Shorai batteries

My C5 appears to have a finicky starter relay. Anything less than 13V and it will not engage. Since the US version of the C5 does not have a kickstarter, that means I cannot start it. Due to travel and constant rain in Louisiana in the summer, I am not riding nearly as frequently as I want. That means the Enfield sits there for long periods of time and eventually the battery voltage diminishes enough that it won't start. I thought I would solve the problem with a Battery Tender, but bafllingly, it failed to work. My theory is that it stops charging at 13V and that is not enough to engage the starter relay. I confirmed this by charging the battery with a regular battery charger instead of the Battery Tender and had no problem starting.

Then I read about Shorai batteries. These are extreme-rare lithium iron prismatic cell batteries (chemistry LiFePO4). These batteries are incredibly small and light (1.6 pounds) and claim to keep their charge for over a year. They come with a bunch of self adhesive rubber pads so you can fit it snugly in the battery box (in the right in the picture, where I also compare it with the stock Enfield battery). They are not cheap (MSRP $153). But it seems to be working as a charm. It was also nice to see Royal Enfield in the pull down menu of their website as one of the options!