I have a Ryobi battery powered drill. Is it ok to keep it in the charger until ready to use? If I don’t it is always just about dead when I go to use it even if stores indoors.
In general with Li-Ion batteries it’s better not to leave them at/near 100% charge (nor near 0%) and they prefer 20%-80% for the longest life. I long time I looked into this and 40% was the sweet spot of longest life and it was an upside down U graph with 100% being bad and 0% being horrible for longevity. But since the middle of the U was more flat then the ends, the middle was pretty OK where ever it was.
In my own use of Ryobi I generally after charging it, remove it from charging and will recharge it after 2 (or less) charge indicator lights are remaining.
I couldn’t find any specific wording in Ryobi’s manuals at least for the 18V tools, but I imagine it works exactly like every other major electrical tool manufacturer: the computer will shut off the charging function, so there is no problem leaving it connected. Allow for regular caveats of it leaving you at risk of surge damage, etc.
The tools should be fully charged upon purchase before use, they don’t ship with a full battery. After that you should charge as needed, @kanicbird’s recommendations are the physics behind it, but as you are a human working under non-ideal situations, the advice to keep using it until the batteries are getting low but not empty and then fully charging it is sound.
I keep my Dewalt batteries in the chargers until I use them, and return them there after use. I expect their dedicated and expensive chargers to manage them reasonably.
The idea of remembering to go back and pull the batteries out of the charger some time later would be enough to make me think cordless tools aren’t really ready for prime time yet.
Lithium-ion technology works the same regardless of the tool/battery/charger quality, and shares the same limitations. The same way that a Lamborghini sports car won’t fly any better than a used Honda hatchback, despite being much more expensive. Smart charging technology does exist, for example my fairly new iPhone will actually slow down charging once it gets near full capacity in order to extend its life, but that kind of technology is not something I’d expect to find even with the highest quality power tools. (And Dewalt tools are very high end.)
That being said…
You should be fine. What kanicbird said is the ideal way to treat a Li-ion battery, but leaving them plugged in just means that they might not last quite as long over an extended period of time. It doesn’t mean you are risking imminent damage to them. For many people the inconvenience of having to replace the batteries a bit sooner is outweighed by the inconvenience of having to babysit the batteries constantly and rotate them through some kind of schedule. (I tend to be somewhere in between with Li-ion devices; I do intentionally try to avoid keeping them charging all the time, but I don’t obsess over it.)
Charge protection circuitry appears these days in a lot of places, but surprisingly not everywhere, until maybe recently. Around 2007-ish I bought a handheld drill with a 20V battery and charger. I believe it was of the NiCd type. Leaving it in the charger, the battery got hot and pretty much lost its ability to charge.
The newer rechargeable devices and battery types don’t penalize you for leaving them charged. Which is great, because who wants to go remember to charge up those batteries several hours before the device is needed?
That’s a charger issue. I have an old NiCd cordless drill that I mostly use as a cordless screwdriver, and it does not get hot if you leave the battery on the charger. I have two batteries for it, and both batteries are pretty well shot at this point (NiCd batteries typically have a max lifespan of 15 to 20 years and these are probably closer to 25). I leave one battery on the charger and the other one in the drill. When I need to use it, the one that is in the drill will be complete dead, so I swap it with the one in the charger. The batteries still have enough life in them that I can use the drill to do what I want long before the battery runs dead. Then when I’m done I set the drill aside until the next time I use it, by which time the battery in the charger will be fresh (as fresh as it can be) and the one left in the drill will again be completely dead.
The charger and the battery left in it do not get hot, even if left there for months.
Nothing bad will happen if you leave the batteries on the charger. You’ll just end up replacing them sooner than I will (I tend to leave mine in the tools until they need to be charged).
Every battery type has its quirks. There is no perfect battery with no downsides to it at all. Lithium-ion batteries are lighter than other battery types, and they have a much better energy density than other battery types. This makes them ideal for cell phones, laptops, tablets, tools, and all sorts of things. But the downside to lithium ion batteries is that they start dying from the moment they are made. They also have the quirk that leaving them fully charged is bad for their long term lifespan. An even worse quirk is that if you don’t treat them kindly they tend to explode. Their tendency to go ka-blooey necessitates a much more sophisticated charger than a lead-acid or a nickel-cadmium battery requires.
We put up with these quirks because of lithium-ion’s lighter weight and significantly greater energy density.
The fact that lithium-ion batteries don’t regularly go ka-blooey is a good indication that they are in fact ready for prime time. In fact, nothing bad at all will happen to you if you leave the batteries on the charger. But if you want to maximize your battery’s longevity, keeping it on the charger isn’t the best thing to do. That doesn’t mean that there is a problem with the battery or the charger. It just a quirk of the battery chemistry.
This makes me curious about something. There’s probably a microprocessor in the charger, right? Something is working the blinking light display at least. It’s DeWalt’s charger, their batteries, and their reputation. Since the incremental cost to add operational features by further microprocessor programming is so small, and they’re making so many chargers and batteries and their tools rely on them, don’t they have a big incentive to make the charger more intelligent, by having it stopping charging them when they’re at an optimal point?
I think I’ve noticed what might be evidence that they do. The indicator blinking indicates that there is charging going on, and it’s steady when the battery is finished. If I pull a battery out briefly and put it back in, without even powering a tool, the blinking indicates that it’s charging the battery over again. That makes me think it pays attention to at least a little that it knows about that battery’s history, and not simply its voltage.
Eh, I dunno. There are dedicated lithium ion charging controller chips. I’ve never taken a close look at one to see if they are smart enough to call them a microprocessor.
I don’t know what DeWalt uses, but the typical charging algorithm for lithium ion batteries is a constant current until the cells reach their maximum voltage. If you have more than one cell (like you do in a tool battery) then there will be some balancing done here to insure that all of the cells are at the same charge. Then the charger will switch over to a constant voltage mode, and will continue to use that mode until the current drops to basically zero. At that point the charging stops, so yes, the charger is paying attention to the battery’s charging history, at least for this charging cycle. Once you remove the battery, then the charger has no way of knowing if it’s the same battery or another battery, so it has to start over.
Lithium ion charging a lot more complex than just the simple constant voltage charger that you could use with NiCd batteries, but it’s simple enough that some very basic switching logic could be used. It might not be a microprocessor. Adding a new feature might not be trivial.
What is the optimal point? For a lot of folks, the optimal point is going to be fully charged, which is what the chargers do. That way they get the most use on a single battery charge.
If you prefer long term battery life over the maximum short term charge, well, that’s a completely different point.
Modern laptops usually have a setting in their power management software that lets you choose which type of charging you want. You can choose to have it charge all the way to full charge, which is the way older laptops always did it, or you can choose to charge it for maximum long term battery life. There are advantages and disadvantages to either charging method. If you run the laptop for long periods of time with it unplugged, then you’ll probably want to have it fully charge, so that you won’t run out of battery charge in the middle of a meeting or whatever. If you are like me and you mostly have the laptop plugged in (mine is either plugged in at home or plugged in at work), and you only rarely need to run it unplugged, then it makes more sense to set the charging to maximum battery life.
These sorts of options aren’t usually available on simple devices like tools, lawn mowers, leaf blowers, etc. People just want simple. You plug it in, it charges. That’s it.
All Ryobi batteries have a BMS (Battery Management System) built into each battery. These shut off the battery when it gets too low (unless you decide to be silly and keep pulling the trigger over and over until the last breath of juice is drained from it) and cut off charging when they get close to full. They will also prevent you from charging when there may be a dead or reversed cell.
Other companies (deWalt, Milwaukee I believe) have the BMS capability in the tool itself. Either way, BMS chips are relatively inexpensive and no well-known tool brand is going to build a tool/battery system without one. I’m talking about Ryobi, Hart, Milwaukee, Ridgid, DeWalt, Bosch, EGO, Greenworks, etc. as well-known tool brands. Black and Decker, Porter-Cable, and some others are now positioned as “value” brands and may or may not spend the extra thirty-five cents to include this technology, or they may have it but use really cheap low quality battery cells which die sooner.
Yes.
So by the magic of getting a completely new system…new cordless drivers, new batts, new batteries, I’m hoping I can make that old charger’s problems go away completely. The (single) driver, while still functioning, wasn’t that great. What I really needed was an impact driver. And of course, the battery has been toast for years, and the charger is/was bad.
Absolutely never leave your litium power cells in the charger unattended.
I deal with a couple fires a year from unattended charging lithium batteries. I don’t get the ones where the house burns to the ground.
It is highly unlikely your batteries will catch fire. The consequences if they do are enormous. Its a negligible inconvenience. I run lots of power tools. They charge fast. Extra batteries are cheap. Just charge them as you need them.