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  1. Tohuwabohu

    Simple guide to using a DMM for measurements

    Hello HKJ, have you ever tested the resistance of the probe leads of the cheap DMM? I got a Best DT9205A today to compare it too a good multimeter. The DT9205A is not very accurate but usable but the probe leads are crap, their resistance is far too high. I measured 0.46 ohms - ten times the...
  2. Tohuwabohu

    Problem with new Pila IBC charger and/or AW Li-Ion 18650s

    A red light blinking fast next to the solid green light is what I see with an empty slot in my Pila. With 2 of my 18650's I see this also with the batteries in the charger close to the end of the CC period. Both batteries are EagleTac 2400mAh with a very low voltage threshold PCB. When removed...
  3. Tohuwabohu

    JETBeam Intellicharge i4

    I tried to explain it in this thread in the MarketPlace. I think there are two charging circuits/channels, one for the bays/slots 1 and 3 and the other for 2 and 4. Each channel can deliver 1A but when both bays of a channel are used the charge is applied alternately to both bays. It is a bit...
  4. Tohuwabohu

    Nitecore D10 internals: '14'? -and ss14 question

    Re: Nitecore D10 internals: '14' ? I think the part is a Schottky diode, probably a SS14
  5. Tohuwabohu

    Running tests on the WF-139. Interesting results. A must read for WF-139 users.

    ...charging current at that point is 635mA. Assuming a protection curcuit resistance of 50 milliohms that would result in a voltage drop of 0.635A * 0.05 Ohm = 32 mV and a voltage at the Li-Ion cell of 4.20V. During the CV stage the voltage at the battery contacts slowly drops to 4.213v as the...
  6. Tohuwabohu

    AW RCR123 750mAH Actual Capacity!

    No. The voltage drop across a diode will not increase the capacity. The current flowing out of one end of the diode is exactly the same as that going into the other end. It would need a switching buck converter to get a higher current and a higher capacity at a lower voltage. In the RCR123s...
  7. Tohuwabohu

    Maglite XL100 LED Flashlight Review

    Here you are: With 3 AAA Alkaline batteries, time in hours: Detailed view of the first 35 minutes: After 8 minutes the flashlight starts to regulate down in small steps. With 3 AAA Eneloops: The first 35 minutes with 3 AAA Eneloops. The stepping down begins after approx. 16 minutes...
  8. Tohuwabohu

    Consumer Li-Ion "cradle" charger roundup...

    The 4.5V were measured during the charging pulses at the charger terminals. In the short breaks between the pulses the battery voltage was at 4.2V. Not the recommended charging method but quite fast at moderate charging currents because there is no time consuming CV stage. 230V AC here. Thats...
  9. Tohuwabohu

    Consumer Li-Ion "cradle" charger roundup...

    That Cytac looks like the Digital Li-Ion 18650 Battery Charger sold by DX, KD and others. You can find a lot of usefull information about this and some other cradle type chargers on this Japanese page (Google translation). The circuit is very different from the Soshine SC-S2. You would have to...
  10. Tohuwabohu

    WF-138 acting odd?

    An open voltage of 5V is normal for this charger. It charges with (nearly) constant current pulses of 1.4s duration and checks the resting voltage of the battery in short breaks. With no battery connected it is in idle mode with approx. 5V open voltage. What type of battery are you using? You...
  11. Tohuwabohu

    Soshine SC-S2, Li-Ion Charger.

    The curve isn't prettier, its better. The Soshines charge much faster than my HXY. I can deduce it from the current vs. voltage graph and I know it from real worl experience because I used to charge my 18650s quite often with the HXY charger. But there are quite a lot of chargers that look like...
  12. Tohuwabohu

    Soshine SC-S2, Li-Ion Charger.

    That does not only apply to cheap charger but also to the good and expensive ones because there is always the internal resistance of the battery. A high output resitance of the charger will lengthen the duration of the CV stage. A good bench power supply has an output resistance near zero and...
  13. Tohuwabohu

    Soshine SC-S2, Li-Ion Charger.

    march.brown, probably I was just using the wrong words. It's more than 25 years ago that I learned English at school and I don't speak or write English very often. I spend more time looking up words than actually writing. That's why I like to add photos or graphs to my posts. Of course the...
  14. Tohuwabohu

    Soshine SC-S2, Li-Ion Charger.

    old4570, I didn't notice that you had marked R31. I didn't even look at that part of the photo. Thanks for your help Wulf. R30 is close to the other MC34063 at the edge of the PCB.
  15. Tohuwabohu

    Soshine SC-S2, Li-Ion Charger.

    old4570, yes, that is R13. Here is a better photo of that part of the curcuit: You can read the marking on the resistors: 2402 on the 24 kΩ resistor R13 1002 on the 10 kΩ resistor R2
  16. Tohuwabohu

    Soshine SC-S2, Li-Ion Charger.

    Mr Happy, of course you are right, a battery in the modified charger will never reach 4.20V. But I prefer to have a charger that will never charge beyond 4.2V over one that will charge up to 4.25V when the batteries are left in the charger too long. The battery voltage will be lower than 4.2V...
  17. Tohuwabohu

    Soshine SC-S2, Li-Ion Charger.

    Wulf, thanks for the explanation. I'm sure it will help others to understand the graphs. It is easier and faster to do this type of measurement than to monitor voltage and current when charging a battery. When I have done some more measurements on the Soshine I will start a thread in the...
  18. Tohuwabohu

    Soshine SC-S2, Li-Ion Charger.

    ...The MC34063 has an internal voltage reference of 1.25V. The theoretical output voltage is Vout = 1.25V (1 + R13/R2) = 1.25V (1 + 24k/10k) = 1.25V * 3.4 = 4.25V The real value can differ quite a lot since the voltage reference only has a 2% accuracy and the resistors used for then voltage...
  19. Tohuwabohu

    How do i test the capacity?

    I think the Multiplex LN-5014 is fine for doing discharge tests but less than ideal for charging the Ultrafire 3000mAh battery. The charge rate can not be chosen independently from the battery capacity. Setting the charger to 3000mAh would result in a charging current of 3A - too high for this...
  20. Tohuwabohu

    LiIon 18650 battery comparison

    Thanks for yor work HKJ. DX sells two different versions of the UltraFire XSL 2600mAh batteries. I'm quite sure you tested the cheaper and longer version (sku.28677). sku.26247 is shorter, has a higher capacity and a higher voltage under load. I posted results for both versions here in the...

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