The ONLY reason to leave a battery on a tender is if you have a parasitic draw Lithium or otherwise.
Lithium isn't big yet but it will be.
Lead Acid is old, Eco unfriendly technology.
As the demand increases so shall the supply. As the supply increases prices, hopefully, will come down.
Lithium is green technology also. Use it up throw it in the recycle bin.
Try that with lead acid.
Lithium breaks open and nothing spills out.
Try that with lead acid.
With a properly maintained charging and electrical system a lithium battery will last up to 8 years.
Try that with lead acid.
I could go on and on.
And remember I am talking about Motorcycle batteries not the automobile industry, not old Carbon Lithium technology but the New LifePO4 technology made by A123. A123 knows there business too because they are the same company that almost went bankrupt from the older technology and all the problems, overheating/catching fire/explosions, that went with it. A123 saved themselves by developing the new LifePO4 technology.
This thread gives a much better explanation
Lithium Batteries the real scoop for 2014
If you have the money and want the best a good Lithium battery, 3 phase 40 amp charging system and charging system monitor is more than worth the money.
And seriously, who can't afford to lose a few pounds and gain some space. In lithium's case 10 pounds. Gives one the ability to rearrange their battery box and go to a completely different EHC system if they want to without trying to cram everything into a tiny space on the side of the battery.
Of course all this is just my humble opinion after spending months communicating with some of the brightest in the industry......
