Li-Ion Batteries, how many is too many?

[71goldss]

Thanks to GJ I've slowly acquired a somewhat sizable collection of cordless power tools over the last 3-4 years. Everything from Milwaukee M12, M18, Craftsman C3 and Craftsman Nextec. Along with these platforms, I'm finding myself acquiring a sizable amount of the Li-Ion batteries to go with them. In the M18 line alone I have five 4ah and four 5ah batteries (9 total) to be used with 7 tools on an occasional DIY basis. My M18 vacuum gets used frequently and is somewhat of a power hog, but battery rotation still isn't all that frequent. It's pretty close to the same battery ratio with my other tool platforms as well.

Now recently I'm finding some great deals on the C3 XCP batteries and finding them pretty hard to pass on, especially since a couple of my standard C3 Li-Ion's are showing signs that death is near. I know there's a shelf life on batteries even when just stored, so I'm wondering if I'm shooting myself in the foot by keeping up my battery inventory, or should I just thin the herd by replacing as needed, and hope for a great deal on prices when the time comes?

I pretty much know the answer to my question, but I'm curious to know how others deal with this issue?

 

[sberry]

I am all for being ahead of the game. We about had a couple serious injuries when ours were dying and resorted to other tools where we would have grabbed the right stuff. No point in waiting till they are dead and you need them, I have about 10 or so and its been good and is super handy, dont have to feel like you are starving the place when we walk out the door with a couple and never worry about charging on the job.

 

[pi_guy]

As you add more batteries make sure you keep up on the fire suppression equipment.
Water is not a good item to use if one of them lets go.

 

[a52-830]

i write the year i bought the battery on it, so i know how long they are lasting. my ni-cads are holding out pretty well, my li-ion are still pretty young, and none have failed.

aside from that, to address your question:

you should own enough batteries of a given type (and charger slots), so that you can stay ahead of the tool. if you can blow through a battery in 45 minutes of heavy use, and it takes an hour to charge a battery, you need a total of three batteries, and, ideally, two charging slots.

 

[Brian_WK]

Store them at 50-60% charge storing Li-ion at full or no charge causes damage to the capacity and longevity to the battery. Lithium ion has a good shelf life when stored this way and has a slow self discharge rate. I try to rotate through all my Li-Ion batteries at least once a month. I have 2 separate rows on my work bench labeled half charged and full charged. I use the all the full charged ones to half charge then swap out to the next full charge. Once all the full charges are used I use the first discharged half battery until it needs to be charged. Once dead I put it in the charger.
My batteries are lined up front to back recently used gets put in the back oldest used gets pulled from the front. Doing a big multi tool job they will all get charged up and mixed up but they will usually all get cycled in that time.
One of my batteries is 8 years old, 2 are 6, 2 are 5. No battery issues here.

I would say if you can get a good price on the new go for it and store in proper state. Continue to use the old batteries until they have used up their usefulness then recycle.
Brian

 

[71goldss]

Store them at 50-60% charge storing Li-ion at full or no charge causes damage to the capacity and longevity to the battery. Lithium ion has a good shelf life when stored this way and has a slow self discharge rate. I try to rotate through all my Li-Ion batteries at least once a month. I have 2 separate rows on my work bench labeled half charged and full charged. I use the all the full charged ones to half charge then swap out to the next full charge. Once all the full charges are used I use the first discharged half battery until it needs to be charged. Once dead I put it in the charger.
My batteries are lined up front to back recently used gets put in the back oldest used gets pulled from the front. Doing a big multi tool job they will all get charged up and mixed up but they will usually all get cycled in that time.
One of my batteries is 8 years old, 2 are 6, 2 are 5. No battery issues here.

I would say if you can get a good price on the new go for it and store in proper state. Continue to use the old batteries until they have used up their usefulness then recycle.
Brian

Sounds like you have a great system! I'm going to go out and date my newest batteries in a few minutes. Storing the Milwaukee batteries at half charge would be simple because of the 4 dotted lights, but the Craftsman's would be a bit more difficult because of their green, yellow, red light system. Yellow may be where to store them at, but seems like it's nearly discharged by that stage?

 

[a52-830]

not to say that other systems are not better, but . . . . .

when i first got in the the craftsman C3 set, they were nicad. nicads could have a "memory" issue, where they would lose the ability to completely charge if they were constantly charged to keep them "topped off". so, i would charge them to full, and set them aside. i stored most of my batteries in my drill/drivers, with the extras placed nearby. when one went dry i would drop it in the charger, and take a battery from another driver, since the loose ones were last seen full, and the driver ones might have been used.


aaaannnnnyyyywwwwaaaaayyyy, as i started getting li-ion batteries, i treated them the same way. stored charged, with the "current" ones in the drivers.

i haven't seen any issues. they are stored in an unheated building, so they can get really freaking cold.

but, so far, no issues. while li-ion batteries can have issues, i think they are primarily in places where you get several cells in tight proximity to each other, or a lot of them wired together. while the packs we are talking about are made of these kinds of small cells, they are not packed tightly together, nor are a large number of them wired together. YMMV

 

[ptgarcia]

In my experience, the failure mode of Lithium based batteries has been the tabs holding them together. More often than not the spot weld on one breaks loose long before cells go bad.

 

[Ign]

I've pretty much phased out Nextec. The flo light is replaced by the M12 stick light

The RAID is replaced by M12 with a much smaller head.

The only thing Milwaukee can't replace is the inflator.

I do keep one Nextec 3/8 drill because I love the fit in my hand. It lives at my mill w small countersink(s) loaded up.

 

[rice rocket]

The answer is, two times the number of tools you plan to use in a given hour.

So one drill? Two batteries, one for the drill, one for the charger. A drill and an impact? Four batteries, one in each tool, a spare for each on the charger. Drill, impact, and sawzall? Six batteries. Etc etc.

If you're using more than 3 tools at a time, then you probably need to take some meds and focus your work a little more.

 

[a52-830]

The answer is, two times the number of tools you plan to use in a given hour.

assuming, of course, that you can charge a battery faster than you can empty one.

i have not always found that to be true.

 

[cja245]

I guess I must not use mine that much. I have the rigid 4 ah batteries. I have the 2 the kit came with plus one spare. It takes about 30 min or less to charge a dead battery and at least several hours to drain one. I haven't felt like I needed more. Batteries and chargers are miles ahead of what they were 10 years ago.

 

[rice rocket]

assuming, of course, that you can charge a battery faster than you can empty one.

i have not always found that to be true.

True, if you want to get technical, it should really be one, plus the time your charger takes to charge from fully depleted, divided by the lowest amount of runtime you get from running a tool constantly.

So with a 30 minute charge time and a 30 minute depletion time at full bore, you would only need one spare. But with a 30 minute charge time, 15 minute runtime at full bore, you would get 2x spares for a total of three. Times the number of tools you plan to do the same with at the same time.

 

[rice rocket]

I guess I must not use mine that much. I have the rigid 4 ah batteries. I have the 2 the kit came with plus one spare. It takes about 30 min or less to charge a dead battery and at least several hours to drain one. I haven't felt like I needed more. Batteries and chargers are miles ahead of what they were 10 years ago.

For a DIYer, drills and impacts don't really tax batteries that much, unless you're drilling hundreds of holes at a time, on an assembly line, and/or using the wrong drill for the job.

When you get into things like grinders, sanders, blowers, vacuums, etc., then there is often a need to do constant battery swaps.

 

[nickleone]

Look at this Craftsman charger:
http://tinyurl.com/zeflzkt

I have one and am pleaed with the performance.

Nick