EEMB Lithium Polymer Battery 3.7V 3700mAh 103395 Lipo Rechargeable Battery Pack with Wire JST Connector for Speaker and Wireless Device- Confirm Device & Connector Polarity Before Purchase

I got this for an airsoft pistol and learned that said pistol needed higher voltage to run properly. Said pistol uses a faux extended magazine to house the battery, and this one was a reasonable fit.I'm a bit disappointed it didn't work out, but I have plans for this battery. I own and operate some 3D printers as a hobby and this battery will work great for a few LED lamp projects I have in mind, but I digress.I appreciate the fact that this battery has a built in low voltage cutoff, though I have no intention of testing it. I see a lot of folks use this for microcontroller applications though I can't comment on this battery's efficacy there.For test running LEDs with a buck converter, this battery is working great, it has a much higher capacity compared to the numerous tiny single cell Lithium batteries I have laying around, yet it's compact enough to fit in portable lights.As for the battery connector, I again can't comment. I removed the molex connector that came with this battery and soldered a Deans connector onto it's leads (after testing it on my programmable charger with the molex connector on) and I haven't had any issues.I'm very pleased with this battery, and should I ever need one like this for a future project, I'll gladly order another one.

I've used these with a DIY camera and they work great!

It’s a very long lasting battery. Got it for a project to use with Leds and stuff; it works great and lasts long

I paired this with an Adafruit LiPo charging board and the polarity was reversed on the battery compared to the charge board!!! Make sure you check the polarity of the battery input on your charge board or what ever device you are putting the battery in. You can look at the end of the JST connector and compare them like the picture shows. Swapping the polarity on the connector is really easy! Use a pick or razor blade and lift the little pin lock (red arrow points at the plastic locking tab) and then slowly pull the pin out making sure you do not short it across the other pin! Once you have them both out swap which hole it was in and just push it back into the JST connector and you will feel it snap lock into place, you can verify it locked by lightly pulling on the wire to check it. Once you have both pins back in with the correct polarity you are good to go!

Nice compact battery with connector. I changed the connector polarity by carefully removing the sockets and changing sides. I used a mini screwdriver and microscope to “unlatch” the sockets. If you are familiar with this type of connector this is fairly straightforward. If not you might want to look at the sockets on JST site to see the latch tab that holds them in. Perhaps the batteries could be shipped with the connector loose to have the polarity determined by the user. I use them for the U-Blox C099–F9P gnss rtk unit and they are great and last a long time. (Haven’t run one out yet even with half day of work)

I have oh two dozen lipo batteries with JST connectors on them. They are always the same polarity always work fine with the Adafruit, spark fun and clone chargers…. This manufacturer went rogue and have the normal +\- polarity mixed up and I found out when I plugged it in and let the magic smoke out of my adafruit charging boost board … should I have looked? Yeah maybe by now the JST Polaroty position should be pretty well cemented as a standard. I broke the JST off and used another connector and this battery works fine … just expect to make some modifications if you’re using anything standard. One star because if thr cooked $25 BOB.

Bought second as first still going strong under all loads of FPV camera (e.g. 200 mw) on a homemade transportable platform of multiple RC aircraft. Holds voltage and capacity in cold and hot Texas winter and summer temps. I use small battery charger on these and takes awhile to charge fully when drained which almost never happens. If you need longer run time with device that can manage the added weight, this is the best deal I've found.

..If you will look very closely...."as shown in the picture"....the polarity is wired into the connector WRONG for most applications.....I burnt up an Adafruit USB charger board when I hooked the battery up for an initial charge...there goes $ 7...lol...went ahead and spliced another connector on and its charging OK it seems...At this price and charge capacity I hope this battery works out to be good as I need about 4 more of them. We will see.