Un-Attended Battery Charging - - Caution

[1cargarage]

I haven't personally or known somebody personally who has had an LI overcharge result in a fire.

BUT... my neighbor/buddy is heavy into RC cars, and I can tell you those LI packs burn up ALL THE TIME. I don't know if it's just rapid chargers, wholly and dangerously cheap and under-spec'd battery construction, leaving them plugged in too long, etc. but it's such a common issue with RC people that 'common' practice is to charge battery packs in a "LIPO BAG".

Seriously, the occurrence is so frequent that there is an entire market for fire and explosion proof bags/containers in which you can "safely" charge your batteries. No thank you.

Google: RC LIPO battery fire

I'm sure there are distinctions between RC packs and the ones we attach to our drills and coffee makers. I don't RC myself so I haven't gone down that rabbit hole, just peered into it.

 

[Bill Bowman]

I worked at a shop, where the owner would walk through the shop and pull anything that was plugged into the wall outlets. As soon as he pulled a plug, he would carefully wave his hand back and forth in front of the outlet.

 

[Kscardsfan]

Like to stir up shite, do you?

Yes, put enough unattended appliances plugged in and eventually one will combust. Happens to coffee pots, toasters, hair curlers and several makes of electric vehicles.

Yes, put enough piles of dirty rags in corners and eventually one will combust.

Yes, put enough rats chewing through insulation and eventually there'll be combustion.

Yes, enough harried parents trying to get kids to school and themselves to work and eventually one will leave a pot of oatmeal on a gas burner and the fire department will be there.

Yes, there are meteor strikes on the earth every day. If I keeping the kids LIPO stuff in a metal box when not in use give one piece of mind, no harm in so doing.

jack vines, who lives dangerously and leaves all manner of chargers plugged in every day.

Way to live on the edge buddy.

 

[theoldwizard1]

I don't like leaving any battery on any charger for days on end. IMHO, not good for the battery.

 

[MushCreek]

As long as you trust foreign shite made by the lowest bidder, there's nothing to worry about. Same reason I have all of my gasoline-powered equipment in a seperate shed. I charge batteries while I'm working in the shop, but I have forgotten and left them over night. I think I'm gonna wire up a charger outlet on the light switch. The car battery chargers are another issue. I have a seldom-driven Miata that has a parasitic draw that runs the battery down in 2-3 weeks. This is death to an AGM battery, which is why I switched to a regular lead acid. My old battery charger started smoking while I was using it, so I never leave them unattended.

 

[billt460]

I'm leery of ANY type of electrical device than can discharge A LOT of power in a short time. (Think lightning bolt here). Or, these Lithium Ion batteries that are no larger than 2 packs of cigarettes placed end to end, that have the ability to jump start a V-8 Diesel truck. These things just scream FIRE!

I don't own one of those, but will readily admit they could save the day. But I would be damn careful using them.... Both discharging, or putting energy back into them.

I was watching a show called "Battlebots" a while ago. They place expensive custom made robots against each other, in a fight to the death. These things are ALL battery powered, by high power Lithium Ion batteries. It's amazing how many end up catching on fire and burn themselves to destruction.

 

[Terra Nova]

no, it's very black and white. lithium battery chargers STOP CHARGING at whatever voltage is max SoC for that pack. this MUST happen. exceeding max pack voltage WILL cause the pack to fail catastrophically. On average, 4.0V is peak voltage, but often you manage the battery somewhere under that.

the other side of that are defects. chargers that don't stop (e.g. garbage from the internet for too-good-to-be-true prices). batteries that are defective. aftermarket batteries that are now the wrong voltage for the original charger.

perfect example: the Chevy Bolt.


any pack with batteries in series requires some kind of BMS so the charger can avoid exceeding the voltage of any single cell (or parallel group of cells) - to top up or finish charging an M18 pack (i.e. while it's flashing slow green) requires the use of bleed resistors.

another example is eGO batteries. they actually run them down to 30% on purpose if you leave them unused for a month. even if they're sitting ON THE CHARGER!

simple little things with a single cell don't have this added complexity, it can be done in the charger.

That was the point I was trying to get at, when everything goes right nothing catches on fire. The vast majority of the time things go right. Some people are comfortable trusting a bundle of cheap electronics to do the right thing all the time every time to keep their house/shop from burning down. Darn near every piece of computer controlled technology I have used has, at one time or another, gotten confused as to what it's supposed to be doing. When the consequences are a battery fire I'm cautious and when the fix is simply to pull the battery off or unplug it, it's worth the effort. But like I said others feel different and process risk differently than I do.

Having seen first hand people's lives turned upside from a charging hoverboard or battery maintainers has shaped my feelings on the matter.

 

[American Locomotive]

I don't worry about my chargers being left on. Any UL/TUV/Intertek approved piece of equipment is going to have safety features to prevent fire, shock, etc...

....and the ugly truth is most fire root-cause investigations are pseudoscience at best. Someone's entire garage will burn down and they'll point to the charred remains of a battery charger and say "That caused it!" Uh huh, I'm sure.

 

[MushCreek]

My UL listed Schumacher battery charger let out a lot of smoke. I didn't wait to see if it would actually catch on fire.

 

[Ilikeike]

I guess it could happen,
but we've always left the cordless batteries plugged in 24/7 starting with Makita 9 volts in the 1990s.
bunch of marine deep cycles in our shop on tenders 24/7 for years also, some in out buildings on new solar chargers.

Living life on the edge...

 

[FordTruckWench]

While growing up, two nearby houses burned because of some problem charging (lead acid) car batteries. In the second instance, from our classroom, we could see a column of black smoke rising in the distance - two miles away.

I never charge car batteries in a garage, only out on the driveway. Also won't leave lithium batteries charging unattended.

 

[joseywales]

It's funny, I prefer to be home when batteries are actively charging, but I do leave my 18V cordless vacuum on it's charger 24/7...

I posted a thread the other day about 9V batteries in a drawer, causing fires when paperclips contact + / -. I saw the video and said, "meh...what are the odds." A few weeks later, we cleaned out my in-laws' and was tossing stuff here and there. Bunch of **** into a tool bag, with some 9V batteries, etc.

3 days later, I reach into the bag, and pulled out a wrench that was certainly too hot to place in one's pocket. I took note and adjusted future actions accordingly.

 

[m6z]

I don't use my power tools all that often, so I only plug in the chargers when I need to use them. I've never had any issues, but some of my stuff is way more than 10 years old at this point and I'd rather not take any chances.

 

[PoorUB]

Been to far too many house fires that started from battery maintainers. 12v lead acid batteries are cheap, certainly cheaper than burning your house down, just buy a new one when needed.

Sure, but what do you do about modern motorcycles that draw power from the battery constantly while parked? At one time I had two motorcycles that need to be on maintainers if ignored for more than a week or two. In a month the batteries were, as far as running the motorcycle, dead.

It is impractical to disconnect the battery while parked.

 

[dkmc]

Not about charging but unattended batteries...
A number of years ago a local town DPW barn burned down due to a certain older model truck having battery cable insulation worn thru and the batteries shorting overnight and starting the fire. About a year later, another not so local town barn burned, same model truck, same cause. Then 3 years later, yet another town barn burned, same model truck with shorted battery cables. After the second incident, I began disconnecting the negative cable on all my powered machinery when not in use. And I never wrench tighten the clamp on the negative terminal, just wedge the clamp on the tapered post with a twisting motion, so it could be pulled off if there was a major short. I've since added disconnect switched to both forklifts, but other machinery without switches, gets the 'snug' terminal treatment. Works fine. Prevents fires in old machinery.

 

[rlitman]

Loose connections build up heat. If you want a quick disconnect, crimp on Anderson connectors.

 

[Ign]

These threads come down to a persons comfort with risk, there will not be a black and white answer to the question.
{snip}

Wearing a mask significantly mitigates the risk. I saw it on the news. Problem solved.

 

[u3b3rg33k]

That was the point I was trying to get at, when everything goes right nothing catches on fire. The vast majority of the time things go right. Some people are comfortable trusting a bundle of cheap electronics to do the right thing all the time every time to keep their house/shop from burning down. Darn near every piece of computer controlled technology I have used has, at one time or another, gotten confused as to what it's supposed to be doing. When the consequences are a battery fire I'm cautious and when the fix is simply to pull the battery off or unplug it, it's worth the effort. But like I said others feel different and process risk differently than I do.

Having seen first hand people's lives turned upside from a charging hoverboard or battery maintainers has shaped my feelings on the matter.

Energy storage will never be without risk. we used to play "flaming tennis ball catch" on the farm as a kid. get a tennis ball, cover it in fuel, light it on fire, and whack it at your siblings while wearing welding gloves. works until the fuzz all burns off.

That said I try to stay away from cheap batteries/tools in general. any defects in the production process increases risk.

Sure, but what do you do about modern motorcycles that draw power from the battery constantly while parked? At one time I had two motorcycles that need to be on maintainers if ignored for more than a week or two. In a month the batteries were, as far as running the motorcycle, dead.

It is impractical to disconnect the battery while parked.

mine has an LCD clock. it sat for about a solid year on a charger, and fired right up the first button press. EFI and a full tank of e10 premium, no stabil. Battery is under the fuel tank, It's a pain to change it.

 

[PoorUB]

mine has an LCD clock. it sat for about a solid year on a charger, and fired right up the first button press. EFI and a full tank of e10 premium, no stabil. Battery is under the fuel tank, It's a pain to change it.

I have owned late model Harleys, and I now own A BMW and both would pretty much kill a battery in a couple weeks if not on a maintainer.

I have been doing a house remodel since last spring. The charger for my cordless tools has been plugged in since then.

Have you guys heard that cars can suddenly catch on fire for no reason? Better not park them inside!

Like another post pretty much any appliance you can think of has caused a house fire. Best you just pop the main breaker when you leave!

You can try minimize your exposure to fire by unplugging unused tools an appliances, but for most of us it won't happen.

 

[mikedodge]

There are safety features built into chargers but it's still relying on cheap Chinese parts. There are lots of cases of either a tool charger or car battery being charged causing fires so I'd rather play it safe then loose everything. Tool batteries charge fast any way.

Years ago I smelt something burning in my bedroom and found my phone charger was overheated and melting. Another time we smelt hot electronic type smell and found it coming from the battery in a handheld vaccuum being charged. We've had a ups at work overheat before from its batteries also. So its been enough to make me cautious.

 

[dacan23]

I had a nimh RC battery explode 30 secs after taking off a charger, had it still been hooked up prolly would of started a fire.

I think most accidents happen with cheap/knockoff batteries or those which have been damaged/dropped hard or excessively.

One of the reasons I try to stay away from cheap batteries. Ones I dont trust right now are the knockoffs for my ring devices, heck I barely trust the ring genuine ones.

Just wait until 2040 when it will be an everyday occurrence an EV burning something down in every town.

 

[Showkey]

Is it an issue for power tool batteries? Probably not, but they charge so fast why leave them on the charger? I don't leave anything charging overnight/unattended.

Been to far too many house fires that started from battery maintainers. 12v lead acid batteries are cheap, certainly cheaper than burning your house down, just buy a new one when needed.

ATV, motorcycle AGM batteries are cheap compared to the shop or home……..but they are not cheap in replacement cost typical quality battery is $125-$200.

Vehicle lead battery charging risks are far less than Lithium battery charging.

As side note:
If your shop or garage burns……the first question they ask what was recently being used and what was plugged in:

Recent use like the lawn mower with dried grass and leaves, the vehicles, welding, saws Etc
Plugged in like battery charger, computers, shop vacs, garage door openers, refrigerator/freezers, drier, dehumidifier heater, tools, ……

The questions are not to blame you…….they looking for deep pocket.
So if and or when they investigate the fire all those product reps get invited to the party.

So………Yes……all lithium batteries are on the top 10 list. Yes…..the risk is very low for a quality battery from a quality well known source.

 

[kelpaso1]

I would like to see statistics on fires caused by rechargeable batteries compared to all other causes in the last 20 years. Are they REALLY causing more fires?

 

[1cargarage]

I would like to see statistics on fires caused by rechargeable batteries compared to all other causes in the last 20 years. Are they REALLY causing more fires?

Rechargeable batteries have their positives and negatives.

 

[zendriver]

I would like to see statistics on fires caused by rechargeable batteries compared to all other causes in the last 20 years. Are they REALLY causing more fires?

The risk is causing fear, what else matters?

 

[VolvoRyan]

FWIW, batteries are also known to cause cancer in California.

-Ryan

 

[Showkey]

I would like to see statistics on fires caused by rechargeable batteries compared to all other causes in the last 20 years. Are they REALLY causing more fires?

Home vs shop/garage would be a different list……

Home……list
1. cooking
2.heating including space heaters
3.electrical ……….which includes a large list of items
4.smoking
5. candles

Home Fires starting in garage only represent 2% of the total.
Cars as a rule are pretty fire safe……..people working on cars not so much.

 

[Steve_P]

Ok, so if you hook up a Li Ion battery on a 1-2A dedicated feed, what will happen? Because this is what we're talking about. The charger fails, doesn't shut off, and 1A keeps getting fed into the battery even though it's already charged. And it overheats. It can't be a good thing so I'll try to avoid it.

 

[toyotadriver]

Personally I prefer to only charge tool batteries when I'm around. Occasionally I forget but most of the time I take them off the charger before I leave for the day. I have seen fires caused by charging batteries (not mine but a number of other peoples' places) so I prefer to minimize my risk. Most batteries will never have an issue while charging while a small number will. I've never seen a battery catch fire if NOT charging (not counting shorting out battery terminals). I like to manage risk in my favor even when it's low risk.

I don't lose sleep over it but I also don't tempt fate.

 

[toyotadriver]

FWIW, batteries are also known to cause cancer in California.

-Ryan

California causes cancer.

 

[Outahere]

Everything you would want to know about residential fire statistics:

https://www.nfpa.org//-/media/Files/News-and-Research/Fire-statistics-and-reports/Building-and-life-safety/oshomes.pdf

I did not see battery charging mentioned in the report while doing a quick read of it.

More than one-quarter of the reported fires in 2015–2019 (26 percent) occurred in home environments.

Most home fires and fire casualties resulted from one of five causes: cooking, heating equipment, electrical distribution and lighting equipment, intentional fire setting, and smoking materials. Over the five-year period of 2015–2019, cooking was the leading cause of home fires and home fire injuries. Smoking materials caused the most home fire deaths.

Electrical distribution or lighting equipment was the leading cause of home fire property damage. An average of 32,000 such fires caused 430 deaths; 1,060 injuries; and $1.3 billion in direct property damage annually. Wiring and related equipment accounted for 6 percent of all the home fires and 7 percent of all the home fire deaths. Cords or plugs were involved in only 1 percent of the fires but 7 percent of the deaths. Extension cords dominated the cord or plug category.

Electrical failures or malfunctions can occur in any type of equipment powered by electricity. In 2012–2016, half of these fires involved electrical distribution or lighting equipment. Cooking equipment, heating equipment, fans, air conditioners, and dryers accounted for most of the remaining home fires started by electrical failure or malfunction. More information is available in the NFPA report Home Electrical Fires.

 

[billt460]

Charging rate matters a lot. Especially with Lithium Ion batteries. Today everyone is in a big hurry, and fast charging rates can cause much more internal battery heating, than slow charging. A lot of portable tool battery chargers advertise fast charge rates. Because contractors need their tools up and running. So they are drawn to chargers that advertises the fastest charging rate possible. This equates to less downtime of their power tools.

Unfortunately this also generates the most heat, and thus increases the possibility of over heating the battery, and causing a fire. Stick with slow charging, and your batteries will not only last longer, there will be a much less chance of them turning into a blowtorch.

 

[beemerphile]

....and the ugly truth is most fire root-cause investigations are pseudoscience at best. Someone's entire garage will burn down and they'll point to the charred remains of a battery charger and say "That caused it!" Uh huh, I'm sure.

I remember reading a news article many years ago about a historic old building that had burned down. The newspaper said that "...the cause of the fire could not be determined because the building wasn't wired."

 

[Sumboodie]

Lance from Pirate 4x4 had a charging LI(iirc) battery explode while it was charging in his RV while driving down the road.
Burned the RV down and he had leg burns.

It was several years ago and my memory may be off.

Since then I don't leave tool batteries charging unattended.

It was for an RC car from what I recall.

That's been probably 10+ years ago. I'd be on there since the early 2000s until it went to **** a few years ago.

 

[Sumboodie]

I remember reading a news article many years ago about a historic old building that had burned down. The newspaper said that "...the cause of the fire could not be determined because the building wasn't wired."

I had to call in a forest fire.l that I came upon.

They brought in an investigation team. They ran a magnet around a maybe 10ft sq area, out of a acre burned, found a few flecks of metal.

Cause of fire... hot sparks from an exhaust.
I didn't argue, they were starting to but blame on us for a bit and that absolved us.
(No, wasn't us, just came up on it)

 

[u3b3rg33k]

Ok, so if you hook up a Li Ion battery on a 1-2A dedicated feed, what will happen? Because this is what we're talking about. The charger fails, doesn't shut off, and 1A keeps getting fed into the battery even though it's already charged. And it overheats. It can't be a good thing so I'll try to avoid it.

except that's not how electricity works. you have to have a potential difference for current to flow. so your charger has failed, but in a specific way that causes it to choose to increase the voltage to maintain a specified current?

most chargers use buck converters. is the DC bus high enough for 100% duty cycle to even allow for this to happen? all the failsafes for the voltage sensing has failed, and the charger is still active, and chose to increase its output?

there's a lot of things that have to go wrong very specifically to let this happen. Li-ion chargers aren't remotely similar to the old transformer based lead acid chargers.

 

[MarkH]

One of the things to think about is how the risk has changed over time.

When I was a kid. We took all of the batteries out of any vehicle that would not be used in the winter. We had a series of pallets on a concrete floor in a steel building One pallet for combines, another trucks, etc. When it came close to time to use them we would put a slow charger on them and see if they were good. That was our battery charging period. All tools that used electricity were plugged in and had an on / off switch

Today
The machine batteries are treated the same way. It is the tools that have changed. In the main shop there is a line of chargers for various tools. It would be smaller if there were universal batteries or less change for planned resales. I counted 18 of them plugged in at the main shop. Some with batteries on them for a few days on end and a pile of batteries that needed charging. Tech change has given us a new risk.

We do try to keep them in a separate area that is supposed to have no flammable substances near with one of the fire extinguishers close by. Even though risk is low it was one our insurers wanted us to mitigate. There words to us was as tool battery charging and batteries had changed we needed to look at it closer.

 

[mikedodge]

Everything you would want to know about residential fire statistics:

https://www.nfpa.org//-/media/Files/News-and-Research/Fire-statistics-and-reports/Building-and-life-safety/oshomes.pdf

I did not see battery charging mentioned in the report while doing a quick read of it.

That probably falls under unclassified or garage and vehicle storage areas.

 

[GreyOwl]

California causes cancer.

California is a cancer and it is spreading way too fast.