I recently purchased a Dewalt 20V Impact Driver to replace a very old and worn out Makita cordless drill. The set came with (2) 20V lithium ion batteries. I will not be using the new driver very often. But, as you know, when you do need them, they’re worth their weight in gold. The batteries are quite expensive so I’d like to do whatever I can to keep them in good shape. I charged one battery and the other has remained in the package.

In order to make use of the one battery, I bought a Dewalt 20V flashlight which has been getting some exercise. For a general “around the property” and “working on projects” light, it’s pretty good. It’s very bright and it will run for over 11 hours. Even with using it on a daily basis, I’m really not making a dent in the battery.

So, what’s the best way to manage these batteries? I assume that the one still in the package can’t remain in there for much longer without some attention.

Picture of the light for the flashaholics :

Keep them both on a charger when not in use. Presumably, you have a single battery charger for two batteries. Invest in another single charger or get a double charger.

Lithium-ion batteries should be stored 1/2 charged.

https://www.protoolreviews.com...ntenance-tips/12527/

I have a set of Dewalt 20v lion batteries for my drill and impact. I charge them every 2-3 months...…..or if I use them, then I recharge them. They still work perfectly and Lion are a hell of a lot better than the previous Nicads in regards to longevity.

quote:

Originally posted by PowerSurge:
Lithium-ion batteries should be stored 1/2 charged.

https://www.protoolreviews.com...ntenance-tips/12527/

This. The worst thing you can do to a lithium battery is leave it at full charge for extended periods of time.

quote:

Originally posted by PowerSurge:
Lithium-ion batteries should be stored 1/2 charged.

https://www.protoolreviews.com...ntenance-tips/12527/

I have been a RC hobbyist for years. The battery chargers that I use have a wide range of settings one of the settings is storage that will charge or discharge battery to 50% level. I have a number of drill, leaf blower, impact, etc battery tools that came with their own charger. Only one listed in the manual that it would drop charge to 50% when battery was left on charger for an extended time.

Not all batteries have a charge level indicator and I don’t feel like getting a meter out to check voltage I just use and charge when needed.

Don't over charge them. If you are using a dewalt charger it will have protection buuilt in for that. Not a good idea to try to charge them with improvised methods.

Don't let them drain all the way down.

Don't let them get hot, don't let them freeze.

The extreme temp swings can trigger a "fault" condition in the microcontroller in the battery pack, and at least with makitas, they become trash after that.

I will say Lithium batteries are AWESOME compared to the god awful NiCad and NiMH packs of yore...

Charging the batteries is where the wear comes from, not using them. Like others have said, store them off the charger at partial power. Charging the first and last 20% of battery capacity is also harder on the battery, so if you're really trying to maximize life don't ever run them all the way down, and pull them off the charger before they are all the way full.

Thanks everyone.

It seems like the consensus is to maintain them at around 50%. I'm not sure how I'm going to accomplish that without additional, special equipment or turning this into a job. I'm not too keen on buying anything further.

I'll read the manufacturers literature again in case I missed something but I recall it being a list of things to avoid like extreme heat and cold etc. I think I'll just charge both batteries and alternate them in the flashlight and I'll recharge every few months.

quote:

Not all batteries have a charge level indicator and I don’t feel like getting a meter out to check voltage I just use and charge when needed.

To my knowledge, you can't use a meter to ascertain Li-Ion charge level.

No expert here. I have a small vac for the car that has a wall hanger with builtin charger that I use. Have 4 batteries for other tools just switch batteries every now and then.

quote:

Originally posted by pessimist:
Thanks everyone.

It seems like the consensus is to maintain them at around 50%. I'm not sure how I'm going to accomplish that without additional, special equipment or turning this into a job. I'm not too keen on buying anything further.

I'll read the manufacturers literature again in case I missed something but I recall it being a list of things to avoid like extreme heat and cold etc. I think I'll just charge both batteries and alternate them in the flashlight and I'll recharge every few months.

Your plan is sound. The difference in normal life between 'ideal' & 'possible' storage scenarios is minute. One or both might die an early death - that's luck of the draw & why there is a warranty.
Use them. don't charge them if you've only used 2 minutes of light time.
Leaving the charger plugged in/charging will cost more than you'll gain in battery life, and that will be minute.

I have 12V bosch Li-ion batts that are 8 years old & none have croaked or show signs of deterioration. YMMV, but the gains aren't worth the effort to think about it much, let alone put in a procedure.

There is absolutely no reason to "store your batteries at half charge." Modern Lithium battery chargers from Dewalt, Makita, etc switch to a trick charge when they reach full charge. You can leave your batteries on them indefinitely without damage. Read your dewalt charger manual and it will tell you this.

You will get very good life out of a Lithium battery keeping the battery charged in the 40% - 80% range. Read up on the 40-80 battery rule.