Tom, here it is:
http://www.faa.gov/about/office_org...fo/media/airline_passengers_and_batteries.pdf
Scroll down to the table on page 2, it's easier to read. Your document is about spare batteries only, but it says same thing - max 2 larger batteries.
"Spares must be carried in carry-on baggage only" means that spares must be carried-on. You can't have spares in checked-in luggage. Doesn't mean that you can't have equipment with larger Li batts in carry-on. Refer to the Table where it says Yes or No.
Technically, it doesn't limit the number of 100-160WH batts in devices when it's carried-on, but this is of little use to you because they won't let you carry an ebike on.
20 or unlimited number of Li batteries refers to small batteries like laptop etc.
Again, airlines are not authorized to increase the limits - they can only approve what FAA had already approved. They can also disapprove it.
I am taking a 48V powered hub and renting a bike to install it on. I agree you cannot take typical ebike batteries. You can take 4 -12V lithium batteries and run them is series. to make a 48V battery
All of my batteries are under 100 Watt Hours. That is the criteria. They use laptops as an example, not as a limiter. The restriction is 100 watt hours or less and all of mine are.
The one exception I saw was for wheelchairs - up to 300 watt hours.
They allow battery packs as carry on. See 18.iv below.
I'm following the regulations and won't have any problems as long as I carry it on as 12V batteries and the terminals are protected.
From the actual regulations
https://www.ecfr.gov/cgi-bin/retrie...&ty=HTML&h=L&r=SECTION&n=49y2.1.1.3.12.1.25.5
(18) Except as provided in §173.21 of this subchapter, portable electronic devices (e.g., watches, calculating machines, cameras, cellular phones, laptop and notebook computers, camcorders, medical devices etc.) containing dry cells or dry batteries (including lithium cells or batteries) and spare dry cells or batteries for these devices, when carried by passengers or crew members for personal use. Portable electronic devices powered by lithium batteries may be carried in either checked or carry-on baggage. Spare lithium batteries must be carried in carry-on baggage only. Each installed or spare lithium battery must be of a type proven to meet the requirements of each test in the UN Manual of Tests and Criteria, Part III, Sub-section 38.3 and each spare lithium battery must be individually protected so as to prevent short circuits (e.g., by placement in original retail packaging, by otherwise insulating terminals by taping over exposed terminals, or placing each battery in a separate plastic bag or protective pouch). In addition, each installed or spare lithium battery must not exceed the following:
(i) For a lithium metal battery, a lithium content of not more than 2 grams per battery; or
(ii)
For a lithium ion battery, the Watt-hour rating must not exceed 100 Wh. With the approval of the operator, portable electronic devices may contain lithium ion batteries exceeding 100 Wh, but not exceeding 160 Wh and no more than two individually protected lithium ion batteries each exceeding 100 Wh, but not exceeding 160 Wh, may be carried per person as spare batteries in carry-on baggage.
(iii) For a non-spillable battery, the battery and equipment must conform to §173.159a(d). Each battery must not exceed a voltage greater than 12 volts and a watt-hour rating of not more than 100 Wh. No more than two individually protected spare batteries may be carried. Such equipment and spare batteries must be carried in checked or carry-on baggage.
(iv) Articles containing lithium metal or lithium ion cells or batteries the primary purpose of which is to provide power to another device must be carried as spare batteries in accordance with the provisions of this paragraph.
