Lithium ion battery question

[Nimrod]

I just bought a new Craftsman lithium ion battery for my old 19.2 volt Craftsman impact wrench. I use the impact wrench only occasionally, but I do carry it with me for tire changes and such when wheeling. The instructions that came with the new battery say to store it at 30% to 50% charge when not in use. So that raises some questions.

What will happen if I store the battery fully charged, for example after a wheeling trip if it doesn’t get used? Will this decrease the battery life or it’s ability to hold a charge? If storing the battery at less than fully charged really is important, is there an efficient way to discharge it? And how do I know when it is at 30-50% of full charge? The crappy instruction that came with the battery answer none of these questions, but I’m hoping someone on will know the answers. My intuition, BTW, is just to ignore the instructions.

 

[Rob Mayercik]

Is there any sort of charge indicator on the battery itself?

From what I've read, storing lithium ion batteries at either fully charged or fully discharged is not good for their health. Having it fully charged is probably OK for a day or two, but not long-term.

In the Radio-Control world, the chargers have a "storage charge" function that automatically charges or discharges batteries to that half-charge state. Not sure about tool chargers, though (will find out with I unbox my new LiIon-powered drill and driver set tonight), but with my LiIon-powered lawn trimmer, I try to charge it up the night before I use it, and don't recharge before putting away until the next lawn trimming. You might want to consider doing the same with this tool - only charge just before you go out, and then leave it partly-charged until just before the next trip.

LiIon has a "nominal" voltage of 3.7V per cell, so two of them is about the same voltage as 6 NiCd or NiMH cells. You don't typically want to run them down past about 3.3V/cell, so you could use a DMM across the terminals to gauge this.

Was this driver originally LiIon-based? If not, the charger you have won't work with the new battery.

If you want to geek out on the battery tech, head on over to www.batteryuniversity.com - lots of heavy info there.

 

[Nimrod]

The driver came originally with a NiCd battery, but when I bought the new lithium ion battery I also bought an appropriate charger for it. The charger has no “storage charge” function.

There is a color-coded indicator light on the battery. Red: needs charging. Green: fully charged. Yellow: will need charging soon. But the instructions do not disclose the capacity percentage at which the battery goes from red to yellow to green, so I do not know from the indicator when the battery is in the recommended 30-50% range for storage.

If I charge before the battery putting in my tool bag but then don’t use it, how do I partially discharge it for storage, and how do I know when it’s in the prime 30-50% storage charge range? I’ll check out the link and see if I can find answers there. Thanks.

 

[Rob Mayercik]

Maybe get it down into the Yellow range then? Not sure.

if the instructions came with an email address for support/questions, maybe put the question to them.

This link might be useful too: https://woodworking.stackexchange.c...ld-i-store-the-batteries-of-my-cordless-drill

 

[cal]

I have been using LION batteries on Ridged cordless tools since 2013 (impacts, drills, etc). I store them fully charged. Sometimes I store them fully discharged.

I have.. 8 batteries? I have not had a battery fail yet.

 

[Nimrod]

I have been using LION batteries on Ridged cordless tools since 2013 (impacts, drills, etc). I store them fully charged. Sometimes I store them fully discharged.

I have.. 8 batteries? I have not had a battery fail yet.

Good to know. Thanks.

 

[Rob Mayercik]

Yeah, thanks. I just joined the LiIon tool crowd myself (Craftsman drill/impact driver set), so real-world feedback is good to hear.

 

[GordoSmasho]

I have only Milwaukee tools. Both m12 and m18. Two sets of each. Ive built my collection for work and home over the last 10 years. I have had two batteries go bad on me. And I abuse them thoroughly. Stored dead and fully charged for months at a time some times. Sub zero temps as well. What has killed my two batteries was heat. They got left out in the sun for a week by a friend that i loaned them to. I would not worry at all.

 

[Bent]

Al, I use the same C3 19.2 batteries and tools that you have. I don't pay any attention to the amount of charge the batteries have except for when I will be taking one of the tools with me on the trail. Say I'm taking my reciprocating saw with me on an AAT, Then I'll top all 6 or 7 of them off to a full charge. When I get home I'll charge the dead ones and put the unused ones back in a tool.

I've been using the Craftsman 19.2 volt C3 system for years and not had a problem with the batteries or tools.

 

[Nimrod]

Thanks, Tim.

 

[WB9YZU]

Lots of good information here!.

Rob had some good info on voltages, but unlike our old RC packs, modern Li-Po packs for Tools are just about fool-proof.

Commercial Li-Po packs for tools have a voltage limiter for discharge. You don't see it, but it shows itself when you pull the trigger, the tool runs for a bit at speed, then suddenly stops.

This feature exists to save the battery as a fully discharged (0V) Li-Po will not come back from where you sent it.

As Cal stated, store ""discharged"" or charged makes no real difference.
They do not discharge over time like NiCads and NMHI batteries did, and though I like to store them charged so they are ready to go, I sometimes forget and move on to the next thing in my day.