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1

You can't charge such batteries via their +/- terminals. These must be charged through micro USB port on the side. This is confirmed on Q&A of the product page. Basically these are casual 3.7V Li-Ion chemistry inside with some step-down DC-DC module built-in. And a charger circuit which actually charges them from 5V USB as a casual Li-Ion cell charger. ...


1

This requires an update in 2020: For most modern batteries, 2.5V is the discharge limit. Older batteries were usually rated at 2.75V or 3.0V, but as I've said, that's not the case in 2020. However, to be completely sure, you do need to consult the battery's manual, as the parameters vary wildly. For example, a typical Sanyo cell will have safe discharge ...


2

Parallel connection and increasing total Ah (batteries are from different manufacturers). That's a really bad thing to do. You should never connect batteries / battery packs in parallel unless you REALLY know what you're doing and then the batteries should be of the same model and preferably of similar age and wear level. If you ignore this advice and do it ...


2

If you can measure charge (and discharge) current rather than involve voltage in any way you are liable to get a superior result. LiIon ENERGY charge efficiency at various states of charge is high but varies and decreases at increasingly high levels of SOC. Whereas, CURRENT charge efficiency is extremely high - typically over 99% when new and INCREASES with ...


2

This is where some more info can be found about the component I was looking for. Here is the datasheet: (Click image for larger version) Source of original PDF version of datasheet image: Ogatama In my case, I removed the fuse, and looked underneath to be able to see the reference. It said SEFUSE D6X238. Happens that the '238' part is apparently a lot ...


0

Don't use a TP4056 for charging LiFePO4 batteries; it won't stop charging until about 4.2V has been reached and while some LiFePO4 batteries will probably handle that without exploding, it could damage them and will shorten their cycle life (the number of times they can be charged and discharged without noticeable deterioration/capacity loss). The maximum ...


0

LiFePO4 cell may be charged by CN3058E or MCP73123, if you want to make the charger yourself, condensers and heat-sink is necessary. It may also charged using a 3.6V power source and a resistor. LiFePO4 6V/12V/24V battery pack can just use a lead acid charger unless it's out-of-balance.


1

First one, of we assume the 18A is accurate, the peak-to-peak voltage is 18mV/m\$\Omega\$, average is half of that. An average-reading multimeter (not a true-RMS type) will read about 11% (just \$\pi\$/\$\sqrt{8}\$) high so you’ll get about 10mV/m\$\Omega\$. Divide the reading in mV by 10 to get m\$\Omega\$. Whether the 18A is accurate depends on the actual ...


0

The internal resistance of a battery is generally calculated from its open circuit voltage Vo, load voltage Vl, and the load resistance Rl: Ri = (Vo/Vl - 1) * Rl. It's that simple and you can manually make such a circuit easy. There can be many alternate methods but in a general sense the easiest one is usually recommended. Some basic info with example can ...


1

I was able to solve this by using an H-Bridge wired as an active rectifier. By using the recommendation here as inspiration, I bought a MOSFET Array 2 N and 2 P-Channel H-Bridge (DMHC3025) and wired it up as shown in the image below. This removed the voltage drop across the diode bridge and fix the inconsistent performance of my charging circuit.


1

I have spent much time in the back shop of one of our local battery pack builders / re-builders. They are often required to remove individual cells from packs. They use a large box-cutter type knife and a hammer to cut the existing nickel or nickel-steel strip from the individual cells. This is the kind of knife with snap-off blade segments. You want to ...


1

In series cells, the weakest has the largest voltage mismatch error prone to over/under voltage damage during CV charge or low SOC. In parallel cells the “strongest” battery has the largest current mismatch due to $$ΔI = Vc / ΔESR [mΩ]$$ Therefore all cells must be perfectly tested and matched before any strings series or shunt or both. Balancing extends ...


3

By symmetry, the current through each cell is the same at 20/12 = 1.66A per cell. There would be no current through the lateral connections (assuming all cells are matched). The current through each of the lengthwise connections would be the same and each would contribute half of the current. The current through each successive leg of the interconnect would ...


0

In the linked video, the designer provides an external charger that match the cells he used (~8.4Vdc). This is the reason why it works with its own design. The BMS he used is over-dimensioned and adding fuses in the B+/B- lines might mislead the voltage detection provided by the BMS (there is necessarily a small voltage drop across the fuses). The BMS doesn'...


0

As comment said: slightly off topic here I found this in less than 30 seconds searching the web: https://en.wikipedia.org/wiki/List_of_battery_sizes#Cylindrical_lithium-ion_rechargeable_battery plus of course you can mount almost any smaller type of cell with some handicraft work.


1

1 - Nothing else than the batteries shall be connected to B+/B- ports of the 2S BMS module. Its purpose is to protect the batteries for over charging, over discharging and over current. User access to charge and discharge is done using P+/P- ports only. You're right on this point with your first schematic. 2 - Connections must be short (low resistance) ...


0

So first of all there are two ways the battery can produce heat. Due to Internal resistance (Ohmic Loss) Due to chemical loss Your battery configuration is 12S60P, which means 60 cells are combined in a parallel configuration and there are 12 such parallel packs connected in series to provide 44.4V and 345AH. Now if the cell datasheet says the Internal ...


0

You have to add a step-up converter that will boost the 3.36V up to 5V. You need 5V to charge li-ion up to 4.2V


4

The cells in your current battery are all the same age. They've all been put through the same load in the same environment. Barring some obvious external trauma, the likelihood that another one of the cells wears out soon is fairly high. You'll probably have better (and possibly cheaper) results replacing the whole thing at once than replacing the cells ...


2

There is a protection circuitry on the batteries, once it senses a failure or interference it transmit to the computer not to charge or use the batt, there is nothing you can do to reset it. Replacing any of the cell is a waste of time.


3

I'd suggest a single slightly LARGER capacity replacement cell. A smaller mAh one will again "bottom out" first and if the BMs is not doing a per cell protection it will again die. A larger cell will tend to have more charge than the others IF all are fully charged to start. Testing cell capacity is a very good idea and not hard - only annoying ...


6

Don't mix different batteries! (unless you know very, very well what you are doing) The battery management system is probably going to keep them from exploding, but they will not work as intended and will probably fail quickly. If you have a balancing charger/analyser and a lot of patience, you may be able to measure the capacity of all the cells that you ...


2

I am no specialist for batteries, but after a quick query at DIN at least I would consider these 4 IEC 61959:2004 IEC 61960-3:2017 IEC 62133-2:2017 IEC 21A/690/CD:2018 EDIT: IEC standards only apply if they are 1:1 equal to EN standards. CE is European, so the EN standards apply. https://www.cen.eu/Pages/default.aspx https://www.cenelec.eu/


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