


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## KayJay (Jan 20, 2008)

zappy said:


> cordless batteries?Any damage they might cause?


I have been using a hard wired Whistler 300/600 watt inverter with the Dewalt NiCad batteries for 10-years with no noticeable problems. 
Putting this inverter in my truck was easily one of the best things I ever did. 
I also use it to run a Dremel as well as a 120V fluorescent drop light. 
For service calls, it is unbelievably handy for testing 120V light fixtures, bulbs, ballasts, relays, solenoids, small fan motors and control transformers right in the back of the truck.

BUT,... it is a Modified Sine Wave [square/stepped wave] inverter and the user manual says to check with the charger/battery manufacturer before using with chargers or any electronic equipment. If you do a web search on this subject you will see a lot of squawk about only using a True Sine Wave inverter to charge batteries or run electronic equipment. These are usually way more expensive.

As I said though, I personally haven’t had any noticeable issues using it with the Dewalt batteries. Since I always engrave the date of purchase on new batteries when I get them, judging from these dates, I can safely say that I’m generally lucky if I get 3-years out a new 18V XRP battery anyway though, because of all the heavy use they get.


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## zappy (Mar 6, 2009)

Yep, that's why i was wondering because of the modified sine wave.I'm still kinda hesitant to use them.I gonna see what makita says about using them thanks.


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## randomkiller (Sep 28, 2007)

I have had good luck charging batteries in the truck with one. It does seem to charge them faster than a standard outlet.


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## TOOL_5150 (Aug 27, 2007)

Check this out, Modified sinewave is the closest to a sinewave - youll be fine.










~Matt


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## Dennis (Oct 10, 2008)

zappy said:


> cordless batteries?Any damage they might cause?


 
Your cordless charger has a build in AC to DC rectifier inside, so your batteries are being charge with DC Voltage.

When you want to use your car battery (which is a DC Voltage) you need
to change it back to AC signal, thats why you use an Inverter. The charger then change it back to DC Voltage to be use.

The most impotant part of using an Inverter is the POWER RATING. Make sure you are not using more than what the Inverter can produce.


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## RePhase277 (Feb 5, 2008)

YES, if you use a modified sine wave inverter with certain chargers, you will either damage the charger, the battery, or both. It only happens to chargers that say "Warning! Line voltage present at charger terminals" or some such. I killed a Craftsman and another kind I don't remember like this before I read the instructions. 

I have a 1500 W inverter hardwired into my truck and it is one of the best things I have ever done. I have a 120 V in the cab and a connector sends it to the enclosed trailer when it is hooked up. I have a 200 A monster alternator and big battery under the hood. I can leave the truck idling and run my cord out of the trailer and get jiggy all day. And when get in the truck, it's already ice cold inside!


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## KayJay (Jan 20, 2008)

InPhase277 said:


> YES, if you use a modified sine wave inverter with certain chargers, you will either damage the charger, the battery, or both. It only happens to chargers that say "Warning! Line voltage present at charger terminals" or some such. I killed a Craftsman and another kind I don't remember like this before I read the instructions.
> 
> I have a 1500 W inverter hardwired into my truck and it is one of the best things I have ever done. I have a 120 V in the cab and a connector sends it to the enclosed trailer when it is hooked up. I have a 200 A monster alternator and big battery under the hood. I can leave the truck idling and run my cord out of the trailer and get jiggy all day. And when get in the truck, it's already ice cold inside!


I was checking mine out again today, I have 50V DC at the DeWalt’s charger terminals. When I put my scopemeter leads in the inverter receptacle, I could see the stepped wave clear as day. 

Here is something to look out for though… apparently the grounding receptacles are only for convenience, because there is no ground connection to them at all. I removed the inverters front panel to verify this and found that the ground terminals are completely unused. No on board GFCI either, so that could be dangerous under the wrong circumstances. Have to be sure and use a GFCI adapter with this.


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## Mark W. (8 mo ago)

KayJay said:


> I have been using a hard wired Whistler 300/600 watt inverter with the Dewalt NiCad batteries for 10-years with no noticeable problems.
> Putting this inverter in my truck was easily one of the best things I ever did.
> I also use it to run a Dremel as well as a 120V fluorescent drop light.
> For service calls, it is unbelievably handy for testing 120V light fixtures, bulbs, ballasts, relays, solenoids, small fan motors and control transformers right in the back of the truck.
> ...


My old Ni-cad Dewalt smart charger that is close to 25 yrs old was buzzing like crazy and could smell something burning before I unplugged it. It seemed to shut off and started flashing. It is still OK as I checked but boy... my new COBRA "PRO" CPI1500W modified sine wave invertor didn't like DEWALT at all. My Sears microwave seems OK but buzzed a bit louder. COBRA said it was OK. Same with Samsung S5 phone so I'm going to try it out this weekend. We shall see what we shall see.


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## micromind (Aug 11, 2007)

I would never use a modified sine wave supply with a switching device. A switching device is supposed to switch on and off of a sine wave, not a bunch of square waves.


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