18v batteries on T15

[Staniam]

Hey there,
    By accident I put one of my PDC's 18v batteries on my T15. It slid on fine and I drove a couple screws with it. When I went to take it off to charge it was crazy hard to remove. I assume the locking mechanism on the 18v batteries are different than the 15v which is why it was so difficult to remove. So my question is...

What is the drawback to using an 18v battery on a 15v tool? Are there any? My T15 worked perfectly with the 18v battery.

 

[GarryMartin]

To the best of my knowledge, you shouldn't have been able to put the 18V battery on a 15V tool due to the way they're keyed. Are you sure it was an 18V battery? They're not compatible with 15V tools.

In the photo, the 18V battery is on the left and you can see that both of the keyed "tracks" extend all the way to the rear of the battery whereas the 15V battery on the right has a half-length "track" on it's left side. When I try to put the 18V battery on my T15, it won't slide all the way on.

(The locking mechanisms are identical by the way)

[attachimg=1]

 

[Staniam]

Definitely sure it was an 18v battery being as it was the new 2.6ah that was recently released. I also looked at the tracks and noticed they were different. As far as getting it on, for years I've been in the habit of "slapping" batteries into cordless tools. Similar to the way you might see someone slap a new clip into a gun. It went on fine, but was a pain in the butt to get off.

I can post a picture in a few hours.

 

[chrisrosenb]

The 18 volt can be forced on a 15 volt drill, but as you say they are hard to get off.

 

[NHSP759]

I know your asking the question Stan but did it actually affect the tool? I'm curious if it will cause the tool to shut down or burn up.

 

[Staniam]

I know your asking the question Stan but did it actually affect the tool? I'm curious if it will cause the tool to shut down or burn up.

It didn't effect the T15 at all. Ran perfectly fine.

 

[Staniam]

Here's a picture of a BPC 18 battery working on my T15. You can see the light obviously on and you can tell the shift is spinning the drill bit. Also, here's and link to a video of this in action.
https://www.instagram.com/p/BDzRSLnIHTg/

 

[scary]

Huh.....well,that's cool

 

[GarryMartin]

You can see in the photo that the gap between the battery and the tool increases toward the rear, indicating it's a forced fit rather than a natural one.

I'm going to go out on a limb here and say Festool and other manufacturers would have very good reasons for designing batteries such that they don't fit certain tools. Using a higher voltage battery than a tool is designed for is not a good idea and I'm guessing would also likely invalidate warranty in some way.

In the same way that using a lower voltage battery in a tool would see the motor going slower, using a higher voltage battery than designed would see the motor going faster and working harder, and that may be outside the design tolerances for the motor itself or for the electronics that power it, or for the gearbox, or for any number of other components.

Not something I'd be willing to take a risk on personally.

 

[Staniam]

You can see in the photo that the gap between the battery and the tool increases toward the rear, indicating it's a forced fit rather than a natural one.

You know, I thought someone might see that so I decided to check the "gap" with the 15v battery and compare it to the 18v battery on this T15. Virtually identical gap. I also checked the "gap" on my PDC with the 18v battery and 15v battery. Same exact gap.

I can understand what you're saying about voltage verse motor tolerances but there has been no increase or decrease in performance. The drill is already out of warranty so that's not a concern.

I don't plan on using this 18v battery on my T15 but I'm curious as to why someone from Festool hasn't replied and we are left to ponder. No biggie either way I'm just curious because if in fact there's no real risk, I'd be inclined to purchase one or two more of these 2.6ah batteries for their compact size. Now if there was a 1.5 or 2.6 battery for the T15 I wouldn't bother.

 

[GarryMartin]

Now if there was a 1.5 or 2.6 battery for the T15 I wouldn't bother.

There's definitely a 2.6Ah Li-Ion T15 battery, at least here in the UK, but I'm not sure how it compares weight/size wise against the 18V equivalent.

 

[semenza]

Now if there was a 1.5 or 2.6 battery for the T15 I wouldn't bother.

There's definitely a 2.6Ah Li-Ion T15 battery, at least here in the UK, but I'm not sure how it compares weight/size wise against the 18V equivalent.

The 1.5 12v pack works on higher voltage tools if you want a compact battery option for the 15v.

Seth