Hotronic: Ski Boot Heaters Guide

What are Hotronic Boot Heaters? 

Happy toes, happy feet, happy skiing.

 Installing Hotronics in General Footwear & Shoes

You don't have to be skiing or snowboarding to enjoy the warmth of Hotronic Electric Ski Boot Warmers. Hotronic's can also be worn in your general footwear, meaning your toes can stay warm regardless of your activity. While activities like snowshoeing may initially come to mind, Hotronics can also be installed in your horseback riding boots, bike shoes, or fishing waders. You can also use them in your snow boots for extra cold days spent doing errands around town. While you don’t need to use a Hotronic insole to use your elements, you may decide that using the insoles provides more comfort. However, some footwear may not have removable insoles that allow an element to be placed under them. If this is the case you can install your heating elements with a Hotronic insole. Any of the Hotronic insoles work in general footwear shoes so your choice will likely be dependent on the comfort and shape of your shoe.

Installing Hotronic heating elements into your general footwear is very similar to installing them in your ski or snowboard boots.

  • First, place the heating element under the insole of the shoe. Make sure the power cord is flat so that it doesn’t create any discomfort.
  • Then, run the power cord up the side or back of the leg.
  • Securely fasten the battery pack to the back or side of the footwear.
  • Plug the power cord into the battery pack and you are ready to go!

If your footwear is smaller, such as a bike shoe then you may want to purchase extension cords and attach the battery somewhere on the waist. We recommend that you place the batteries either on the back of your footwear or on the outside to reduce the chance of knocking the battery off.

 Slide Strap vs. Strap Bracket


   Both the slide strap bracket and the strap bracket are mounting brackets that better helps secure your Hotronic batteries. To use the slide strap bracket you must remove the stock metal clip that comes with the battery. Because of this, it can be hard to transfer the batteries from boot to boot. If you are going to be using the Hotronic batteries on multiple boots, then it may be best to get the slide strap bracket. If you are only using the batteries on one pair of boots then the slide strap bracket is easier to maneuver and use.

Hotronic Slide Strap Bracket vs. Strap Bracket:

Slide Strap:

Pros:  Secures Hotronic battery on to the boot power strap, easy to use

Cons: Can only use Hotronic battery on one set of boots

Strap Bracket:

Pros: Secures Hotronic battery on to the boot power strap, can use the Hotronic battery on multiple pairs of boots

Cons: Harder to use

How to Mount and Install Your Strap or Slide-Strap Brackets 

A slide strap bracket or strap bracket will make it easier for you to quickly attach and remove your Hotronic batteries. Mounting brackets also will keep your batteries more secure on your boot, so you don’t have to worry as much about losing your batteries. This is especially important if you are an aggressive skier, like moguls, or will be carrying your gear for longer periods.

To mount your Slide Strap or Strap bracket

  • Determine the best location to mount the bracket on your power strap
    • Too far forward will obstruct closer of the power strap
    • Too far back conflict with the top back spoiler of the boot.
  • If you are using a slide strap bracket then remove the preinstalled wire clip and locking plate that comes with your Hotronic batteries.
    • You will need to aggressively push the plastic locking plate away from you to release it.
    • You can then squeeze the metal clip together and out of the battery.
    • Store this in case you would like to use it in the future
  • Insert the wire form into the ends of the bracket
    • The horizontal section should be on the backside of the power strap
  • To secure the bracket, push the horizontal section of the wire form over the center section of the strap bracket until the power strap is tightly in place between the bracket and wire form.


 Attaching Your Battery Packs to Your Slide Strap or Strap Bracket

Strap Bracket

Using a Hotronic strap bracket helps keep your battery pack better secured to your ski boot. They are also relatively simple to use.

Attaching Battery Pack to Strap Bracket

  • Position the battery pack horizontally so that the Battery Clip wire form slides over the top edge of the bracket
  • Slide the battery pack down on the bracket firmly until the lower wire section of the battery clip snaps into place over the bottom edge of the bracket
  • Turn the battery pack 90 Degrees so that it is in a vertical position

Removing Battery Pack from Strap Bracket

  • Turn the battery pack 90 degrees into a horizontal position
  • Push the battery pack down and pull out the lower wire form section of the clip until it releases from the lower edge of the bracket
  • Slide the battery pack up and off the strap bracket

A slide strap bracket makes Hotronic batteries more convenient and accessible to you, while also securing the batteries to your boot. A Hotronic slide strap bracket is a popular addition to foot warmer purchases because it helps prevent the battery from unclipping from the boot and falling off while skiing.

Slide Strap Bracket

Attaching Battery Pack to Slide Strap Bracket

  • Place the battery pack wire clip channel over the top of the strap bracket
  • Slide the battery pack down over the bracket until it snaps into position

Removing Battery Pack from Slide Strap Bracket

  • Press together the flexible legs that are on the bottom of the battery pack
  • Lift the battery pack up and of the slide strap bracket

Turning Hotronic Batteries On and Off

  • To turn ON
    • Press and hold the ON button until the LED light turns on.
      • The light will either glow green or red
    • To turn OFF
      • Press and hold the OFF button until the LED light turns off completely
        • This can take up to 5 seconds
      • To change settings
        • Press and hold the ON button to turn the level up
            • An additional LED square will light up
        • Press and hold the OFF button to decrease the level
          • You will notice this change of setting in the LED lights.
        • S4 and S3 batteries operate the same

    • Turning your Hotronic batteries on and off

How to Recharge your Hotronic Battery Pack

Your Hotronic batteries should be recharged every night after you ski. Charging them promptly after use will help keep them conditioned and ready to use. If you are going a week or longer without skiing, it will be best to also charge your batteries the night before you go skiing or snowboarding to maximize the charge while you’re on the hill. The battery packs should not take longer than three hours to fully recharge. However, if your boot batteries are not properly conditioned, your batteries cannot reach their full temperature or duration potential. It is recommended that you turn off your battery pack before you start charging it. This means that all of the LED lights are off as well. Your Hotronic battery pack will still charge if it is left on, but changing the level setting on it can cause the charging process to stop.

When you’re ready to start charging your heating system batteries, plug the recharger into the wall outlet using the correct plug adapter (North American, European, Other). The recharger accepts electric input ranging from 100-240V AC. 50-60Hz and hotel room razor outlets are not recommended. The recharger will perform a short self-test with a brief red LED followed by a green LED, and then the LED will shut off. The recharger is then ready for you to attach the battery packs.

The LED on the recharger will remain red while the batteries are charging. If it starts flashing red, the recharger and battery are not compatible or there is an issue with the battery itself. The LED light on the recharger will turn green once one or more of the batteries are fully charged. One of the batteries may fully charge before the other so it may be a good idea to leave the battery packs on the recharger for a while after the LED glows green. Once the battery charging process is complete, you should unplug the battery from the recharger as well as remove the recharger from the wall outlet. This will help maximize the charge after recharging. It is recommended that you occasionally fully drain the batteries before charging them to maintain optimal strength.

You can unplug and reattach the battery pack at any time during charging. It can also be beneficial to occasionally fully discharge the batteries before recharging as this can help maintain optimal strength. It is also possible to only recharge one battery, rather than both batteries in the pack. Additionally, you can recharge differing Hotronic batteries on the same charger at the same time. After you have completed your recharging process, you are ready to hit the slopes with your Hotronic ski boot warmers!


What to Expect from your Hotronic Battery Packs

If you’re new to electronic ski boot warmers, you may not know what to expect out of your Hotronic heating system. While each system may differ slightly, there are a few common things that occur universally with boot heaters.

  • Newer Hotronic battery packs perform more optimally and all battery types eventually lose strength over time.
  • Your batteries perform the best shortly after charging. Meaning, charge your battery pack shortly before using them.
  • Unconditioned battery packs produce lower temperatures for a shorter duration. You should condition your batteries if they are new or have been unused for more than 2 months.
  • Your battery will decrease in power if it is left on, even if it is unplugged from the power cord.
  • Your batteries will self-discharge at a rate of 2 -5% a month.
  • The battery will discharge at a faster rate if it is on a higher setting. Meaning, they will have a longer battery life if left on a setting such as one or two, rather than three or four.
  • Your Batteries will not last as long in extremely cold weather.
  • Expect imperceptible heat in your boots, rather than fireplace warmth.

It is important to remember these factors when using and caring for your electric ski boot warmers. Taking the above into consideration will help keep your batteries well maintained and your feet warm.

Hotronic Summer Storage

As the snow on the ground melts and the weather warms up, you’ll likely be putting away your winter gear, including your Hotronic heating system. While you’re not using your batteries and heating elements, it is still important to properly take care of them to ensure maximum functionality the next time you use them. You can keep your heating elements and power cord inside your ski or snowboard boots, but make sure that you store your boots in a dry environment to avoid any rust or mildew growing inside the liner that could affect the overall performance of the boot. Before you store your batteries, make sure to recharge them. When recharging, turn the battery pack off before plugging it in.

The charging process should then take about three hours or less. Remove the batteries from the charger before storing them and store them unattached from the heating elements as well. Do not store the batteries below 32 degrees or above 105 degrees, as this will harm the batteries. When you’re ready to begin using your heating system again, perform a battery pack conditioning charge for 24 to 72 hours uninterrupted. This will allow for a fuller charge and keep your feet warm for a longer amount of time. You’re now ready to tackle the cold weather!


General Tips for using Hotronics

  • Be careful getting on or off the chairlift. If the chairlift hits your boot warmer it can cause damage.
  • Take care walking down the stairs as the battery packs can catch the stair edge if they are mounted on the back.
  • Keep your boots and socks dry to avoid excessive heat loss
  • Condition your boot batteries to maximize their duration and temperature potential
  • Turn your foot warmers on before entering the cold to maintain warmth
  • Do not place another insole on top of the Hotronic insole

Hotronic Battery Pack Compatibility

How do I know which series my Hotronic Batteries are?

Sometimes you may have a hard time distinguishing which battery series your Hotronic batteries are. Knowing which series your batteries are is important for determining which charger you can use. If you do not know which Hotronic battery series you have, the following descriptions may help.

Power Plus S Series/E Series

  • All batteries manufactured after 2006 are compatible with the same white charger. The E and S series have white ‘On’ and ‘Off’ buttons on the top.  The model will be printed on the front of the battery, as with all of the models.



 Power Plus m Series

  • This Power Plus m series is the first Hotronic battery to be compatible with the white plug charger. Although very similar to both the and S series, it is very light gray. Additionally, the ‘On’ and ‘Off’ buttons are yellow, rather than white.


Power Plus 3.5 Series

  • The 3.5 Series was in production between the years 2003-2005 and is compatible with the blue plug charger. The batteries are light gray and have a black top. The level adjustment switch is blue to designate that it works with the blue plug charger.


Power Plus 2.7 Series

  • Power Plus 2.7 was in production from 2004-2005 and is compatible with the red plug charger. It looks similar to the Power Plus 3.5, but the level adjustment is red to show that is works with the red plug charger.


Power Plus 2.5 Series

  • The Power Plus 2.5 Series was only in production during 2003 and is also light gray. However, the level notch is in the center, rather than the side. It is also black, rather than color specific to the charger it is compatible with. However, it is also compatible with the red plug charger along with the Power Plus 3.5 and Original Power Plus.

Hotronic 2.5 Power Plus Battery

Original Power Plus Series

  • The original power plus series was in production during the years 2000-2002. It has a similar shape to the Power Plus 2.5 but is black with ‘Power Plus’ written on it. This battery series is compatible with the red plug charger.



Hotronic NiCad Series Battery

  • The Hotronic NiCad series is the original Hotronic Footwarmer battery. It is predominantly black, with a little bit of yellow and red graphics on it. This series can be used with both the red plug charger and the dark grey plug. However, the dark gray plug cannot be used with any of the Power Plus battery packs.



Hotronic Socks vs. Footwarmer Batteries

Hotronic has been producing electric ski boot warmer batteries since the 1990s. However, they just recently began making battery controlled heated socks as well. While they both serve as electronic boot heaters, they are a little different in their design and functionality.

Hotronic XLP One Heat Socks


  • Better for use in sports other than skiing- like biking, hiking, snowshoeing
  • Easier to set up
  • Heat is transferred throughout the entire foot and calf


  • Can sometimes feel the wires below the foot
  • Only works with BootDoc socks

 Foot warmer Batteries


  • Works with any sock
  • Has a longer battery life
  • More affordable


  • Heat is primarily distributed in the toe area
  • Not easily transferable

Hotronic Heat Sock Sizing Chart

If you are looking to purchase a pair of Hotronic XLP One Heat Socks, but do not know which size you should order, then check out the chart below. Often, Hotronic Heat Sock sizes are very similar to your other ski socks.

Hotronic Heat Sock Sizing Chart

 How to tell your Hotronic Production Year

Foot Warmers

Hotronic Battery:

On the bottom of your Hotronic battery, there will be two clock type circles of numbers. The first one will have 12 numbers on it, with an arrow pointing to one number. This number will coincide with the month that the battery was manufactured. The second circle has fewer numbers and dictates which year the Hotronic battery was manufactured in. Typically it is common for every battery within a production year to have the same production month as well, but this is not always the case.


The production year on the Hotronics is a little harder to find, but still very simple. The second line on the back of the recharger includes the model number, which includes the production year in the end.

Heating Element

The production date on the heating elements is printed on the lower part of the black grommet. At the base of the plug will be a two-digit number that correlates with the last two digits of the year that the heating element was produced.


XLP Series- XLP One

These batteries have their production year printed on the bottom. Just as the Foot warmer batteries have a clock style circle with numbers, the XLP Series batteries do as well. There is only one circle on these batteries and the arrow will point to the correlating production year.

XLP Series Recharger

The production date on the XLP Series recharger is located directly under the plug adapter. There is a 3 number code that marks the year.

XLP Series- Heat Sock

The production date on the Hotronic Heat Socks is located on the inside of the cuff. Just below the three snaps is a small copyright symbol with a date after. This date directly corresponds with the year that the sock was manufactured.

Hotronic Warranty

Hotronic foot warmers a very durable product, designed to withstand cold outdoor conditions. However, in the case that any of your Hotronic items become defective, Hotronic provides a 2-year limited warranty for all of their S Series foot warmer products. In addition to our satisfaction guarantee, Utah Ski Gear is an authorized Hotronic dealer and the Hotronic limited warranty extends to all purchases made through Utah Ski Gear. The two-year timeframe begins at the time of purchase, and a dated proof of purchase is required for any warranty item. The limited warranty is still valid if you purchase your Hotronic items through a third-party vendor such as eBay or Amazon. For any foot warmer from the 2014 production year or earlier requires a proof of purchase within the last 2 years.

The limited warranty does not cover damage relating to misuse, neglect, abuse, inconsistent use with operating instructions, normal wear, and tear, changes in exterior appearance, improper dealer service, improper dealer or consumer modifications to the product, or loss of product due to improper attachment. The warranty does not extend to variations in the heating element temperature and duration of charge due to improper charging. If you find a defect in your Hotronic batteries, heating element, or accessory, please return it to Utah Ski Gear immediately for replacement or repair.


Other Frequently Asked Questions about Hotronic Ski Boot Warmers

Can you feel the Hotronic heating element under your foot?

No! You should not be able to feel the heater under your feet if it is properly installed. The Heat Ready Insole has a designated slot for the heating element so the insole can remain completely flat. Even if you are using your Hotronics with custom insoles, you should not be able to feel the heating pad. It is extremely thin and should only create a slight bump- about 1mm high. The wires for the heating element go under the insole so they should not noticeable.

Do Hotronic batteries get in the way?

We recommend placing your Hotronic battery on the outside of your boot, behind the buckles so that it does not get in the way. Using a slide strap bracket and placing your snow pants over the Hotronic battery will protect it and reduce the chance of it becoming an obstacle. If you have a further concern about the battery getting in the way, then the S3 is an excellent option as it is a bit smaller.

How long do Hotronic batteries last?

During a ski day, the S4 Hotronic battery can last up to 21 hours when on the lowest setting. The S3 battery will not last as long as there is not as much internal battery power. If your batteries are at an ambient temperature of less than 20ᵒ, your batteries will die more quickly. Properly conditioning your Hotronic battery pack will extend both their daily battery life as well as their overall lifespan. Typically Hotronic batteries can last about 3-7 years if they are well maintained. Over time, the life duration of a single charge will begin to decrease slightly.

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