Originally Posted by cyborg
Amazing the EarthX battery is much smaller than the Shorai, but then the Shorai's can have a lot of airspace above the flat-packs and the case is sized more for the expected application.
As for running heated gear, GPS , heated grips etc, as long as you don't draw more than your alternator puts out, your battery will stay charged just fine. A small panel voltmeter is all you need to tell that. If it drops below 13V or so your charging system/alternator is not keeping up with the loads on the bike, and starts to draw on the battery. If you were to ride a long way in this configuration, your battery would eventually die.
I size my loads on the bike I'm riding to always leave some overhead watts so the alternator can keep up. I don't count on any kind of battery to run my heated gear directly since they will all run down quick.
Even my Husaberg FE390 dirtbike has 200Watts out and running a Gerbings heated jacket liner, heated grips, the EFI system, GPS and my 44Watt LED headlight, I have 80+ watts left over and my alternator on that bike easily keeps the Shorai in it as fully charged as it can be. I would think BMW's have even larger alternators.
My KTM 990 (~450watts) has even more power out and has no problem keeping any battery on the bike fully charged along with EFI, heated gear, HID lights, navigation, etc. even on short rides. If you are managing your loads properly, you should basically never be drawing from your battery while the engine is running.
keep in mind we are talking about an adventure bike ... and we all know that nothing ever goes wrong in the middle of nowhere
sure would be nice to be able to crank that heavy pig of a bike over .. and over and over .... clearing that bad load of fuel out, etc.
don't know about you, but I'd want that extra amp hour capacity to deliver that reserve cranking with me.
another factor to keep in mind is LiFePO4 batteries operate on a different voltage scale as lead acid. think in terms of pressure in a pipe... meaning charging voltage has to be higher than resting voltage of battery to push a charge into battery.
depending on charge state of your battery, 13v my not be enough to charge your LiFePO4 battery back up to full.