Micheal Posted December 24, 2019 Report Share Posted December 24, 2019 I have a DeWalt DCB107 charger and x2 dewalt 18V lithium ion 1.5AH batteries. I was using my dewalt DSC390 circular saw and drained both batteries, or so I thought, I was only sawing for maybe 2 minutes each battery, I was sawing a fresh 2x4 at an angle so it was under pressure. When I put one battery on the charger the yellow over heat light came on so I tried the other and the yellow light also came on. So I left both sit outside for 10 minutes then tried x1 on the charger, the red light came on and stayed, this indicated full charge, I tried the other battery and it did the same. I tried both batteries in the saw and my drill and neither worked. I tested both batteries with a volt meter and they read 14v to 15v. I read online that the batteries can shut down if they overheat and to reset them place them in the charger for 8hrs, I did this with one battery overnight and it’s still the same. It seems that the batteries are charged but have shut down!! Is this possible? How are they reset? Quote Link to comment Share on other sites More sharing options...
RDC Posted December 24, 2019 Report Share Posted December 24, 2019 14v to 15v is far from charged. Make sure your DMM battery is good and check the voltage of the battery again measuring from the B+ to B- terminals. Thermistor check #1 Measure the voltage from B- to TH, you should get the same voltage as the B+ to B- measurement. Thermistor check #2 Measure the Resistance (Ohms) from B+ to TH, it should be around 12k If that is all good, then test the individual cells to see if one has gone bad. Measure.. B- to C1 = ?.??v C1 to C2 = ?.??v C2 to C3 = ?.??v C3 to C4 = ?.??v C4 to B+ = ?.??v All of those measurements should be the same, or within a hundredth of a volt of each other. Quote Link to comment Share on other sites More sharing options...
method Posted December 24, 2019 Report Share Posted December 24, 2019 If it will not take charge just jump start it with another good fully charged battery. I recently did this with an m12 battery that I hadn't used for over 6 years and it's as good as new now. Quote Link to comment Share on other sites More sharing options...
Cr8ondt Posted December 30, 2019 Report Share Posted December 30, 2019 Your voltage is too low and the charger won't charge them, time to jumpstart them. Take a fully charged working battery and 2 short wires, stuff one end of each wire in the the + and - of the working battery then connect one wire to the matching terminal of the dead battery, and tap the 2nd wire to the other terminal for 1/2 a second or so. This should bring the voltage up enough to get your charger to work. Also, those 1.5 ah batteries shouldn't be used on any saw, obviously they get you no runtime, the draw is too much for those little batteries. I only use double stacked batteries on like the 4ah and larger one mine, you'll get noticably more power. 1 Quote Link to comment Share on other sites More sharing options...
JakeDewalt Posted December 30, 2019 Report Share Posted December 30, 2019 Just send it to dewalt that’s what I did No questions asked every dead battery replaced and shipped to my door free of charge. 1 1 Quote Link to comment Share on other sites More sharing options...
DewaltLandlord Posted January 2, 2020 Report Share Posted January 2, 2020 Has anyone had luck just returning it to the store it was bought, like Home Depot? Quote Link to comment Share on other sites More sharing options...
WaterGirlToday Posted April 4, 2020 Report Share Posted April 4, 2020 On 12/24/2019 at 4:20 AM, Micheal said: I have a DeWalt DCB107 charger and x2 dewalt 18V lithium ion 1.5AH batteries. I was using my dewalt DSC390 circular saw and drained both batteries, or so I thought, I was only sawing for maybe 2 minutes each battery, I was sawing a fresh 2x4 at an angle so it was under pressure. When I put one battery on the charger the yellow over heat light came on so I tried the other and the yellow light also came on. So I left both sit outside for 10 minutes then tried x1 on the charger, the red light came on and stayed, this indicated full charge, I tried the other battery and it did the same. I tried both batteries in the saw and my drill and neither worked. I tested both batteries with a volt meter and they read 14v to 15v. I read online that the batteries can shut down if they overheat and to reset them place them in the charger for 8hrs, I did this with one battery overnight and it’s still the same. It seems that the batteries are charged but have shut down!! Is this possible? How are they reset? On 12/24/2019 at 4:20 AM, Micheal said: I have a DeWalt DCB107 charger and x2 dewalt 18V lithium ion 1.5AH batteries. I was using my dewalt DSC390 circular saw and drained both batteries, or so I thought, I was only sawing for maybe 2 minutes each battery, I was sawing a fresh 2x4 at an angle so it was under pressure. When I put one battery on the charger the yellow over heat light came on so I tried the other and the yellow light also came on. So I left both sit outside for 10 minutes then tried x1 on the charger, the red light came on and stayed, this indicated full charge, I tried the other battery and it did the same. I tried both batteries in the saw and my drill and neither worked. I tested both batteries with a volt meter and they read 14v to 15v. I read online that the batteries can shut down if they overheat and to reset them place them in the charger for 8hrs, I did this with one battery overnight and it’s still the same. It seems that the batteries are charged but have shut down!! Is this possible? How are they reset? Did you ever find out the answer? My saw keeps shutting down too after 3/4 of the 1st 2x4 being cut. I can get it to spin but as soon as it hits the wood it fizzles out to nothing. Recharging now to see if that helps. Quote Link to comment Share on other sites More sharing options...
WaterGirlToday Posted April 4, 2020 Report Share Posted April 4, 2020 On 12/30/2019 at 8:29 AM, Cr8ondt said: Your voltage is too low and the charger won't charge them, time to jumpstart them. Take a fully charged working battery and 2 short wires, stuff one end of each wire in the the + and - of the working battery then connect one wire to the matching terminal of the dead battery, and tap the 2nd wire to the other terminal for 1/2 a second or so. This should bring the voltage up enough to get your charger to work. Also, those 1.5 ah batteries shouldn't be used on any saw, obviously they get you no runtime, the draw is too much for those little batteries. I only use double stacked batteries on like the 4ah and larger one mine, you'll get noticably more power. Quote Link to comment Share on other sites More sharing options...
WaterGirlToday Posted April 4, 2020 Report Share Posted April 4, 2020 Thank you for the heads up that I need my double stacking battery pack for the saw! Will go try that! And can you please post a set of photos showing the battery wiring stuff you just commented about. My with wiring with our photo instructions may not end up in a good place! 🙂 1 Quote Link to comment Share on other sites More sharing options...
JaneB Posted September 28, 2021 Report Share Posted September 28, 2021 So, I just called dewalt and a service center in orlando. Both said they will not replace the batteries because they are beyond 3yo. 2 20vMax Lithium Ion XR 5A-H are 2017 and one smaller one from 2015. How exactly are you guys getting them replaced no questions asked? I tried jumping one but it apparently screwed up the other one and the smaller one only holds charge for like 15 mins. very frustrating. i have work to do! grrr Quote Link to comment Share on other sites More sharing options...
TBone2000 Posted July 1, 2022 Report Share Posted July 1, 2022 On 4/4/2020 at 3:47 PM, WaterGirlToday said: I tried connecting a variable power supply and ran it at 0.5A and the battery was taking a charge. Starting at about 17.5v and I charged it to about 18.3v and the LED charge status showed 2 out of 3. I then disconnected from the lab supply and connected the battery to a Dewalt slow charger and immediately it showed fully charged. So, I think the issue is a bad or damaged cell and I'm not willing to do anything else with it as it's not work a fire or explosion. Quote Link to comment Share on other sites More sharing options...
Johnny93 Posted July 14, 2022 Report Share Posted July 14, 2022 I know this is an old thread, but I'm desperate here. I have a 9AH Flexvolt battery here that just will not work in 18v (20v) or 54v (60v) tools. It wouldn't charge on any of my Dewalt chargers so I took off the covers and individually balanced all 15 cells to 4.1v. The pack is completely balanced to 4.1v per cell, or 20.5v per 5S pack. The thermistor reads 12K ohm between B+ and TH, the same as all my working batteries, and 12v between B- and C3, again like my working batteries. I've even had the battery sitting on the charger for 24hrs to "reset" the battery as some videos/forums suggest. What am I missing? I'm in Australia and current pricing is to high to "just replace it" It's a 2017 build date and well out or warranty, again, Dewalt will NOT just replace it. No physical cell damage is visible, nor have a submersed the battery in water. None of the physical fuses have been blown/melted, I am getting voltages on C1 through to C4 as well as between B+ and B- Quote Link to comment Share on other sites More sharing options...
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