Jump to content

Milwaukee XC batteries - leave on the charger overnight?


Recommended Posts

So I've seen this question and a Huge variety of different answers over the net in the past few years... As for you Milwaukee guys do you leave your XC batteries on the charger overnight. I used to do it with my old 18 V Dewalt sawzall battery's. I'm convinced that's what ruined the batteries and only give me about 15 minutes of run time a year down the road.

I have 3 XC 5.0 batteries that are all at about 50% charge right now. Do you guys just pop them all on the charger and head to bed and take them off at some point tomorrow or do you charge them and come back in a few hours later and take them off during the day??

Link to post
Share on other sites

I take them off as soon as I noticed they are done, but I don't stress about them. I've left them overnight plenty of times. Modern battery controllers, lithium ion batteries, etc. aren't remotely as sensitive as the old stem packs. 

  • Like 2
Link to post
Share on other sites

Occasionally I've left some batteries on a charger for a few days not thinking about it but I make a habit of keeping them off the charger once they charge

Jimbo

Sent from my iPad using Tapatalk

Link to post
Share on other sites

Agreed with that. I've read of several fires directly attributed to tool chargers. Every once in a while I forget but the mental lashing I give myself keeps me straight for a while. Most of the Chargers now a days have conditioners in them to protect the circuitry in a battery so we don't kill our tools but my biggest concern is fire.

  • Like 2
Link to post
Share on other sites

Age and use caused the old batteries to get 15 minutes of run time. The Milwaukee batteries will eventually do the same down the road. The charger had nothing to do with it. As batteries age and get use, their performance deteriorates. You can help them along by not storing them in extreme temperatures, or if you don't use them for a long time, store them at 50% full.

 

The other reason the DeWalt batteries gave you 15 minutes.. Well they were DeWalt batteries. ;D

  • Like 3
Link to post
Share on other sites

The old chargers were basically a power supply.  No feedback from the battery.  Lithium ion chargers need feedback for the constant current and constant voltage charging especially with the limits of different batteries on rapid chargers, so they've implemented most of that stuff you had to remember in the past into the charger.  Used to be if a battery overheated you had to decide when it was cool enough to charge.  Makita and I believe some others the charger will cool it before it starts charging.

  • Like 1
Link to post
Share on other sites

Lithium batteries need a controller to handle charging so it doesn't really matter if you leave it on the charger. Basically most decent modern chargers will periodically top off the battery but lithium batteries don't drain quickly standing by so it's prob better to remove it from the charger but you don't have to worry about leaving it on the charger either. The things to avoid with lithium batteries is overheating them constantly and never leave them on a tool, especially when nearly depleted. If a tool goes into shutdown mode and the battery is depleted the battery should be removed immediately. Some experts seem to say it's good to deplete them to near zero once a month to condition them but I'm not sure that's necessary.  

 

The reason it's really bad to leave a nearly dead battery on a tool is the battery is made up of a bunch of cells. All the cells aren't identical and some might be a little weaker and have a slightly lower voltage. If a single cell's voltage drops too low the controller on the pack will determine the whole pack is fubared and will refuse to charge it. That's why it's dangerous to leave a nearly depleted pack on a tool; as it discharges slowly over time the weakest cell might start to drop to or below the safe voltage threshold and when you go to pull the trigger it might do the cell in taking the whole pack out. It's possible if you have a voltage meter to take the pack apart and find the bad cell and either try to save it individually or replace it but if you avoid leaving depleted packs on your tools you can avoid all that.

  • Like 2
Link to post
Share on other sites

It ok to leave them on a tool short term but it's a bad habit for long term and never when the batteries are nearly dead. The controller in most modern tools will prevent you from overheating the battery and shut power down when voltage drops too low in the pack with a safety margin to ensure the battery doesn't go too low a voltage state and become irrecoverable, an old pack can wear out over time and become irrecoverable anyway, but leaving the nearly dead pack on a tool for a long time will allow the pack to lose power naturally and cause issues with weaker cells in the pack. Also some tools drain packs more than others. I think we had a discussion a while back where some Makita die grinder or something could deplete a large pack in a matter of weeks just sitting on the shelf so ymmv...

Link to post
Share on other sites
I have also heard that people say it's not good to charge the battery unless it's fully depleted. For example one today was at 2 of the 4 led's so I charged it. Is that bad? Should I be running them fully down?

I've been informed this is only true of ni-cad packs

Sent from my XT1585 using Tapatalk

  • Like 1
Link to post
Share on other sites

There are some things you can do to lengthen the life of your batteries, but if you do nothing special and just use the batteries how you will without thinking about them it will almost certainly be fine (a couple old makita tools will kill 3Ah batteries left on for a long time but that's about it).  The battery protection circuit will take care of the battery for you, but there's only so much it can do if you try to kill it.  Draining the batteries completely before charging, trying to heat or cool them, or anything else special just makes it harder for the battery to protect itself.  Sure things like leaving them off the tool might help but you're not likely to waste a spare pack on a spare tool you never use so it's unlikely to be a problem.  Even the makita tools I mentioned having a problem take about a month and a half to discharge that battery so unless you put away a dead battery on the tool it's not a big problem.  For safety I just leave the battery in the slides but not locked in to the tool for that one and it doesn't discharge or cause any problem.

 

tldr: use the batteries charge the batteries and quit worrying about them

  • Like 1
Link to post
Share on other sites

I have left batteries on the charger for days at times or I grab it when I see the light turned green either way I don't worry to much about it. I charge my batteries when ever they need it. about the only thing I do is never leave them out in the freezing cold overnight.......and that is just cause I wouldn't want to be there....lol

Link to post
Share on other sites
1 hour ago, RickyMcGrath said:

I built my charging station with a manual timer on one outlet. I turn it to 120 minutes and forget about them until I need them.

 

I'm not sure it's better to leave the battery hooked up to a charger while it isn't energized. The battery contacts are still on the charger and might cause some extra discharge. I'd just as soon leave it plugged in and let the battery and charger do their things respectively. If you're worriedjust pull the battery off the charger some days later at your convenience, I think people get all bent out of shape because of old school dumb chargers years ago that cause problems with different chemistry batteries that don't apply today. These chargers and batteries are smarter than you or I and know what they're doing. Any electrical device could potentially be a hazard and lithium packs store a lot of energy in a small space so things can happen even if you do everything right.

Link to post
Share on other sites
  • 4 years later...
14 hours ago, Revsilk13 said:

i just got some milwaukee xc batteries, should I charge right out of the box?

Yes, you should charge them before using.  What I have heard is that the batteries are in "Sleep mode" when shipped so if they sit on the shelf to long, they don't do dead.  Not sure if that is true or a myth.  Everyway, it's always good to fully charge them before you use them.  Yes, I leave mine on the charge a lot, sometimes for weeks at time because I forget they are charging.  Charges and the batteries are smart and will not overheat or damage the battery.

Link to post
Share on other sites

from my experience with Milwaukee batteries they are smart enough to not worry about charging habits like you had to worry prior to this style. I have batteries that have sat for long periods of time and others that have been sitting on a charger for weeks with no difference in performance or logivity.

  • Like 1
Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Member Statistics

    14,889
    Total Members
    859
    Most Online
    Cgbusa
    Newest Member
    Cgbusa
    Joined
×
×
  • Create New...