Adapter to use Lithium batteries in Nicad tools

[jlanciani]

And that is the risk.  Performance characteristics and therefore controller requirements are different for both types of batteries.

It's rather unsafe to run a LiIon battery in a tool designed for NiCads.  You might get lucky and it only destroys the battery or burns up, or you may well have an explosion.

Not worth it, don't do it.

I guess you’re smarter than the folks at DeWalt then; https://www.dewalt.com/products/accessor...er/dca1820

[geek2me]

I have a Ryobi 18v cordless drill. I've had it for at least 10 years.  After the original NiCad batteries died (they outlasted a 14.4V Dewalt by at least 5 years)  I replaced them with Ryobi LiIon which were approved to use in my drill.  The 18v LiIon were still cheaper than the replacement DeWalt  14.4v batteries.

As you said "which were approved to use in my drill" - that is the key.  Some tools are designed for both, some battery packs have protection, so it is possible to design systems to accomodate both.

That's not what the OP wants to do, though, he wants to just substitute into a system that is likely not designed for it, which is dangerous as I said.

[geek2me]

Can you explain the science/technology behind why this is so?  ... One of the reasons I thought about this was specifically that Ryobi did market Lithium batteries that could be used in older tools but not used in older chargers.  

And most manufacturers did not, but my thought was it was more a marketing thing to get you to buy new tools rather than just new batteries

The system can be designed to accommodate both, and that's fine.  The problem arises when LiIon are substituted for NiCads in systems that were not designed for it.  Biggest issue is heat, LiIon system monitor temperature and scale back current draw as the limit is approached.  NiCads don't need that, they are essentially self-limiting.
That's also a reason many prefer NiCads - they can supply a broader range of current/time requirements.

[geek2me]

I guess you’re smarter than the folks at DeWalt then; https://www.dewalt.com/products/accessor...er/dca1820

You mean the "Do not use with premium DEWALT batteries in DC970 or DC759 tools."??

As I said, a system can be designed to use both, but the OP was asking about substituting one for another in a system that was NOT designed for it.

[fixtureman]

It doesn't matter whether the power comes from lead acid, nicad, nimm, or lithium batteries the power is the same.  You just need the correct charger just like where does your power come from in your shop.  Do you know if they are using coal gas solar or wind to produce it.

[EricU]

if a liion battery burns up my almost 20 year old tool, then I have a pretty good excuse to buy a new tool.  I think most of us that are limping along with crummy old tech tools wouldn't be too upset about that.  It's not a life-threatening event when you burn up an brushed motor. Or at least I'm failing to see a plausible scenario where it would be a life-threatening event.

There are 3d printed adapter designs on thingiverse for many liion batteries. Not sure it's worth it, but one of them glued to an old nicad battery pack top would make a pretty good adapter, I think.

[Carl10]

As fixtureman and others have said the TOOL does not care what source the voltage comes from. You can run a DC power supply with the right current and the tool will run fine. The batteries and charger care, they have electronics and sensors to monitor, heat, current, etc..

If you are still doubtful google your tool for service parts and all you will see is a switch and a motor. The only tools I am aware of that have anything more are the 60V Max Dewalt tools. There appears to be a heat sink and probably a voltage regulator in the tool.

BTW What motivation does a tool manufacturer have to extend the life of your old tools and not buy new ones?

Hope that helps.

Carl

[geek2me]

It doesn't matter whether the power comes from lead acid, nicad, nimm, or lithium batteries the power is the same.  You just need the correct charger just like where does your power come from in your shop.  Do you know if they are using coal gas solar or wind to produce it.

Sorry, that is not correct. Different battery technologies produce different voltages and different voltage/current performance.

The shop power analogy is not accurate - in that case, the power is produced then conditioned to look the same, regardless of source.  To use your analogy, putting a LiIon battery on a NiCad tool is like trying to run a windmill with coal.

[geek2me]

if a liion battery burns up my almost 20 year old tool, then I have a pretty good excuse to buy a new tool.

Just to be clear, by "burn" I meant "fire" and by "explode" I meant flammable pieces of lithium flying everywhere.  A customer burned down a plant and killed a few people when one of their workers somehow managed to get an LiIon battery installed in a NiCad handheld.

[geek2me]

As fixtureman and others have said the TOOL does not care what source the voltage comes from.  You can run a DC power supply with the right current and the tool will run fine.  The batteries and charger care, they have electronics and sensors to monitor, heat, current, etc..

The problem is their statement was incorrect, the tool "does care".  A DC power supply is yet a third option, but then you have lost the "cordless" benefit.

You are assuming the electronics and sensors are in the batteries - and they are, for SOME brands and battery packs.  The problem is that the electronics are in the tool for some other brands - and mix and match and you will likely get fire and explosions.