Cost Effective Charger for Lithium 10180 and 10150 Cells (50mA and 100mA charge rate)

I'm really hooked on the latest rechargeable lithium ion keychain lights such as the Fenix UC02 or the Helius Sigma VI. There are also models from MecArmy, Convey and Wuben among others. They are all somewhat similar sized (around 1.7" length, 0.6" diameter), output around 130 lumens of light (on high) and use either a 10180 or 10150 rechargeable Lithium Ion battery. Most of the these flashlights incorporate an internal charging circuit – so you merely plug in a Micro-USB cable from a typical cell phone charger – and the cell is recharged in under 1 hour.
I have a number of these lights and found their general performance quite good – but have had issue with the internal battery charger not doing a great job (often didn't charge the cell fully). There isn't much space to put high-tech charging circuitry into the flashlight, so there are obviously compromises. I looked for a suitable external charger and was really surprised there aren't many out there that can charge these 10180 or 10150 lithium cells (primarily because the typical Lithium Ion chargers output TOO MUCH current). From the 10180/10150 battery data I can find, the charging current should be around 100mA max, with a 50mA charge current most likely giving better long term life.
Most all common Lithium Ion cable chargers operate at 500mA or 1000mA charge currents (10x the current that you want).

Fortunately – I found you can modify the LiitoKala Model Lii-202 charger to output 50mA or 100mA (instead of it's standard 500mA and 1A modes). The LiitoKala Lii-202 charger is fairly easy to find and pretty in-expensive (I got mine for around $11 on Amazon: https://www.amazon.com/dp/B0742CNDC8/?tag=cpf0b6-20 ) It's a reliable charger that can charge two cells concurrently and automatically determines the battery chemistry voltage along with decreasing current to trickle once you've reached full charge.

NOTE: You will be modifying the charger – voiding any warranty. These changes worked for my unit, but I make no guarantee that it will work for all Lii-202 charger models. If you aren't familiar with soldering/de-soldering small components – I advise not proceeding any further.
I have no affiliation with LiitoKala or any charger or flashlight manufacturer.

You will need the following items:
· LiitoKala Lii-202 Battery Charger
· 0.62 ohm size 1206 surface mount resistor (Qty 2) Available on DigiKey: https://www.digikey.com/product-det...e-product/RLP73K2BR62JTD/A109861CT-ND/4032627
· Tools: Small Philips screwdriver, Soldering Iron, Solder

Here are the general modification steps:
1. Unpack the Lii-202 charger and remove the 6 Philips screws securing the base (figure)



2. Remove the base and pull out the Printed Circuit board. You will find two small resistors marked "R10" and "R20" close to the Positive Battery charging connectors (see fig).

3. Using a soldering iron, remove the existing R10 and R20 resistors and replace with 0.62 ohm 1206 size surface mount resistors.

NOTE: The original R10 & R20 resistors are 0.050ohm (which provide 500mA and 1000mA charge currents). Converting to 50mA and 100mA charge should require a 0.50 ohm resistor – but in practice I found that gave a little too much current so settled on the 0.62 ohm value to stay closer to 50/100mA.

4. Once the resistors are in place – replace the printed circuit board and secure the base with the 6 screws previously removed.

All Done. The charger will now charge at 50mA or 100mA rates – depending on the selected mode (0.5A mode is now 50mA and 1A mode is 100mA – see figures). You will need to add a spacer to accommodate these short 10180/10150 batteries. I've use a large diameter metal screw with good success – but any suitable metal spacer should suffice.

See charging measurements below on a 10180 battery (the Multimeter probes complete the circuit and measure charge current):


Hope this information comes in handy.

Not a cost effective solution, but the SkyRC MC3000 can charge 10180s at 50ma per the review here:

This charger can also charge with very low current, i.e. handle small LiIon cells like 10180. Here I am charging with 50mA and it is a stable 50mA current (Very nice)

Click to expand...

Are there any other standard chargers that are designed to handle 10180s?

https://www.gearbest.com/diy-parts-and-tools/pp_136124.html

Chris

ChrisGarrett said:

https://www.gearbest.com/diy-parts-and-tools/pp_136124.html

Chris

Click to expand...

This charger on Gearbest (IMO) is about the same as the Internal charger that's built into most of these flashlights like the Fenix UC02 and others. The DQG Flashlight requires this external charger as it doesn't have a built-in one. You need to attach it to the DQG flashlight to use it (it's not a stand-alone charger).
My issue was that I wasn't getting the best performance out of the "built-in" charger on some of my 10180 lights (such as the Wuben G339 10180 lights). After a full charge (using the built-in micro-usb charger) - I would get very mediocre run time (< 1hr on low lumen setting). Switching to this external charger made a BIG difference (at least on that flashlight).

I fully expected that companies like NiteCore or Easttshine would make a charger that would support these newer small lithium batteries (along with lower charge currents), but so far I didn't find any.

I did see one or two chargers on eBay that supported the 10180 cells - but they were over $30 and not names that I was familiar with.

I'm not saying that all the internal chargers on these light's are bad (I expect some are better than other's), but I certainly know that my modified Littokala charges at a proper rate (user select-able for 50mA or 100mA) and have confirmed that it drops to a low trickle charge (around 5mA) once the cell is fully charged.

FYI: I did just find the following in-expensive (<$6) external charger on GearBest - https://www.gearbest.com/chargers/pp_748502.html
Although it "claims" to support the 10180 batteries, I didn't find any indication of support for 50mA charge current and searching through the web and even UltraFire website didn't show any pertinent info.

I don't trust it, but if anyone can find true specs on it - I'd be interested.