Ian emailed in, asking about a rather interesting difference in Dewalt’s 20V Max 2.0Ah XR Li-ion battery packs. I thought that this would be an interesting discussion topic, although simply asking Dewalt for clarification would be the quicker and easier route.
Dewalt came out with their DCB203 20V Max 2.0Ah XR Li-ion batteries about 2 years ago. I thought that there was only one kind – the one with a vented bottom and visible heatsink, but it appears that this isn’t the case.
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Here’s what Ian had to say:
I recently did the ol’ ebay sell/buy to upgrade my DeWalt 20V non-brushless/1.5 Ah batteries to a new XR brushless/2.0 Ah battery setup.
I bought three DCB203 2.0ah XR batteries ala carte on ebay, and two of them came with a vented bottom and exposed aluminum heatsink, while the third came with a closed plastic bottom just like my old 1.5ah had.
I attached a photo of the two batteries so you can see what I’m talking about.
I did a good little bit of googling, but couldn’t seem to find anything about this for whatever reason. Do you know anything regarding the story on these two different versions of DCB203? Are they side by side models, or is one of the two out of production?
Interestingly, the vented bottom DCB203 I received are marked as older manufacture than the closed bottom batt that I got…. which makes me sad if it means Dewalt abandoned the new vented battery design and went back to the closed design, because the vented batteries are darned cool and they make a lot of sense to me.
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Also, the vented batteries are of Korean manufacture, which is new to me for Yellow & Black, the closed bottom is Malaysian, which is what I normally have seen in the recent past on most Dewalt in this tier.
I just checked all of the Dewalt DCB203 2.0Ah XR Li-ion batteries I have at-hand, and they all have vented bottoms and visible aluminum heatsinks. My higher capacity battery packs do not – they have closed/solid plastic bottoms.
Why an aluminum heatsink and vented bottom? To dissipate heat. Whether during use or charging, Li-ion battery cells can heat up, and adding in a heatsink and air vent will help prevent heat buildup that can damage the cells.
Going by my post timestamps, the 2.0Ah battery pack was released prior to the 4.0Ah battery pack. The 4.0Ah packs, at least all of the ones I’ve seen, have fully closed bottom pieces.
What I’m thinking is that Dewalt engineers came up with the vented bottom design, put it into production, and upon conducting further testing on the design they found that the heatsink and vented bottom were not actually needed. There might still be a heatsink within the larger battery packs, but I haven’t opened one up recently to check.
If the visible heatsink and vent holes aren’t needed to help protect the battery cells from heat buildup, then that’s a production step that could – and should – be skipped to save costs. While some cool-looking features are worth the production costs, which are passed along to retailers and end-users, I think most would agree that’s not the case with power tool battery packs.
It is also possible that Dewalt’s initial batch of batteries were manufactured with one make and model of Li-ion cell, and that they moved to another make and model after that. Or maybe they tweaked the internal design a little, with the result being lower thermal heating of the cells during charging or high-power discharge. Or maybe new circuitry was added to help prevent high heat build-up.
The point is, the most reasonable explanation is that Dewalt nixed this vented battery feature because it simply wasn’t needed.
I suppose that it’s also possible they removed this feature because it provided a means for water ingress, although I don’t think that’s the case. Examination of a vented 2.0Ah battery showed no perceptible gap between heatsink and bottom of the battery. For all intents and purposes, it effectively looks to be weather sealed.
So there’s my thought on the matter – that Dewalt probably discontinued production of the vented battery bottoms to cut costs and simplify production. As they already had a pricey injection mold made, they probably had a good number of vented battery bottoms produced before switching over to the same solid cap as the 4.0Ah and 5.0Ah battery packs.
What do you think? If you made it this far into the post, surely you have some thoughts you’d like to share!
In the meantime, I’ll see if someone at Dewalt can shed light on this.
Nathan
the fact that the larger cap ones don’t have the vented bottom and exposure – speaks to further development testing proving it wasn’t necessary.
and it might be detrimental over all – IE you see lots of sealed up batteries these day – even LI-Ion, LI-PO. since it exposes to humidity, fluids, even more heat in some cases, and dirt
it’s possible dewalt/black and decker saw that batteries were susceptible to dirt or other damage via not being seals and if the 2AH battery lives fine with out the vent holes.
another issue might be – and this is done with processors alot. the early 2.0 packs were actually made with 1.5 batteries but over driven based on batteries that exceeded testing during assembly of the 1.5 packs. then after a year or 2 more and more stable higher cap batteries were being produced (perhaps even a switch in maker) and no more vents needed.
Stuart
I don’t think that battery cells are binned in the same way as memory chips and CPUs. As you mentioned about processors, I know that lower performing ones will often receive lower clock limiters, while higher performing ones could be set to higher clock speeds. Overclockers can usually push the lower CPUs to higher clock speeds but they need better cooling than the stock heatsinks and fans.
But with battery cells? Charge capacity isn’t something that I think batteries are tested and binned for. Discharge rate? Maybe, but I wouldn’t think so. With battery cells, I know you might be able to overdrive them in terms of max discharge rate, but max discharge capacity seems to be a lot harder to push.
SteveR
As I read through this, I thought perhaps the venting permitted the discharge of internal fluids or vapors as the battery heated up. Acid is a big component of battery fluid, and would cause burns to end-users. Just the release of fumes could cause skin irritation, breathing issues and/or eye problems, both short- and long-term. They potentially could also cause damage to work surfaces or the objects being worked on.
As heat increases, so do the chances of an explosion. I’m of the view that the most likely chance for an explosion comes during the charging cycle, when a lot of heat is generated. The charger is attached to 110v-120v, and a spark from the charger could cause an explosion. They may have discovered that vented batteries are more prone to “excursions” and “undesirable events” during the charging cycle. Most automotive batteries are sealed during their manufacture, so perhaps they’re following that example.
This is all supposition, of course; what does the manufacturer claim is the reason?
Stuart
There are no loose fluids inside a Li-ion power tool battery pack. No vapors either. No acid, no fumes.
12V and 20V Max battery packs are built with sealed 18650 Li-ion cells (https://www.google.com/search?q=18650+battery&tbm=isch).
Lithium-polymer batteries carry greater risk during charging or deep discharge, but are perfectly safe when treated with proper care and charging procedures.
Ian
Stuart,
Thanks for featuring this… I started thinking about it more, and perhaps the very first high capacity cells that DeWalt got ran hotter than they liked, similar to what the poster above mentioned.
I suppose the other option is that they just found it unnecessary, and did away with it, as you said.
I do really like the idea of an exposed heatsink, but I suppose it could be a really bad day if not completely sealed, and you set the drill down on a wet floor at a job site, it could end up drenching the batt.
I like the idea that the old ones are Korean made, they have some very solid electronics manufacture. Perhaps a company in Korea was the first to have the high capacity cells available on market?
That is the part where I really scratch my head… in my recent memory, all dewalt I’ve seen has been Mexico or Malaysia. Switching to an entirely new country for manufacture, and then switching back, is quite unusual IMO.
Jerry
Perhaps their normal sources for batteries didn’t have enough to meet demand, and DeWalt sourced some from another maker. They could have already been making a pack of similar size, and just modified the top of the case so it fit the DeWalt platform. Once their usual suppliers caught up, they no longer needed the ‘extra’ ones.
This could explain why the short run made in another country.
john
My small capacity batteries which are either 1.3 or 1.5ah are solid bottomed but my 2.0ah and 5.0ah are vented I think. This is the reason why Toolguyd is the best tool related resource either side of the Atlantic. Proper in depth analysis of tools. Nice work Stuart.
Jonatan
I only have 4Ah batteries at hand, but all are sealed. I didn’t think they’d make any open vented battery designs. I do understand the cooling need, but tool batteries are in hazardous environments. I recon there’s way too much dirt around to open up the shell.
I recon this is twofold: Possibly new battery cells / the vent wasn’t needed, and the vent got clogged with dirt and debris in no time making it even worse than if they were closed to begin with.
Re SteveR: Lithium cells are completely closed (even if you have vents like these batteries) and do not discharge any gases. You’re thinking of open lead-acid batteries. They do however burn violently if they get shorted.
SteveR
For what it’s worth, I have three (3) DCB201 Batteries at 20-volt, 1.5aH; I have one (1) DCB 200 Battery at 20-volt, 3.0 aH; all of these were made in Japan. NONE OF THE BATTERIES ARE VENTED. I have two (2) DCB101 Chargers, which will handle either of these batteries, and presumably 2.0 and 4.0 aH batteries as well. The two chargers were manufactured in Thailand.
The three 1.5 aH batteries and one charger belong to an impact drill/driver purchased in November, 2011. The 3.0 aH battery and the second charger belong to a reciprocating saw purchased in June, 2012. All items are DeWalt labeled (yellow and black). Obviously, mine are a few years old, so I don’t know what’s occurred with batteries produced either before or since I acquired these.
All this will probably do is confuse the issue. It all comes down to the understanding that companies source products and parts of products globally, so they may vary from one country to the next. These changes will depend on the safety rules and manufacturing requirements in effect in that country at the time of the product’s manufacture. The manufacturers are keen to remind us, however, that they don’t owe us anything if current safety requirements render the version of the product we bought, say three years ago, incompatible with a newer battery platform. So, caveat emptor.
kevin
i have the compact brushless drill and inpact driver, with the 2.0 batteries, they came with the vented bottoms. after a particularly wet week, one of the batteries took issue with the moisture i would assume, and would no longer take a charge. im thinking the vent did not help.
reasons why they could have done it
-less weigh(marginal)
-less material(marginal)
-looks cool
reasons they probably stoped
-a high percentage of the batteries coming back for warranty repairs with the honecomb style base warrented a change.
Greg
I find this interesting and took me back to a thought I had the other day about the Chargers. Why in the heck are all battery chargers so LARGE. I can charge my phone with a tiny block looking thing but have these HUGE chargers for all my tools. I think its alot of wasted plastic in the charges and they could all be made much smaller. Dewalt, Milwaukee, 20v, 18v, and 12v chargers i think are just too large.
Pablo
The Makita chargers are even bigger, but they have built it fans to push air through the pack while charging.
The Metabo packs are also forced air cooled, but the charger is more Milwaukee sized.
Stuart
Certain brands do have smaller and slower chargers for their holiday special consumer kits. The larger regular charges can be wall/bench/truck mounted, and have larger components that can withstand faster charging rates.
Your phone charges in what, 2 hours? A power tool battery pack might charge in 30-90 minutes depending on capacity, and they pack a lot more power.
Nathan
specifically current. but yes your phone is 5.2 or so Volts of charge – by around 2.1 Amps if you have something like a samsung note 3-or 4, 1 amp for most others.
vs say a 18 volt pack with a 2 Ahr capacity (or 2000 mAh if you want to compare that way). so charging voltage is probably closer to 22 or 24 volts, and a current of 2 amps. significantly more power required – and inside your tool pack – the charger has circuity to load balance the cells – something your phone does internally – very minimally.
Pablo
Or they violated some patent/stopped licensing it, and then Bosch picked it up.
Pablo
This is also relevant:
https://www.youtube.com/watch?v=xbIBqzsnv6w
Granted it’s from a competitor (Milwaukee), but it debunks the idea that the DeWalt has “good enough” cooling, because it clearly doesn’t, especially with the unbalanced cell configuration.
Brian
there is a C rating to lipos that denotes their internal resistance. Higher C can accomidate higher discharge with less heat. down side is a bit of size/weight/cost.
Its possible that they sourced such batteries later to eliminate the more expensive vented molding.
Speculation, or maybe the vents were just overkill, or just costed out, repurcussions be damned.
William Gierhart
The reason the compact batteries had the heat sinks and the larger ones did not is because there are less cells in the compact and they need to provide the same amount of current that as the packs with more cells