Battery capacity is rated in Amp / Hrs. A larger capacity battery is like getting a larger bucket. It "holds more" and hence can supply more at a given rate of discharge. Conversely, it take longer to fill back up to full, i.e. fully recharge. I am not up to speed on the charging system (yet) and am not sure if it would be equivalent to an alternator or a generator set. [UPDATE - 13AUG 07 - We have an alternator with a fixed field (permanent magnent rotor). The stator / perm magnet rotor generates a 3 phase AC (alternating current) voltage that is rectified by the diode rectifier bridge in the R/R.]
I have an on going interest, I want to add a Big Pair of driving lights. When I turn on my front lights, I want like it to look like I am working for Speilburg FX :-) and that requires lots of Amps. Power (Watts) =I (Amps) X E (Volts) . 55W+55W = 110W; 110W / 12Volts = 9.2 Amps of additional load. A 10 Amp/Hr battery alone would only run this load for about an hour. After that the alternator set would have to handle this load, plus the standard system load.
Back on track, The alternator set is a constant voltage charging device. The Regulator / Rectifier (R/R) should maintain a maximum voltage at RPM greater than the battery voltage to the battery to charge and in effect, at that max voltage, regulate the nominal amount of current (amps) out of the bikes stator (alternator) to the system. The system, being the load, will include the battery, lights, etc. A larger capacity battery is a larger load on the alternator set, depending on its charge state. If it is fully charged, and there is minimal load on the system, the battery will greatly assist the alternator. BUT, if the battery is heavily discharged, it posses a threat of being a large load. I do not know what the "continuous current" capacity of it is, but it IS limited by the stator and the ability of the R/R to maintain this output without burning up itself or the stator windings / brushes as a result of too much load. And therein lies the rub.
The Frankenstator mod, if it increases the amperage output, will merely charge up a battery faster than the standard stator, and source more current to the system, as it has greater current output capacity. It will not damage anything unless the R/R has failed.
Addressing the Tender, in all likelihood it is a constant current source and it will only output say 1 amp/hr. Simply stated, a 7 amp/hr battery will take 7 hrs to fully charge, a 10 amp/hr battery will take 10 hrs to charge, etc. Using it should maintain the battery in a fully charged state. The limiting factors being the output rating, the capacity of the battery, and how much time you have to let it charge.
I would appreciate all leads and links to additional technical information regarding our electrical system.
Light On Dude!
Last edited by flash.sr; 08-13-2007 at 10:47 AM.