New answers tagged

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You can just use enable pin of IC3 to turn off the power to the MCU. Driving the enable pin (EN) high turns on the regulator. Driving this pin low puts the regulator into shutdown mode. The TPS735 only draws a quiescent current of 45 μA when it is not enabled. So, add a switch between pins 4 and 6 of the TPS735 and add a 10k resistor and a 10nF or ...


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I had something like this come up in a job interview once. I thrashed around for a hardware-only answer (and I’m not so shabby in this area.) However, the solution they wanted to hear was have the MCU control the main power switch, and the button would ‘force’ the power on until the MCU would hold it on. They expected the user to hold the button until they ...


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Tipically the initial constant current ionizes the battery chemistry and the voltage cycle adds the potential. if the charger has no enough current thevoltage cycle may find larger resistance and thus try to push more voltage than battery requires causing trouble. Charger is supposed to have plenty of current for the initial chemistry cycle at LiPos..


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Whenever you parallel supplies, problems arise from the voltages being slightly different. With a high impedance source that can supply amps, even a few hundred uV can create large currents. The other problem is the converters themselves, they need to be parallelizable (usually by sharing the same clock or some other synchronization method). So if ...


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Assuming this is a single cell Li-Ion due to the buck converter circuit topology so you'd stop charging at a voltage within the ADC range (higher voltage would need accurate resistor divider). Charging Li-Ion batteries is a two stage process and you can find lots of info on the charging particulars online. Generally the first stage is Constant Current (CC) ...


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For Li-ion batteries you need to guarantee three things: don’t discharge below 2.8 ~ 3.0V don’t charge above 4.2V don’t exceed the battery 1C charge rate Your proposed solution really doesn’t address these items. It could damage the battery, or worse, cause the cell to catch fire. Please consider a purpose-made controller IC that’s designed for managing ...


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Generally, yes, you can build a switch-mode power supply using a microcontroller. It'll certainly be more work than just buying a dedicated controller IC, though, and your digital control scheme must take software reliability risks into account. Here, these risks are increased: if your MCU software fails for some reason, or the MCU doesn't properly power ...


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Yes you can connect two 12V batteries to a 24V alternator to charge them. You shouldn't. But you can. First thing: a 12V lead acid battery is not 12V, it's somewhere between around 11V up to around 15V, depending on its state of charge. So if your alternator puts out a static 24V, each battery (if balanced) will see 12V, and therefore will only charge to ...


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The main parameter is the charge rate, or 1C, to determine the maximum current delivered while the battery is being charged. It is important to meet this specification to ensure the battery is not damaged, and to prevent overheating or catastrophic failure. It is equally important to not exceed the maximum charge voltage of 4.2V, nor to discharge below 2.8 ...


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On the face of it, not really unless you use switches to take the batteries offline while you charge them. Now if you can use 2 chargers, and the chargers have a floating (ungrounded) output, you could connect each one across each battery. If the batteries are to be kept online ensure that the charger has current limiting and reverse-current blocking. Or, ...


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A= 100A current reg. B=12S protection cct. C= balancers. Applicable for  43V    (3.6V * 12S) lithium battery & packs 44V    (3.7V * 12S) lithium battery & packs 50.4V (4.2V * 12S) lithium battery & packs Lithium battery (Li-ion) Prismatic Lithium Polymer battery (Li-Po)   Technical Parameters: Balanced current: 60mA (VCELL = 3.90V when) ...


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You are not seeing an increase in your battery voltage for two reasons: The solar cell is NOT providing its full current/voltage capability, so your perception of 'full sunlight' is wrong. Test your solar panel on it's own and use a light meter to get some idea of the span of capability the panel has. Your ESP12F IS NOT asleep, it's just in a lower power ...


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You should be able to measure the sleep mode current draw and determine where the current is going. Always active are the L293, the LM1117 and the sleeping ESP. None of these should be close to the notional 150 mA PV input current. The most likely "rogue" load is the ESP not being in sleep mode. You MUST NEVER "float" modern NimH batteries. Older batteries ...


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You need overvoltage to charge NiMH batteries, or batteries in general for that matter. Do note where it says that constant voltage charging is not a good idea, you need to control the current. According to Wikipedia, the minimum charging voltage is 1.4V per cell so you'd need 4x1.4 = 5.6V to charge it. You should check the charging voltage to make sure it ...


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It's relatively simple. Your battery pack has a maximum wattage. bw. You source or charger needs to produce at least twice that wattage. 2bw. The circuit will charge your pack at a rate of efficiency x in time t where t is the time it takes to fully charge the pack @ x. Now the rest is vague it's been some years since they covered it in school but you ...


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Overcharging a lead-acid battery will overheat it and cause it to eventually lose its electrolyte through excessive gassing. What should happen is your charge controller should switch to a ‘topping’ or ‘float’ charge when full charge is reached. More here: https://batteryuniversity.com/learn/article/charging_the_lead_acid_battery They give a range of 2.3 ...


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Overcharging is harmful for almost any kind of batteries. It damages the electrode plates. The battery life decreases drastically. The PV cut-off should be at 13.2V. You can use 13.8V cut-off,but 13.2V cut-off will increase the battery life.


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In automotive charging systems the alternator output current is controlled by adjusting the alternator field current. The alternator regulator senses the battery voltage and adjusts the field current to keep that voltage at a suitable level to keep the batteries charged.


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Current limiting is based on the fact that I = U/R And the easiest way to reduce I (if it exceeds some limit) is to decrease U (voltage) which is what Great Scott is doing in his hacked video and explains it very well. It is also important to understand how op-amps works, since they are doing all the logic here. Typical simple DC-DC converter IC is an ...


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No, standard, "off the shelf" NiMH batteries have no electronics or monitoring system. If you want a circuit to prevent draining low batteries, look for UVLO or Under Voltage circuits or ICs. https://www.mouser.com/ds/2/268/50002561A-1102171.pdf is an application sheet for a MCP16251 One-Cell Boost Converter with an External UVLO Circuit, compromised of ...


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over pin 2 and 6 the DW01A sense the votlage drop over the FS8205, if the voltage drop is to high it will detect over current or short circuit and so on. However it's the voltage drop over the MOSFETs that sets the trip point! and the voltage drop over the mosfet varies due to that the RDS(on), varies depending on different operations modes like change in ...


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Monitoring the battery voltage The DW01A monitors the battery voltage using its power supply pins (pin 5 and 6 of DW01A ) as shown above. The comparators shown on the left side trigger in case of overcharge (battery voltage too high) or overdischarge (battery voltage too low). The battery voltage is not measured directly. There is an RC filter (R5 & ...


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Given a fixed field voltage and a rotating armature, the dynamo will produce AC, with a commutator included to produce full-wave-rectified-by-the-commutator fluctuating DC.


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The dynamo voltage isn't constant at 12VDC. It will vary depending on how fast the rotor is turning. The dynamo probably can't deliver as much current as the battery. Inverters need a lot of current. Inverters step up the voltage. If you step up to 120V and need 1A of current, your inverter will have to draw 10A of current at 12V. Even if the dynamo can ...


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Check the battery datasheet for proper voltages that are exactly correct for your battery. Otherwise use safe values. I have a commercial solar battery charger that by default overcharges the battery once per month to 15 volts to equalize the cells. Otherwise it charges it to 14 volts. These voltages can be changed from the user interface. If you use too ...


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The available charge current is determined by the capability of the outboard transistor and the CC output current. The applications section of the datasheet has typical charge circuits such as the one below: There is a guide on how to choose that transistor starting on page 15 of the datasheet which shows how to calculate the pass element power dissipation ...


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will each battery charger IC only pull the required 500mA of current from the main supply line? Yes. Will this design work, and can it scale to even larger numbers? Yes, so long as the power supply wires are thick enough to handle the current without excessive voltage drop. Would a person touching the main line risk getting electrical shock? No. ...


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To answer one small piece of your question, the component you have linked in your question will not work in the circuit you have shown. USB power is 5VDC while your calculations show you're planning on a 12VDC system, so you can't just connect the wires directly. You will need to include a 12V USB Adapter similar to this item USB Adapter. The azimuth of ...


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At Battery University, Safety Concerns with Lithium Ion (the last source, at the bottom), the following is said: ...Li-ion must not dip below 2V/cell for any length of time. Copper shunts form inside the cells that can lead to elevated self-discharge or a partial electrical short. If recharged, the cells might become unstable... Therefore, before ...


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The simplest of all implementations will be using a current sensing resistor - a very low value, high precision resistor (0.1 - 1ohm). The voltage drop across the resistor can be fed to an opamp amplifier, configured to amplify input signal to 0-5V range. You can interpret this signal on a microcontroller and using ohms law, thus print the current. There is ...


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If you want to use the same USB port as host (delivering power) and node (accepting power), you should use a connector which can act as both, e.g. micro USB. Then you will be able to use the ID pin to determine which way the current will flow on VBUS, as explained here. Relying on voltage differences between two USB supplies will lead to a situation when ...


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There is no conflicts with any examples. parallel operation is to boost currents by sharing series to charge 1 card to 1 battery from a higher voltage. arrays to combine both above You can use as many cards in parallel as long as do not exceed the source current limit. Each card has a Rprog to set say for 0.5A or 1A and USB charger hubs often support 2.4A ...


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There are several effects that can be modeled with increasing complexity, among them: Open Circuit Voltage (ideal voltage source, current unrelated to voltage) Stage of charge (tracks capacity/efficiency and has memory) Linear polarization (adds series resistance) Diffusion voltages (discharge creates polarization, and departure from Open Cell Voltage) ...


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I realized that the lipo had a protection circuit, charging it completly with a correct voltage solved the problem.


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Chargers that use the USB VBUS as power source are very sophisticated mixed-signal processors, with extended analog functions and digital controllers. Below is a typical simplified diagram of a charger IC that takes and limits the intake, charges a Li-Ion cell in accord with source capabilities and follow CC-CV charging algorithm, and provides system voltage ...


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Back in the days when people used NiCd batteries, you could buy off-the-shelf chargers that would charge them. I still have a 7.2V "racing pack" charger specifically designed for such a job. A 9V adaptor would over-charge the pack, quickly damaging either the adaptor or the battery. You would need to limit the current to no more than 400mA (C/10). ...


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Depends. If you want to charge it slowly, as stated in @hekete's answer, charge at a rate of C/10 (means 4000mA/10=400mA) for 16 hours and the charger's output voltage should be 1.4V per cell, which equals to (7.2V/1.2V) x 1.4V = 8.4VDC. But with this method, you need a mechanism (i.e. MCU, timer, etc.) to stop charging so that it does not past 16 hours. ...


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You made the battery, shouldn't you be telling us what we need in order to charge it? Typically I would say you need a 400mA constant current with a voltage of 1.41V * number of cells. You would then charge it for 16 hours with some sort of timer. At that rate it would be fairly safe regardless of discharge level, but you still don't want to leave it ...


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I found the issue and resolved it. The GATE was directly connected to the DRV pin(as mentioned in datasheet) which was creating low resistance path. But when connecting the multimeter to measure the DRV pin voltage, means some extra resistance is added to that line and it was working. So I added a 22 ohm resistor between the GATE and DRV pin which worked ...


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When I remove the ground port near the Diodes, the value read by Arduino become absurd, is there any way to measure the load current without grounding the diodes by using the similar configuration? No, not using anything similar. Think about what voltages are produced on the output of the three phase rectifier. The cathode's of D1, D2 and D3 will ...


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You need to have a reference potential somewhere, anyway. If the source is grounded, than you already have it. If it's floating, then you may attach a ground like you did. In case a source already has a connection to ground, then you have to pay attention on max. common mode voltage of difference amlpifier. The schematisc is not very clear, a clearer view ...


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The simple answer is that often they do not limit the current. If you plug your thing that charges at 2.5A into your dumb wall plug charger that only supplies 1.5A, there is a good chance it just causes the wall plug to burn out (or at least shut down). Apple has its own system where a certain voltage is present on the data pins to indicate what current the ...


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Even though DCP has "Charging" in the name it does not incorporate any charging functionality inside it. Think of the USB DCP as a 5V power supply with a maximum output current of 1.5A. The device on the other side of the cable will have its own charging controller circuitry that will limit the current and voltage that is delivered to the battery. For Li ...


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Does it really protect my digital circuit in case of Hazardous situations like lightening and others? The data sheet says this about surges: - EN55024, heavy industry level (surge L-N : 1KV), criteria A And all that means is that the unit will survive a 1 kV surge when applied to the AC lines. It doesn't mean that a surge will not produce a knock-on ...


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Thanks for the answers. Apologies for lack of clarification in the question. I will look at the MPPT charger and see if it has two outputs. Otherwise it sounds like a custom job for an electrical expert. The switch idea did occur to me Hekeke. It's probably best to rig it up, and see if there are any performance issues and take it from there.


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This really difficult to answer without a schematic of your e-bike system. But you almost certainly cannot connect your panels to the motor and expect the battery to charge. I've never seen an off the shelf e-bike that has any sort of regenerative system, I assume because the amount of recovered energy simply wouldn't be worth the bother. You could rig it ...


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Is this possible? Or will the MPPT controller sort this out? It is physically possible, but you would need a combined controller for the MPPT, battery charging, and speed control. It would be a fun project for an experienced circuit designer or two, but it's not something that you could likely make from off the shelf boxes.


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your approaches won't work – the LM7805 is so ancient, that it's voltage drop at reasonable charging currents will be > 1V (and that would be bad already if your alkaline batteries are totally fresh and not half discharged. Also, using a linear regulator in a battery-powered device is a bad idea; you'd be wasting one sixth of your energy. Use a switch-mode ...


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Lead acid 36V would have 18 cells, assuming that 12V lead acid has 6 cells. Stage2: The correct setting of the charge voltage limit is critical and ranges from 2.30V to 2.45V per cell. So 18 x 2.40 = 43,2V Stage 3: The recommended float voltage of most flooded lead acid batteries is 2.25V to 2.27V/cell., therefore 2.25 x 18 = 40.5V. Source of the ...


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I would not recommend to jury rig a charger for Li-based chemistries. Li-ion and LiFePo batteries are very sensitive to being properly charged and, due to the large energy they pack, can be disastrous if they even feel like being unkindly handled. While what you propose is safe for NiCd and NiMH chemistries, it is not for Li chemistries. If you want to build ...


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