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Adapter to charge new 12V "Max" batteries in traditional chargers


JKoltner

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I hesitated for several months before getting some of the new 12V Max lithium ion tools based on the fact that they use a new charger, and it annoys me to have to carry around several different chargers.  As such, I've been contemplating building an adapter to allow these new batteries to charge in the older chargers -- at least the "older" ones that support lithium ion batteries, specifically the DC9310, DC9320, etc.

(As most of you are probably aware, the 18V lithium ion battery packs contain all the charging circuitry inside the "turret" portion of the pack and the DC9310 becomes largely a "dumb power supply."  While I suspect that even the really old NiCad-only DeWalt chargers could be "dumbed down" like this, I imagine that doing so reliably is a little tricky and hence can understand why DeWalt just brought out a new series of chargers instead -- and they certainly know a lot more about their chargers than I do.)

The idea here is that you'd snap the 12V Max battery pack into an adapter that would look largely like the turret of the traditional battery packs with a flat surface at the bottom.  (Except for being two pieces rather than one, this is really exactly what the DeWalt 18V battery packs do, as mentioned above -- so this isn't at all a new or novel idea!)  *Possibly* you could also actually *use* the new 12V Max batteries in the old 12V tools, although in practice I'm not sure this is that horribly useful in that the "12V Max" packs are really only ~10.8V under load (...maybe using them with 9.6V tools would be better!), and don't pack in as much energy as the original battery packs anyway.

I realize that you'd still end up carrying your old charger plus an adapter or two around in this scenario, but at least to me that's still better than carrying around two separate chargers.  (And note that while you can purchase an old charger that works off of 12V cigarette lighter connection -- the DC9319 -- you can't yet purchase something comparable for the 12V Mac batteries... although I suspect that sooner or later DeWalt will remedy this.)

Does anyone else think this would be pretty useful?  If so, might I ask how much you'd be willing to pay for such an adapter?  My gut feel is that these could be sold easily (i.e., actually turn a profit) at $40, possibly at $30, and probably not at $20/ea.  Even for me, $30 is a bit on the high side, but it's pretty difficult to build much of anything electronic when you're talking the low quantities that tend to require that you keep the manufacturing in the U.S. and don't benefit from any significant quantity discounts on components.

Your thoughts are appreciated!

Thanks,

---Joel

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I hesitated for several months before getting some of the new 12V Max lithium ion tools based on the fact that they use a new charger, and it annoys me to have to carry around several different chargers.  As such, I've been contemplating building an adapter to allow these new batteries to charge in the older chargers -- at least the "older" ones that support lithium ion batteries, specifically the DC9310, DC9320, etc.

First of all the 12v Max would not be in the sub-compact range and have the improved ergonomics if DeWalt had stick with the tower pack design; that would be redundant, and after about 18 years with the tower pack design i think it was a well deserved change, can you think of one competitor that does this?..........I would not hold my breath  ::)

(As most of you are probably aware, the 18V lithium ion battery packs contain all the charging circuitry inside the "turret" portion of the pack and the DC9310 becomes largely a "dumb power supply."  While I suspect that even the really old NiCad-only DeWalt chargers could be "dumbed down" like this, I imagine that doing so reliably is a little tricky and hence can understand why DeWalt just brought out a new series of chargers instead -- and they certainly know a lot more about their chargers than I do.)

Is that a fact?  If so the lithium packs should come with an outlet or even a power cord so you do not need the charger, so unless you really know what the circuitry inside the lithium packs do and how it communicates with the charger i think it is safe to say someone is a chicken mcnugget short of a happy meal.  The fact is the lithium charger senses which battery pack chemistry when you are charging your batteries weather it is NiCd, NiMh, or lithium; different chemistry have very different charging curves so the moment you insert any chemistry battery the charger will determine how to charge and when to stop charging.  And yes, even the non lithium charger can tell the difference between NiCd and NiMh; but it will not safely charge lithium.

The idea here is that you'd snap the 12V Max battery pack into an adapter that would look largely like the turret of the traditional battery packs with a flat surface at the bottom.  (Except for being two pieces rather than one, this is really exactly what the DeWalt 18V battery packs do, as mentioned above -- so this isn't at all a new or novel idea!)  *Possibly* you could also actually *use* the new 12V Max batteries in the old 12V tools, although in practice I'm not sure this is that horribly useful in that the "12V Max" packs are really only ~10.8V under load (...maybe using them with 9.6V tools would be better!), and don't pack in as much energy as the original battery packs anyway.

The 12v batteries contains a different chemistry of lithium compared to the current 18/14.4v lithium tower packs so attempting to create an adapter just for the sake of charging the packs with one charger is not only reckless but very dangerous.  Seriously, how hard is it to carry two different chargers?

I realize that you'd still end up carrying your old charger plus an adapter or two around in this scenario, but at least to me that's still better than carrying around two separate chargers.  (And note that while you can purchase an old charger that works off of 12V cigarette lighter connection -- the DC9319 -- you can't yet purchase something comparable for the 12V Mac batteries... although I suspect that sooner or later DeWalt will remedy this.)

I really do not see the logic in this, so if carrying a charger around is such a dread and puts too much stress on your body i would suggest switch to corded tools.........at least you can get rid of that pesky charger ;D

Does anyone else think this would be pretty useful?  If so, might I ask how much you'd be willing to pay for such an adapter?  My gut feel is that these could be sold easily (i.e., actually turn a profit) at $40, possibly at $30, and probably not at $20/ea.  Even for me, $30 is a bit on the high side, but it's pretty difficult to build much of anything electronic when you're talking the low quantities that tend to require that you keep the manufacturing in the U.S. and don't benefit from any significant quantity discounts on components.

Your thoughts are appreciated!

Thanks,

---Joel

I think this will be useful for only one person  :o

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First of all the 12v Max would not be in the sub-compact range and have the improved ergonomics if DeWalt had stick with the tower pack design; that would be redundant, and after about 18 years with the tower pack design i think it was a well deserved change, can you think of one competitor that does this?..........I would not hold my breath  ::)

No argument there -- from looking at the shape of the new handles, one likely couldn't have efficiently stuck another cell in a turret the way the old NiCad/NiMh batteries do.

[18V lithium packs contain charge circuity inside]

Is that a fact?  If so the lithium packs should come with an outlet or even a power cord so you do not need the charger, so unless you really know what the circuitry inside the lithium packs do and how it communicates with the charger i think it is safe to say someone is a chicken mcnugget short of a happy meal.

Well, that's a fair point -- although it's clear there's a significant amount of electronics inside of the 18V lithium packs (just take a look at the pictures over in the "A Look Inside" forum), I definitely don't know how much of the "smarts" is in the pack vs. the charger itself.  

The fact is the lithium charger senses which battery pack chemistry when you are charging your batteries weather it is NiCd, NiMh, or lithium; different chemistry have very different charging curves so the moment you insert any chemistry battery the charger will determine how to charge and when to stop charging.  And yes, even the non lithium charger can tell the difference between NiCd and NiMh; but it will not safely charge lithium.

I'd agree the 9310 (and similar) clearly detect the difference between lithium and non-lithium, although I'm not so sure you'd find any particular signal line (or software bit) that differentiates between NiCd and NiMh: Both of those can be charged with a standard constant current with end-of-charge detection via decreasing battery voltage or pack heating, so I don't think there's any fundamental reason the older chargers necessarily had to make that determination.  I.e., it's implicit during charging, but a charger doesn't necessarily have to "recognize" that fact any more than it has to specifically recognize high-capacity (XRP) packs vs. compact (low-capacity) packs.

The 12v batteries contains a different chemistry of lithium compared to the current 18/14.4v lithium tower packs so attempting to create an adapter just for the sake of charging the packs with one charger is not only reckless but very dangerous.

What makes you think it's dangerous?  I haven't taken apart the 12V pack, but I'd bet you quite a sum that the battery pack itself contains overcurrent, overdischarge, and overcharge protection -- no reputable manufacturer in the U.S. would sell a lithium battery pack today that didn't have them.  Indeed, even *purchasing* individual lithium cells in the U.S. that *don't* have a built-in protection PCB is relatively difficult -- for liability reasons, most manufacturers just don't sell to individuals.

I haven't looked at the data sheet for the cells in the 12V lithium packs, but I'd be quite surprised if the charging algorithm is not the standard "constant current to 4.2V [or whatever]/constant voltage until current drops to 10% [or whatever] of initial current" algorithm.

Note that in my scenario here the idea really *is* to turn the charger into a "dumb power supply" and stick the charge controller IC into the charger.

I think this will be useful for only one person  :o

You probably don't use, e.g., Nikon lens on Canon cameras either, do you? :-)  Also check out the guys who use the DeWalt 36V lithium batteries for eBike projects -- many of them built their own chargers, since they use so many of the things and want to charge them simultaneously.  

You're not in the marketing group at DeWalt and just unhappy you guys didn't think of this, are you?  Just kidding. :-)  I appreciate your input on the subject here!

---Joel

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I just do not understand how it can be such a inconvinent to have two chargers. I have my little Wolksvagen caddy car full of tools and stuf so one more or less charger really does not make any different. I also do not carry the charges around the whole day. My small DCF610 need a charge very seldom since I more or less only use it for screwdriving and not drilling, so it can take days before I need to charge it.

I mean, when the workday start I bring in the toolcases and start to work. When I need to charge I pick up the charger from the tool case and plugg it into a outlet and charge the battery. If this is so hard work I think the rest of things you do in a workday must be worse than 1000 years in a concentration work camp with a big whip lashing your back every minute.

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First of all the 12v Max would not be in the sub-compact range and have the improved ergonomics if DeWalt had stick with the tower pack design; that would be redundant, and after about 18 years with the tower pack design i think it was a well deserved change, can you think of one competitor that does this?..........I would not hold my breath  ::)

No argument there -- from looking at the shape of the new handles, one likely couldn't have efficiently stuck another cell in a turret the way the old NiCad/NiMh batteries do.

[18V lithium packs contain charge circuity inside]

Is that a fact?  If so the lithium packs should come with an outlet or even a power cord so you do not need the charger, so unless you really know what the circuitry inside the lithium packs do and how it communicates with the charger i think it is safe to say someone is a chicken mcnugget short of a happy meal.

Well, that's a fair point -- although it's clear there's a significant amount of electronics inside of the 18V lithium packs (just take a look at the pictures over in the "A Look Inside" forum), I definitely don't know how much of the "smarts" is in the pack vs. the charger itself.  

Yes there is electronics in the pack, that is there mainly to protect the cells from low voltage cutoffs and pack performance, so there is no way a battery can contain its own charge circuits. 

The fact is the lithium charger senses which battery pack chemistry when you are charging your batteries weather it is NiCd, NiMh, or lithium; different chemistry have very different charging curves so the moment you insert any chemistry battery the charger will determine how to charge and when to stop charging.  And yes, even the non lithium charger can tell the difference between NiCd and NiMh; but it will not safely charge lithium.

I'd agree the 9310 (and similar) clearly detect the difference between lithium and non-lithium, although I'm not so sure you'd find any particular signal line (or software bit) that differentiates between NiCd and NiMh: Both of those can be charged with a standard constant current with end-of-charge detection via decreasing battery voltage or pack heating, so I don't think there's any fundamental reason the older chargers necessarily had to make that determination.  I.e., it's implicit during charging, but a charger doesn't necessarily have to "recognize" that fact any more than it has to specifically recognize high-capacity (XRP) packs vs. compact (low-capacity) packs.

The 12v batteries contains a different chemistry of lithium compared to the current 18/14.4v lithium tower packs so attempting to create an adapter just for the sake of charging the packs with one charger is not only reckless but very dangerous.

What makes you think it's dangerous?  I haven't taken apart the 12V pack, but I'd bet you quite a sum that the battery pack itself contains overcurrent, overdischarge, and overcharge protection -- no reputable manufacturer in the U.S. would sell a lithium battery pack today that didn't have them.  Indeed, even *purchasing* individual lithium cells in the U.S. that *don't* have a built-in protection PCB is relatively difficult -- for liability reasons, most manufacturers just don't sell to individuals.

All lithium cells have circuit protection and the cell manufacturers specify the charge/discharge current based on the internal chemistry.  they also specify the failure mode and low voltage protection, the problem is if you charge a lithium cell without the proper charge current there is no way the circuit protection will work, thus permanently damaging the cell and causing internal short and or explosion; have you ever seen what happens to a lithium cell when it fails?  These lithium cells pack a lot of energy and that energy can pack a lot of punch.  NiCd chemistry is a little more forgiving as it has it own way of releasing overcharge energy and still maintain its reliability 

I haven't looked at the data sheet for the cells in the 12V lithium packs, but I'd be quite surprised if the charging algorithm is not the standard "constant current to 4.2V [or whatever]/constant voltage until current drops to 10% [or whatever] of initial current" algorithm.

Well i suggest you do some research before you speculate on what it will take to charge lithium cells....

Note that in my scenario here the idea really *is* to turn the charger into a "dumb power supply" and stick the charge controller IC into the charger.

Again, dont speculate and think you know on what really goes on when a battery is in its charge cycle

I think this will be useful for only one person  :o

You probably don't use, e.g., Nikon lens on Canon cameras either, do you? :-)  Also check out the guys who use the DeWalt 36V lithium batteries for eBike projects -- many of them built their own chargers, since they use so many of the things and want to charge them simultaneously.  

You're not in the marketing group at DeWalt and just unhappy you guys didn't think of this, are you?  Just kidding. :-)  I appreciate your input on the subject here!

---Joel

And how is that the same?  It's like comparing apples to oranges really.......and with the ebike project?  I bet the guys there did their research.  No i am not in the marketing group, i am actually a Sr. designer who designs power tools with the intention of making a tool or battery idiot proof, but there is only so much i can do  ::)

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I just do not understand how it can be such a inconvinent to have two chargers. I have my little Wolksvagen caddy car full of tools and stuf so one more or less charger really does not make any different. I also do not carry the charges around the whole day. My small DCF610 need a charge very seldom since I more or less only use it for screwdriving and not drilling, so it can take days before I need to charge it.

I mean, when the workday start I bring in the toolcases and start to work. When I need to charge I pick up the charger from the tool case and plugg it into a outlet and charge the battery. If this is so hard work I think the rest of things you do in a workday must be worse than 1000 years in a concentration work camp with a big whip lashing your back every minute.

well said......

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It's not necessarily that horribly inconvenient to carry two chargers around, the idea is that it might be more convenient overall not to have to.  Just consider the case of carrying a "big" drill like the DVD970KL around in additional to the new 12V Max drill: Plenty of people do this, even thought it means lugging more tools around -- but overall it's more convenient in that you don't have to change bits nearly as often.  (Heck, isn't this also why most everyone carries around a separate impact driver these days?)

Clearly, at some point it does become ridiculous to carry a whole bunch of extra chargers around -- whenever you decide to get a new cordless tool, everyone considers which battery packs, chargers, and other accessories they already own, right?  And manufacturers absolutely use this to their own advantage -- there's no solid technical reason that, e.g., Makita, Milwaukee, and DeWalt couldn't all get together and come up with universal batteries and chargers (especially for the lighter duty tools that don't compete so much on the battery technology itself), but instead each one insists on having their own proprietary system -- sometimes even down to using the exact same cells as their competitors, but in every-so-slightly different case so as to prevent them from being interchangeable.  (Not that there's all that much inherently awful with this -- the best interest of manufacturers and those of their customers often don't line up entirely, but that doesn't necessarily preclude a "win-win" situation either.  ...but you can also bet that Ford would require you to use Ford-branded gasoline if they thought they could get away with it!)

In any case...

I'm thinking something a bit less ambitious might be a better start: Anyone want a 12V (cigarette lighter) charger for their 12V Max batteries?  I suspect DeWalt will release one of these themselves sooner or later, but I wouldn't be surprised if that isn't until 2012.

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All lithium cells have circuit protection and the cell manufacturers specify the charge/discharge current based on the internal chemistry.  they also specify the failure mode and low voltage protection, the problem is if you charge a lithium cell without the proper charge current there is no way the circuit protection will work, thus permanently damaging the cell and causing internal short and or explosion; have you ever seen what happens to a lithium cell when it fails?  These lithium cells pack a lot of energy and that energy can pack a lot of punch.

Well, I've personally designed a six-port charger for a military application that used Saft lithium-ion batteries (about the most unforgiving chemistry there is -- and we've built nearly a thousand of these widgets to date, and no, none of them have exploded yet!), and I've spent awhile talking to their engineers about the built-in protection circuitry they were using.  They sent me their schematics of their pack's built-in protection circuitry, and encouraged me to purposely abuse the packs, by over- and under-charging them, and using several times the rated charge current, to demonstrate that their just wasn't any real safety issue involved.  I did those tests (with a fire extinguisher at hand...), and -- not surprisingly (Saft has been in the battery business for many years now...) -- I was unable to get the packs to do anything "exciting."

I'm confident DeWalt's packs are designed with just as robust protection in them as Saft's.  Do you believe otherwise?

I'll give you that own can readily damage a lithium battery pack with improper charging techniques, but I defy you to provide a means by which a DeWalt pack could prove unsafe (i.e., exploding or catching on fire) when subjected to, say, no more than double the proper charging voltages and currents: It just isn't going to happen.

My understanding is that vast majority of fires from lithium battery packs are due to defects in the individual battery cells (this was the case in, e.g., the famous Sony laptop that started on fire) and have nothing to do with charging/discharging practices (...when a "safety PCB" is included in the cells or pack, that is).

Again, dont speculate and think you know on what really goes on when a battery is in its charge cycle

Hey, if you could point me to some documentation on DeWalt's battery-charger interface, that'd be super useful. :-)

No i am not in the marketing group, i am actually a Sr. designer who designs power tools with the intention of making a tool or battery idiot proof, but there is only so much i can do  ::)

Give yourself (and other engineering group members) some credit then -- your battery packs are quite safe, even if they're being subjected to significant abuse (which I wouldn't be doing anyway, of course).

---Joel

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All lithium cells have circuit protection and the cell manufacturers specify the charge/discharge current based on the internal chemistry.  they also specify the failure mode and low voltage protection, the problem is if you charge a lithium cell without the proper charge current there is no way the circuit protection will work, thus permanently damaging the cell and causing internal short and or explosion; have you ever seen what happens to a lithium cell when it fails?  These lithium cells pack a lot of energy and that energy can pack a lot of punch.

Well, I've personally designed a six-port charger for a military application that used Saft lithium-ion batteries (about the most unforgiving chemistry there is -- and we've built nearly a thousand of these widgets to date, and no, none of them have exploded yet!), and I've spent awhile talking to their engineers about the built-in protection circuitry they were using.  They sent me their schematics of their pack's built-in protection circuitry, and encouraged me to purposely abuse the packs, by over- and under-charging them, and using several times the rated charge current, to demonstrate that their just wasn't any real safety issue involved.  I did those tests (with a fire extinguisher at hand...), and -- not surprisingly (Saft has been in the battery business for many years now...) -- I was unable to get the packs to do anything "exciting."

I'm confident DeWalt's packs are designed with just as robust protection in them as Saft's.  Do you believe otherwise?

I'll give you that own can readily damage a lithium battery pack with improper charging techniques, but I defy you to provide a means by which a DeWalt pack could prove unsafe (i.e., exploding or catching on fire) when subjected to, say, no more than double the proper charging voltages and currents: It just isn't going to happen.

My understanding is that vast majority of fires from lithium battery packs are due to defects in the individual battery cells (this was the case in, e.g., the famous Sony laptop that started on fire) and have nothing to do with charging/discharging practices (...when a "safety PCB" is included in the cells or pack, that is).

I not familiar with Saft batteries so i cannot give any insight into it, so if you have tested these batteries then i will believe what you say.  I am not an electrical engineer so i cannot give any specifics on what test DeWalt runs on various lithium batteries, and as for the sony laptop issue that happened a few years ago?  Yes, there was a big recall on it and i am not sure what specific chemistry they were using at the time nor do i know what was the outcome, but i would "assume" that the internal circuit failed and caused a terminal runaway, but that is just my opinion without have all of the facts.

Again, dont speculate and think you know on what really goes on when a battery is in its charge cycle

Hey, if you could point me to some documentation on DeWalt's battery-charger interface, that'd be super useful. :-)

No can do, trade secrets......

No i am not in the marketing group, i am actually a Sr. designer who designs power tools with the intention of making a tool or battery idiot proof, but there is only so much i can do  ::)

Give yourself (and other engineering group members) some credit then -- your battery packs are quite safe, even if they're being subjected to significant abuse (which I wouldn't be doing anyway, of course).

---Joel

Thank you, we do a lot of testing and some might say its a little over the top but we have fun with it  ;D best job in the world, playing with power tools all day; talk about anger management tools  ;D ;D

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The adapter is a good idea, but not for charging.  It seems it would make sense for Dewalt to make an adapter to allow the new 18V slide pack to be used in older 18V stem pack tools.  There wouldn't be a need to continue producing  a seperate battery line and also give users more flexibility as they upgrade and replace tools.

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The adapter is a good idea, but not for charging.  It seems it would make sense for Dewalt to make an adapter to allow the new 18V slide pack to be used in older 18V stem pack tools.  There wouldn't be a need to continue producing  a seperate battery line and also give users more flexibility as they upgrade and replace tools.

also have one to use current packs in new tools
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The adapter is a good idea, but not for charging.  It seems it would make sense for Dewalt to make an adapter to allow the new 18V slide pack to be used in older 18V stem pack tools.  There wouldn't be a need to continue producing  a seperate battery line and also give users more flexibility as they upgrade and replace tools.

also have one to use current packs in new tools

Well, a adapter to use the new battery in old tools should not be any problem to manufacture but a adapter to use the old battery in a new slide stool I do not think will be an easy task. The handle will for sure be thinner on the new tools so some horny tool reviewers can say how great that is. But with a thinner and smaller grip it will be almost impossible to make an adapter for old battery in new tool.

Do not know what you guys think but in general I found most so called profesionell reviews on powertools very worthless, at least here in scandinavia. It seems to me that those "expert" do not really work on the sites with the tools. Thay are doing some test that really says nothing about the tools quality and durability. But I guess it is important for the manufactures to get possitive testing results and a thinner grip is one way to achive that.

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  • 7 months later...

I am so sick of all the battery variations by DeWalt and everyone else. I am not a tradesman with super performance requirements but an ordinary homeowner/hobbyist who uses power tools on occasion. I cannot guess how much money I have thrown away on batteries that go dead just sitting around. I have a pair of expensive 12V XRP packs that have hardly been used but are now nearly dead. What I want is an adapter that will allow me to use the new Li-ion battery packs in my old tools. I will be happy to buy the appropriate charger, although I would rather not if the Li-ion packs could be charged in the old style chargers.

If I could buy a universal adapter that would allow all these battery styles to be used in any tool of any mfgr. I would be happy as a clam. In fact, I have cannibalized a DeWalt 12V XRP pack and a Rigid 18V Li-ion battery and have married them with glue and tape. The 18V battery in the 12V tool works just fine, in fact I get some extra speed as a bonus. I have to charge the Rigid battery with jumpers, but it still works. Any fool can see that this is doable, so why don't the mfgrs. do it? I will bet that if someone produced commercially such an adapter, then DeWalt and others would follow suit lickity-split.

Does the 18V battery in a 12V tool ruin it? The question actually is, when, how long will it take? I have used DeWalt (and other) cordless drill motors for a long time in robotics projects. I can tell you that the motors are very, very robust. I have not yet ruined one even though I routinely run them at 24V for speed. So running a 12V tool on 18V is likely to ruin the battery pack before it ruins the tool.

I am all for the adapter idea, for both chargers and tools. It's time has surely come. We are being victimized, ripped off, by all the manufacturers as it is now simply for the battery incompatibility issue alone.

What say you DeWalt? Are you going to keep it up, or let users like me get what WE want for a change?

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