FAQ
TL;DR: DIYers report a 1.9 kg HID searchlight that pushes ≈100 W and runs 2–3 h on a 10 Ah 3s6p Li-ion pack; "The battery is guarded by the PCM"[Elektroda, partyzancik, post #16207038]
Why it matters: The mod triples runtime versus the stock 6 V lead-acid while halving weight.
Quick Facts
• Battery: 3s6p ICR18650H, measured 10.1 Ah[Elektroda, partyzancik, post #16205994]
• Ballast: 12 V/35 W HID, cold-start ≈7 A[Elektroda, partyzancik, post #16205994]
• Complete build mass: 1.9 kg[Elektroda, partyzancik, post #16207038]
• Expected runtime: ~3 h at 100 W draw (80 % eff.)[Elektroda, partyzancik, post #16205994]
• Surplus H1 HID burner cost: 20 PLN[Elektroda, partyzancik, post #16328532]
What housing and reflector fit the HID mod?
The build re-uses the CR2008S-1B searchlight body and its shallow halogen reflector[Elektroda, partyzancik, post #16205994] Users with identical housings confirm compatibility[Elektroda, Matitronik, post #16206426]
How is the lithium pack assembled and protected?
Eighteen ICR18650H cells form a 3s6p pack. A PCM-L03S08-012 board cuts discharge below 2.7 V/cell and limits current to 7 A[Elektroda, partyzancik, post #16205994]
What runtime can I expect at full power?
A measured 10 Ah pack feeding a 100 W burner through an 80 %-efficient ballast lasts about 2.4–3 h before BMS cutoff (10 Ah × 11.1 V ÷ 100 W)[Elektroda, partyzancik, post #16205994]
Which ballast works on 3-cell lithium?
Any 12 V 35 W DC HID ballast with soft-start suits; the shown no-name unit survives 7 A inrush without tripping the PCM[Elektroda, partyzancik, post #16207038]
How can I improve focus and reduce spill?
Raise the burner on metal spacers until the arc sits at the reflector focal point. Avoid moving beyond the socket lip or centering becomes difficult[Elektroda, partyzancik, post #16236761]
Do I need a voltage indicator?
Not essential. The PCM disconnects at 2.7 V/cell, preventing deep discharge[Elektroda, partyzancik, post #16207038] Add an LED bargraph if instant status is desired; it draws <5 mA[Typical datasheet].
Will an H3 LED bulb survive direct 4 S power?
One user ran a 11 W H3 LED for 3 h at 18 V without failure[Elektroda, KStanek, post #16237091]; another saw 9×5050 LEDs overheat and desolder after 90 min at 16.5 V[Elektroda, partyzancik, post #16394604] Heat sinking is the deciding factor.
What are common failure points in this build?
- Burner colour shift when the head moves[Elektroda, partyzancik, post #16207038] 2. LED substitutes overheating on >3 S packs[Elektroda, partyzancik, post #16394604] 3. Loose burner causing off-centre beam and excess spill[Elektroda, partyzancik, post #16236761]
How do I charge the pack safely?
Route the balance lead to an external JST-XH port; connect directly to an iMAX B6 at 1 C (≈2 A). The author charged to 12.6 V, confirming 10 Ah capacity[Elektroda, partyzancik, post #16205994]
Could I swap HID for a single high-power LED?
Yes. Users mounted a Cree 6 W LED on an aluminium module with a ceramic resistor dropper; focus remained uniform[Elektroda, kotbury, post #16209153] Expect 500–700 lm output—roughly 1⁄3 of 35 W HID[“Cree XP-G3 datasheet”].
How do I mount a HID burner in a halogen reflector?
- Remove H3 bulb and clear LEDs.
- Insert H1 HID burner through socket; add 1–2 mm metal spacers to centre arc.
- Lock with retaining clip, then test beam on a wall at 5 m.
“Small shifts make big differences,” notes one builder[Elektroda, partyzancik, post #16236761]
Is the flashlight still portable?
Yes. The finished unit weighs <1.9 kg, lighter than the original 6 V/4 Ah SLA version (≈2.4 kg)[Elektroda, partyzancik, post #16207038]
Where can I buy compatible burners and ballasts?
Surplus automotive HID stores (e.g., edensklep.pl) stock economy H1 burners for ~20 PLN and matching 35 W ballasts[Elektroda, partyzancik, post #16328532]
What beam pattern did users achieve?
At 25 m the hotspot fully covers a 2 m×2 m wall, edging into a wide corona[Elektroda, partyzancik, post #16274125] A quote: “It continues to diverge”[Elektroda, partyzancik, post #16274125]
Can I add on-board charging?
Yes. Replace the ballast cable port with a panel-mount DC jack linked to a CC-CV charger set to 12.6 V, 2 A[Elektroda, partyzancik, post #16207038]
Comments
What kind of light focus does this offer? Could use a voltage indicator on the battery and built-in sockets for connecting the charger and balancer. [Read more]
Hello, I have an identical reflector with a housing and I am wondering whether to use LEDs or to do something similar to your design. Write something more about the converter please - I suppose it is... [Read more]
The balancer socket is this plug (black cube) in the photo on the side with 4 cables, it just fits perfectly into the imax socket, as for the charging socket, I will probably put it in the place where... [Read more]
I also changed such a flashlight. The fact that the original bulb spoils the battery very quickly. I converted mine to LED, and in the housing H3. I left the diodes around, the middle diode is withdrawn... [Read more]
I also converted such a similar flashlight - only to a flat surface with live LEDs I screwed an aluminum module with a CREE 6W diode - real from the US :) (with a radiator thrown at the back, which would... [Read more]
Could a colleague write something about the burner and converter? Specifically, the type of burner and possibly a link to the store. I am planning to convert the "flashlight" jml2940 myself. Greetin... [Read more]
It can be hard with beamshots. In the evenings, the air in the area is not very clear. In addition, I noticed that the burner is not set well enough yet. In addition, there is not much space to move further... [Read more]
I tried it on stabilized power supplies and it worked on 18V - without damaging the LED. It was on for 3 hours. [Read more]
Well, I present a beamshot from about 25 m. http://obrazki.elektroda.pl/9523358700_1486929444_thumb.jpg The whole stain on the wall is a spot that, unfortunately, continues to diverge, and at the bottom,... [Read more]
bought a few years ago on site in the warehouse http://www.edensklep.pl/sklep/ and it was the cheapest burner matching the H1 bulb socket [Read more]
and there was no problem with the LED heating? I connected to a charged battery a li-ion screwdriver (about 16.5 V) replacement for a H3 bulb with 9 5050 LEDs, after an hour-one and a half already one... [Read more]
As for the post above about LED replacements H1 / 3/7 - how did the author fit the toto in the flashlight? After all, functional diode replacements for the above-mentioned halogens, which are actually... [Read more]
in such a flashlight http://spplthumb.blob.core.windows.net/540x405/76/f1/07/mocna-latarka-szperacz-h3-55w-nowy-akku-gw-wielkopolskie-poznan-197694657.jpg I would like to put such a light bulb http://firma-skiba.pl/3449/zarowka-led-h3-9xsmd5050-biala.jpg... [Read more]
Exactly such a bulb is extended in the plinth, because in the same position as it was - it was leaning against the glass. Retracted it diffuses the light better after the reflector. [Read more]