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Description: The PowerCell board is a single cell LiPo boost converter (to 3.3V and 5V) and micro-USB charger in one.  The board comes with a JST connector for a single cell LiPo battery, a micro-USB connector for the 5V charge input, and selectable 3.3V and 5V output pins (labeled 'out'). There are also two charge pins broken out (labeled 'charge'), so you can use another 5V power source to charge the batteries, if you don't have a micro-USB cable.

We've also broken out the power-save and enable pins, so that you can have full control of the switching regulator. Keep in mind, if you keep your battery connected to the Powercell, it is recommended that you disable the switching regulator (pull EN low) in order to prevent the battery from discharging and reaching the under voltage cutoff on the battery itself. There is also an under-voltage lockout on the Powercell board which is tied to a solder jumper so that you can disable it if you like.

The micro-USB charger uses the MCP73831 and allows you to charge 3.7V LiPo cells at a rate of 100mA max. If you want to charge at a faster rate, you will need to connect a separate power supply to the pins labeled '5V' and 'GND' under the label 'charge'.  

The boost converter is based on the TPS61200 from TI and has solder jumper selectable 5V and 3.3V output, and an under voltage protection of 2.6V (which can be disabled via solder jumper on the back of the PCB).

Note: This board does not have reverse polarity protection, so please be sure to recognize the polarity of your connections!

Dimensions: 1.03 x 0.95"

Features:

  • MCP73831 Single Cell LiPo charger at 500mA
  • TPS61200 Boost Converter
  • Selectable output voltage 3.3 or 5V
  • 5V @ 600mA max
  • 3.3V @ 200mA max
  • Undervoltage lock out at 2.6V (with disable jumper)
  • Quiescent current, less than 55uA
  • JST connector for LiPo battery
  • micro-USB connector for charge power source
  • Inductor: 4.7uH, 1.2A Sumida CDRH2D18
  • Over temperature protection

Documents:

Replaces: PRT-10300

Comments 111 comments

  • I’d like to see one of these with the D+ and D- pins broken out, so the battery can charge without requiring an additional USB connector, for USB-driven battery-backed devices.

    I suppose it’d be possible to simply use the 5V in with another USB breakout board, but that seems somewhat inelegant given that there’s already a USB connector onboard.

    • I’ll second that - let it be a bit wider, but with D+ and D- broken out. Currently, the capacitor in front of micro USB connector prevents using these pins directly, and de-soldering the connector to place it on separate board is not so nice variant.

  • Sparkfun, can you please start breaking out D+ and D- on your chargers? Would be great. Smaller would also be nice.

  • Should I try to use this in a solar charging system? What happens when the input voltage drops below the minimum operating voltage when using the alternate 5v source from solar power? Side q, is using a regulator (7805) appropriate, or is there a better option for regulating the volts from solar as the 5v input for charging. Thanks anyone.

    • If you put a large cap (~10,000 uF) across the solar panel it will work much better for charging. Otherwise the current will porpoise up and down and the charger never really gets to go through it’s cycle without interruption. Adding the cap smooths out the current and stabilizes the whole system, making it much more efficient.

      Note - just use a standard electrolytic cap. Supercaps do not seem to work well for this.

    • Should I try to use this in a solar charging system?

      It’s hard to say, because every solar charging system is different and will have a unique power budget. On the Powercell, you could attach a solar cell (like the ones we sell) to the input on the MCP, but the system would only charge if the solar cell’s loaded voltage is above 3.75V. If your system only draws power for short periods of time (e.g. on for a minute a day) and your solar cell gets good sun, the Powercell should work well. But if you have much tighter power constraints then you need to boost the efficiency and use something other than the MCP charger. However the TPS regulator on the Powercell is great for low power applications since it has a low quiescent current and can take input voltages as low as 0.3V and boost it to 3.3/5V. Hopefully we’ll get some more documentation on this subject soon.

    • +1

    • I am wondering this a LOT too!!!

  • You’ve broken out PS and apparently pulled it high. That means “disabled” for PS, according to the 61200 docs, but contradicting what you’ve written in the tutorial (which is saying that both EN and PS are enabled by default). You also don’t discuss what we might want to do with PS in your tutorial. Since you’ve bothered to break it out, you must think that some people would be interested in using it… any advice on why/how? Are most people safe not using it at all?

    • Power Save Mode The Power Save (PS) pin can be used to select different operation modes. To enable Power Save mode the PS pin must be set low. Power Save mode is used to improve efficiency at light load. If Power Save mode is enabled, the converter stops operating if the average inductor current decreases below about 300 mA and the output voltage is at or above its nominal value. If the output voltage decreases below its nominal value, the device ramps up the output voltage again by starting operation using a programmed average inductor current higher than required by the current load condition. Operation can last for one or several pulses. The converter stops operating once the conditions for stopping operation are met again. The Power Save mode can be disabled by programming a high at the PS pin. In Down Conversion mode, Power Save mode is always enabled and the device cannot be forced into fixed frequency operation at light loads. The PS input supports standard logic thresholds.

      and looking at the figures on the 61200 docs it looks like it smooths out efficiency at low currents (<300ma). since i plan on using higher currents anyway my application is irrelevant.

  • Charger board very hot! I have this charger connected to a 1 cell battery (sparkfun prt-08484). I have the enable pulled to ground. I am charging the battery through the board by connecting the micro USB to a wall charger. The whole board got very hot. Tis does not seem correct. Cn anyone tell me what I adoring wrong and how to fix it?

  • Can you explain “The micro-USB charger uses the MCP73831 and allows you to charge 3.7V LiPo cells at a rate of 100mA max. If you want to charge at a faster rate, you will need to connect a separate power supply to the pins labeled ‘5V’ and ‘GND’ under the label ‘charge’. ”

    Your schematic shows A) 2KOhm on PROG, which should mean a 500ma output charge current, and B) the USB and pad inputs tied together.

    • I think Sparkfun might be referring to the fact that USB specification states that a USB slave device can’t draw more than 100ma without first enumerating the host and requesting it.

      Although many controllers aren’t spec compliant and will let a device draw whatever it wants.

  • I have a 3 cell lipo battery. Will this work? Can someone show me a product that will charge a 3 cell (each a 3.7 v and 2000mah)

  • Can I use this circuit to charge multiple Lipo’s in parallel? (All the same size, 1000mah). Thanks

  • As Member #126605 already mentioned, tying EN and PS via 10k Ohm to VBATT is not that good of an idea. A much higher resistor like 500kOhm should do it, or even better, tie the inputs via resistor to GND and add a jumper to pull it high when enabled.

    I observed a strange behaviour when starting up an Arm controller board (OLinuXino imx233): I had short voltage dropdowns to 4V or so, which led to continous restarts. Then I removed the C2 100nF cap at UVLO, which removed this behaviour. Maybe my findings help sombody and a next revision removes these flaws. I would expect a reduced responsiveness to battery voltage change with C2 installed, but the contrary seems to be true. TI datasheet (which is available in a more recent revision than here) doesn’t mention anywhere the need for filtering UVLO input.

    1. Why is the undervoltage lock out at 2.6V? Shouldn’t you stop discharging lipo cells at ~3.6 to avoid damage?

    2. After the low voltage lock out, is it safe to leave the battery in “indefinitely”? (ie, without further discharge/damage)

  • It emits a low-volume high frequency tone while charging and it is giving me a headache. Anyone else experiencing this?

  • can i use this with a 3.7 lipo and a COM-11288 heating panel or with the regs overheat?

  • A word of warning for those thinking of using the STAT line for both states. The “CHARGING” LED is connected between VIN and STAT, the “CHARGED” LED goes between STAT and GND. When the charger is not in use that leaves a couple mA quiescent drain on the battery which might be undesirable for most battery applications….

  • The USB is limited to only 100mAh in charge? Is not 500mAh?

  • I put it to charge the computer’s USB, after a while, I realized that the “MCP73831” very heated. I thought it was normal because the battery was carrying … After a while, when I recheck the charger and the led was off, I thought the battery was 100% charged, but was not, after about 15 minutes of use, the battery drain completely, then went on to charge again, and after a few hours the LED still flashing, and the battery never charged!

    So? I lost my $ 19.95 on the first day of use?

    • Sorry to hear you had trouble! Contact techsupport@ with your order number and a detailed description of exactly what happened. They should be able to help you further.

  • Can I use this to charge the following battery: PANASONIC - PA-LN19 - BATTERY, LI-ION, 1S1P, 3.7V, 2.9AH?? (http://nl.farnell.com/jsp/search/productdetail.jsp?SKU=1900168#accessories)

  • I’m trying to charge a battery (sorry, no idea how much mAh, because it is permantly covered) via USB connected to my computer, but the red light turns off after a few minutes. Whey I unplug it and try it again it turns on for less time and turns off again. This does not mean that the battery is charged, right? Because when I use the battery it only powers the devices for a few minutes. Any idea what this could be?

  • I am having a problem with this unit. When a battery is connected, no load is present AND the charge cable is disconnected, the battery is run down to almost 0v. This is terrible for (unprotected) Li-Poly cells, it ruins them and I have a couple of dead cells because of this.

    I have checked the UVLO jumper, its open, so one would assume that the under-voltage protection circuit would kick in and stop the battery from draining below 3.6/3.7v? From what I read and heard is that the booster is constantly on regardless of load and this is what drains the battery, BUT shouldn’t the under-voltage protection kick in?

    I have had to add a switch to disconnect the battery from the charger on my projects when not in use. What am I missing?

  • I thought I might be able to power an Arduino Due with this, but am skeptical after giving it a try.

    I loaded the “fade” sketch and had an 10mm LED and 220kΩ resister on pin 9, soldered the 3.3V jumper on the PowerCell, hooked up SFE’s 6Ah battery, and connected the grounds. The VCC went to the Due’s 3.3V pin.

    The results weren’t good. First, the Due’s “L” LED (associated with digital pin 13) was only sort of half-bright, when normally it is full bright with other power sources. Also, the sketch wasn’t running. The LED on pin 9 was at full bright. So I pressed the reset button and then LED on pin 9 burned out.

    Due’s regulator was bypassed using the 3.3V pin, but the PowerCell’s regulator should have taken its place. Maybe someone can explain why not. I don’t think I can use this to make a LiPo-powered Arduino – it was kind of an expensive lesson.

  • I’ve been thinking about making a portable power bank using this board alone by adding a female usb connector to the output and adjusting the D+ and D- pins with the extra resistors like in MintyBoost3. I was just wondering if the 600mA is enough for some of the modern devices or will it be a problem?? Please also advice if I’m missing something with the whole idea. Thanks

  • I used a photo Darlington (from NTE) with a 10K resistor pulled high on the collector, emitter to GND, and connected the collector to EN to make my circuit only operate after dark. So, I can charge with a solar panel during the day and run arduino lights at night automatically. I put a switch across the EN to GND connection in parallel with the Darlington so I can switch the whole thing off manually.

  • I have an Arduino Esplora that I’m going to use this with. If I run a 5V line from the Esplora to the 5V charge pin and also to the Vcc pin, will I be ok? I want the power from the Arduino’s USB connector which will be exposed to be available to charge the battery and when I disconnect it, I want the battery to take over.

    I will have a switch to allow me to turn off the system when it is not connected to USB and I know I’ll have to disable this board.

  • Hey…. Nevermind (as Rosanna, Rosanna Dana would say), I just discovered the landing page and it pretty much answered my questions! Thanks!

  • I’m A total newbie at this.. so here goes: I have a device that requires 4v minimum. The device will draw a maximum of 1A for 500ms per event. I’d like to power it with a single cell 3.7v lipo. Will the PowerCell work for this app? Thanks!

  • I plugged my lipo battery into this, and the inductor in the upper left corner started to get so hot that it melted the plastic coating on the board. I quickly unplugged the battery. After measuring with a multimeter, I discovered that the positive and negative of the connector on the board for the battery were shorted together. The battery did not get hot though, only the inductor. What could I have done wrong? Help please

    • Same thing happened to me, except it turned out that the VCC and GND pads were shorted together, and EN was pulled to ground. Can’t seem to wrap my head around it either, the EN pin worked fine on boards I bought previously.

  • The datasheet for the TPS61200 definitely says I can pull 600mA (figures 1 and 2), just at a lower efficiency of around 50-60%. Is there anything wrong/dangerous with doing this? I don’t know why you or the datasheet says 600mA when it can go higher at a lower efficiency (which is okay in my application). I am hoping to pull between 600-1000mA for no more than 2-3 minutes every 15 minutes. I really would love this board as it does the charging and boost converting in one, which is perfect in my application and don’t have time to make my own PCB.

    Need to know before I purchase. Thank you!

    • Is there anything wrong/dangerous with doing this?

      It completely depends on what you are connecting to (i.e. your load). If you are roughly powering a bunch of LEDs or maybe if your load needs 600mA for a fraction of a second, maybe the drop in efficiency won’t matter. However, if you are powering a microcontroller or if you are drawing continuous high amounts of current, you don’t want your power supply to be operating in the margins of the specification. There really isn’t a reason not to use a higher power, power supply board. They should be comparable in cost, although we don’t have one at the moment. We’re actually working on one that should support up to 3A.

      I am hoping to pull between 600-1000mA for no more than 2-3 minutes every 15 minutes.

      I would probably go with a higher power regulator board (and separate battery charger). 2-3 minutes continuous at 1A will really strain the regulator on this board.

  • Can I use this with the Polymer Lithium Ion Battery - 6Ah (PRT-08484)? I know that this says to use it for single cell only, but I wanted to make sure. Thanks!

  • How can i get it to output 5v@1000ma(1A) or more? what could i do?

    • The TPS IC is only rated to 600mA @ 5V. We don’t carry a charger and regulator combo capable of 1A. You will need to combine the battery charger and some type of regulator (here is a linear one that might work for your application).

      EDIT: I couldn’t find it initially, but we also have a beefy 6A switcher.

  • The red light will light up even there is no battery connected?

    • Correct. If you just have USB plugged in and no battery, you should see the red LED on.

  • There are a few of changes I’d like to see.

    VBATT should be available as a pin, both for powering something directly from the battery and for battery monitoring. There is a pad for it but the connection is rather hard to solder to as the hole is capped by the JST connector.

    The STAT signal should be broken out for monitoring by a CPU.

    I would eliminate the resistor pullups on EN and PS and add a solder jumper from EN to VBATT and another jumper from PS to VBATT or GND. To use either the (dis-)enable or power saving feature, the resistors draw 370 uA each when you ground one of those pins. This greatly overshadows the 55 uA quiescent current.

    Otherwise a nice, useful part

  • Hi I’m using this product with the PRT-00339 battery I disabled the UVLO on this board because the battery has it’s own… My application is running high power LEDs so I will typically drain the batteries to the point where the UVLO of the battery engages… The problem is when I plug in 5V for re-charging the charger will not begin until I unplug and re-plug the battery. This is not good because I need the battery to be pertinently connected but also recharge from dead. Is there any trick to fix that?

  • I am confused.. When I pull the EN low, does the board continue charging Li-po or shut down everything?

    Any suggestion so that I can pull low automatically at night? I am doing a solar tracker project.

  • I was thinking to use this in order to power a 3.3V circuit (no 5V around) from a LiPO battery. My problem is that I need to be able to power my circuit when I have USB connected (and this I think can be accomplished with this board) but also when there is no battery connected.

    If I tie (with a piece of wire) the VBUS to the VBATT net (TPS61200 VIN) I’m afraid that I could damage the battery. Is this correct? If yes, any idea of what could be a quick turnaround? Thanks!

    • If I tie (with a piece of wire) the VBUS to the VBATT net (TPS61200 VIN) I’m afraid that I could damage the battery. Is this correct?

      Yes, if you have the battery, USB, and VBUS to VBATT all connected, that is not good. There really isn’t an easy way to do this with the Powercell. You would need an external circuit to switch between the battery and USB supplies; similar to the one used on the Arduino Uno.

  • I just checked the unit I have received and found that it has 3.2 volts cut-off voltage, not 2.6 as written here. When battery level is below 3.2 volts there is zero at Vcc. That is very good since 3.2 volts is best cut-off voltage for battery I have.

    I still curious how that may happen.

    • OK, I see in the TPS61200 datasheet that there is a hysteresis on undervoltage lockout threshold. So, the possible scenario is following: battery discharges down to 2.6 v, the device turns off, then the battery voltage goes up to 3.2 volts since there is no load.

      Am I right?

  • How much does it weight and what is the effect on the current drawn from the battery. For example if the battery provides 250 mAh what will it be after I connect it to the power cell.

  • I have a few questions before I order. I’m sorry if they are dumb questions or if I overlooked something but I just want to make absolute sure what I am buying is what I want.

    1) What happens when the supply voltage falls below 5V? I see from the MCP datasheet that the minimum supply is 3.75V.

    2)I would also like to know what the minimum supply current is. I ask this because I am using a solar panel system as the supply source.

    3)Can you recommend a voltage regulator that I could use in conjunction with this in order to supply a constant supply voltage?

    4) Using the “charge” inputs as supply, is there any reason I could not charge the battery using this device and discharge it using a load as well?

    Thanks

    • 1) As you approach 3.75V the charger will shut off.

      2) This will depend on the state of your battery. You should look at the DC characteristics and the performance curves in the MCP datasheet for a complete description on this.

      3) There is a switching voltage regulator on this board that can supply 3.3 and 5V.

      4) Sure, that is the purpose of this board.

      See this tutorial for more information.

  • I purchased three of these for use with XBees, and moved the solder jumper to 3.3v. Of the three, one entirely failed to work, and another output 4V, destroying an XBee. Purchase this product at your own risk.

    • Please contact techsupport at sparkfun dot com. You either have defective boards or you are using the boards incorrectly. Tutorial on how to use this board can be found here.

  • Hi I was wondering if it would be possible to increase the max current output for the 3.3v to around 300mA (as stated in the TPS61200 datasheet)?

    • You might be able to get away with drawing 300mA@3.3V, depending on what you are powering. But with our testing, in general, reliable operation is around 200mA max @ 3.3V.

  • So how do I get the DRC in batch pcb to accept and not fail the pin spacing (TPS61200)?????? obviously you guys did it. Thanks

    • Check out the forums as well on the BatchPCB site-there’s a lot of great fixes posted from other users for various board errors.

    • I would contact batchPCB directly, they should be able to push it through. Also, we don’t use batchPCB for our red boards.

  • Do I constantly have to pull en low to keep the battery from discharging of can I just pull it low before I turn everything else off and it won’t discharge even without the en pin being pulled low constantly?

  • Is this product suitable for building a UPS for a Raspberry Pi? I’m thinking of using the Power Cell and a PRT-00339 1000mAH battery to provide my Pi with roughly 1 hour battery backup (hopefully much longer in sleep) in case of failure.

    What I’m actually trying to achieve is an in-car solution that sleeps (but doesn’t completely power off) the Pi whilst the vehicles ignition is off, providing a quick start-up as soon as the ignition is turned back on. I’d use a 5V 2A regulator connected to the Power Cell, connecting the Pi to the output, as soon as power is applied there should in theory be enough juice to power the Pi unabated whilst charging the battery.

    I’m hoping that I can somehow implement a power management system whereby the Pi is put into deep sleep with no ignition power and then woken up when ignition power returns, and hopefully the 1000mAH battery is strong enough to run a Pi in deep sleep + the Power Cell in power saving mode for a few days, although I can envisage jumping up to the 2000mAH equivalent.

  • From reading this description, the landing page, and the comments, this looks like the board I need to connect a solar panel (PRT-07845), battery (PRT-00341), and 3.3v arduino for an “always on” project out in the woods. The arduino code uses a lot of sleep mode and other power reservation techniques that would allow a stand alone battery to power this project by itself for months, possibly years. I want the power to be as self-sustaining as possible, so I wanted to add a solar cell to recharge the battery daily.

    I am concerned because I read the comments below that indicated that the power regulator itself can drain a battery in a few weeks even with no load. I realize that the solar panel will help with recharging the battery during the day, but during winter or long periods of overcast days, I can’t have the power regulator sucking this battery dry.

    I am a beginner, so maybe I am misunderstanding a concept here, but it seems I need to be able to make up for the draw of the power regulator with the charge of the solar panel before I even consider my project power draw. Is this correct? Is this the right path to go down for this type of project? Thanks!

    • comments below that indicated that the power regulator itself can drain a battery in a few weeks even with no load

      In the Powercell’s default state, this is true. However, if you want to shut down the regulator, you can pull the EN pin low. This will allow for little to no power draw off of the battery, if you aren’t able to charge the battery.

      • Maybe I am confused, if I turn off the regulator (pull EN low), doesn’t that turn off my arduino, assuming the battery is my primary power? My project will be using sleep mechanisms in the arduino to wake up in daily intervals, take samples, broadcast them, and then sleep. I can do that off of a 3.3v battery for a very long time. Obviously I need a regulator in the circuit somewhere to give me 3.3v instead of 3.7 with a lipo. Perhaps I just don’t understand the cost of using a power regulator.

        • if I turn off the regulator (pull EN low), doesn’t that turn off my arduino

          Yes.

          If you want to power your Arduino with a regulated voltage, you will need to have the regulator running, can’t get around that.

          If you are running at 3.3V, you should get good efficiency from the regulator. If you run at 5V, you will need to use the PS pin.

          The EN pin is good for a switch or to tie low if you just want to use the charger.

  • If my power source device generates about 6.1V, do I need to put a 5V voltage regulator before the board or does it tolerating a little over 5.5V?

    Can I use 2000mAh battery there as well?

    Thanks! :)

    • If you want to charge your battery, you can use a source up to 6V on the pins labeled charge. This value is defined in the MCP73831 datasheet

      Can I use 2000mAh battery there as well?

      The capacity doesn’t really matter, in this case, as long as it is a single cell LiPo.

  • Please with next revision, reverse the enable line (ie. via a mosfet) so that GND will turn on Switching Regulator and no connection will turn it off. This allows better power saving (no dischage through pullup resistor R2). It is also much easier to control from an Arduino.

    • Hey thanks both brian193 & a1ronzo for the tips. I feel even more silly now as I took a look at the Fio specs which has it’s own built in charger! I just hooked up my batt to the Fio and used its USB charge circuit (uses a USB micro cable that I do have..) and that got me up and running.. So I guess I didn’t over-discharge after all. I’ll have to play with THIS charger at another time, when I need to power both my uC and keep battery charged, but for now I just wanted to get up and running wireless again with my Arduino so I’ve switched my focus to my project again.

  • noob question:

    Can I charge the LiPo just using the secondary source (5V/Gnd)? I have one of those LiPo batteries (110mAH 3.7V) from sparkfun and this charger. I switched the jumper to 3.3V (although it looks like the jumper is just for the USB charging circuit) and have two wires (hi/gnd) tied to an arduino fio’s 3.3V/Gnd pins to the charger’s pins labeled for 5V/Gnd. The status LED of the booster turns on but I haven’t been able to use the battery yet. Not sure if it just takes a long time to charge this way or if the threshold voltage is not being met (maybe only works with 5V power supply??).. The arduino has a USB plug in from my PC and the board is powered up and ‘charge’ LED is turned on.. I was trying to charge this way because I didn’t realize my micro USB adapter on my cable is a different size than what is needed for the charger/booster. I’ll probably just get a proper cable for cheap, but thought I might be able to avoid that scenario..

    Thx for any feedback!

    NOTE: I had the older version charger and LiPo plugged in to that for a while and I think the battery has pretty much discharged so perhaps I need to do what Dr. Bogger did…

    • Check out the landing page for the Powercell, it should tell you exactly how to use this board. Also, we should probably throw the landing page link up there.

      If you leave your battery plugged into the Powercell as is, you will drain the battery. You should pull the EN pin low, to turn off the powercell if you are not using the battery. All of this info is on the landing page.

      Hope that helps.

    • Ha! nevermind.. description even says “use a 5V supply if you don’t have usb cable”.. Still kinda curious is 3.3V is ‘good enough’ though. Apparently not. K, I’ll get another source.

  • I used mine stock, as they came, without the LVDO jumper. I plugged in 2 brand new batteries I bought at the same time. Charged them up. Let them sit for a couple of weeks. Now the batteries are pulled down to zero, nothing, nada. I’m not overjoyed at the moment.

    • If you leave the batteries plugged in, the switcher will drain the battery to the UVLO on the battery itself. If this is the case, the battery will need to be trickle charged to get back up to a safe voltage. To prevent this, you should pull the EN pin low when not in use.

      If your batteries are taking a long time charging once they get to the UVLO on the battery, you can jump start the battery with a 3.3V supply for a second or so. This is not recommended, since LiPo batteries need to be trickle charged once they get low, so be careful. But this should allow you to quickly re-charge the battery.

      • I will occasionally bring back Lipo’s with a non-zero voltage by constant current charging them at some low value. Since these have been depleted to zero, and the batteries were less than $10 per, I don’t feel it is worth my time or the risk.

        • If you are using the LiPos we sell, the battery shouldn’t goto zero. I have drained our batteries and always was able to bring them back, at least with a low voltage/trickle charge. That being said, I am not completely sure how the battery is handling the UVLO and it never really is a good idea to bring back a LiPo that has discharged past 3V.

          • I cut into the kapton to get some measurements. Using a Fluke 179:

            • The taps going to the JST pigtail = 0.001 V

            • The larger pads which presumably go directly to the cell = 2.972 V

            So not sure what is going on with the little embedded safety circuit.

            All this being said, I bet the thing is going to work. I just need to learn some more about it, and bring the EN line into the project while it is still in the bread board stage.

            • OK, duh I got it, the safety circuit is preventing me from seeing any voltage. Presumably trickle charging will bring the cell back into a ‘safe area’, beyond some gate, and then I will see it on the JST again. Just not use to Lipos with this type of circuit. Thanks.

  • Where can I purchase the JST connector for this board?

    Am I able to safely charge multiple li-po packs? will this overcharge?

    • Where can I purchase the JST connector for this board?

      Just added it to the related items.

      Am I able to safely charge multiple li-po packs?

      No, not really, unless they are balanced like this one.

      will this overcharge?

      No, there is a cutoff on the charger IC and on all of the single cell LiPo batts we sell.

  • Is it possible (and/or advisable) to pull current from the battery and keep the Vout at the same time? I need to pull around 1-1.5 amps from lipo for maybe 1-2 secs @ 4 intervals, is this doable for this configuration? The voltage out of the battery would be acceptable (3.7-4.2) I just need more current, plus steady stream on the regulated Vout to remain intact while doing so..

    • If I understand your question correctly, you should be able to draw current from the battery, while at the same time running the switcher (Vout). You just need to make sure your battery has enough capacity, given your current draw and the C-rating of your LiPo battery (2C).

  • Mine is putting out 6.5 volts with a 3.7v LiPo and no load. I have the output going to a USB port, with straight voltage to the voltage pins, and a voltage splitter supplying 3/5 voltage to the data pins. But, my iPod (second gen Nano) refuses to charge. I think my iPod is rejecting it because of over voltage, but I thought I would check to see of anyone else has done this and had similar problems.

    • I contacted customer service, described my problem' and sent a picture of my meters reading 6.48 volts. Tech support was very fast in their reply. Not just a reply that they got my message, but a personal response that they had tested their own charger, agreed that mine seemed out of spec, and said they would send me a new one. That’s a fine example of customer service handled the right way.

    • Please contact techsupport at sparkfun dot com, they will help you with this.

  • The MCP73831 is supposed to be used to charge 4.2V LiPo cells. Is it really OK to use this to charge 3.7V cells?

    • If you look at a LiPo’s discharge curve (this isn’t one of ours, but it’s typical of the shape), you’ll see that you do charge them to 4.2V. Under use, this falls off very quickly to 3.7V, which stays fairly flat until the cell is almost depleted. Because the flat part of the curve starts at 3.7V, this is what the cell voltage is specified as.

  • This looks interesting. But why does it not have any reverse polarity on board? It already has several features, adding this would make it even better.

  • I was wondering, why is the UV lockout way down at 2.6v? Assuming you’re not discharging super fast (>1C I’d consider fast for an electronics project unless your lipo was TINY) a higher threashold of say 3.1v would seem to be a lot safer and still use >99% of capacity.

  • can you point to an example of something like this that does have polarity protection so I can compare the differences in the circuits?

  • OK I feel kind of newbish to ask this but from looking at the pictures I can not tell. Can I charge a battery and power my systems from this board at the same time?

    • Yes. For example, you can have the ‘VCC’ and ‘GND’ pins connected to your system and charge the board, with 5V, on the pins labled ‘5V’ and ‘GND’ with ‘charge’ above them.

      • And you can still have the battery connected okay? Will the battery charge if it’s set up like this? Is that what you mean by “charge the board”?

      • Can you recommend a good lipo battery that is 5v? I like the amp hours on this one http://www.sparkfun.com/products/8484 but it is only 3v output

  • Does this board solve the issue with not being able to charge the battery if the battery voltage gets too low?

    Cuz right now I am stuck with a dead battery, and a non-working system, cuz it allowed the battery to get too low, and now it wont charge the battery at all, and my circuit wont even turn on..

    • Does this board solve the issue with not being able to charge the battery if the battery voltage gets too low?

      Yes. There is a jumper labeled ‘UVLO diable’ on the back of the board, which will disable the under voltage lock out. If your battery (LiPo) has under voltage protection, it is fine to close the jumper, but if your battery doesn’t have this protection, you need an under voltage lock out at some voltage, so the battery can trickle charge.

      • I got the new board today. I disabled the UVLO by closing the jumper, and it still won’t charge my battery??

        I dont know what else to do… I need to get this system back up and running, but idk what to do..

        • What voltage are you measuring on your LiPo? You can force charge the LiPo if you use a different voltage source. Any very low current source, or an adjustable power supply, or something around 4.5vs would work fine. check the voltage of whatever wall wart you want to use.

          But LiPo is actually quite dangerous when overdischarged. It’s typically on the recharge after a very excessive discharge (

          • The LiPo Battery itsself was reading 0v, because the internal built-in UVLO in the battery was active.

            So what I did was hooked up a Multimeter to the battery wires, and with the charger hooked up to the battery, I was only reading 0.5v.. So I took a CR2032 Coin Cell Battery, and connected it parallel with the battery for a split second, that kicked the charger to start charging the battery… I watched the battery voltage slowly increase on the Multimeter. I had to re-connect the CR2032 a couple of time, cuz the charger suddenly went back to 0.5v. Once the battery was above 3v, everything went perfectly fine!

            So I’m assuming this is a fault with the MCP73831T IC.

            • Ok, so UVLO is important. If you have drained your battery enough to where the UVLO (on the battery, not the Powercell) kicks in, then you must trickle charge the battery and unfortunately, this takes a while.

              • Yes, but the UVLO on the Powercell is set at 2.6v, and the UVLOof the battery (According to the datasheet) is set at 2.75v… So the battery’s UVLO would kick-in before the one on the powercell would..Plus I let it sit to charge for over a day, and it didnt charge at all.. so idk, but what I did above did get the battery working again…

                Plus, I have a 2.5M Ohm replacement resistor on the way that I’m going to replace the default 2M Ohm with, to increase the UVLO to 3v, instead of 2.6v.

                This should help prevent this problem from happening again.

      • Could you run a system from the battery when the board isn’t powered, then charge the battery and power the board while it is powered? For example, running a system off a solar array, or a wireless battery operated prototype.

        Basically, how would you handle a senario where the power supply is frequently interrupted?

  • Thanks for the new board revision. This makes it much easier to create low-power standby modes. It would be even better if there was an easy way to remove the PS/EN pull-up resistors!

  • Thank you for adding “enable” i remember asking. It will be great if you could add LTC2950. If required I can send eagle files


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