Battery adapters

moefoemil · Post by **moefoemil** » Wed Jul 14, 2021 6:05 pm

Evening everyone,
I’m looking for some info/advice if anyone can help? I’ve got an old 18v Ryobi circular saw that runs on NI-MH batteries. All the batteries have had it now and don’t hold charge. If I was to buy a Dewalt to Ryobi battery adapter, would I be able to use my 18v Dewalt batteries even though they are LI-ION?
Any help on this matter is appreciated.
Many thanks

Rorschach · Post by **Rorschach** » Wed Jul 14, 2021 7:03 pm

Yes, the tool doesn't care about the battery type.

kellys_eye · Post by **kellys_eye** » Wed Jul 14, 2021 8:48 pm

Hmmmm.... I'd be a bit more careful. It's down to the battery internal resistance that actually limits the amount of power that can be delivered i.e. in a situation where your NiMh battery might cause your drill to stall under load, the Li-ON will try to keep it going.

Good way to prove the old 'smoke test'.......

The modern drills that use Li-ON have current limiting circuitry built-in to prevent this happening.

So yes, you can. But WITH CARE.

big-all · Post by **big-all** » Wed Jul 14, 2021 9:50 pm

just be careful and only buy one off these adapters from a trusted source recommended by actual people

Rorschach · Post by **Rorschach** » Thu Jul 15, 2021 7:56 am

kellys_eye wrote: ↑Wed Jul 14, 2021 8:48 pm Hmmmm.... I'd be a bit more careful. It's down to the battery internal resistance that actually limits the amount of power that can be delivered i.e. in a situation where your NiMh battery might cause your drill to stall under load, the Li-ON will try to keep it going.

Good way to prove the old 'smoke test'.......

The modern drills that use Li-ON have current limiting circuitry built-in to prevent this happening.

So yes, you can. But WITH CARE.

The safety circuitry is almost always built into the battery for Li-ion, at least it is in any that I have seen. The OP is using Dewalt batteries and these have that built in so it will be fine.

Grendel · Post by **Grendel** » Thu Jul 15, 2021 6:36 pm

As a bit of an experiment i wired up a couple of 18v tools to a car battery. Worked ok except of course they became much less portable. If the tools had been better quality i would probably have been tempted to use them in the workshop or maybe in the van but at least it worked in principal.

kellys_eye · Post by **kellys_eye** » Thu Jul 15, 2021 7:37 pm

Rorschach wrote: ↑Thu Jul 15, 2021 7:56 am The safety circuitry is almost always built into the battery for Li-ion,

Yes, for short-circuit conditions. They can still deliver a lot more energy even when used within their operating parameters. Given the instantaneous current available from them it is wise to take precautions. Otherwise the manufacturers themselves may have suggested the user can swap them.

You would, of course, need the correct charger to go with them too.

Rorschach · Post by **Rorschach** » Fri Jul 16, 2021 12:34 pm

kellys_eye wrote: ↑Thu Jul 15, 2021 7:37 pm
Rorschach wrote: ↑Thu Jul 15, 2021 7:56 am The safety circuitry is almost always built into the battery for Li-ion,
Yes, for short-circuit conditions. They can still deliver a lot more energy even when used within their operating parameters. Given the instantaneous current available from them it is wise to take precautions. Otherwise the manufacturers themselves may have suggested the user can swap them.

You would, of course, need the correct charger to go with them too.

Well with Ryobi for instance they specifically made their new lithium batteries the same size and style as their own NiCDs so you can use a new battery on a tool that might be 15 or more years old.

Rorschach · Post by **Rorschach** » Fri Jul 16, 2021 12:35 pm

Grendel wrote: ↑Thu Jul 15, 2021 6:36 pm As a bit of an experiment i wired up a couple of 18v tools to a <a href="http://shop.ebay.co.uk/?_nkw=car+battery" class="skimwords-link" target="_blank" data-skimwords-id="771404" data-skimwords-word="car%20battery" data-group-id="0" data-skim-creative="300003" title="Shopping Link Added by SkimWords" occurrence="1" data-skim-node-id="292:Asabitofanexperiment_1" style="">car battery</a>. Worked ok except of course they became much less portable. If the tools had been better quality i would probably have been tempted to use them in the workshop or maybe in the van but at least it worked in principal.

My cordless tools are all 10.8V/12V so when I had a battery die I took out the guts and wired in a bit of flex that connects to a car battery I keep in the workshop. Works great and lasts for months between charges. Saves me wearing out the expensive lithium batteries.

Someone-Else · Post by **Someone-Else** » Fri Jul 16, 2021 12:46 pm

Rorschach wrote: ↑Fri Jul 16, 2021 12:35 pmMy cordless tools are all 10.8V/12V so when I had a battery die I took out the guts and wired in a bit of flex that connects to a car battery I keep in the workshop.

................So it is no longer cordless. I understand why you have done it, but it does defeat the object of buying a cordless tool in the first place.

Rorschach · Post by **Rorschach** » Fri Jul 16, 2021 3:47 pm

Someone-Else wrote: ↑Fri Jul 16, 2021 12:46 pm
Rorschach wrote: ↑Fri Jul 16, 2021 12:35 pmMy cordless tools are all 10.8V/12V so when I had a battery die I took out the guts and wired in a bit of flex that connects to a car battery I keep in the workshop.
................So it is no longer cordless. I understand why you have done it, but it does defeat the object of buying a cordless tool in the first place.

Correct, it is no longer cordless but when I am working at my workbench (most of the time for me), that doesn't really matter, the cord is about 3m long which handles most workshop tasks like drilling, sanding etc on the bench. If I need to go further afield then I pop a battery in (I am not sure if it was clear but I have several batteries).

kellys_eye · Post by **kellys_eye** » Fri Jul 16, 2021 4:39 pm

Rorschach wrote: ↑Fri Jul 16, 2021 12:34 pm Well with Ryobi for instance they specifically made their new lithium batteries the same size and style as their own NiCDs so you can use a new battery on a tool that might be 15 or more years old.

I can get with that! Quite unusual isn't it. Welcome though

I have three other drills that had NiCad and are now 'dud' pending whether I can be arrised to wire up new packs or convert to Li-Ion.

The one tool I did convert was a 1/2 impact wrench - fitted an old Aldi tool battery to it in place of the dud NiCad set and it works a treat.

moefoemil · Post by **moefoemil** » Fri Jul 16, 2021 5:14 pm

Thanks for all the replies and info!, I would only be using the circular saw rarely so I’m going to give them a go. Once again, thanks for all the help!

Rorschach · Post by **Rorschach** » Sat Jul 17, 2021 9:56 am

kellys_eye wrote: ↑Fri Jul 16, 2021 4:39 pm
Rorschach wrote: ↑Fri Jul 16, 2021 12:34 pm Well with Ryobi for instance they specifically made their new lithium batteries the same size and style as their own NiCDs so you can use a new battery on a tool that might be 15 or more years old.
I can get with that! Quite unusual isn't it. Welcome though

I have three other drills that had NiCad and are now 'dud' pending whether I can be arrised to wire up new packs or convert to Li-Ion.

The one tool I did convert was a 1/2 impact wrench - fitted an old Aldi tool battery to it in place of the dud NiCad set and it works a treat.

Yeah that's exactly the kind of "green" thinking I can get behind. If I had to buy new cordless tools today it would probably be Ryobi as they have a good range too.

In the past I threw out old drills and grinders because the poor NiCd batteries packed up etc and I have passed on many free tools. In the past few years I have learned how to build my own easy Li-Ion battery packs and chargers and now of course I have hardly any free tools to do that with! lol.

The tech is so cheap now, you can get premade battery holders for any size pack or assemble your own from modular components. Lithium chargers cost hardly anything, certainly less than a quid each if you go for USB style (slow charging but simple and reliable) and for a few quid you can buy automatic balancing circuits to keep everything in check. You can build really quite sophisticated battery packs for very little money and little effort, or you can go redneck like me and build simple ones that require some manual input/balancing but cost pennies are easy to repair and maintain.