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geek2me,
I stand by the fact the motor does not care what the power source is for the tool (of the same voltage). You are correct different battery technologies have different voltage current performances. That is why a NiCad slowly depletes and the tool slows to a stop. A corded DC connection would not have that issue. That is why I mentioned a corded solution, because the motor does not know the difference between 18V coming from a transformer or a Sodium-ion battery, assuming they can produce the required current to operate the tool.
I have yet to see a cordless tool with more than 2 connections +/- or with any battery related smarts. If you can reference any please let us know. That would be curious about what they were thinking. In case there are, then anyone with a NiCad powered tool with more than 2 connections, then changing the power source to Lithium Ion may not work correctly.
Specific to the OPs question could you please explain how changing a NiCad operated tool to Lithium Ion battery power source create a problem? It's been years since electrical engineering school and I understand some battery technologies and properties but do not see in this situation how an "explosion" would occur?
Carl
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The issue seems to be that you cant draw Lithium batteries too low, since that may cause them to overheat. So in general there is some sort of circuit that monitors the output voltage and at a certain point it cuts off the battery.
I did do some research last night. Some brands have quite a bit of circuitry in the battery packs: Milwaukee, Ridgid, Makita, Ryobi. Others, very minimal: Bosch, Dewalt. So if the circuitry is in the battery, it is either working the discharge function or working on the charging side. If it is not in the battery, then it has to be in the tool or in the charger.
From looking at a few Youtubes of people that have done this, they tend to rely more on practical experience with the tool then any type of scientific testing. Some covered the issue by saying something about not drawing the battery down too low by watching the speed or power level for decrease and then recharging the battery before that point.
I did also look to see if there are any commercially available circuit components that would let you wire them into the adapter that could perform the function, so far I havent found any, at least they didnt seem speced out for 18VDC
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(02-02-2018, 02:30 PM)Carl10 Wrote: I stand by the fact the motor does not care what the power source is for the tool (of the same voltage).
...
I have yet to see a cordless tool with more than 2 connections +/- or with any battery related smarts. ...
Specific to the OPs question could you please explain how changing a NiCad operated tool to Lithium Ion battery power source create a problem?
You are welcome to you opinion, but it does not change the facts.
I'm curious which LiIon battery powered tools you think don't have "smarts" - it's pretty much a requirement for LiIon batteries, and products would not pass certification testing without it.
Already answered, but LiIon batteries have temperature and discharge rate limits. Exceed either one and you get a fire or explosion. NiCads, in contrast, really don't - short one, and it will destroy the battery but won't explode and may not even catch fire. No "smarts" are required for NiCad batteries or chargers, many "chargers" are a half wave rectifier.
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(02-02-2018, 07:47 PM)geek2me Wrote: You are welcome to you opinion, but it does not change the facts.
Yes, I am thank you. That is what is great about these discussions/forums, getting advice from fellow members. But back to the facts. I am sure it was an oversight on your part but I never said a tool doesn't have any smarts (obviously the electronic motor speed control is a level of "smart"). What I said was "any battery related smarts", which I have yet to find in a tool.
Again this keeps getting away from what the OP is asking, can you put a LiIon battery on a NiCad tool. It appears the only caveat to that is if the LiIon battery pack somehow was manufactured and shipped out without any self protection. The tool, NiCad or LiIon, having only a +/- connection does not and can not know what its power source is with only those connections.
Already asked, but I would still like to know what tool manufacturer moved the battery protection away from the battery and into the tool. Not sure why they take on such liability or if they even could, but that fact would be noteworthy.
Carl
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(02-02-2018, 07:47 PM)geek2me Wrote: I'm curious which LiIon battery powered tools you think don't have "smarts" - it's pretty much a requirement for LiIon batteries, and products would not pass certification testing without it. This is the Ryobi drill I have. I've had mine at least 8 years. I replaced the original that I bought in 2000, or thereabouts.
https://www.ebay.com/i/273047976481?chn=ps
The battery pack in that pic is the old school NiCad pack the tool was originally sold with. When one of my NiCad packs died, I replaced it with a LiIon pack. For a while I used both types in the drill until the second NiCad pack died, so I replaced it with a second LiIon pack. I still have the original 18 year old circular saw and sawzall I got in the kit. I use the same LiIon batteries in those, and the flashlight for that matter. I can assure you are there no 'smarts' in any of them.
You're wrong. LiIon batteries can be used in tools originally designed for NiCad. The tool doesn't care where the power comes from. 18V is 18V. The tool will draw as much amperage as it needs. This is DC power. If the battery can't deliver the power, the tool will run more slowly (like a NiCad battery that's running out of charge).
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lithium will "vent with flame" if overcharged or, less likely, discharged too far/quickly. This usually is described as an explosion, but it's not really as severe. I would be interested in any information about fatalities from this. Tesla fires get a lot of attention, but they don't explode, just burn up the car. Most lithium cells are sold with a protection circuit, but I don't know if tool batteries typically have that. Most often the problems happen on charging. I am assuming there is some kind of balancing circuit or we would be hearing about a lot more fires.
I just got my adapter and batteries. The adapter fits really well. unfortunately the stupid usb port means you have to disconnect the battery when not in use or it will discharge.
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(02-02-2018, 10:12 PM)crokett™ Wrote: You're wrong. LiIon batteries can be used in tools originally designed for NiCad. The tool doesn't care where the power comes from. 18V is 18V. The tool will draw as much amperage as it needs. This is DC power. If the battery can't deliver the power, the tool will run more slowly (like a NiCad battery that's running out of charge).
The problem is that NiCads will indeed just slow down. LiIon can get hot and catch fire. There should be circuitry in the battery pack to prevent that but is there? Or does the battery pack/tool rely on circuitry in the tool to limit LiIon discharge rates? If a battery pack relies on circuitry in the tool and the substitute tool doesn't have that circuitry, you could have a LiIon thermal runaway. Or at least that's how I interpret it.
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Ok, somebody has to say it. why not get the NiCad batteries rebuilt? I've used Batteries Plus several times and the cost was about half of a new battery. Also, there's a member here that does it also, he has gotten great reviews from those that have used him. just a thought.
I no longer build museums but don't want to change my name. My new job is a lot less stressful. Life is much better.
Garry
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They give away free tools in order to sell batteries. Your old tools are worthless without batteries and even with new batteries the old tools are heavier, weaker and probably not worth buying new batteries for compared to new tools. Give up your emotional attachment to your good OLD tools that are taking up space for no good reason. Or, you can throw good money after bad.
RD
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"Boy could I have used those pocket screws!" ---Duncan Phyfe
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(02-04-2018, 09:13 AM)kurt18947 Wrote: The problem is that NiCads will indeed just slow down. LiIon can get hot and catch fire. There should be circuitry in the battery pack to prevent that but is there? Or does the battery pack/tool rely on circuitry in the tool to limit LiIon discharge rates? If a battery pack relies on circuitry in the tool and the substitute tool doesn't have that circuitry, you could have a LiIon thermal runaway. Or at least that's how I interpret it.
Well for aat least Ryobi the LiIon batteries apparently have the circuitry they need. I doubt there's any circuitry in the tools that were originally designed for NiCad.
Geek2Me made an unqualified statement that you shouldn't run tools designed for NiCad on LiIon. I've been doing it for years with batteries sold by the manufacturer for that exact purpose.
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