Originally Posted by 2bold2getold
It looks like Lithium batteries need a 14.3 volts charging rate. This is a higher level than some bikes produce. My old Transalp puts out about 13.8 at it's highest point, observed. I noticed that a common problem, from reading the Transalp sites, is over charging and boiling the battery dry. The general concensus is the problem is resistance in the voltage sensing circuit to the regulator/rectifyer, and the cure is to clean all of the connectors and/ or run a new wire from the RR to the battery so there's no resistance build up. So if too much resistance to the RR causes the regulator to charge higher, then why not install a quality variable resistor in that circuit, and an accurate volt meter on the insturment pannel, so you can set the charge level at an optimium level. I suspect newer bikes have different configurations, and wouldn't allow this.
Hey Bold, Actually if it was indeed 13.8v max output and that was in fact consistent, that would be fine for an A123 based lithium battery... it does not need to be topped off at 14.4 or 14.6... the nominal voltage is 13.2v for the A123 Based packs and that is fine for the performance required of the battery, and that performance would be great at 13.2v. After a full charge up to 14.7 it will drop down into the 13.3-5 range by the next day or so, and that will still flip the bike extremely well...no one should be looking at the 14v range as the realistic operating range of the battery though it is a nice charge to point.. You want the bike to start effectively at is nominal voltage and a little below that because a majority of riders actually let the bike sit a couple days/weeks in between rides...so they really need it to work even after a little parasitic drain.
This goes back to my Power is King rule....For example...if you have an 240 CCA battery at 13.2v it will have trouble starting a bike above 1300cc.... but if you have a 360 CCA battery at 12.8v it will still flip that 1300cc bike even though its only at roughly 70% capacity... this is because it more powerful it can deliver more power with a lower state of charge.... So in fact voltage is only relevant to a certain degree itself...which I will discuss later....