Lithiun Ion Battery Caution

Battery Tender sells Lithium Iron batteries for ATVs, motorcycles etc (not sure about automobiles), but I have a couple I use in my ATV's and they're great. They weigh a fraction of what the original lead acid batteries weigh, they hold a charge way better and last longer (I find that with limited use my ATV battery would only last 3 or 4 years, but this one I've had for at least that long and it still works great. If they get the batteries figured out for vehicles I think that would be an easy way to save 25 pounds plus and you can mount it sideways upside down etc, but with daily use, vibration etc they may not have the longevity of the classic lead acid we all use.