Greetings. I have an older Black & Decker string trimmer. It's 40V lithium Ion, 2AH. (LBX2040) The battery will charge fine, show 3 lites (full charge) on the battery indicator, Plug it into the trimmer and it will run normally for about 5 minutes. then act like the battery is dead. The charge indicator lights are either 1 or none. I disassembled the pack, tested all the cells and each are 3.9. The battery test 39 volts at the contacts. The battery worked fine until I left it in my unheated garage (western PA) over the winter, then it started dieing quick. I could not observe any corrosion, discoloration, or signs of overheating on the PCB. These batteries are expensive $$$. and I would rather fix them if all possible. Thanks.
40V B&D lithium ion dies quick but charges fine.
- Thread starter Gluckmysock
- Start date
It's difficult to recondition or repair failed Li-Ion batteries.
You can get off-brand replacements on ebay for $30 or so. I would check for wording like "brand new" and a multi-year warranty before buying.
You can get off-brand replacements on ebay for $30 or so. I would check for wording like "brand new" and a multi-year warranty before buying.
Replacement for Black and Decker LBXR36 3.0AH 40 Volt Max LBX2040 | eBay
LBX2040,LBXR36, LBX2040, LBXR2036, LST540, LCS1240, LBX1540, LST136W. Replace for Black and Decker 40V MAX Lithium Ion Battery LBX2040 LBX36, Compatible with all BLACK & DECKER 40 Volt Cordless Tools.
www.ebay.com
Is this immediately after charge, or after the trimmer starts acting like the battery is dead? A fully charged li-ion cell of the typical chemistries should be around 4.2V when fully charged.
This is something you should never do with li-ion batteries. Allowing the cells to freeze can damage them internally due to the expansive nature of water (can internally crack components of the cell). Charging the cells when cold (for example, if you left them on the changer) will damage the cells, since it will cause the lithium metal to plate onto the anode inside the cells, and this is irreversable.
It is possible to fix the battery by replacing the cells, but this requires special equipment. You need a battery spot welder to weld nickel strips onto the new cells. Soldering should never be done directly to the cells, since it gets the cells hot enough to permanently damage them and make it more likely they'll fail in a very spectacular fashion (i.e. a lithium metal fire).
This happens after the trimmer acts like the batteries are dead. I will recharge the batteries and check the voltages before placing in the trimmer.
I have had rigid 18v power tools for many years and none of them have reacted to the cold. I will take care to bring them all inside from now on however. FWIW, I have a B&D 24v cordless drill whose batteries have failed in the same way as the B&D in my trimmer. They may have been affected by the cold.
Thanks for the replies.
I checked my freshly charged other battery and it tested 41.8 volts at the contacts. when I took it apart, all the cells tested 3.9???
It's likely that you have permanent damage as if you've done a significant number of charge cycles. So it'll hold some power, but the actual capacity sounds like it's extremely low, and probably even worse, the internal resistance is probably excessively high, causing major voltage sag as the trimmer not just starts the motor, but then is under load as it's cutting through stuff.
And leaving them out in winter cold like that, yeah, it's toast. Get a replacement battery, this is just a dangerous battery waiting to cause havoc.
And leaving them out in winter cold like that, yeah, it's toast. Get a replacement battery, this is just a dangerous battery waiting to cause havoc.
Make sure the replacement battery you buy is genuine. Not "compatible", not counterfeit, and not whatever else. Genuine or you're risking your safety and the tool.