Storing Lithium Polymer Batteries at Home and in The Car

Tsubasa on 02/07/2023 - 13:10

Hi all

Hoping to get your views on safe storage of lithium batteries at home and in the car.

At home, I have the usual assortment of power tool batteries (ozito mostly) and some powerbanks plus lipo torches and small devices (headsets, laptop). Currently these are stored in a cupboard for the tool batteries and in or on desks / bedsides for the rest. Anything I should be doing differently?

For the car, I want to keep a powerbank handy in case my phone dies. The car can get really hot in summer, is this a good idea? In this case, the powerbank would stay in the car and not be part of a go-bag. I've seen some storage bags for drone batteries, will these work?

Thank you for the advice.

Electrical & Electronics Battery Lithium Battery

Comments

  • scrimshaw on 02/07/2023 - 13:17
    +2

    The car would be the worst place for battery storage. There's wild temperature swings and humidity variances that would accelerate the rate at which the battery self discharges.

    Room temp is probably best. Don't put them in the fridge though.

    If you're placing lots of batteries close together, put it inside a fire resistant box (or bag designed for drone batteries) and use some electrical tape to insulate / cover the contacts so you don't accidentally short them if they touch together.

    • Tsubasa on 02/07/2023 - 22:39

      Thanks. Will be getting the bags as suggested for the items inside the house. My power tool batteries are slotted into the holders you get at bunnings, within the cupboard so they do not get contact.

  • wombat81 on 02/07/2023 - 13:36
    +2

    My son and I use these lipo bags for our RC car lipo batteries. But those are more prone to failure/explosion than "normal" lithium batteries.

    https://www.ebay.com.au/itm/195301559027

    You definitely want to keep Lithium batteries out of hot environments as much as possible.

  • Italkdigital on 02/07/2023 - 14:23

    Not cheap best use those small Lithium batteries used for motorcycles (replaces original motorcycle start battery) but place outside of car, obvisiously if want to be more cautious somewhere away from heat of car motor/fuel lines and importantly direct sunlight, or compartments like boot etc that accumulates heat, something I've been wanting to do and have it wired somehow with a switch to be recharged from car battery while driving but these use specialized charges so dont think can wire directly to car battery

    • shaybisc on 02/07/2023 - 17:18

      Can you recommend a good charger/discharger with volt reader like those in the wikihow advice?

      Balance charger, huh. I need one.

      • wombat81 on 02/07/2023 - 18:40
        +1

        I use a ISDT Q6 Nano to balance and storage charge lipo cells. The one in the article is a SKYRC Imax B6.

    • Tsubasa on 02/07/2023 - 20:07

      How far do you go? I can get the storage bags as suggested. Do you use the fireproof case and sand bags?

  • skid on 02/07/2023 - 17:08
    +1

    The Lithium battery kept in the car cabin under the Australian sun has a high chance of exploding, even if the battery is not being used or charged. Happened to me.

    • Tsubasa on 02/07/2023 - 19:55

      Thanks for the lived experience. Storing a battery in the car is off the cards then.

    • AdosHouse on 02/07/2023 - 20:08

      Well this is boding well for the lithium battery I keep in the backseat of my car to run the fridge.

      • Protractor on 02/07/2023 - 20:43

        aka booster seat

  • Prong on 03/07/2023 - 13:59
    +1

    Keeping a power bank (or other batteries) in the car is doable, if you take some basic steps first.

    Ideally you want a LifePO4 based power bank, as it is safer. The ones that can start cars are usually LifePo4. Best practice is not to use it when it is too warm.

    First though you need to actually measure the temperature in your car in the sun. I suggest using a data logging Bluetooth thermometer. They are about $20 - less on sale. I have a Govee one, but Inkbird also have one that looks decent. You can then get a log of the temp over the course of a day / week / month.

    Measure the temperature in the glovebox, or center console storage with the car parked in the sun all day. (also compare by measuring the main cabin temp)

    Depending how much glass your car has, window tinting etc, you will find that certain areas stay much much cooler than the rest of the car. Ideally you want the place you will store the power bank not to exceed 30°C on a worst case day, but up to 40°C is ok.

    If the storage area gets too hot, then you need to add insulation. My previous car had a lot of glass but no tinting, so I used foam to make an insulated false bottom on the storage area. That kept it it under 35°C on a worst case day. Keep the bluetooth thermometer with the power bank so you can easily pull up the temp log now and then.

    Another option is under a seat. Put the power bank into an insulated lunch box (the vacuum insulated hard sides ones are good) and measure the temp it reaches. If still too hot, then put that insulated lunch box in an insulated lunch bag.

    Insulation makes a huge difference, and it is relatively easy to keep the power bank from ever getting too hot. And there is enough time for everything to cool off over night. But actually measuring the temps is key, so you know for sure how hot it gets, and how quickly it cools off.

    For other batteries, such as tool batteries, then you can do the exact same thing. Use an old eski and put it in the car and measure the inside temp of the course of a day. It makes a huge difference to keep the sun off the outside of the eski, so ideally have it in a covered area, or cover it with something like a towel or blanket. It does not have to be a hard sided cooler either - I have an old soft sided cooler (~$20) I chuck tool batteries in if they have to go in the car.

    You can also chuck some ice packs in - just put something like a towel over them something to stop any condensation on the ice packs reaching the batteries. Humidity isn't really an issue, since the condensation means the air in the cooler becomes drier, but the temp sensors also monitor humidity.

    Since it is winter, you can start the process now. Just keep checking the temp as we head into summer, and if it gets too warm, then add more insulation.

    • Italkdigital on 03/07/2023 - 19:39

      Thanks for the detailed info 👍 but my complaint at the moment is Melbourne's cold weather lolz 😆 thanks too gonna buy one of these thermostats 👉😁👈

    • Tsubasa on 05/07/2023 - 14:12

      Thanks for the response. I didn't think of an eski or lunch bag as the options for storage in the car :)

    • lgacb08 on 06/07/2023 - 21:07

      This precaution should only apply to lipo only (powerbank) because they are prone to expanding overtime due to temp and general degradation. Power tool batteries are almost always li-ion and is safer, provided you don't overheat them to the point of destruction or inducing some mechanical damage on the cell.

      • Prong on 07/07/2023 - 13:43

        It's not so much about safety with LiFePO4 batteries, such as power tool batteries. It's about capacity loss from cell degradation at high temperatures.

        Above about 40°C you get significantly accelerated capacity loss and increased cell resistance. On a hot day cars can be over 60°C inside. If the batteries are actually in the sun, they can get even hotter. Occasionally getting this hot is not hugely problematic, but for batteries stored in a car, it can add up quickly.

        The other aspect is if you actually want to use the batteries - especially for at high current draws. Using very hot batteries increases wear, and the BMS may activate thermal protection and cut power.

        Most of the time simply making sure power tool batteries are out of the sun will be enough. But chucking them in an old eski, or $20 cooler bag, will mean they stay cool enough to actually be used as needed without issue.

  • burp on 05/07/2023 - 14:06

    "For the car, I want to keep a powerbank handy in case my phone dies."

    Could you just use a phone charger that plugs in to the cigarette lighter?

    • Tsubasa on 05/07/2023 - 14:12

      Was more for portability. I can take the powerbank with me as the phone charges.

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