Pertinent Current Info on these new Super Lightweight Batteries
I'm not going to get into the details of these batteries in terms of the differences between them in electronics or the actual components they are made of. Instead of am simply going to tell you what has worked and what has not.
These new super lightweight Lithium-something batteries are taking the motorcycle industry by storm. I have been selling them commercially for several years now in the form of Ballistic, Shorai, Earth-X and Speed-Cell Brands.
As of this writing in 2014 I have stopped selling the Ballistic and Shorai brands due to multiple failures and unhappy customers. Those brands are cheaper than the Earth-X and Speedcell brands and quite frankly it appears you do get what you pay for. In addition to the flat out failures and the difficult cold starting issues that are well documented on web forums all over the place, we have ran into a lot of weird issues when using these batteries as well like pulsing dash board lights and on my personal 600F4i the Ballistic battery started go bad after about a year of use and caused the regulator/rectifer to overheat and fail. What I had noticed, but did not initially attribute to the Ballistic battery over that period when the battery was still functioning normally was the actual running of the bike was different.. The bike physically had a different feel to it in that the engine just felt a little soft, didn't quite rev as cleanly as it did with the lead acid battery and it would lope along at different engine temps during the warm-up cycle almost like it wanted to stall between 138° & 150° even though the idle would stabilize at proper operating temps. I figured this was part of the custom mapping I had just done after installing the Ballistic battery, but when the original Yuasa lead acid battery was reinstalled after the Ballistic battery failed the engine lope during the cold cycle went away completely and the bike regained its snappy throttle response with no other changes to the bike. That tells me the Ballistic Battery was somehow upsetting the electronics of the fuel injection on the F4i.
EDIT: 03/03/15 As it turns out I am not the only professional in the industry to notice electronic issues pertaining to how the bikes run with these new batteries. Very credible tuners in the global powersports manufacturing arena have also been experiencing similar issues which tells me this problem is a lot more widespread than I realized.
02/19/17 The Ballistic battery I purchased solely for testing in my wife's Track Only 1000RR got so weak after 3 years that it had to be replaced. Considering the Ballistic battery in the F4i failed in less than a year and almost took my rectifier with it I am kinda ok with 3 years of intermittent use, but it should also be pointed out that my Speedcell battery in my ZX-10R which is going on at least 4 years maybe 5 by now and has never been on a charger and is used even less than my wife's 1000RR sometimes going for months in-between starts still fires up like it was kickstarted by Zeus.
For the record I have decided to purchase a Shorai to replace the ballistic in the 1000RR. This is again solely for personal testing. So many people always tell me I am wrong because their experiences do not mimic what I have claimed here as a vendor so I want to try all these things for myself.
We've sold quite a few of the more expensive Earth-X batteries and only had one failure as of current and the same with the Speed-Cell Batteries which we have sold the most of. I am personally using the Speed-Cell batteries in all my track bikes. Including a 4 cell (.83lb) unit in my 1000RR which has never failed to start the bike in spite of how small it is. Taking into consideration that sometimes I go for months without ever firing the bike up and the fact the battery is several years old currently shows how good these batteries really are. . I am also using an 8 Cell Speed-Cell (1.5lb) in my Gen 4 ZX-10R due to its heavy reliance on electronics and it has been flawless as well. BTW I disconnected the Regulator/Rectifier recently because it is mounted to the inside of the race fairing which I had to remove to gain access to the radiator and ran the bike on battery juice long enough to open the thermostat back up and when I put it all back together it still cranked like it was brand new several weeks later when I made it back to the track.
Another key selling point to the Speed-Cell batteries is that they come with heavy duty Quick-Disconnect Fittings. Which makes replacing them or swapping them to a different bike literally a snap. The Speed-Cell batteries are the most expensive, but they also seem to be the best.
The last comment I will make and another reason why I will no longer sell the cheaper batteries is that when failures did occur I had a difficult time getting warranty replacements from Ballistic, but Speed-Cell and Earth-X were both very attentive and quick to fix their isolated issues.