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The problem is that high current surges aren't a problem for batteries but a power supply typically doesn't like them. So you'd need a huge PSU to replaces the batteries of a cordless drill (for example). Somebody I know has experimented with this and his results wheren't stellar. If you want a corded power tool, buy a corded power tool.
I suggested looking to the ones on cameras: the actual SMPS doesn’t fit into the battery compartment, so the power brick is connected via a cable so that the camera stays compact (= existing accessories will still fit).It’d certainly be trivial for the manufacturers to make an AC-powered dummy battery, akin to what’s common in cameras.
That PSU most likely will be more expensive than AC powered tool, and likely oversized quite a bit to have enough power. I doubt you want something like 0.5-1.5kW PSU attached to the tool. Somewhat reasonable only for low power tools.
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The problem is that high current surges aren't a problem for batteries but a power supply typically doesn't like them. So you'd need a huge PSU to replaces the batteries of a cordless drill (for example). Somebody I know has experimented with this and his results wheren't stellar. If you want a corded power tool, buy a corded power tool.
I have used a cordless drill with a dead battery from a PSU in a pinch and can confirm that a 12V 30A Meanwell clone power supply (look at how big these are) was needed to be able to do anything and even that sagged (10A lab supply was tested first, totally unusable). And it was a supply capable of working in CC mode; those that fault out or enter hickup mode are unusable. A simple 18650 power cell easily puts out 30-40A of peak current. Many 18650 power cells are actually tested for a full continuous discharge cycle at as high as 25A; sure the cell temperature would be beyond 60degC at the end, but that's also why professional power tool chargers have battery cooling: they can bypass long cooldown waiting times. -
Then you will need very thick or very short wires to provide reasonably low voltage drop to not hinder performance. And again, PSU price will be prohibitive to the point of making no sense of using this contraption rather than just buying another tool that works from mains voltage natively.
I suggested looking to the ones on cameras: the actual SMPS doesn’t fit into the battery compartment, so the power brick is connected via a cable so that the camera stays compact (= existing accessories will still fit).It’d certainly be trivial for the manufacturers to make an AC-powered dummy battery, akin to what’s common in cameras.
That PSU most likely will be more expensive than AC powered tool, and likely oversized quite a bit to have enough power. I doubt you want something like 0.5-1.5kW PSU attached to the tool. Somewhat reasonable only for low power tools. -
Big enough brush/commutator combinations will run for years without maintenance. The snag is people want their hand held power tools to be hand sized.Yep. And while efficiency per se is not that much different as you pointed out, a brushed motor will by design wear out much faster. When it does, either you feel like renovating the motor by changing the brushes yourself (as long as you can find the parts), or you throw it away as finding the motor itself as a spare part is even less likely. Brushless motors have much, much longer lifetime.
Not all brushed motors wear up quickly, it's again a design decision. Larger brush area not only increase efficiency by decreasing current density, but slows down the wear. High-quality brushed motor power tools easily lasted years of daily professional use while cheap ones fail in worst cases in just few hours. Similarly, some brushed EV traction motors were good for easily 150 000 kilometers before brush swaps. -
The snag is people want their hand held power tools to be hand sized.
Yeah. I think the biggest advantage in BLDC power tools was not efficiency or even performance increase, but it made those tools visibly smaller and lighter. -
I think motor life on battery powered power tools isn't that important as batteries replacement cost is the real cost. By the time the motor goes bad it's about time to buy another tool. The price of the tool+battery isn't all that much different from the battery alone.
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I think motor life on battery powered power tools isn't that important as batteries replacement cost is the real cost. By the time the motor goes bad it's about time to buy another tool. The price of the tool+battery isn't all that much different from the battery alone.
While usually you get a significantly better deal when buying a tool with battery bounded rather than separately, the cost difference is huge actually. -
I think motor life on battery powered power tools isn't that important as batteries replacement cost is the real cost. By the time the motor goes bad it's about time to buy another tool. The price of the tool+battery isn't all that much different from the battery alone.
Usually the all in one kit includes the charger too. And the batteries on my Bosch drill are still good after 5 years, I expect them to more than double that life. A friend had a lawnmower with Li-Ion batteries, one of the first generations, and it did 10 years of summers (two batteries used per 'mow') before the batteries finally went bad. I think modern Li-Ion batteries are likely to last even longer. Once you get over that point you get to issues of obsolescence, will I be able to buy these batteries any more for instance... -
Fully charged storage in hot conditions is what kills these power tool batteries. It's not as much capacity drop, it's the electrolyte reactions and thickening of the SEI layer which increases the equivalent DC resistance of the cells, so that they would still measure decent capacity under low discharge current, but sag in voltage in power tool use, so that low-voltage cutoff is reached way before 0% state-of-charge. It would be best to store the batteries between maybe 20%-60% SoC but then you need to remember to charge before use. I have made it a habit that I don't charge the batteries after use for this reason (but I don't attempt to optimally discharge them either, so maybe they are at 30%, maybe at 90% depending on what I was doing the last time). I remember some BOSCH batteries didn't last for more than 3-4 years or so when they sat in charger all the time.
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It's a new one on me as I only heard it 'in passing' last week or the week before and I don't have any firm references yet (it's on the 'must look into' list) which is why I wrote 'some suggestion' rather than asserting it as fact.
*added*: I listen to a lot of 'stuff' whilst working, driving etc. for background noise, it might have been the latest Ham Radio Workbench podcast (hardly an authorative source on EU regs) with W1REX
This is EXACTLY how rumors and urban legends are spread and then amplified by algorithms and upset culture on social media and in coffee tables. If you do not know where you heard something and if you have not double checked the information to be accurate, do NOT regurgitate it forwards in ANY way. No matter if you mention or try to say that it's a rumor.
Someone WILL read/hear it "in passing", will forget/miss that it was supposed to be a rumor and will regurgitate it forwards as a fact.
Only way to stop bad information and misinformation is to not repeat anything unless you're absolutely sure about what you say is true.
This thread has devolved into meaningless chatter beside the topic. Are we talking about USB-C or are we talking about battery heating, is the battery in your milwaykee 18 or 20v and about construction workers using battery powered tools from PSU's?
Nobody's coming and stealing your Milwaukees nor putting an USB-C to an EV... just calm down everyone and get back to the topic.
And remember, legislation in EU is not made by idiots. People reading the legislation badly and then reacting to it loudly are idiots. They just jump to a conclusion and then rage about it and balloon the issue with imagined scenarios and horrors. And also, people writing news and articles MIGHT have anti-EU or anti-regulation stance, thus they will lie to you and get you reacting and retweeting before you even know that they just lied to you.
Our bananas are still not straight, our cucumbers neither. Kids can still play on playgrounds, mozzarella is still not made with powedered cheese, British kept their wonderful power plugs and we do not have to worry about USB-C in stupid and nonsensical use cases being forced onto people.
Calm down and keep discussing about the topic at hand
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nor putting an USB-C to an EV
What? I won't be able to charge the EV from my phone's wallwart? What is the point of it all, then
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nor putting an USB-C to an EV
What? I won't be able to charge the EV from my phone's wallwart? What is the point of it all, then
Think about the possibilities - at 200W USB-C quick charge, during 12 hours of overnight charge, you could get 15 km of driving range in your EV. All you need to do is to apply a bit of extra engineering bypassing the car's existing power-hungry always-on-during-charge systems like unnecessary computers, poorly designed BMS and whatever, so that you can put most of that 200W (minus the main contactor) to do actual work. Then you just need to design an isolated, say flyback converter from 20V to battery voltage (400V-ish). Easy-peasy! -
Having all that extra stuff in the device can make it bulky and expensive. I prefer having the smarts in the charger too. Plus, it makes chargers more versatile for different devices. But it seems like the industry is moving towards USB-C for uniformity.
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I prefer having the smarts in the charger too.
It's not clear if you mean instead of, or as well as, smarts in the battery.
If it's the former then that would, IMO, be a bad move since the charger would need to know about the battery. Use the wrong charger and it could be goodbye battery (and whatever is nearby).QuotePlus, it makes chargers more versatile for different devices.
Actually, less versatile. Consider that the charger would need to know about everything it might ever be charging, which is an impossibility. So there would be a subset of everything, and the likelihood is that the subset would be quite small. What happens about the stuff the charger doesn't know? Not awfully versatile with those, I guess.
On the other hand, a 12VDC supply is pretty versatile and generic. Doesn't give a damn about what's sucking juice from it, won't try to control whatever it is erroneously, etc. Of course, that means the batteries would need smarts, but once all of them have it the cost of adding it is very small. As an example, once upon a time a simple one-axis electronic gyro cost serious money, eventually falling to "er, I'll think about it" cost. Nowadays you get 6DOF sensors for peanuts, mainly because every phone contained a gyro or accelerometer or, more often, both.
I think things like charging, where there are two distinct entities that share nothing except the connection, should conform to Postel's law: "an implementation should be conservative in its sending behavior, and liberal in its receiving behavior". Perhaps USB PD does that.QuoteBut it seems like the industry is moving towards USB-C for uniformity.
I think uniformity in this context is a Good Thing. The problem is that USB-C is quite complex, needing even special cables with smarts in them to really do the business. But it falls back to something sensible if you're cheaping out and just want simple. -
Think about the possibilities - at 200W USB-C quick charge, during 12 hours of overnight charge, you could get 15 km of driving range in your EV. All you need to do is to apply a bit of extra engineering bypassing the car's existing power-hungry always-on-during-charge systems like unnecessary computers, poorly designed BMS and whatever, so that you can put most of that 200W (minus the main contactor) to do actual work. Then you just need to design an isolated, say flyback converter from 20V to battery voltage (400V-ish). Easy-peasy!
Somewhat more useful would be the capability to charge the 12V battery from USB-C. It wouldn't take much power at all to overcome the self discharge and keep the battery from going dead in a car that's only driven occasionally. If the USB-C port is already there for some other purpose (most likely charging portable devices when the car is running), it would only be a little more complexity to have the converter be able to run backwards. That said, it would make much less sense in an EV or plug in hybrid which already has a power input. -
Somewhat more useful would be the capability to charge the 12V battery from USB-C.
True, but I would prefer engineering the 12V system correctly to begin with, so that the 12V aux battery simply never dies. This should be well possible, although I know some EVs have had problems with it.