Lithium Ion Battery - 850mAh

These are very slim, extremely light weight batteries based on the new Polymer Lithium Ion chemistry. This is the highest energy density currently in production. Each cells outputs a nominal 3.7V at 850mAh! Comes terminated with a standard 2-pin JST-PH connector - 2mm spacing between pins. These batteries require special charging. Do not attempt to charge these with anything but a specialized LiPo charger.

Battery includes built-in protection against over voltage, over current, and minimum voltage. Please use caution when using this battery in wearable projects. When using conductive thread, a short in the thread can create sparks and heat. We recommend using coin cell batteries for beginners.

Note: This battery is not available to ship to Alaska or Hawaii, or through any express services (2-day, overnight), or internationally. This is temporary! Check out our blog post for more information. Additionally orders may take longer to process and therefore do not qualify for same-day shipping. Sorry for any inconvenience this may cause!

Note: Although these cells are rated for 2C continuous discharge, the wiring and connectors are only rated up to 1A, so be sure to take that into account when determining your power requirements.

Note: Be careful with the JST connectors. They can stick in pretty good and tugging on them can damage the connector. Check this tutorial for an easy way to remove them safely.

Note: This item is non-returnable. If this item arrives damaged or is not functioning properly, please do not hesitate to contact us to see if further actions may be taken.

Weight: 18.5g (0.65oz)

  • 2C continuous discharge
  • Excellent long-term self-discharge rates (<8% per month)
  • Robust power source under extreme conditions (-25 to 60C)
  • 0.23x1.16x1.9" (5.7x29.5x48.27mm)
  • [Datasheet]( Li-polymer.pdf) (LiPo Cell)
  • Datasheet (Protection Circuit)
  • JST connector
  • [MSDS]( Ion Battery MSDS.pdf)

Lithium Ion Battery - 850mAh Product Help and Resources

Core Skill: Electrical Prototyping

If it requires power, you need to know how much, what all the pins do, and how to hook it up. You may need to reference datasheets, schematics, and know the ins and outs of electronics.

1 Electrical Prototyping

Skill Level: Noob - You don't need to reference a datasheet, but you will need to know basic power requirements.
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Looking for answers to technical questions?

We welcome your comments and suggestions below. However, if you are looking for solutions to technical questions please see our Technical Assistance page.

  • Jonathan S / about 13 years ago / 3

    Any idea when these batteries become available again? They are now already more than a month out of stock.

    • Jonathan S / about 13 years ago / 1

      Awesome! They're back in stock now!

      • Young Maker / about 13 years ago * / 2

        now their out again! :(

        • elijahparker / about 13 years ago / 2

          yep, wondering the same thing... I'm thinking of incorporating this into a design but am wondering what the future availability will be -- is SparkFun just not ordering enough at a time, or is this product actually hard to get?

          • Member #40792 / about 13 years ago / 1

            Anybody knows when this battery is going to be available again?

    • foxxjnm / about 13 years ago / 1

      I would like to know also.

  • Bret Mattingly / about 14 years ago / 3

    It might be worth pointing out to newbies that the battery needs charging when it arrives. I mean, I knew it, but others may not.
    I, too, had a battery marked 900mAh (no complaints there!), but also had trouble with the JST connectors. Hmm...Good thing I'm ditching them anyway.

    • Bret Mattingly / about 14 years ago / 2

      'Fixed' the JST by whittling off the two plastic latches on the top of the wire-side connector, then trimmed a SMALL amount off the top guide piece.

  • Member #361241 / about 10 years ago / 2

    I'm a little confused. You are limiting 2 per customer now but have you pricing tiered out to 100+ units. Please clarify this as I would like to buy more than two at a time as I have done in the past. Thanks again for caring this LiPo battery.

  • Tredlock / about 14 years ago / 2

    Anyone know of a good voltage step-up to use this to power an Arduino?

    • VirtualBoxer / about 11 years ago / 1

      This is very easy.

    • the Lilypad line uses this one which also allows a charger to be connected too. Sparkfun gives the schematics if you want to make it yourself.

  • thonycortes / about 15 years ago / 2

    It's great that is has a protection against over voltage. But how long it will be whenever i use my laptop... Is it cheaper than the old ones....?

  • AgustinGS / about 10 years ago / 1

    how do I down-regulate to 3.3V? I have looked for a suitable regulator but they all have an output current of 100mA I would greatly appreciate your help!

    • M-Short / about 10 years ago / 1

      There are plenty of regulators out there that will do more, it depends on what you are doing and how much current you need though. For example the regulators we use on the Pro Minis (really any of our 3.3V boards) should be 500mA.

      • AgustinGS / about 10 years ago / 1

        That's great to hear! I'll look at your schematics and see what I come up with 500 mA seems cutting it short a bit I think I would use 300 mA but there must be a 20% extra just in case it exceeds the calculations....

        I actually saw the regulators you had on some boards and you were using the lm1117 which have an output of 100mAh that's why I mentioned it.

        Thanks again

  • Kirk R / about 10 years ago / 1

    Hey. Is it possible to ship two of these batteries + another type? Or is the 2 limit due to air shipping?

    • Hello! If you can send an email to cservice at sparkfun dot com with the amount you'd like to purchase and where you're shipping to and we can see how many we can send per package. :)

  • Member #457326 / about 10 years ago / 1

    Can the batteries be places in series with each other? If so, would there be any possible problems with elements of the batteries such as heat, current, or problems with the surge protectors?

  • LED addict / about 11 years ago / 1

    Will this still work if it can't get 500 mA in the first place? Of course the charging rate will go down, that's okay, but if I only gave it 74.428 mA would it still charge at 74.428 mA?(I want to wire up 14 of them in parallel with only 1 Amp to share)

  • Member #434982 / about 11 years ago / 1

    does these work with el sequencer ? if no what is the best to use with el sequencer ?

  • Shifted / about 11 years ago / 1

    In case anybody is wondering, I ran an Arduino Pro 5v/16mhz for about 72 hours before the battery protection kicked in. This was bare board running the default "blinky" program with nothing but the battery connected (and about an hour of the BlueSMiRF connected).

  • Member #413079 / about 11 years ago / 1

    hello everybody, Does anybody know about a alternative because of the low availability? Im planning on using it with a MAX1555 and i need as much mAh as possible.

  • Member #399803 / about 12 years ago * / 1

    This price for these batteries is BRUTAL!!!. I JUST got a new battery for my iPod and I paid 5 bucks! On this site, they want $8.95, that's ridiculous!!!!.

    I'll just stick with my new battery and replacing battery tool kit for $5.00.

  • Member #392750 / about 12 years ago / 1

    Do these batteries carry any certification markings i.e. UL, CSA, TUV, CE etc..

  • Member #374451 / about 12 years ago / 1

    Hello all: i recently picked up three of these plus the usb charger for a school project and i have a few concerns.

    I require at least 11.1V so i need to hook up all 3 into series, my concern is both the strength of the leads and the protection circuit.

    Will i need to replace the leads with a stronger gauge of wire? Will the protection circuit allow 3 of these in series? If i was to permanently wire them in series is it still safe to use the usb charger? or should i make sure to keep the ability to charge each cell individual.

    For further information they are being used to power 4 ecs/motors on a quaqrocopter.

    • MikeGrusin / about 12 years ago / 2

      Sorry for the late reply, but FYI, these batteries are not designed for high-current-draw use such as model aircraft motors. The protection circuit built into them will limit the current draw to that shown in the datasheet (2C, which is 850mA * 2 = 1700mA). This is to prevent fires due to short circuits or overcharging. Model aircraft motors can draw huge amounts of current, which will trigger the protection circuit in these batteries.

      For these uses, we also carry special RC batteries (7.4V in several capacities, and 11.1V) that have no protection circuitry built into them. These can provide HUGE amounts of current (the 11.1V model is rated to 20C of discharge; 20 * 1500mA = 30A of current), but the burden is on you not to short or overcharge them. For these you'll need a special charger, which requires a separate 12V power supply.

      I hope this helps, good luck with your project!

      • T-1000 / about 9 years ago / 1

        Would it be possible to have 2 of these in series to create a 7.4V package? I like the dimensions of two of these stacked on top of each other compared to the bigger 7.4V batteries you sell. Also I wouldn't need a huge current draw. What chip could I use to charge such a double cell package? Something like this: for 2 cells in series would be ideal.

  • Member #364155 / about 12 years ago / 1

    This battery works as a replacement battery in the Archos 32. It is not a direct replacement. The voltage and amp/hour specs are similar and it is the same thinkness while slightly smaller in width. The battery in the Archos has three wires coming out of it from a circuit board in the plastic wrapping surrounding the battery itself. That circuit board has two tabs that connect into two flat connectors coming out of Archos 32 batttery. I kept the circuit board that was part of the original Archos 32 battery connected to the Archos, and soldered the two wires from this battery to the + and - tabs marked on the circuit board.

  • Bajaj / about 12 years ago / 1

    Hi, I'm using a 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.

  • gardnsound / about 12 years ago / 1

    By not re-stocking this, you are killing my creative output. How does singlehandedly holding up production of crazy laser-gloves make you feel, sparkfun!? Just kidding, I subscribed to auto-notify. I hope they're in stock soon!

  • Member #144094 / about 13 years ago / 1

    Just an FYI, unlike the old 900mAh batteries they used to offer, these batteries consistently test between 89-92% capacity. So at best are ~780mAh (out of ~40 of these we have tested). The old batteries similar to this over the last few years were much better, i.e., the old 900mAh battery tested at 100-104%.

  • Zefkilz / about 13 years ago / 1

    Im a noob W/ these type of Bats, im hope a peep can help :) I have a Android tablet, (Archos 32 Icecream sandwch) The battery is just like this. 3.7v 900mah 0.2C . It died, and I took the unit apart to replace the bat. Im wondering 2 things: 1. Do I need to buy the "special charger" mentioned above, or can I just cut off the tips, and attach the wires to tablet, and charge it thru its USB port in the same way the last batry was charged? 1b. EXACTLY what charger do I get? 2. Is the 850/900Mah sort of like the "storage capcity" of the battery? And nothing bad would come of it, if I get a bigger/higher one? THNX!!!

    • JRad / about 13 years ago / 1
      1. the tablet has the special charger built in, so yes you can swap the batteries

      2. Yes 850mAh is the capacity. It's fine to attach a higher/lower capacity battery (though the tablet may not be calibrated to it and may possibly show different battery levels)

  • Member #237315 / about 13 years ago * / 1


  • udawat / about 13 years ago / 1

    I have successfully used this with an Arduino FIO (MAX1555 IC). A question: How can the setup be used to drive a Servo (Power HD 1900A 9gram)?

  • Yarg_Nomis / about 13 years ago / 1

    About 827 Farads. Cheaper, but not near as fast to charge.

  • swort / about 13 years ago / 1

    Will there be stronger lepos in the future? I need more Ah.
    Like 2 aH ?

  • EliTheIceMan / about 13 years ago / 1

    Did these just change from 900mAh to 850mAh? What's up with that?

    • The manufacturer keeps switching the capacity on us. They're probably the same thing, with different labels, as the dimensions are identical. They've done this before.

  • Econaut / about 13 years ago / 1

    Estimated time of when these will return would be nice to have. If there's no hope of return I will just have to search elsewhere.

  • Paul Olson / about 13 years ago / 1

    I just received 2 of these batteries, and they are both marked 850 mAh.

  • doobie / about 14 years ago / 1

    How can I use a battery like this to power an Arduino? Also would there be a way for the Arduino to determine if the battery needed to be charged?

    • J.Sweet / about 13 years ago / 1

      I would suggest researching the Arduino's Brown-Out Detector. It can be programmed to detect when the input voltage level drops past a certain threshold and resets when it does detect this. Whenever it performs a reset due to brown-out, a special flag (BORF of the MCUSR) is set.
      Something I've done with this is always check this flag upon start-up, and if it's set, disable all other outputs (to save as much power as possible) and output to a red LED (or something similar) to indicate that the batteries need to be charged.

      • Young Maker / about 13 years ago * / 1

        That is a great idea. Now, how would one go about setting the BOD? (some code please (: )
        Edit: I need to set the Fuse bits? set them as what??

        • J.Sweet / about 13 years ago / 1

          Young Maker,
          This is the website I use to find what my fuse bits should be:

          There is an immense number of option available, I'd really suggest taking some time to wade through them; using custom fuse bits settings can allow for some really intense customization of your Arduino.
          Here is a blog that goes into some detail about to use the website and how to use avrdude to actually modify those bits in the hardware:

          The blog post is written with an ATtiny85 in mind, but the same techniques can be applied to any Atmel micro. Some of the later posts on that same blog deal with how to absolutely minimize power consumption of the micros, which is really interesting and useful for certain projects! Good luck.

          • Young Maker / about 13 years ago / 1

            Thanks ill use that in my Arduino Space invaders handheld game

  • Naturesyouth / about 14 years ago / 1

    hi is it possible to make make up 7.4 volts by placing two in series/parallel? or would this blow these up or something?

    • Like any other battery type, you need to be careful when using batteries in parallel or series. Two in series will give you ~7.4V, while in parallel will increase the "drain-time". A couple quick pointers:
      *Always use batteries of the same type and voltage level
      *Never mix batteries at different stages of charge level (i.e. one full, one half-full)
      *Always use an appropriate charger for the battery type and size
      *Never charge batteries in parallel unless you have a charge balancer
      Make sure that you are informed when you are using something potentially dangerous like Lithium-based batteries. Here are a couple quick links:
      Wikipedia: Battery
      Battery University: Serial & Parallel Battery Configurations

  • Azayles / about 14 years ago / 1

    I don't suppose I can link, say, four of these together in parallel and charge them from one lipo charger can I? Or can I? Each battery pack has its own charge level circuit built in after all.
    How would I go about using four of these in a project for the purposes of having more mAh?
    Four of these will fit nicely in the enclosure I plan to use, whereas one of the higher mAh battery packs won't.

  • AndrewLynch / about 14 years ago / 1

    When will these batteries be back in stock ?

  • pstemari / about 14 years ago / 1

    Does anyone know if the Tyco/AMP 440055-2 (Digikey A100043-ND) is compatible with this connector?
    The drawings look about the same, but the exact locations of the detents aren't shown.

    • pstemari / about 14 years ago / 1

      Answering my own question--yes, the AMP is compatible.
      Second question is whether the 2C discharge rate is accurate. The current limiting kicks in when I run a Tamiya motor box of of this, and I can't imagine that it's drawing 1.8A.

  • AndyOlivares / about 14 years ago / 1

    Is it possible to charge this baterry with a MAX1811 IC? Have anyone tried this? (The datasheet says it can charge 4.1V or 4.2V Li-Ion baterries... could it charge this one?)

    • NateB / about 14 years ago / 1

      I disagree with Tim, Im highly confident the MAX1811 would work fine. The 4.2V setting is the maximum voltage the charger will output, or rather the point at which it will enter CV (constant voltage) mode. Based on the datasheet above which lists 4.20?0.03V as the charge cutoff, Id put the MAX1811 in 4.2 mode by tying SELV to IN. The 3.7V rating is the nominal voltage, these Li cells will vary from 4.2V at full charge to 2.75V at full discharge.

    • Hi,
      Thanks for the question. We have not tried this here in Sparkfun, but I see one major problem with your specs. If it is intended to charge 4.1V or 4.2V Li-Ion batteries, these are 3.7V. I would not recommend that you charge a LiPo with a ic that is not in proper spec. You should take a look at our Max1555 charger

  • ajray / about 15 years ago / 1

    I had the same problem as robomaniac; the JST connector 'glued' itself into the LiPo USB Charger JST connectors.
    Still havent managed to get them apart, but i damaged the battery wires trying :-(
    I'll have to get some JST connectors elsewhere in order to make this usable.
    (also, my battery says 900mAh as well)

  • TheGreat837 / about 15 years ago / 1

    is it possible to charge this through the lilypad LiPower supply board?

    • It appears as though you should be able to connect a LiPo charger to pin C of the LiPower board and charge that way. The only thing standing between you and the positive terminal of the battery is a reverse-polarity protection diode.

  • The only problem I had was using those JST Right Angle Connector.
    When you completely plug the battery in those JST connector, it is very hard to get them unplug! So hard that I pull off the wire out of the battery connectors and made them useless since I rip off the small metal notch! They are literally glued together once snap in.
    I had to use a small screw driver to get them unplug.

    • domino14 / about 14 years ago / 1

      This is a common misconception about these connectors. To unplug them, you have to yank hard and quickly. If it's too slow it won't come out no matter how hard you pull on it.

  • What is the output voltage? Description says "Each cell outputs 3.7 Volts". Is it a 2 or 3 cell battery? Thx!

  • Vexer / about 15 years ago / 1

    Great battery, mine was actually 900mah.

  • BrianN / about 16 years ago / 1

    The description says "Battery includes built-in protection against over voltage, over current, and minimum voltage." Is this all the protection that is needed? Is the low-voltage protection meant to be a last resort, or can I rely on it to safely cut off the load, so that I can then recharge the battery?

Customer Reviews

4.7 out of 5

Based on 11 ratings:

Currently viewing all customer reviews.

2 of 3 found this helpful:

good deal

je suis tres heureux d'avoir trouve et recu cette batterie pour mon gps. Merci beaucoup pour cette rapide transaction

0 of 1 found this helpful:

Great little cell

This is a nice little LiPo cell and the USB charger I bought works well with this cell. As it turns out, however, I need a higher voltage so I'll need even smaller cells to connect in series. Probably three or four 300Ah cells will work.

Nice to Have a Battery with A Protection Circuit

I was sick and tired of buying poor quality cells from the RC arena. It was great to find a cell from a quality manufacturer that had a protection module. This is a quality cell, not junk sold to the RC market.

They also follow the proper shipping regulations for lithium cells. This is a good thing.

I will continue to buy cells from Spark Fun.

Works Great!

I am using this for a wearable project. It is just the right size and holds a charge for a long time.

Awesome battery

Works great!

Works great!

I had no problems incorporating this into my project, and it works as expected.

Does the job

The only issue I had was that I can only purchase two at a time. Otherwise, the battery performed admirably and per specification.

Works like a charm

Good size vs performance char.