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May i ask what this test is all about? You test if the battery can supply the current of a tool idling? What does that tell you? Only thing you do is risking shorting your battery out and bricking it with what? copper plates? I mean, you can test the battery against the cell manufacturers datasheet - capacity and high current runs with a electronic load. Or you can measure internal resistance with an impedance meter. Even then - what are you going to do, you have data. But what counts is if the battery works for what you do WITH the particular tool under LOAD. You have probably discarded batteries with 85% State of Health in your life before, and still use some with 60%. The current under idle test is superfluous, you can pull the trigger and hear if the motor slows down. If it doesn't your battery current is constant. Have fun..

Eh, you should be aware that tools and batteries are capable of a lot more than the 10A current range of your Multimeter. You could damage it. I used a clamp meter when measuring battery current. If you want to know if your battery is still good, just try out the tool. If you can screw in a screw with your known good pack, the other one should be able as well.

In this special case it could kinda be an indicator Normally, it really isn't - even a worn pack will show similar voltage directly after charging, because normally a Li-Ion battery is charged with a CC-CV charging characteristic. So first the current is limited and when the voltage comes up, as the battery fills the voltage is held constant, to slowly fill up the last few %. Makita doesn't do that, they skip the CV phase. I don't really know why exactly maybe the self balancing effekt (which they used at their early LiMn2O4 batterys, the non star ones) works best that way, or they said "we at the site ain't have time for topping the battery up". Yes that looses some capacity, on the other hand it is good for lifetime. If you take that into account with your old/new battery therory - the charger always cuts off at 4,1V per cell in CC mode. A worn battery will have higher internal resistance and therefore more voltage drop when charging - and will have a lower "idle voltage" when finished. But there are a lot of factors to take in account when doing this, mostly battery chemistry and temperature. A worn 5Ah will have a lower voltage after charging than a new 5Ah (if they have the same cells). But to compare a 3Ah and a 5Ah can be misleading, the 3Ah will probably have worse internal resistance right out of the box so...

The main problem with this would be letting people cope with unprotected Li-Ion cells. Just look at all these e-cig guys that put unprotected 18650 in the same pocket with their keys. Further annoying would be the no doubt higher price. You would have to have all time cell voltage monitoring because you could put non-matched cells in there, the contacting would be non trivial etc. But i have to say the concept is interesting

Exactly. Each cell is 2750-2850mAh (if that is the correct datasheet for the actual cell and the rating is correct). So the whole pack is rated at 5,5-5,7Ah depending on which rating you want to go with (nominal or minimal). With cells in series the voltage adds up, with cells in parallel the capacity and current handling capability adds. Your pack has 5 cells in series and 2 parallel. 3,6V*5cells=18V and 2,85Ah*2cells=5,7Ah. (If you want to know the energy stored you multiply those and get 102,6Wh). There is no discharge current specified but the internal impedance of the cell. The internal impedance decides how much energy is wasted as heat in your cell and therefore dictates how much power you can draw and how hot the cell gets. 35mOhm is not really powertool cell territory. Typical maximum values are: Samsung SDI 25R (2,5Ah): 18mOhm; LG Chem HB6 (1,5Ah): 20mOhm; LG Chem HG2 (3Ah): 17mOhm. So i would expect poor performance with high drain tools and thermal issues. But I didn't try them and therefore can't say if they are up to the work you do. And yeah, for 40 bucks even getting something that sort of has 6Ah is more surprising than disappointing to me

Source: http://li-b.cn/post/43527.html Seems to be more of an electric vehicle cell, sadly i couldn't find a discharge current rating. If you look at the internal impedance you can expect less power than from an powertool cell. You will probably find this 2 row pack performing like a original 1 row pack (with longer runtime). Nothing for angle grinders or circ saws but on an impact I'd expect it to run fine. Thanks a LOT for showing us the insides, very interesting indeed.

As much information as possible. Sure just a very small of buyers would be interested, but enthusiasts and more tech heavy people sure appreciate it. I don't know about the US homepage but in europe DeWalt states at least some info on output power from battery tools. Like 360W output from the DCD795 or 800W from the DCG405, for this one even 1000W input power is stated. That is worth gold if you want to compare tools or choose batteries. Or one time i wanted to find out the dimensions and weight of a XR 6.0Ah battery. Couldn't find them on the homepage so i had to search reviews on forums and blogs to get the info. Why? Just state it...

Oh, okay Sodium solid electrolyte batteries. Even further off but maybe we'll find a working solid electrolyte material that works

I don't know which battery you are referring to, but I don't know any coming soon... I heard some excitement about Li-Ion batteries with solid electrolyte, which are expected to come to market in the mid 20s. I don't want to dampen your enthusiasm, and we certainly don't really know the exact specifications but I don't think powertool will be one of the early uses of any solid electrolyte batteries (lately marketed as "solid state"). Solids are not that good at conducting ions so fast charging and high power are not their principal strengths. The mayor advantage will be energy density and safety, so phones or electric cars will be the first examples that come to mind. With Li metal negative electrode material (which is enabled by the solid electrolyte) you of course don't have problems with lithium plating because It's what you do in this case and lithium plating is limiting the charging of today's Li-Ion batteries. But if the internal resistance of the electrolyte is kinda high you would just heat up your battery and don't charge it much. If you read specs about solid electrolyte cells in research they never mention power output or charge times when comparing them to "todays technology" and 5min charging claims don't have traceable sources behind them. I am excited for anything regarding batteries, don't get me wrong, just don't know when this technology is ready for powertool use

It is indeed a bit sad that tool manufacturers don't offer real fast charging. With those Powertool cells you could go 3C or something if you would care a little about cooling. Especially if the battery was used before. If i got that right it uses the piece where the lock is to suck/blow air through the battery. Could be wrong, never seen the "fast"-charger (8 amps) in person. I would personally even think about active cooling with a peltier cooler or something. Then 16amp charging or something, limited to 3C or there about. That would be a real fast charger. Seems nobody really cares too much, and you can have more batteries as well as solution...

Don't be mistaken, the Ah rating tells you the capacity, not the power. You can push a 4Ah Pack harder than a 18650 6Ah Pack, because it is empty before it can get too hot for instance. And the maximal peak power would be about the same. And I don't know too much of aftermarket batteries, but 40$ for a 6Ah Pack seem a little bit too good to be true. Without knowing i would suspect used 2,5Ah cells or something like that in there. AvE on youtube once had a aftermarked pack with used cells (premium cells, but yeah, can't expect the full lifespan is left). If you buy one please tear it apart and show some pictures, would be very interesting what hides in there.

Maybe a TIG. Welding would be a great hobby i guess, i have a little ac stick welder buzzbox but fine and/or stainless is more interesting to me...

New toy and I absolutely love it. Very powerful and compact, even comes with a slide switch (not too much of a fan of the trigger or paddle versions). In Europe the paddle style version is called DCG406 and in America it is DCG413, so you may know this unit under a different name. I made a little hands on video with an input power measurement:

Hey guys, I'm in the middle of doing a conversion from an defective DeWalt 4Ah 5s2p Pack to a DeWalt 4,5Ah 5s3p. Even though this is a very niche thing to do (as you guys in the states have the 20700 6.0Ah Packs) you may be interested in how i made a very low cost solution for a high power battery, until 6.0Ah batteries arrive in europe. I documented the process on youtube pretty much as an experiment (gaining experience for a single tool review i want to do in the future). I can share the CAD for the 3rd battery cage and the case enhancement as soon as it is done. Feel free to ask stuff! I don't know if I am even allowed to share this here as there is some self promoting limitation. That said I don't really care for YT views or subscriptions, because I don't plan on doing much on YT (not really that good at it either :D). Then again mods will delete it anyways if it is against the rules.

That is the safe version and in most of the cases it turns out to be right. But when you know what you're doing and follow the recommendations of the cell manufacturer you can possibly revive packs. I don't mean stupid and dangerous "hook it up to a NiCd charger" or "jump start it with another battery" youtube videos. More like read this https://www.nature.com/articles/srep30248 and understand whats going on in a serial string of batteries. Then measure cell voltages and decide if you want to proceed (when all cells are at 3,6V and one is at 0V then yeah, extract the good ones if you need them for anything else but your pack is toast). If all are like 1,5V-2,5V one should consider reviving the pack. There is no guarantee though that no cells have been negative charged in the previous discharge cycle! So look up the cell manufacturers datasheet and look for the recommended revival current. This current is that low, that a cell with a internal short wouldn't come up to voltage. You'll find something like: With low discharged cells (as you can read in the article above) you expect a damaged SEI layer in the cell. The life and performance is greatly dependent on the SEI layer of you battery. Therefore you should consider to make a low current charge (charger with current set or maybe a bench power supply and good supervision) and discharge (lamp or radio) cycle. This should help to properly form the SEI again which translates to the best possible recovery for your cells (if it works out). If the battery can't hold the charge, its defective, if it doesn't perform properly its defective and should never used again. But maybe you have just discharged the cell that little amount that the threshold of the charger isn't reached anymore. Oh and btw. It is not a bad idea to make such a low current cycle with a new out of the box battery as well. The SEI isn't 100% formed yet and low current means less stress for the battery until the SEI is fully there.

Those are expensive packs. Do you have any method of checking voltages? Overdischarge is not desired by any means, but one should check if the cells are still up and alive may they can be revived.

I'm not too familiar with impact drivers but a quick look on the homepage says, there is the DCF887 rated at 400W output power, so the single row 20700 3Ah Pack would be perfect for this tool. It can supply enough power to get the tools full potential and be still quite compact. Although the 3Ah version would be a very nice fit for my DCH253 small SDS Plus and my DCD795 compact drill i can use these with my 4,0Ah Packs to their full potential, so I don't know if I go for these. But when the DCG405 (125mm angle grinder) comes around with 1000W imput power rating the 4,0Ah would hold the tool back. And this grinder looks so nice I see very small chances that I can resist getting it (sorry wallet). The 18V 6,0Ah battery would be a perfect fit for that kind of power, and if DeWalt doesn't give these to europe at least we can buy a 3,0Ah and easily modify it to a 6,0Ah.

YHESS finally. 20700 Packs for europe <3<3 And if the 6,0Ah don't show up, hack up a second row of 20700s in there, here you go. Easy the best news of the week

To have the possibility at least would be nice. A new 1,5 or 2Ah battery most likely handles a high drain tool as good (or as bad) as an old 1,3Ah (expecting the "good old 1,3" like the original Sony VTC in the BL1815, newer 1,3Ah are often "budget" versions with lower rating cells). It is a decision to make, will I completely restrict getting poor performance on these occasions or tolerate it for emergencies and inform users that for some tools you need more than 1 row of cells. I like that i can use my angle grinder for a light duty job with the 2Ah battery when my 2 row packs are flat, even though it is completely unappropriate thing to do.

Oh no! A Makita vs. DeWalt Flameware. Thats a bit problematic for me :S

Hello, I'm not really new to toolsinaction on youtube but new to the forum. I'm Michael and i like everything battery related, like electric cars, storage, my computer mouse and of course powertools. I'm from Austria (Europe), where we don't have kangaroos - apart from the zoo maybe. At age 23 I am a college student and mostly broke, but every tool purchase is something special for me then and I enjoy tinkering with them as well (which mostly lands on instagram). So yeah, looking forward to read (and maybe post if I can't shut up) some stuff here in the forum. Cheers

It is a persistent rumor, that the Bosch ProCore features 21700 cells but they are Sanyo NCR20700C cells, the same as in the new Metabo LiHD batteries. There are no 3,5Ah 21700 cells from a major cell manufacturer yet.

I have to thank you, for making OTT, I'm a big fan of the show. There are so much details covered in your reviews, please keep on doing them

Current output (power density) and energy density is a tradeoff in the first place, you can't be very good at both. Runtime depends on both in a way, more capacity - more runtime is logical and correct, but at high loads (which tools are) internal resistance as an effect on runtime as well. Internal resistance decides how much Energy is wasted in the cell, and how much you can use. The power wasted in the cell grows at square to the current you draw (as power does), therefore the effect can get very considerable. With 18650 cells the goal over the years was (at least we can assume from how the cells react) to get more capacity and not hurting the internal resistance too much (we know it is a tradeoff). So you can draw 30A for 5s from an 2009 1,5Ah cell and from an 2016 3Ah cell and get basicly the same. The voltage will drop according to the internal resistance and you will get similar power out, and heat up both batteries about the same. So, now you look at the datasheet and see, wait the 1,5Ah cell is rated at 30A continuous discharge, and the 3Ah cell at 15A. The reason beeing, the 1,5Ah cell is empty before it can get too hot. They can supply both similar currents - if you use it in a drill or an impact, but in an angle grinder you would send the batteries with 3Ah cells into thermal overload quickly. So with 20700 (and 20650 and 21700) cells they went a new direction. They could use the bigger cells to lower internal resistance. Low internal resistance is very pleasant, you can get more current output, more power output and less wasted power due to heat. The first generation 20700 cells are the 3,1Ah Panasonic NCR20700A cells, featured in Metabo LiHD, DeWalt 18V 6Ah, FlexVolt 9Ah, Bosch Core/Eneracer and as we know these work an absolute dream. Continuous discharge rating is 32A with room for 40 or 50A overloads, no worries. To get back to the FlexVolt 6.0 and XR 18V 6.0 comparison, DeWalt wanted to make an physically smaller 18650 version and the beast 20700 version of FlexVolt batteries. But the FlexVolt tools are very much high drain tools, and to avoid thermal issues they hat to go for a quite low energy 18650, a 2Ah cell. Samsung INR18650-20Rs Of course they may have been revised for extra % at internal resistance over the years, but the 20R is a quite old design still. Nothing really wrong using them, they are well chosen for the application and as we know with 18650 at those levels of power you can't make a better choice. Now the XR 18V 6.0 (which is really a 6,2 Ah to be honest) are a few years newer and get you just very good power density and still good energy density, as you expect with the latest technology. As far as i know the internal resistance of 3 paralleled up 20Rs (FV) and 2 NCR20700 (XR6.0) should be similar, the XR6.0 has a slight capacity advantage - so the runtime is comparable. The advantage you get from the newer tech is the size in this instance. And what does a third row of 20700s do to your runtime? 50% more capacity + lower internal resistance = over 100% more runtime. EDIT: Oh and DeWalt, we do want the 18V XR 6.0 battery EXTREMLY bad here in europe, at least i do. Pleease make it happen