Fixing your Lumea Battery Charging Issue, for less than $1/£1/€1

My original post about how to repair your Lumea when the batteries are dead is becoming quite popular. As a result an electronics designer from the UK, Shamus Husheer, reached out with another, cheaper solution.

He was handed a dead Lumea and just like you did, searched for a solution online. He found my original post and noticed that the Lumea is using a LiIon battery. As an electronics designer he knew a better, cheaper way to fix the battery that he would love to share:

 

The background (you can skip this if you like):

The underlying problem with the Lumea is that it uses a LiIon battery, yet the charger circuit in the device breaks some fundamental rules for designing such things. When fully discharged, a LiIon battery needs to be gently charged at a small constant current (e.g. 0.02A) until it reaches approximately 3V, after which point it can be safely charged at the full current (e.g. 1.0A).

The Lumea detects that the battery is discharged to below 3V, and so for safety reasons won’t apply the full 1.0A charge unless the battery voltage is over 3V. But for reasons either of design incompetence or commercial cunning, it does not apply a low-current charge to fully discharged batteries, hence the problem when you leave one discharged for months.

We will make an incredibly simple current-limited charger from the Lumea’s own power supply and a single component – a resistor. The Lumea power supply is 8.5VDC, which is about what two fully charged LiIon batteries can deliver in series (which is how they’re wired). Worst-case, if you get the power supply around the wrong way, we want to limit the current to a safe level (less than 0.1A). That means we need a resistor of about (8.5+8.5)/0.1 = 170ohm, and in this worst-case scenario would be dissipating 1.7W of heat (enough to feel, but entirely safe). A convenient, easily available value is 180ohm, which has the colour code brown-grey-brown, and easily available in a 2W power rating for a few cents.

When fully discharged, this resistor will allow us to charge the batteries with (8.5-0)/180 = 0.047A, and when at 3V per battery (with two in series) we will charge at (8.5-6)/180 = 0.014A. Because only a small amount of charge is necessary, on my Lumea this took only about 15 minutes from dead to alive enough to charge normally.

The total charge delivered over 1 hour, after the batteries reach 3V each, will be less than 0.014AHr. The batteries are rated for >1Ahr each, so it’s entirely safe to leave them charging through this resistor for an hour (but don’t leave them over night).

 

The solution:

There is nothing wrong with your battery – you just need to give it a tiny bit of juice, at a safe level of current, then the Lumea’s own internal charging system can take over. The easiest way to do this is to use the Lumea’s own charger, and a 180 ohm, 2W resistor (available from any electronic shop for a few cents, e.g. £0.76 for a pack of 10 here: http://uk.rs-online.com/web/p/through-hole-fixed-resistors/7078833/) or here at Amazon.

Open your Lumea as per the photo [in the original blog post], but don’t even bother taking the battery holder fully out. All we need to do is locate the red and black terminals at the bottom of the battery pack (not the terminals of the charger inlet).

Hold the outer ring of the charger barrel against the black (negative) terminal – this can be held in place using e.g. a clothes peg.

Push one end of the resistor into the inside of the barrel (it’s easier to do if you bend the resistor lead back onto itself to make a snug fit).

Connect the other end of the resistor to the red (positive) terminal, and hold it there with e.g. a clothes peg.

Plug in and turn on the plug for the Lumea charger.

Leave charging like this for about half an hour.

Disconnect your resistor from the battery pack, and try plugging the barrel into the usual socket on the Lumea. It should light up and charge normally – if not, try repeating the connection between barrel, resistor and terminals in case you didn’t get a good connection the first time.

Once charging normally, let the Lumea charge up fully. And you won’t forget to keep it charged every couple of months again, will you?

If this article helped you to fix your Lumea, please donate a small fee to keep this site running so I can write and help others to. Thnxs!

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58 thoughts on “Fixing your Lumea Battery Charging Issue, for less than $1/£1/€1”

  1. Hey guys. I have a lumea sc2003. Iv tried the resistor method and have no luck. No change. Does the charger end side need to be touching the black wire. Or does the end of the resistor need to be touching the black wire.

    If anyone lives in England, I’d be happy to post then my machine and a resistor if they wanted to help me.

    Many thanks

  2. Spot on. Simple fix for me. Pry the base off by inserting a small screwdriver in the power socket in the base of the unit and lever gently and it should pop off. Remove the two screws and again pry off the base this time with the power socket and move aside. You will see the battery terminals. I soldered a 180 resister to a piece of wire and then clipped the wire to the positive side of the battery, inserted the other end into the middle of the power supply plug and them clipped the outer of the plug to the negative side of the battery. Make sure there is no danger of a short and turn the power supply on for about 30 mins. After that turn the charger off, remove the wiring and plug the charger into the normal socket, turn on and hopefully the charge light will flash and the battery will charge. After a couple of hours recheck and if all good pop it back together. No damage done to the casing other than perhaps when prying the purple base cover off. Well done OP.

  3. Hi Just An update
    Ibhave alsof fixed the probleem with the resistor.
    Check with a voltage meter of een you do the resistor trick, the voltage is going up.
    Around 6 v is enough tot switch tot the normal lading procedure.

  4. Hello!! Thanks for giving a bit of hope. I’ve got a newer version of Lumea, it’s Prestige IPL – BRI956. I was wondering if the above mentioned technique will work on this model or not? Mine’s battery just died today and I desperately want to fix it. But it seems like it won’t be easy to open and it seems closed from all directions from the handle. Not sure if I can get hold of battery by opening it or not. I would appreciate thoughts from you if you are able to suggest something or anyone else who has the experience of fixing the same model?
    Thanks!

    • I don’t have any experience with this model. After a quick look on Google, I think you should be able to remove the top part of the white cover (where buttons are) and maybe you can work your way down.

  5. Hello,

    What fantastic solutions in both posts, Ruud and Shamus. Congratulations to both.

    I would add a little add-on if I may. One doesn’t really need to open the full tool to get access to the batteries.

    At the bottom of the Lumea there is a little bluish cover where one inserts the charger. This is easily pried out with a small screwdriver or tool alike.

    Then, two screws are exposed and by removing those and prying out once more the bottom case from the front side of the tool, you immediately see the red and black cables.

    Note: I can’t upload any picture but in the second picture of this post the two clips holding both covers are visible (the smaller blue one and a bigger white one) .

    Finally, applying your findings leads to the same result without anybody, not yours, neither Lumea’s body 🙂 being damaged in the process.

    Hope it helps.

  6. Dank voor je snelle reactie, super fijn & tof
    Batterijen zien er eigenlijk nog helemaal gaaf uit, ik heb 2 rode batterijen. Ik meen op de foto’s van jou te zien dat deze zwart zijn, correct?
    Ik vermoed toch dat ik iets verkeerd doe met het connecteren van de metalen delen. Helaas kan ik geen foto sturen.

    Dus toch nog 1x voor de zekerheid:
    – uiteinde van de resistor dubbelvouwen en in de oplader steken (gele kant)
    – de ‘mond’ van de oplader tegen het metalen klepje (goudkleurig) van de zwarte draad bevestigen
    – ander uiteinde van de resistor tegen het metalen klepje (goudkleurig) van het rode draadje batterij bevestigen

    Correct?

    Groetjes!

    • Correct, meer kan ik er niet van maken. Bij mij waren het ook rode batterijen, maar die waren zwart uitgeslagen omdat ze stuk waren.
      Als het opladen niet lukt is de goedkoopste “gok” toch de batterijen vervangen. Is wel iets lastiger, maar een andere optie weet ik zo ook niet.

    • Thanks so much for this instruction! You have given new life to my seemingly dead lumea! Orked out fine as described. Only opening the body of the lumea was hard work, but totally worth it. Thanks again!

  7. Dank voor je snelle reactie, super fijn & tof
    Batterijen zien er eigenlijk nog helemaal gaaf uit, ik heb 2 rode. Ik meen op de foto’s van jou te zien dat deze zwart zijn, correct?
    Ik vermoed toch dat ik iets verkeerd doe met het connecten van de metalen delen. Helaas kan ik geen foto sturen.

    Dus toch nog 1x voor de zekerheid:
    – uiteinde van de resistor dubbelvouwen en in de oplader steken (gele kant)
    – de ‘mond’ van de oplader tegen het metalen klepje (goudkleurig) van de zwarte draad bevestigen
    – ander uiteinde van de resistor tegen het metalen klepje (goudkleurig) van het rode draadje batterij bevestigen

    Correct?

    Groetjes!

  8. Hallo Rudy,

    Ik heb exact de beschrijving gevolgd en de RESISTOR 180 OHM 2W 5% gekocht maar het lukt helaas niet. Wat nu wel weer is na 4 pogingen is dat het ledje 1x knippert als ik op de aan en uit knop druk, dus dat is gewonnen! De uiteinde geel duw ik dubbel gevouwen in de oplader en met een wasknijper tegen het onderste mentale klepje van de zwarte batterij. De andere uiteinde met een wasknijper vast aan de rode batterij, metalen klepje onderaan. Dan half uur laden, eruit, oplader in de Lumea en er gebeurt niks. Doe ik iets verkeerd? Hopelijk kan je helpen en hoor ik snel iets. In elk geval alvast dank!!

    Groet

    • Hoi Jacqueline,

      Hoe zien de batterijen er zelf uit? Bij mij waren ze gevlekt aan de buitenkant, duidelijk teken dat ze stuk waren. Het kan zijn dat je batterijen zelf defect zijn, dan is de enige oplossing deze vervangen. Het rustig opladen zoals je beschreven hebt klinkt goed.

      Denk dat je het probleem dus eerder in de batterijen moeten zoeken.

      Gr, Ruud

  9. I wasn’t sure if I’d connected it up properly with the resistor but after half an hour I tried charging it normally and it works!

    It was very difficult to open the case though, and I caused a bit of damage but it was worth the effort.

    Thanks 🙂

  10. You are amazing and its charging.

    I found out after struggling to get the case of that if you pop off the inner piece of the base you will find two screws underneath. Once the screws are undone, the base pops off and you have clear access to the battery points. My IPL is now working. Thanks

  11. Instead of opening the gun, is not easyer to cut the battery charger cord and put the 180ohm resistor on the red wire (for the half hour) and then reassemble the red wire without the resistor to complete che charging?
    Sorry for my bad english.

  12. Omg I have a green light and it’s charging! Took a couple of attempts but seems to be fixed. Thank you so much!!

  13. Fantastic – mine was dead as a dodo as I hadn’t used it for about 9 months and missed the bit in the instructions about charging it every 2-3 months. Your trick worked on the third attempt – the first two times I mustn’t have had it connected in the charger barrel properly. I’ve not put it back together yet while it’s charging but have probably done some damage pulling the casing off – some little bits of plastic fell off and the edge is rough and scratchy and will need smoothing down. Fingers crossed it’s easier to put the casing back on than it is to get it off! Thank you so much!

  14. Ruud! You are genius.
    I found my Lumea ( SC2002)died one week ago so tried to repair it in computer shop ( where perhaps they could kick the power ) paid £ 25 ( waste money ) they back it to me in couple days and said that nothing they can do ( the batteries shown 0 ). So I searched all websites ( even Russian) to solve the problem. So found your explanation, but as a woman couldn’t manage to open my Lumea and waited when my husband will arrive. So we together managed to open it and followed your rules. It is working. I can’t find words for thanking to you. You are just smart genius guy.
    We so grateful for you. Thanks a lot (Spasibo- in Russian language)

  15. Thanks! It is working again. Opening the device is pretty difficult so I was wondering if it is more easy putting the resistor outside of the device. For instance by cutting the powerline of the adapter and put it in between one of the two cables? Or using another universal adapter with lower current?

  16. Would this method work with a 300ma 3v unregulated ac/dc charger.

    I’m not great at taking things apart!

    • You *have* to take it apart, unfortunately.

      Your 3V supply would *probably* be fine for recovering the batteries as long as you limit the current in some way, such as using a resistor as described in this post (300mA is far too much for recovering a deeply-discharged Li-Ion cell – you want the charge current to be less than a third of that, i.e. no more than 100mA).

      But the whole problem here is that the device’s internal charging & battery protection circuitry has completely disconnected the battery from the charging port “for safety reasons” because it thinks that the battery is old/faulty, so no matter what power source you plug into the DC socket on the device, it’s not going to do anything at all (well, unless you connected something like a 1000V supply – something high enough to destroy the MOSFETs that are keeping the battery disconnected – but that’s a rather, uh, *permanent* solution! 😉 [hint: please don’t do this!]).

      So you have no choice but to open it up and connect a power source directly to the battery pack, bypassing the mis-designed protection circuit. Annoying, but better than buying a replacement when these things are ~£300 =/

      Thanks for the post, Rudy 🙂 I had already assumed that the problem was something like this, but when I tried to disassemble the thing, it wasn’t coming apart as easily as I would have liked, so I wanted to look up some instructions just in case there was something I was missing – a hidden screw, for example. But it looks like I just needed to apply more force … to something containing two Li-Ion cells and some high-voltage circuitry that may well contain some still-charged capacitors! Eek! o.o

      Given that my unit is something like 5+ years old, and I already have a fair number of good-quality, high-capacity 18650 cells in my supplies, I may replace the cells in mine anyway – we’ll see 🙂

      [P.S. I love the “Leave Empty” anti-spam field in this comment form – that’s genius! :D)

  17. After two years of having changed the batteries I couldn’t believe my lumea died for the second time . This time I tried this batteries charging trick and it’s charging again. I was very worried about having to tear it apart again, it was the most difficult part in the first fix, so I tried to do it only opening the purple plastic at the bottom, where the charger goes, and the two screws that hold that part. I didn’t have any resistors on hand so I cut an USB cable, connected the red to the red battery pole, the black to the black, and plugged it to a 0,5 A plug that I use to charge my smartwatch. I’m definitely setting a reminder for this to never happen again
    Thanks again for all the work behind these fixes!!!

    • Hi Rudd,

      When dismounting the small black component on the black wire to PCM was broken. Can you tell me what it is. I am reading on the posts it is a thermistor
      Is it a simple resistor 10kΩ or a mix resistor thermistor ?
      Someone mentioned 10 K Ohm B = 3380 NTC , can you help ?
      Many thanks
      Kind regards
      Claude

  18. Hi Rudy, thank you for the information. My wife`s Lumea was death and I managed to charge the battery. when charging with Lumea´s charger it doest not blink the green light. when i turn it on, the fan works, but power selector does not work, it does not “shoot” either. Full charged I measure 8.11V, might this be the problem? thanks. Jorge.

  19. It works great, very easy and very simple. Do it just you see on the pictures above and leave it for a 1/2 hour and you will see the result.

  20. Hallo Rudy, Het werkt fantastische. Het apparaat werkt weer.

    Waanzinnig dat je dit hebt kunnen ontdekken. Kan i nog doneren met bovenstaande link.

  21. Hi Rudy. Can you share any video of how to use the resistor. Don’t want to make a mistake. I am zero at electronic stuff.

    • Hi Uzma,

      Sorry I can’t really make a video. Even I havent used the resitor before, I replaced the batteries. Just scroll trough the comments for photo and tips and you will fine.

  22. Big thanks for this tricks. 1 hour plus 180Ohm(2W) and I have 4V on my batteries. After that’s they charges from original power supply. Good work!!!!

    ps: The most difficult thing was to disassemble the device.
    pss: My original IMAX B6 mini refused to charge these batteries separately.

  23. Hi Rudy and Shamus,
    Thanks so much for posting this solution! I gave it a try and it revived my battery. However, my Lumea now shuts down every couple of seconds when I try to use it (I can get a couple of flashes out of the machine, but then it turns itself off). I am able to start it up again, but the same thing happens. Any ideas as to what is going on? Did I perhaps not charge it right with the resistor? Or is meu battery so “dead” that I should replace it (as per the original post)?
    Thanks once again!

    • It’s hard to say from here, but I would try to change the batteries. If it first didn’t charge and now it does but not fully then my first guess would also be the batteries.

    • Hey Amaral!
      I’ll share my experience that I believe might be similar to your situation.
      One of the two batteries in our Lumea got drained. So I did similarly to Shamus/Ruud’s suggestion and used 350 ohms resistor connected for about 1 hr and then attempted to charge w/o resistor. Attempted to turn it on, fan would kick in for 1-2 sec and then lights would go off.
      Checked batteries and each read about 3.5-3.7 Vdc. It got me puzzled for a while.
      Then I thought that perhaps the two tiny wires (black connected to black negative terminal of battery and white one connected to the common plate “+” from one battery and “-” from another) is meant for monitoring charge of one battery, and if it drops below certain threshold value, then some circuitry shuts off fan and lights up red “charging needed” light. To see if this was the case I soldered off white tiny wire from the baterries common bridge and soldered it onto the red wire that is connected to “+” of battery. Whoohoo, this actually solved the problem. Now I get Lumea work like new.
      My explanation to this is that the black and white tiny gauge wires are part of some protection circuit. When this circuit doesn’t read let’s say 3.5V from one battery, it automatically shuts off fan and the rest of equipment.
      Also, after many years of cycling charge/discharge, Li ion battery doesn’t get to 100% of 4.25V and stays at around 3.5-3.7 instead. That in turn triggers the safety circuit. By wiring white wire as I described above, it sort of cheats the protection circuit because 3.5+3.5=7 Vdc, thus it will take a long time to drop both batteries to 3.5 V.
      It would be great if Ruud and Shamus could comment on this and either confirm or disprove my suggestion.
      P.S. I used 350 ohm resistor because ac to dc adapter’s voltage is 12 Vdc and 12/350=34 mA. S
      Thanks and good luck!

  24. Hi guys!! I fixed Lumea battery failure with your precious experience, but unfortunately the protection component ( NTC or PTC? ) was broken durin removal… Can you help me to identify this? Thank you and have a nice day!!

  25. So pleased this worked! It’s tricky to get it open but definitely worth the effort. Thank you so much for the instructions : )

  26. Hello ! after error in the Charger plug end, I followed your procedure, 30mn after my Lumea charge works again! Thank you very much !!

  27. Brilliant, thank you ever so much! Found my Lumea dead yesterday, heart sank. Googled for a way to resuscitate, found this page. Picked up a resistor for 20p today, followed your procedure, Lumea works again! Means I don’t have to bin a device I paid hundreds of pounds for and that I don’t have the means to replace at the moment. This is what the internet is for 🙂 Thanks again.

  28. can you please share video of how to fix it.. its kind a hard to understand your technical terms as i have no electronic knowledge

    • Hi Hala, I’ve just managed to work it out, followed the procedure and my Wife’s Lumea is back up and running. Brilliant! So here’s what I did. I ordered the resistor fro RS components and for a total of 91p they arrived the next day (Smallest quantity pack of 10) but heyho)

      1st Follow the instructions to open the Lumea. It is a bit tricky and I’m afraid I scratched the body of ours, but a small price to pay to get it back up and running.

      2nd Take the end of the charger cable with the connector on it. The bit that looks like a small rod with a hole in the centre and obviously not the Charger plug end.

      3rd At the very bottom of the battery pack you can see 2 terminals. One red and one black. Use a peg or similar to hold the cylinder to the BLACK connector.

      4th Take one of your resistors and bend one end of the wire back on itself and push it into the hole of the cylinder. (If it feels loose, open the the wire bend you just made a little and try again. You want to make a good contact with the inside of the cylinder.)

      5th Again using a peg or similar, hold the other end of the resistor to the RED terminal (I learned by the way that it doesn’t matter which way round your resistor is as they are apparently non polar)

      6th Plug your charger in and turn on the power supply.

      7th Let it charge for about 30 mins. (Apparently it shouldn’t be more than an hour. Mine worked with 30 mins)

      8th Turn off the power and disconnect the resistor.

      9th Put the charger connector into its correct socket on the Lumea and turn the power back on and you should now see the green charger light flashing.

      I left the Lumea charging overnight and all that was left to do was close the body up again. Takes some doing and ours hasn’t closed as neat and tidy as new, but doesn’t appear to be much of a problem as it now works perfectly. Fantastic!

      Hope this has helped and good luck with your repair 🙂

      • Thank you for the help, it’s working cant believe I managed to do it myself. Followed the instruction. Thank you made my day 🙂

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