charging cordless drill and saw batteries

MarcelMarcel Solar Expert Posts: 39
Hey folks. Our off grid system is up and running and here is the first of probably many questions. We have a Xantrex 3624 inverter and wondering if its cool to charge these cordless tools we have. I've heard it might fry the tool chargers. Thanks.

Comments

  • AntronXAntronX Solar Expert Posts: 462 ✭✭
    Re: charging cordless drill and saw batteries

    You should have at least one pure sine wave inverter. The host of this forum sells inexpensive Samlex 24 volt PSW inverters. To charge tools, you would probably need 600 - 1000W rated unit.

    But if you don't mind frying one charger, try it and see what happens. Watch for burning smell, excessive heating and loud buzzing noize.
  • SlappySlappy Solar Expert Posts: 251 ✭✭✭✭✭✭
    Re: charging cordless drill and saw batteries

    here is an older tread on this... http://forum.solar-electric.com/showthread.php?t=1637 ......give it a short read, it is really hard to say if it will or will not work. and some times it will work fine for a while, then it will see the smoke goddess at a later date. But some people will have good luck for along time. It really depends on the quality of the chargers, but to my under standing the square wave is really hard on electronics due to the sharp/sudden wave pattern, instead of the smooth "roller coaster" type wave. But, my personal opinion, would be to get a PSW, so their wont be no worries,
  • MarcelMarcel Solar Expert Posts: 39
    Re: charging cordless drill and saw batteries

    Sounds good, thanks for the help. When I get this inverter, does it connect directly to the 2 volt Trojan battery bank just like the big 3624? Thanks again.
  • mikeomikeo Solar Expert Posts: 386 ✭✭✭
    Re: charging cordless drill and saw batteries
    does it connect directly to the 2 volt Trojan battery bank just like the big 3624? Thanks again.
    Yes is you buy a 24 volt inverter it will connect to the same battery bank through a fused connection
  • landyacht.318landyacht.318 Solar Expert Posts: 82 ✭✭✭✭
    Re: charging cordless drill and saw batteries

    I am the one who started the other thread that slappy linked to, and thought I'd update in this thread rather than the 3 year old one

    I wound up getting about 6 charges on the craftsman charger on my coleman 800 watt MSW inverter, and it quit.

    I then started charging the 9.6 volts battery off of my 12 volt system. The inevitable happened and and I overcharged and smoked the battery.

    Then I hard wired the craftsman 9.6 volt drill to a 12 volt connector, and now run it directly off my vehicle, or jumper pack. Butt loads of torque and requires a 35 amp fuse. I have gotten a lot of use out of this drill in an attempt to save the batteries in the Porter Cable.

    I still have that porter cable drill. The batteries do not really hold much juice anymore. It is slower and lost 25% of it's torque when fully charged and 50% of it's torque for the remaining charge. I never charged it off of MSW.

    Replacement batteries cost just short of a quality new drill. Rebuilding the battery packs would not be much cheaper.
  • AntronXAntronX Solar Expert Posts: 462 ✭✭
    Re: charging cordless drill and saw batteries

    Just tried connecting my DieHard 19.2V charger to my Exeltech 600W inverter via Kill-A-Watt meter. The meter reports 325 VA and just 45 Watts at a 0.13 power factor. The inverter makes audible buzzing. How do these tool makers can get away with selling such junk?
  • BB.BB. Super Moderators, Administrators Posts: 29,333 admin
    Re: charging cordless drill and saw batteries

    Low power factor (perhaps below 0.8 or 0.7) on Sine Wave AC power, and very low power factor (like you measured on Square Wave AC) would be indications (to me) that the electronic devices will not run long on MSW inverters...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • AntronXAntronX Solar Expert Posts: 462 ✭✭
    Re: charging cordless drill and saw batteries

    Exeltech XP600 is a sine wave inverter. On the grid it measured 265 VA and 45 W at 0.17 PF. I am going to open this charger to see whats inside.
  • BB.BB. Super Moderators, Administrators Posts: 29,333 admin
    Re: charging cordless drill and saw batteries

    Whoa... :blush::confused:

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • AntronXAntronX Solar Expert Posts: 462 ✭✭
    Re: charging cordless drill and saw batteries

    Took a look inside this charger. It has one big 45uF 250V capacitor and few 2W resistors. No transformer in sight. It is not a switchmode circuit. Probably this thing is designed to barely run on sine wave with cheapest and minimal amount of parts.

    Edit: I noticed on the warming label in second picture it says tha 120V is present at charger terminals. I suspect his is a chopper design. It uses AC sine waveform peaks as references when to fire a switch to run line current via few resistors in series with batteries. Because switch turn on duty cycle is low, this produces short high current spikes at the AC waveform peaks. This is why power factor reading is so low. This kind of design should be banned from sale. This will put high stress on PSW inverter for no reason.
  • PhotowhitPhotowhit Solar Expert Posts: 4,957 ✭✭✭✭
    Re: charging cordless drill and saw batteries

    Dewalt Battery chargers have worked on MSW for quite some time now, I didn't want to fry mine and inquired back in 2001 while building an 'A' frame, I used and charged with my curent charge controller then, which was the 1st or second model that had no issues with MSW inverters, Framed up the 'A' frame with no issues, and many charge cycles.

    DeWalt chargers could be had for @$25 on amazon last time I checked and will work for the pod type Black and Decker batteries as well ( I would recomend replacing your Black and Decker chargers with the Dewalt regaurdless!)

    This information applies to the pod type batteries and chargers, though I can't imagine them switching away from a good system unless for a complete redesign for the lithium batteries.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: charging cordless drill and saw batteries

    Three possibilities with running small battery chargers off MSW:

    1). It works! Hurrah!
    2). The battery doesn't fully charge (MSW interpreted as low Voltage resulting in low 'reference' Voltage).
    3). The magic smoke comes out.

    So without knowing the specifics of the charger, you have a 33% chance of success. Now, how expensive is the charger that might fry compared to the cost of a small PSW inverter? Is it worth risking a charger, cheap or not? Only you can answer these questions, based on what you feel comfortable with in terms of $ spent and risks taken.
  • MarcelMarcel Solar Expert Posts: 39
    Re: charging cordless drill and saw batteries

    I think we'll get the PSW inverter. Thanks everybody.
  • dwhdwh Solar Expert Posts: 1,341 ✭✭✭
    Re: charging cordless drill and saw batteries

    I have a Ryobi One+ 18v kit with an extra charger and also the 12v powered (car) charger. The 12v charger works great. It will do a full charge on a dead battery in half an hour or less.

    The two 120v chargers, plugged into the grid, take almost twice as long to do the same job.


    (Oh, and just an FYI - I also have a Ryobi One+ 18v angle grinder. It works great and has a lot of power but it will suck a battery dry in no time flat.)
  • AntronXAntronX Solar Expert Posts: 462 ✭✭
    Re: charging cordless drill and saw batteries
    dwh wrote: »
    I have a Ryobi One+ 18v kit with an extra charger and also the 12v powered (car) charger. The 12v charger works great. It will do a full charge on a dead battery in half an hour or less...

    12V DC battery charger is clearly best and most energy efficient solution for the original poster. I did not even know they were available for cordless power tools. Going via 120V AC route is needlessly expensive and inefficient way.
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