This talk of loosing weight with a battery really appeals to me. Especially shedding, in my case, 11 pounds so easily/relatively cheaply.
Like everyone, I'm interested in performance, but not at the expense of safety, as is fire. In the research here, I'm satisfied that Lithium Iron batteries are very safe compared to all the problems with Lithium Ion.... The drawbacks on these Lithium Iron batteries sound like their touchiness to overcharge, undercharge, recharging in general and cell balance. From the sounds of it, earthworks have settled all that's bad with an internal circuit board that protects the batteries from these harmful effects.
So, I made some calls a couple days ago to the tech guys Skytec, my starter manufacturer and to Battery Mfgr Earthworks two days ago to gather some more info.
Skytec - I wanted to get a feel for how much battery is needed to run their starter. It's the hardest load item and wanted to know min batt. requirements. I said I had a cub with their starter, underseat battery, 0-320, 8.5 pistons, and composite prop. They told me the starter uses most amperage at the switch engagement. And, moving the prop the first 1/4 inch is the hardest. Energizing the permanent magnet to move takes a lot and energy draw drops significantly as the prop is moving faster and faster. And, that sounds just like many piston airplanes that spin better and faster through the start cycle. They said, dead start, at most expect around 300amps. And, it momentarily pulls most everything a battery has to offer. The online literature lists ~185-285A @ 11V, 160 RPM Test. But, I wanted to talk to them to understand it better and they were very helpful. Of note: They have a new 6 pound starter coming out this summer. Same energy draw, but lighter components. Interesting.
Then, I called Earthworks and talked about the battery and the new gen battery was ready by April 1st as reported. They said all batteries ready, just waiting on the new circuit boards and expecting them to ship by April 15th. And they clarified some technical questions. They say they've been shipping batteries to AK and other for some supercub guys. They do have a marketing arrangement where an aviation company in TX will rebrand their battery for use in experiementals. But, we can buy straight from them. There is really good info on the website, install manual, faq's etc. It's kind of loosely arranged, but I did feel like I learned enough to satisfy my questions. I think it was mentioned prices are not changing with the new generation.
This battery sits on either face, so you don't have to worry about polarity or which side you need to be positive. If you need positive on the right as I do, turn the battery over, so positive is on the correct side. Some other batteries make you specify as terminals are near the long face.
I was slightly confused at which battery to use, so I did some further research. In my case, a 2.4# battery, the 12 volt ETX24D looks good to me. I've been using an Odyssey PC625 for 2 yrs and its been good, but, I'm happy to drop the weight. This battery has my amperage requirements allowing for some wiring loss. My PC625 back compared to a Yuasa, then forward compared to Earthworks arrives at the ETX24D at $250. The PC680 guys have said the ETX32 is for them at 3.3# and $340.
That saves 11 pounds from 13.5 to 2.4.
Lastly, they asked me to email them to get on the call list for the battery to deliver. So, I'll call back and order when they notify me. They said there should be no delay to ship and not a big backlog.
I hope to report back with results.
price could be an issues at first. 
