KBT 12V 5200mAh Rechargeable Li-ion Battery, DC5521 Male Connector, Replacement Battery Pack with Charger Compatible for 12V Device RC Car, Boat, Robot, DIY, LED Light Strip, CCTV Camera

Nice battery. As others have said, no relevant instructions on charger, but research elsewhere suggested, and experience now confirms, that it's basically plug into power outlet, connect battery and wait until led on charger changes from red to green to show full charge. Battery life and longevity as yet unconfirmed.

I wondered if it would work for the M12 jacket and it does. Works great! Will update with longevity if i remember.

I have 2 of these in 2 different sizes and while they work and do charge to 12.6v they seem like they must be made from extremely old or reject cells possibly because they do not hold a charge even when not used very well. So you have to charge each time you want to use and the runtime is lackluster. These are not rated at what is claimed although I did not do a thorough test. Sadly I am going to attempt to start making my own battery packs with quality batteries because there are so many scam pack out there. Stay tuned perhaps soon I will be making custom quality packs for your devices that are as good as they can be!!!

I ordered this battery, got it quickly. Charged it up using the supplied trickle charger and noticed the input and output terminals presented the same voltage. Found their customer support email in the instructions booklet and asked if I could use either terminal to source my 2 Amp power. They answered Yes after just a few hours. Because other reviewers said NO!, I asked the seller for more details and again quickly got the confirmation I wanted. These batteries repeatedly pump out an initial 2 amps from either set of terminals for at least 2-3 hours. Powers my 12V electric gloves great, light and compact, super easy to use. I bought another battery for extended backup ‘cause the first one works so well. Hope to get good reliability too.

Using it for a motorcycle to bicycle headlight conversion and fits my application perfectly.

Battery looks well made and is working well. I like the connector arrangement. The charger is a little anemic. Takes longer than I would want. It does work fine though.

Charger get warm after 10 min.h

No information whatsoever in the poorly written pamphlet that the battery pack came with about the operation of the charger or the charging process. Sloppy, I believe, for a company that deals in a product that could potentially catch fire or start one.Output voltage is a bit over 11 V but does it have the proper capacity? Who knows? To be determined. Plugging the charger into the battery pack without plugging it into the wall yields a GREEN led. If I then plug it into the wall it turns RED. So does the RED mean it's fully charged? Who knows?I might also mention that shipping a device that can potentially deliver 5.2 Ah, charged, could be considered a risky endeavor.