4ah high power battery repair

[Coen]

I was pretty stoked though cause I only had to boost the cell voltage a minute or two and got them working as good as new, so two free batteries in the end!

Except they are degraded. If you do the impedance and capacity test, you will see they will not be as new at all.

 

[surfjungle]

In previous post #2, I mentioned returning a battery to Festool service and they told me it needed to be replaced and they would dispose of it if I wanted them to. I declined their offer and paid them to return the battery to me thinking I could always re-cell the battery. myself. It's been sitting on the charger downstairs for the last 2-3 months and the charger light is always red. After reading the above @surfjungle post, I decided to try updating the battery because it was also at the V7 firmware level.

Well after updating the battery to V15, I'm now sitting on the couch upstairs monitoring the battery downstairs being charged from 44% to currently 59% 63% 65% and continuing to rise. I wonder why Festool told me the battery was bad and they didn't just upgrade the firmware?

Thanks for the post surfjungle...

My pleasure. I've found this forum to be very helpful. You experience vs mine points to inconsistency in the enablement and training of Festool reps.

 

[luvmytoolz]

Except they are degraded. If you do the impedance and capacity test, you will see they will not be as new at all.

Maybe but I dunno, the app reports 100% capacity, and over time the drop is no different to the brand new ones and they last as long in use according to the times recorded in the app. I've done the same with my Makita LXT's and 10-15 years later they're still going strong. If I get even close to 10 years ad-hoc usage I'll be very happy.

 

[PaulMarcel]

Ooh, excellent info, @surfjungle! I'm updating one of mine from V7 to V15. This pack seems to work okay, but of my 3, one never seems to charge. I put it on the charger to get enough charge to update it. Hoping it works cuz that battery is basically dead otherwise

Other interesting thing: after the update, it showed the current battery level. It started at 89%, updated, resumed at 76% then the percentage was dropping quickly and is now settled at 73%. Almost indicates that V7 wasn't tracking the charge correctly and thought it had more than was there. Each charge cycle would possibly add to the error.

 

[luvmytoolz]

I've got to admit the fact we can't run the Festool app in Australia is just bewildering. Like Paul's post above, I occasionally see people updating firmwares but we don't have that option at all. Very annoying, especially when we get reamed on the pricing like we do.