Got me 5 of these boards for $10 and change shipped, cool find Thanks ordered a DC/DC buck for $4.25 7to24V in 5V 3A out now just got to find the time to play
Why is it not advisable to wire two these two 1A li ion charging board in parallel to get 2A charging current?
Made up four of these and had to change my idea of building into a double 18650 battery holder ... My new 18700's won't fit in , so I am now using flying leads with magnets soldered on ... I charged up a couple of 18650's that I had discharged to 3.65V ... The temperature of the chip reached 62C ... It has now dropped to 55.5C and the voltage is 4.07V ... I will leave it another hour or so and see what the voltage goes up to.
That chip does get warm though ... I wonder if it is designed to take that sort of temperature !
When I have more time to play with the chargers , I will leave them on a bit longer and also check the rested voltages ... The good thing about using magnets is that if I clip paper-clips on my DMM leads , the magnets hold the leads in place ... I just have to switch the meter on when I need to check the voltage.
If mine terminate at 4.16V or 4.17V , it means that the cells are only about 95% charged ... This doesn't worry me as I will be buying 3100mAh (protected) Panasonics from now on ... I have two already plus a couple of new Xtar 2600mAh (Sanyo) cells ... The intention is to buy two more Panasonics next month then two more in a couple of months time ... They came recorded delivery quite quickly from the Far East ... At less than £15 for two including postage , I can justify the expenditure ... The old Ultrafire 2400mAh's will then be retired from service.
I know that these chargers are not as pretty as a Pila , but if they work OK I will put off the evil day when (eventually) I have to (maybe) buy a Pila.
I discharged a 18650 to 3.67V and put it on charge at 1845hrs ... By 1900hrs the chip temperature was 63C and the voltage was showing 3.93V on charge ... At 1915hrs the temp was 62C and the voltage was 3.96.
I will keep a check on the temperature till it is charged ... It just seems a bit cruel to heat a chip up to that temperature.
I have just completed a proper charge from an 18650 cell that was 3.67V ... The cell voltage gradually built up to 4.20V and at the same time the temperature slowly dropped from 63C ... This took two hours ... The cell voltage stayed at 4.20V for over half an hour and I left it for one more hour and the voltage dropped to 4.17V ... I took the cell off charge and one hour later it was still 4.17V ... This seems to me to be a proper CC/CV charger ... Great for the price.
You're discovering what we learned earlier in the thread, Mr. Brown.
These are good little devices and allow people to create flexible, custom chargers to suit their needs.
Anyway , I am relieved to find out that these chips are capable of running hot ... Sorry if I repeated things that were mentioned earlier ... It's probably age-related ... Well , that's what my latest Wife says.
I noticed the heat too, when I first started using them.
I had posted my "workaround" earlier, but the post was lost in the recent server crash.
I use a 2A 5V "wall-wart" (OCV of nearly 6V, 5V under load) charger to run my two boards. When the batteries are very low, ie. sub 3.5V, the voltage differential is quite high, and that poor little chip has to shed a lot of heat. When this is the case, I charge from my iPad charger (2A still, but OCV of 5V and 4-and-a-bit volts under load) but the loaded voltage from the iPad charger is much lower, therefore a lower differential, therfore less heat. Once the batteries are half-charged, I go back to the wall-wart as it charges a bit more quickly from there.
Am I letting my sympathy for the chip over-rule suggestions by other (more experienced) posters ?
As an old (in all senses of the word) electronics engineer , I still have some sympathy for little chips running at high temperatures ... Having been retired for over eighteen years , I am not up with the latest technology of integrated circuits ... If people tell me that these chips will withstand high temperatures , then who am I to argue with them !
I think your setup would work better, with you trimming the voltage. I did read somewhere that the closer to 4.2V the input, the faster the charge.
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I then swopped the thin lead for the thick one and the temperature of the chip is on the way up as happened on charger one ... It seems that I will have to use the thicker lead in future ... After 15 minutes using the thick lead , the voltage is building up nicely (4.10V) and the temperature was 52.5C ... Another 15 minutes on and the Voltage was 4.13V but the temperature had dropped to 42.5C ... It seems that by putting the charger on the thin USB lead for the first half hour , reduced the maximum temperature by ten degrees ... I will let the charger complete the charge to make sure that the final voltage is within the 4.20 limit as on charger one.
One problem is that these Ultrafire cells are fairly old ones and the results might be different on newer cells ... I will have a better idea of the charger performance when my two (more) new Panasonic 3100mAh arrive from the Far East in a couple of weeks
I'm glad that I've decided to upgrade my 18650/18700's ... My Ultrafires are playing up a bit now ... They are less than three years old and have not had too much use except for recently when discharged and recharged to check that my four cheap battery boards are charging OK ... My two unprotected Ultrafires won't now charge up fully even on the Soshine charger ... They get up to 4.20 volts and the charged LED comes on ... When removed and rested , they only read 4.00V and 4.04V ... One protected reads 4.10V when rested , the other four read 4.19V ... I think the two unprotected can be disposed of and I will keep an eye on the 4.10V cell ... I will keep the four good Ultrafires mainly for the Solarforce L2i's and my Maglite 2D with Fusion 36 as the cells are about 1.5 mm shorter than the protected Panasonics ... The Panasonics will fit the L2i , but I would have to slacken the torch head a turn or so (or trim the spring) to make up for it ... I might even go back to using six Eneloop AA's again in the Mag 2D ... I am waiting for two more Panasonic 3100mAh's to arrive and I will order a couple more in a month or so ... I have to be prepared for when the other Ultrafires eventually need replacing which might be sooner than later based on the fact that they are all the same age.
Thanks again for the replies about the high chip temperature ... I'm happier now (a bit).
Last edited by march.brown; 08-21-2012 at 03:53 PM.
that thread) we now know that the TP4057 is not better than the TP4054 in that respect, which leaves little hope for the TP4056.
However, as HKJ rightly said:
The Blue LED is on when charging and the Red comes on when charged ...
Does anyone else have this problem.
Everyone else seems to have Red LED for Charging and Blue LED for finished.
The Blue LED is the one on the left when viewed with the USB socket on the left.
The Red LED is the one on the right beside the battery connection.
I have written to the seller but I don't think he quite understands the problem.
It just seems wrong to have a Blue LED on whilst charging.
1) The datasheet (http://pds24.egloos.com/pds/201206/07/08/TP4056Eng.pdf) lists max Tj=145C, which is well above the temperatures you measured. It also lists an operating environment of -40C to 85C, though the "guaranteed" operating range would be smaller. They don't have it listed in the datasheet but I suspect it's around 0C-65C.
2) From one of my posts earlier in this thread: "The only issue I noted is the LEDs are swapped vs the ebay listing. The charging position is blue and the completed is red."