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Old 07-07-2012, 03:14 PM   #18
Antigravity OP
Gnarly Adventurer
 
Joined: Sep 2010
Location: Los Angeles
Oddometer: 148
A few questions... [B]I answer in BOLD underline[/B]

Full DC conversion (All stator output is rectified and regulated instead of the split AC lighting / DC charging system that comes OEM)
Sorry I'm not familiar with this... but I assume someone like Baja Designs does it? So I would assume (hopefully correctly) that all would be fine with the stock charging system circuitry because there should be no reason to change they charging that is supplied to the battery. If it will in fact charge the same as the stock system then it will be fine for our Lithium.

]Questions:[*]What size are the terminal posts/bolts the 'small case' batteries? Every picture I've seen just shows the plastic coated wing-nut on the top. 6mm bolt size?
The Size is M6 but all the "Small Case" batteries come with the plastic wing nut AND a regular 6Mx10mm regular hex head flange bolt so you can use whichever one works the best for you. In addition all the small case batteries come with adhesive backed foam in the retail box..... BUT keep in mind that we make the exact YTZ7S case with our lithium packs inside too. Either a 4-cell or 8-cell, which means a direct drop in fit if you choose to use our OEM size case for the YTZ7

4-cell vs. 8-cell? I'm leaning towards a 4-cell for size/weight/cost reasons. The 450 will kick-start and run fine with no battery at all, so being stranded in the middle of nowhere isn't a huge concern. Nor is very cold weather performance, as the bike isn't going to see much action below freezing. Stator easily delivers more power when running than being consumed, so I'm not worried about drain while riding. My only real concern is simply not enough juice to start the bike consistently on the first/second/maybe third try in normal use, and prematurely killing the battery.
]The 4-cell is quite a powerfull little battery it would turn over the 450 many times, but it is more effected by cold than a battery with HIGHER cranking amps. So the 8-Cell would be a better bet if you ride in the cold more often. Additionally the 4-Cell is a tiny battery and though powerful enough to easily start the 450 it is still not the best if you have trail side emergencies like water logging your bike, or flooding it and have a problem the will require 10 repeated start attempts... so for that reason if you do MX or Race the 4-cell is great... if you expect to do longer loops, ride way out an be stuck in positions where you may need to do an "in gear" start the 8-Cell is a better choice... It is literally twice the power of the stock YTZ7 lead/acid and our 4-Cell. My four cell can start my WR many many times in a row but I'm out in Calif and do shorter loops and like you have the back up kick starter so I'm not to worried about trailside emergencies


How sensitive is the battery to excessive depletion (you list 10.5v as the do-not-go-below voltage on your web site)? What would be the result if somebody continued to try and use the electric start till it simply cranked too slowly for any hope of a start? What about if I accidentally left the lights on till full depletion? Is the battery then 100% toast? Or might it come back with stator charging with some (hopefully minor) reduced capacity?

I'm going to answer this with alot of info just so anyone reading this can understand about batteries more...

1) ALL batteries have a minimum volatge they must be maintained at or the cells themselves will be damaged and that damage shows as the lack of ability to hold a charge and the loss of power. So when we say 10.5v is the bottom line it is a generalization BUT is in fact the approximate voltage that Lithium AND Lead/Acid batteries are damaged at. So this isn't a Lithium issue... its a battery issue pertaining to Lead/Acid as well as Lithium... So if you take any battery into the 10.5v range for a period of time like a day or so the cells will be damaged. With lead/acid it can appear that you bring it back to life by having a trickle charger on it, but the fact is the cells are damaged and that battery won't start the bike if off the charger and it will be done within a couple month... But lithium is much more sensitive and if you let it hang out in 10.5v it will be damaged and just no work well at all even after a charge. So it is more sensitive to SHOWING its damaged. Lithium just doesn't perform after severe damage. Lead performs right after coming off the charge but won't hold the charge.

2) You bring up the question "what if I am starting the battery multiple times and possibly bring it down to 10.5v" That CANNOT happen actually... The batteries made for 12v system actually only operate within a small voltage range.... A dead battery in not 0 volts... it is actually roughly around 11.5v and lower. At 11.5v most bikes or cars will only get the "click". To explain it more, a lithium battery's nominal voltage is 13.2 so that is where it sits (roughly) after be charged up to 14.4 then settling back down after a couple days...... And for a lead/acid nominal voltage is 12.8v. But both of these batteries will really only produce enough amperage to start vehicles when they have ABOVE 11.8~12v ( again I'm using rough number becuase it will vary with the bike). So your bike most likely won't even start if the battery is sitting at 11.5v so you cannot damage it by starting it to below 10.5v because it won't even start the bike... BUT if you have some other drain like leaving something on that takes the battery below the 10.5v range then you can damage the battery. Hope that made sense to you. It won't be over starting it that damages it but rather a drain like heated grips, or an alarm, or power commander, leaving lights on. This are thing people usually forget about and don't ride for a while and come back to dead and damaged battery. But also keep in mind this is the same thing with Lead/Acid if you drain it below 10.5 you will have ruined it also.


If you have any other question email me at info@antigravitybatteries.com
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