"I purchased my first Antigravity Batteries Micro-Start jump start battery back in February 2015. After just over two years, April 2017, this battery failed. When I say failed I mean began to self destruct! The pack began to swell and come apart at the seams. The internal Lithium-Ion battery failed and was swelling. Yes, the same Lithium batteries that are all over the news. The same Lithium batteries that can't be in you checked luggage on an airplane or shipped via passenger aircraft. Why, because they are know to catch on fire for no apparent reason. Actually, there is usually a reason for Lithium battery failure. Most all Lithium battery failures are due to improper use or manufacturing defect. This battery was just sitting in my garage and had only been used for its intended purpose....

These Micro-Start batteries come with a 1 year warranty. The warranty requires that you register the battery within 30 days of purchase.

This is where I will give Antigravity credit, they did replace my Micro-Start after just over 2 years despite that I had not registered it. Thank you!

Let's fast forward to November 2018. The replacement battery was in constant need of charge from the time I received it. If I left it for more than a couple months it was low on charge. Apparently I let it go too long one time and now it's dead and won't take a charge. Once again I contact Antigravity, however, this time they decline to replace it! They state, "that since the unit is a replacement unit I am unable to replace it for you". They did however offer a 25% discount on a new battery. No thank you!
So if they replace a defective battery with a defective battery they no longer cover their units... Yes, the replacement battery is over one year old however, for $150 it should last longer! I opted for a $79 replacement unit from Costco. If it doesn't last more than 2 years, I won't feel as bad throwing it away!

Did they honor their warranty the first time after the warranty had expired, yes.

Do they appear to have some internal quality control issues, perhaps...

The next failure may be in your car or home and may not be so benign.
Just food for thought before you purchase one of their $150 Micro-Start batteries..."