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Description: If you need to charge LiPo batteries, this simple charger will do just that, and do it fast! The LiPo Charger Basic is stripped down of all features and just does one thing well - charge 3.7V LiPo cells at a rate of 500mA per hour. It is designed to charge single-cell Li-Ion or Li-Polymer batteries. Check the datasheet below to see if it will work with your battery.

The board incorporates a charging circuit, status LED, connector for your battery (JST-type used in the batteries we carry), and a micro-USB connector. A small mounting hole allows this charger to be easily embedded into a project.

Note: This version uses a micro-USB cable. We also have this charger with a mini-USB connection as well.

Dimensions: 29.4x10.8mm

Documents:

Comments 96 comments

  • hello, can this be used to also power a device while the battery is being charged?

    • I have the same question: Wouldn’t a connected load affect the charge profile of the battery?

        • I have the same question. Posting a link to another product doesn’t answer the question. The link you posted is more expensive and doesn’t use micro usb. I have a lot of devices that use micro usb, so i always have one on hand. No reason to pay more and carry around another cable if we can get confirmation that this will charge and power a device at the same time.

  • can anyone tell me how to change the programming resistor? do i have to seperate it from the board and find another surface mount resistor and somehow get that on?

    • It takes a bit of fine surgery on these boards but it can be done. Before you start, note that the larger version has a jumper to choose between 500mA and 100mA charging.

      The programming resistor is the single resistor next to the chip with a tiny “202” on it. You’ll need to remove it, which you can do with the edge of a soldering iron to heat up both ends simultaneously. Don’t force it or you might lift a trace (not the end of the world, but try not to).

      Once it’s gone, you’ll need to put in a new resistor. The datasheet for the chip has the formula for choosing the right value. You can replace it with a surface-mount resistor, but since most people don’t have those sitting around, you can certainly use a wire resistor.

      You should be able to see the trace that went from the resistor to the corner pin on the chip. You’ll need to connect one end of the resistor to that pin (or the pad that held the SMD resistor), and the other side to ground. Even if it’s ugly and hangs off the side, if you have a solid connection, it will work fine.

      It’s not easy, but not impossible. Good luck!

  • Description says “ charge 3.7V LiPo cells at a rate of 500mA per hour"
    Isn’t that similar to saying I was driving 55mpH per hour?
    I’m just sayin….

    • I don’t think this is being too picky. I was actually confused by “a rate of 500mA per hour”, I assumed it meant that the current drops by 500mA per hour as some kind of safety feature.

    • no 500 mA per hour is saying it charges at 500 milliamps per hour.

      • And since the ampere is a rate of current flow (coulombs per second), 14914’s analogy is perfectly valid. 500mA per hour would mean that the electron flow is accelerating by 500mA every hour. Leave it plugged in for a day, and you’ll be pulling 12 amps out of that poor USB socket! That’s obviously silly, and what the description should say is that it charges at a rate of 500mA.

  • Is the charge rate 500mA? Not sure 500mA/hr actually means anything…

  • Nice product!
    A bit of advise for those who don’t like to read datasheets…
    If you are thinking about using this to charge LiPo batteries that are less than 500mAh (like some of the ones listed below in the related products), I would suggest replacing the 2k resistor with a greater one so the current is limited appropriately.
    But like it says above, check the datasheet. You will find the current limiting equation there.
    Also check the datasheet of the battery to see what the recommended constant charge current is. They have more useful advise there too:
    “The batteries must be careful of proceed the operation for it’s soft package."
    "Short-circuit is strictly prohibited. It should damage batteries badly.”

  • Hi, I have 3 Lipo batteries in parallel making 3.7V 6000mA, please suggest will this charger works for me or any other. Thanks

  • Can this be attached to an Arduino Pro mini???

  • Just an idea, could you combine this with a NCP1400-5V Step-Up Breakout (or a 3.3v one)and a 5v low dropout regulator on the input, on one board and have connections for a battery (JST), charge input and load so you just plug the battery in and go?

  • So to confirm, it’s unwise to attempt to charge one of these - https://www.sparkfun.com/products/731 - without changing the resistor to a 40k resistor. I’m not too worried about the life of the battery, more the battery setting alight.

  • can i use the positive and output cut outs as my discharge?

  • Can I use the positive and negative holes for my project to draw power from the battery when not charging?

    • I don’t see why not - those pads are hooked up straight to the battery plug terminals. I’m not sure about doing so while also having the board connected to USB, though, since that would probably end up drawing power from the charging IC as well. But sounds like that’s not something that’s on your mind :)

  • The MCP73831T datasheet indicates the lowest regulation voltage possible is 4.2 V. Since this device is being used to charge 3.7 V batteries, doesn’t this mean that Vbatt will never reach Vreg, meaning that it will keep trying to charge the battery even after it is fully charged? Isn’t this bad for the battery?

    • Since this device is being used to charge 3.7 V batteries

      The batteries - LiPo - are only nominally 3.7V. When they’re full, they should be about 4.2V, and some charging systems willl even try to bring that up to 4.25V or even higher. If you google for “lipo discharge curve”, you’ll find images like this and this which show that while there is some variability between individual lipo cells, the curve should always be the same - from about 4.2V at full, to a fairly quick drop to about 4.0V, then a very slow drop to 3.8V, slightly faster to 3.7V, and then after that it’s like going over the edge of a waterfall.
      ( This is also why it’s always a good idea to check the power tolerances of components in a circuit where you would use a LiPo bare - or make sure to drop in a voltage regulator (be that a simple drop to 3.3V or a boost to 5V). )

  • 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)

  • Will this cut off power when a lipo battery gets below 3.2V to protect it?

    • This board has nothing on the output of the battery, and therefore can’t do anything to cut it off. However, all of our 1C (flat, silver) Lipo batteries have a protection circuit built into them that should theoretically do this.

  • How can I use this to charge a lipo battery less than 500mah such as this guy? I don’t quite understand where I’d place a resistor to reduce the current coming in from the micro USB port.

    • Email techsupport@sparkfun.com. But the short answer is you need to replace a resistor that’s already on the board.

  • I noticed there is a positive and negative terminal right in front of the JST connection. Could I use these to pull power off the battery while it’s not connected to USB? If so, what do you recommend using to make the connections? Just solder wires in?

  • Hello, I’d like to comment that the attachment of the microUSB connector is still a problem, nearly 2 years after the first concerned comments. In my case, simply picking up the charger with the cable attached exerted enough force to physically rip the connector with copper solder pads off of the PCB. Note, that this is a copper layer bonding issue, not a soldering issue. I have two small holes showing brown PCB where the copper used to be. These pads are very small (i.e. size of the microUSB solder tabs. Making them larger would improve their bond strength to the PCB material.

    • Even with that, I think it’s usually wise to use the type that has through-hole structural supports when the device itself has minimal (or no, as in this case), physical support to keep the socket in place. It’s a tad more expensive, but ripped off sockets is never a fun thing to deal with :)

  • I don’t understand why the description says ‘3.7V LiPo cells’, but the datasheet says ‘4.20V, 4.35V, 4.40V or 4.50V’ ? I just got 2 and eager to charge

    • The datasheet covers a family of parts with different peak voltage options. This board contains the 4.2V version, which is the correct peak voltage for the 3.7V Lipo cells we carry.

  • Can I just connect this to a regulated arduino pro mini?

  • I have 2 3.7 V 500mA in series (they are the exact same batteries, same age etc) can I use this to charge them?(https://www.sparkfun.com/products/10217)

    I am using this configuration to provide power to (https://www.sparkfun.com/products/11288)

    If not does spark fun sell a board with usb charging that will charge these batteries in this configuration?

    thanks,

  • UPDATE** Found what I was looking for they are called PolyZen Devices http://www.digikey.com/Web%20Export/Supplier%20Content/Tyco_8004/PDF/te-appnote-usb2-usb3-protection.pdf?redirected=1

    — original message – Any thoughts on using the MCP73831 and this circut to prevent a computers USB port from getting blown out with a short. I want to control a small motor device directly from the USB of a computer and am worried that if it stalls the load may kill the USB.

  • Hello, If I wanted to connect 2 110mAh batteries in parallel to get 220mAh, I would require a 10K resistor instead of the 2K correct? In the datasheet, there isn’t a rating for 220mAh. The max with a 10K is 110mAh. And the min. with a 2K is 450mAh. Would this still fully charge my batteries? Also, I can connect the micro usb straight to my laptop correct? My phone charger also accepts a usb, could I connect the micro end to this board and the other end into my phone charger and simply plug it in without it destroying anything?

    Thank you, Matt

  • I just had the micro-usb connector snap off of this product. I’ve only recharged my project under a dozen times. The connector snapped off while I was inserting the cable.

    Disappointed. I’ve also used the one with the mini-b usb connector, and that one has not given me any problems so far.

  • Hi, i have Polymer Lithium Ion Battery - 1000mAh (https://www.sparkfun.com/orders/530003) when i connect my battery it always red led on. how can i understand my batterry fully charged ?

  • Hi, I’m using this board with the IC MCP73831, when connected to USB port only thing it does is light the LED every 30 seconds, also if you connect the battery. the supply current is minimal, we note that not charging. know what that means?. thank you very much.

  • I saw a question from a while back about using this charger (or another sparkfun charger) to charge multiple LiPo’s simultaneously, though the question was asking about charging batteries configured in series. I’m curious if anyone has tried to use this or another charger to charge multiple batteries configured in parallel and if it did/didn’t or would/wouldn’t work. I’m also unclear as to how to compare the charging rate listed above to maximum USB load ratings (e.g. 500 mA for USB 2.0 from http://en.wikipedia.org/wiki/Universal_Serial_Bus#Power) to know if charging three parallel would even be feasible. Charging the batteries separately is just a nuisance, so any advice is appreciated! Thanks!

    • This is a single-cell charger, so it won’t work on batteries in parallel.

      • Sure it will. In fact, our larger 3.7V LiPo batteries are just multiple cells in parallel and it charges them quite well. The maximum USB current is indeed 500mA, but that only means it takes longer (our largest 3.7V LiPo, at 6Ah, takes 12h to charge).

        The only gotcha is that you’ll want all the batteries you have in parallel to be fairly closely matched. They should be the same capacity, and preferably the same age. If they’re mismatched, the charger will get false indication of full charge and won’t charge the entire stack properly.

  • A word of caution to folks: the polarity on these chargers is opposite of that of a lot of micro batteries from the RC world. E-Flite has a bunch of small batteries (100-300mAh or so) which are equipped with JST connectors that will mate with these. But, again, the polarity is reverse, so connecting a battery will cause damage to the charger and the battery.

  •  Do Not Buy This if you will be imbedding it in any project where it can't be easily removed.  
    

    The MTBF for a micro USB jack is 10,000 insertions. The poorly attacked jack on this item didn’t last even 100 uses. Now I’m stuck with a mass of nearly impossible to remove epoxy where the microUSB jack and circuit board used to be, and no realistic way to remove it without destroying the light housing.
    Seriously, do not buy this until the design is changed so the jack is properly affixed THROUGH the board so that it won’t break off instead of weak reflow that has effectively no structural shearing resistance, and will weaken with each insertion and removal until the jack breaks off the board despite the carefully applied powder doped epoxy that I used to attach it.
    Also, it fails to charge the batteries completely. It cuts out at 4.12 to 4.15 volts instead of a complete 4.2V charge.

    • As I mentioned above, I believe the connector needs 4 solder points for the frame as shown in http://www.hirose.co.jp/cataloge_hp/e24200011.pdf

      The image above http://dlnmh9ip6v2uc.cloudfront.net/images/products/10217-01.jpg shows only two solder points. It also seems that the connector is mounted too far out from the PCB edge, which is convenient for mounting in a case, but makes it even weaker.

      I added the extra two pads to my Eagle device layout and it is much more sturdy now. I am happy to send you guys my layout.

      The charge chip is a standard 4.2V chip and works well. You cannot judge the battery charge condition just by the idle voltage…

      • Have you posted your layout modification anywhere? I’d be interested in having a look.

  • Are there any issues with driving the load from the charge output of the 78831? As it senses and controls charge current (precondition etc), it would seem that an additional load would cause an incorrect charge current. Switching power via shottky / mosfet would be cleaner?

  • Could someone who’s used this board describe the behavior of the status led? Does it stay solid then go off when charged? Vice-versa? Does it blink? Thanks!

  • 100pcs order

  • Can this be made or adapted to charge multiple LI cells in series, for example to boost the 5vdc input to 12V instead of regulating down to 4.2?
    OR do you have another product that will?
    Thank you.

      1. This product will not boost 5V to 12V
      2. You do not want to charge multiple LI pacls in series unless you are very certain that they have the same characteristics including their discharge. I.e. if one pack is discharged more than the other, you’re going to run into problems. You might want to look at parallel charging instead. Hit Google :)
  • Can this be changed on the fly to charge to 4.35 Volts instead of the preset 4.2V?
    Thz,
    Barry

    • not really - the chips are hardwired for a certain voltage with different chips for the different voltages (4.2 / 4.35 / 4.4 / 4.5). So you’d really want the different chip ( MCP7383X-3 ).
      One possible - but unlikely - tweaking point might be in the following:
      4.5 Constant-Voltage Mode
      When the voltage at the Vbat pin reaches the regulation voltage, Vreg, constant voltage regulation begins. The regulation voltage is factory set to 4.2V, 4.35V, 4.40V, or 4.50V with a tolerance of ±0.75%.

      So if you could trick Vreg, you might have a shot. Seems behaviorly iffy, however.

  • I am wondering if I can use this charger to charge this battery? http://www.robotshop.com/lithium-polymer-battery.html

  • is there a way to charge 2 batteries (soldered in series) at the same time? how would that work?

  • Should the red light turn off when it’s fully charged?

    • Summary:

      • LED bright: charging
      • LED off: complete; or no battery or voltage too low

      And it does stop automatically.

      (I was hoping the comments would tell me, too. Notes below.)


      Summary of the STAT pin on the MCP73831, from table 5-1 on the datasheet. Since the cathode (-) of the LED is connected to the controller, setting the pin low turns the LED on; setting the pin high (or putting it in high-impedence mode) turns the LED off.

      • Shutdown: Hi-Z (High-impdedence mode)
      • No battery present: Hi-Z
      • Preconditioning: L (Low)
      • Constant-Current Fast Charge: L
      • Constant Voltage: L
      • Charge Complete – Standby: H (High)

      From the datasheet, this unit features “AutomaticPower-Down”.

      “”“STAT is an output for connection to an LED for charge status indication. Alternatively, a pull-up resistor can be applied for interfacing to a host microcontroller. STAT is a tri-state logic output on the MCP73831 and an open-drain output on the MCP73832.”“”

      The schematic says it’s the MCP73831. So, it should be tri-state. Further:

      “”“The charge status output of the MCP73831 has three different states: High (H), Low (L), and High-Impedance (Hi-Z). The charge status output of the MCP73832 is open-drain, and, as such, has two different states: Low (L), and High-Impedance (Hi-Z). The charge charge status output can be used to illuminate 1, 2, or tri-color LEDs.”“”

      The schematic shows that it’s connected to a single (single-color) red LED; so it doesn’t make use of the tri-state output.

  • .

  • The micro-USB connector is very fragile and snaps off very easily, and when it does snap off, it rips off the pins. You need a soldering iron with a very tiny bit to solder the relevant pins back on.

    • I had the same problem; be very careful while inserting the USB cable. I’d suggest plugging one in and leaving it in there permanently to avoid trouble.

  • Is there a solution for batteries that have a 3rd terminal for temperature monitoring?

  • I just got this charger and hooked it up to a nice project partly made of ceramics. But if I had the choice, I’d go for a Mini-USB connector (in fact, I’d order one right away). This particular Micro-USB connector has strongest link written all over it - way too strong in fact. My ceramics can’t take that, and I’m sure many others don’t build stuff out of hunks of milled titanium.

  • Any chance of offering a 4.35V option? ( MCP73831T-3ACI )
    I have some LG 2800mAh 18650 cells and want a cheaper way to charge them than a $200 bench supply.

  • Can I use this to charge 3.7v, 2200mAh Li-Poly battery?

  • Question: Can more than 100mA be drawn from a USB port without a software request?
    http://en.wikipedia.org/wiki/Universal_Serial_Bus#Power
    This would probably work with a wall-wort/USB micro charger.

    • BlackJester:

      Question: Can more than 100mA be drawn from a USB port without a software request?
      This was my thinking exactly. Has anyone tested the charge current when plugged into a PC or any software regulated cellphone charger? I recall the USB specification saying, “100 mA unless you request more” or something like that.

      • Question: Can more than 100mA be drawn from a USB port without a software request?
        Officially no, but I’ve yet to see that enforced. Watch what you do with PC USB ports as it’s not uncommon for the only current limit to be a single protection device for the whole bank of ports.

  • Hi .. is there a way to drop this to around 300ma without having to change out a smd compoment? Like maybe add an inline resistor?

  • I just want to make sure, but this will cut off charging once the lipo cell comes to 4.2 volts, correct?

  • Making my own… take a look:
    http://atomsoft.wordpress.com/2011/01/08/lipo-charger-with-3-3v-reg-output-300ma-max/

  • Has there been any issues with heat dissipation when used with larger capacity batteries? The datasheet shows much more copper around the part and connected on the bottom side to help dissipate heat. I just got one of the 2000mAh packs and was looking at this charger until I noticed that.

  • hobgoblin612:

    Just an idea, could you combine this with a NCP1400-5V Step-Up Breakout (or a 3.3v one)and a 5v low dropout regulator on the input, on one board and have connections for a battery (JST), charge input and load so you just plug the battery in and go?
    I second this - I have a project in mind, and that’s exactly what I was hoping to find in this. I want to be able to charge the end result without removing the battery.

  • 500mA? So it won’t charge PRT-08818 then. (What will?)

  • I would prefer a device that used a Mini USB instead.
    Also add in breakouts for D+ and D-. It doesn’t look like you have these but you might

    • D-/D+ = interesting idea. I’ll see what I can shoe-horn onto the next rev.

    • I would prefer a device that used a Mini USB instead.
      I can’t find the source with a quick search, but I have read that the USB-IF (usb.org) is trying to phase out the Mini-B form in favor of Micro-B. Even though it isn’t an issue here, they will no longer “certify” a device using Mini-B. Using micro instead of mini seems to be best practice.

  • What swayed your decision to use microUSB instead of miniUSB? As soon as Nokia, Sony Ericsson and Motorola started using them in their mobile phones, we had a 600% increase in charger block repairs.
    I definatly prefer the strength of the miniUSB and its not much bigger.

  • From what I understand, this will work perfectly fine with your 6Ah LiPo battery. Can someone please confirm this, because I’d hate to get a 40 dollar battery and then have a charger that didn’t work.
    If it dosen’t work with the 6Ah LiPo, can you please point me to one that will.

  • Out of curiosity, is there any particular reason why this charger uses micro-USB instead of mini-USB?
    Oh, and neat idea!

    • We’re starting to come to grips with the fact that everything is migrating to micro. It’s a shame really, but since every cellphone now ships with microUSB, we’re starting to convert some boards.

      • Everything is migrating to micro because on mini, the springs that hold the connector in the socket are on the socket. When they wear out, you have to discard the device ($$$). On micro, the springs are on the connector. When they wear out, you discard the cable ($).

      • The micro USB may be giving some people trouble because the solder pattern has only two solder points for the case. If you look ate Hirose’s catalog (e.g., Page 6), they use four solder points: http://www.hirose.co.jp/cataloge_hp/e24200011.pdf . After one of my connectors came off, I added the extra two pads to my Eagle device layout. It is much more sturdy now.

      • I haven’t really heard of Micro USB until now, but I must agree with Repurposer. My PSP, camera–Just about everything before 2010 uses mini usb that is small. Micro USB may lose because almost everyone has a mini USB cord layng around. I still am going to buy this one for its small form factor.

    • looks like you could solder the surface mount usb mini b connector instead. I prefer compatibility to compactness, in this case!

  • By the schematic this is also designed to be built into a project. very convenient :) and much smaller than the 3-cell charger you also sell

  • I didn’t see it mentioned, but it looks like this is a 4.20 Volt device. (The chip also comes in 4.35, 4.40 & 4.50 Volt options to accommodate new chemistries.)
    This should be fine for most cells currently available except LiFePO4.
    Just FYI…

    • Good point! The full part number is MCP73831T-2ACI/OTTR. You are correct - it’s the 4.2V version setup for 500mA charging.


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