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Old 05-15-2012, 11:59 PM   #12
Antigravity OP
Gnarly Adventurer
Joined: Sep 2010
Location: Los Angeles
Oddometer: 161
Originally Posted by Mike.C View Post
Can you comment on balance charging AFAIK your batteries don't have a BMS connection and the competition all seem to think it's necessary.
Hey Mike, good question....Actually they do not have a BMS connection ( though they may call it that) they have what is called a Balance Connector ... a real BMS ( Battery maintenance System) is much more elaborate. a BMS is a circuit board that is "on-board" the battery in between the batteries cells and the final terminal connections. A BMS is a system that balances all the cells in real time, it does not allow for over discharge or over charge of the battery cells. A BMS is NOT balance charging. BMS are often used in power tools and UPS batteries. What the other companies you speak of have is a Balance Port- meaning you plug in your Balance Charger to the port and it balances the cells inside and tell you the voltage of the cells...they do not balance the battery real time while riding the vehicle as a real BMS would since it is inside the battery itself... that would be a nice feature....So yes we do not a Balance Port, but Antigravity does not agree that you need a balance port for our product.

I wouldn't put a 3-year warranty on the battery if I felt they were going to be failing because of unbalanced cells, it would be a huge loser since the cells are quite expensive.. Shorai offers a two year warranty yet claims they have a balance charger for the battery that extends the life of the battery... well why do they only warranty for 2 years? We offer a 3 year warranty and don't have balancing...I think that says something....We have an industrial strength cell that can handle long hard use without the propensity to get out of balance.

In general after the bike is started the battery is kept in a state of full charge by the bikes charging system... If the cells are going out of balance to a significant degree when in this use then they are a low-end cells that will perpetually be going out of balance because of differing rate of discharge between individual cells. If you use a world class cell like the A123 the rate of discharge and charge is very even across the individual cells because of ultra high level of quality control at the factory and because of the consistency and quality of the material used in used in production. Those are truths.

I have yet to see any of our batteiries experiance a detrimental out of balance state even after years of use...I haven't been able to catch it and test it to show that "yes" these cells are out of balance significantly and made a battery fail or affected overall performance.... and the many times we did very deep discharge testing and recharges over and over I didn't get out of balance effect that would harm the performance or damage the battery cells.

In racing they use our Antigravity Batteries a lot in "total-loss" systems I tested with some teams quite a bit. In that use they run the bike's entire electrical system/ignition off the battery... they usualy take the battery into a much lower state of discharge than a normal bike will see and they do it on every ride.... In this case i still did not note a significant or detrimental out of balance state occuring with our batteries...they would just recharge the batteries with our charger and do it again and again all season long...

The real key to battery life is keeping the battery in a higher state of charge more often than not....I don't mean on a charger but not allowing it to dip below 12v rarely if ever... this is about checking up on the battery and not storing it in the bike if the bikes has a parasitic drain and not riding for a couple months... Those are the real killers of batteries ... Funny thing is according to Shorais warranty your battery is void if you allow it to go below.. 12.6v.... Whose battery doesn't go below 12.6v at some time...

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