T18 Battery Issues

[Scout65]

For the 3rd time in 2 1/2 years I’ve got the blinking red light of death on the charger when trying to charge a battery. Is there an issue with the 4.0 Ah batteries? I’ve never had issues with previous Festool models but this is the first time I’ve had the Bluetooth enabled batteries. Insanely frustrating to be on a job & suddenly I’m down a battery. It’s not like I’m using the drill constantly or more than any other Festool drills I’ve had over the years. And good luck trying to talk to a human. Have left messages & even the woman in customer service who sent me over to that department couldn’t confidently say I’d get a call back. Very disappointed, particularly considering the expense & reputation of these tools. I know I can send it in for replacement, but just want to know if this will be a regularly occurring event until the warranty expires.

 

[Jeff Zanin]

Not sure if it will help you but from my post on battery resurrection:

My TSC-55 was sitting on the top of the Systainer with both 18V batteries in place for several months.  When I went to top them up on the charger one charged up with no problem, the other would not take a charge at all and measured around 6V on a voltmeter, and the charge indicator would not light up.

I found nothing on the FOG but lots of videos of people resurrecting rechargeable batteries with a brief connection to a power supply or other battery.  The idea seems to be that if the "dead" pack can't power the electronics that the charger uses to determine pack type, temperature, etc. the charger will not send power.

I had nothing to lose so I attached the Festool pack to a Milwaukee 18V pack for ~ 30 seconds with alligator clips.  After disconnecting the Festool pack showed 18V, I put it on the charger and it charged normally!  After it showed fully charged I took it off the charger and I've had it sitting on the bench for a couple of weeks since then, checking it once in a while and still shows 20.54V.

So the good news is that my Festool 18V pack seems to have recovered – I have tried it on the saw but not used it extensively since the resurrection.  But I am still wondering about the discharge, only on one of the two batteries – could there be some sort of phantom power draw, keep-alive, heartbeat or something going on with the TSC-55?  I am not curious enough to dismantle anything or otherwise investigate, from now on I will just store the saw with batteries removed, probably a best practice anyway.

 

[Chainring]

I've had to do the same as Jeff, but with a car battery. My Prius has been getting lots of garage time and I left a Bluetooth OBDII sensor plugged in, which is powered on all the time. That equals a nice, slow drain to zero. The charger I have wouldn't get it going because the voltage was too low. Cue up a fully charged car battery, some jumper cables and the same charger. All good!

You're giving the dead battery a jump start. You may need to leave the two 18V batteries connected for a bit before trying to get the dead one on the charger.

 

[mrboult]

I only own one if the 4.0 batteries. It lives in the T18 box and goes on every job I do. No issues in 2 years + of owning that battery. Been using the compact 3.0ah, literally since they came out, and not had issues either.

Sorry about your luck.

 

[scb_yyz]

Recently had a dead 5.2 battery on purchase.  Contacted Festool Canada, sent pics.  Redirected to Festool USA as Canada was busy.  Nice lady in customer service promptly sent replacement. No issues. Didn't need to send the dead one in.

 

[Scout65]

Thanks for the replies, guess my experience is an anomaly. It’s a moot point now- coincidentally the drill’s clutch went out the same day I posted this, so sent both battery & drill back. Just got cost estimate to repair drill- $245. Bought a Milwaukee compact for less than the cost of repair & will be selling tge T18 as soon as I get it back. New owner will have a new battery if not a functioning clutch. Done w Festool drills at this point, other manufacturers have caught up for far less cost, IMO.

 

[mino]

...
But I am still wondering about the discharge, only on one of the two batteries – could there be some sort of phantom power draw, keep-alive, heartbeat or something going on with the TSC-55? ...

Yes and no.

The original TSC 55 is a 18V tool with the batteries being parallel AND one being the primary - the "bottom" one. I would guess it was the one which drained. I am not sure how they are connected inside the PCB, but they do not seem to be "hard-wired" together as they have their own "gauges" when in use. That setup would allow only one being discharged while the other not.

The TSC setup is possibly the most complicated solution possible so one rarely sees it anywhere. But it does allow to use the saw with only one battery for easy/light cuts while allowing a good power reserve with two bats.

Every tool with electronics power switch has some idle-drain current when not in use. It may be small but still there. That is why batteries should never be kept in tools for prolonged periods. A month or two should be fine for a good brand. But that is about it.

For a hobby user it is best to learn to remove the bats from anything but the most-used tools.

My rule is:
If I am placing a tool in a box, the batteries go out.
If I have a tool on bench, I keep them in, out of being lazy. A compromise which seems to work so far.