Home Drone Construct a DIY LiPo Battery Discharger utilizing Halogen Gentle Bulbs

Construct a DIY LiPo Battery Discharger utilizing Halogen Gentle Bulbs

Construct a DIY LiPo Battery Discharger utilizing Halogen Gentle Bulbs


I’ll present you the best way to simply construct a DIY LiPo Battery Discharger utilizing halogen gentle bulbs. This discharger is able to dealing with 2S, 3S, 4S, 5S, and 6S LiPo batteries. A halogen bulb discharger is an efficient methodology for discharging LiPo batteries, both for storage or disposal.

Among the hyperlinks on this web page are affiliate hyperlinks. I obtain a fee (at no additional value to you) when you make a purchase order after clicking on one in all these affiliate hyperlinks. This helps assist the free content material for the neighborhood on this web site. Please learn our Affiliate Hyperlink Coverage for extra info.

There are different strategies of discharging LiPo batteries, discover out extra right here: https://oscarliang.com/dispose-lipo-battery-safely/.

How one can Use

Merely plug your battery into the sunshine bulb discharger and place it in a fire-safe space.

In case you are discharging for storage, monitor the battery voltage intently. When the voltage drops to round 3.85V per cell, unplug the battery. The cells might not be balanced and will require additional balancing utilizing a LiPo charger in storage mode.

Additional Studying: how ought to LiPo batteries be dealt with correctly: https://oscarliang.com/lipo-battery-guide/

In case you are discharging for disposal, depart the battery plugged in till the sunshine goes out, indicating that discharging has stopped. Notice that halogen gentle bulbs have a cutoff voltage of round 1 to 2V, that means they received’t fully discharge the battery. Affirm the ultimate voltage utilizing a multimeter set to voltage mode: https://oscarliang.com/multimeter-fpv/#How-to-Measure-DC-Voltage.

If there’s just a little cost left, I merely join it to an influence resistor to carry the voltage to zero, which shouldn’t take lengthy. Lastly, end it off by rigorously shorting the constructive and unfavourable leads within the battery in a fire-safe place earlier than disposing.

This methodology can fully discharge a completely charged 4S 1500mAh LiPo battery in lower than an hour.

LiPo Discharger Circuit Diagram

I take advantage of 6 gentle bulbs on this discharger, together with an on-off toggle swap.

There are alternatives for 12V/24V discharging modes:

  • 12V for 2S/3S LiPo
  • 24V for 4S and 6S

The utmost voltage of a 6S LiPo is 25.2V, which is larger than 24V, nevertheless it must be tremendous for brief durations, particularly since you might be usually discharging half-empty batteries.

The halogen bulbs I’m utilizing are rated at 20W, so at 12V, every will draw 1.67A of present. With 3 bulbs in parallel, the whole present draw will probably be round 5A, theoretically draining a 3S 2000mAh battery in simply 24 minutes. Nevertheless, because the voltage of the battery drops, the present draw decreases, and the discharge will take longer than 24 minutes.


I’ve stored the design so simple as attainable, all of the elements can be found on Amazon or AliExpress. The overall value must be lower than $10.

12V 20W Halogen Bulbs x 6:

3-pin PCB screw terminals x 4:

Prototyping board x 1:

Two lengthy electrical wires appropriate for the discharging present (my max discharging present is 10A, so 20AWG must be sufficient. Try this Wire AWG Chart for the acceptable wire gauge):

Male & feminine XT60 connectors x 1:

Male 3.5mm bullet connector x 1 (might be inserted into XT60 feminine connector):

On-off toggle swap x 1 (optionally available):



Constructing the LiPo Discharger

PCB Screw Terminals

You may solder the sunshine bulbs on to the PCB, however I favor utilizing screw PCB terminals for simpler bulb alternative when wanted (though I didn’t have to exchange a single bulb within the 6 years I’d been utilizing this discharger). In addition they doubtlessly can help you join several types of electrical hundreds, similar to excessive energy resistors, making it a extra versatile system.


Make sure you add loads of solder to deal with the excessive present.


12V/24V Discharging Mode Change

The sunshine bulbs are rated for 12V, so for discharging a 4S battery or larger, it is advisable to put these bulbs in collection, successfully doubling the voltage ranking to 24V.

For this reason I’m utilizing a 3.5mm bullet connector, performing because the “mode swap”. You need to use it to attach both simply the primary array of bulbs for discharging 2S-3S LiPo (3 bulbs linked in collection) , or to 2 arrays of bulbs linked in parallel for discharging 6S LiPo (3 bulbs per array, 6 bulbs in whole).


On-Off Change and Discharge Cables

The on-off swap is optionally available, as you’ll be able to flip off the discharger by merely unplugging the battery (or the bullet connector). Nevertheless, a toggle swap might be extra handy and safer, permitting for fast shutdown throughout an emergency.

I take advantage of additional lengthy electrical wires to maintain the battery as removed from the sunshine bulbs as attainable throughout discharging in case of a hearth.



Future Upgrades

These bulbs can get very heat! I’m contemplating including a fan on high to assist in warmth dissipation. A small fan usually requires 5V, which might require a step-down voltage regulator that will get energy from the battery being discharged.

I additionally plan to use liquid electrical tape over all soldered joints and connections to forestall quick circuits.


I examined the unit with only one bulb linked.

Upon turning on the sunshine bulbs, I noticed an preliminary present surge of two.6A, which rapidly stabilized at 1.6A. If I reconnect the bulb rapidly, the surge doesn’t appear to happen once more, which is an fascinating remark, let me know within the feedback in you recognize why.

These bulbs are rated at 20W. With a battery at 11.9V, the precise energy draw is 19W, which is barely decrease than anticipated however okay.

Within the 24V discharging mode (utilizing two arrays of bulbs in parallel), the ability consumption drops by practically half as anticipated. Due to this fact, when you’ve partially discharged your 4S or 6S battery beneath 12V, it’s advisable to modify to the 12V discharge mode for extra environment friendly discharging.


Edit Historical past

  • Oct 2015 – Article Created
  • Jan 2018 – Up to date article with an inventory of construct parts
  • Jan 2024 – Up to date directions and product hyperlinks



Please enter your comment!
Please enter your name here