Yes or No.

Is saving 22lbs worth the risk of these? Is this a stable technology or is this the bleeding edge?

I've had good experience with Lithium RC batteries but you hear that random fire story once every few years; probably a LOW probability event.

Mike

No Li for me

odyssey batteries are nearly as light and are proven in aircraft (super cubs, cessna 180 STC's, easy to install in others) and they were borne in severe vibration environments (snowmobiles etc)

I second the Odyssey Batteries, in a previous life I was one of the founders of AeroBatteries, we had the rights to distribute Hawker's Mil Spec batteries (same as Odyssey but built to tighter specs and the attachment points inside the battery are sealed in epoxy to eliminate vibration concerns in aviation). We were also in the process of taking the same batteries through PMA approval to open up the GA certified market... but the FAA had a better plan.

The Mil Spec batteries are better... albeit more expensive... and we never actually had any issues with the standard batteries.

The Odyssey PC680 will start just about anything you put it in and weighs less than 16 lbs.

Plus no concern of temp runaway and fire.

two PC680's will fit in a standard gill battery box hole, you can run them in series

i went with replacement Gill batteries when mine got tired, when these give out, i'm going to go with four 680's instead

The True Blue Power batteries are Lithium Iron Phosphate chemistry. Safer than the Lithium Ion batteries used in consumer electronics.

I use Li in my in My rattle and shake Harley. Fantastic batteries and if I could they would be in my airplane as well. The old battery wouldn't hold a charge for 3 weeks, the Li I got holds a charge for two months, there is a drain somewhere maybe the HD clock but it doesn't seem to affect the Li batt. And its as light as air. I thought they sent me an empty display demo casing it was so light.

Long ago I replaced the old corroded alum batt box with a new self fabricated unit, I am reasonably sure that if there is a fire the new metal box will be able to handle it. In a plastic airplane I would almost deem a strong metal box to be essential. Any good welder can fabricate a battery case for you with the requisite vents. I'd go SS if I had a plastic airplane. Better to cary an extra 5 pounds than to have worries about fire. Again I would have a strong metal battery box regardless if its LI or LeCid,

Max, a metal bracket isn't going to help you with a lithium ion fire- not much will

https://m.youtube.com/watch?v=Uex_O2TtTDw
Around 10:45 mark

Comparing a motorcycle to an airplane, with regards to batteries, is a bit off, pressurization cycles and temp fluctuations to name a few key points- I have seen some failures of the earthx batteries in the auto world, but a few vans guys use and enjoy them

Not worth it. Think of the altitudes you will be at and how long it would take you to get on the ground if there is an issue.

Also I think you did the AC where the condenser is mounted in the baggage area? Lightening the plane is good. But do a W&B. Taking any more weight off the nose isn't going to help you. Unless you do the light weight rudder at the same time. Which last I heard was about $9000 alone. The Lancair doesn't fly well as the CG moves aft as I'm sure you have found.
Also you and the wife with baggage aren't going to notice any performance difference by removing 20#.

They're in over 500 787s now with no problems since the fix. How many plane-hours do you need before you feel comfortable?

NOVA on PBS just did a show on batteries. A large part of the episode focused on the dangers of lithium ion batteries. After watching the fires from the lithium batteries, I would not want one on an airplane with me.

Well, now in all honesty, part of the 787 battery fix was to install a big(ger), heavier metal box for the battery to live in as well as various vents and monitoring for said battery. It was not an easy, cheap, just change the battery fix by any means.

And back to the monitoring issue, I thought that Li, NiCad and such type batteries needed a battery charging controller to control the charge rate and battery internal temp. Not just hook them up to the battery cables and you are good to go. Maybe just for the big batteries that the airlines have to deal with, I don't know about the smaller ones?

I think that you can buy discounted ones from Samsung.

Well, now in all honesty, part of the 787 battery fix was to install a big(ger), heavier metal box for the battery to live in as well as various vents and monitoring for said battery. It was not an easy, cheap, just change the battery fix by any means.

"Lithium battery" isn't a generic thing. Lots of different chemistries, controllers, etc.

Do I feel safe on a 787, yes
Do I want some random lithium battery in my plane, no.

Do I envision ever feeling happy about using that technology to fix something that really isn't a problem, no.