You did ask :smile2:
A typical thyristor based R/R will produce 13.5-14.5V if it's healthy... And in semi healthy condition usually 13.2-14.8V... But depending on the temperature in the R/R, RPM and how fast the RPM changes it will swing wildly between these values at random...
A MOSFET based R/R in new condition usually provides 13.5-14.5V, and in semi healthy condition (which takes about 20-30 times longer than the thyristor's to age into) the same 13.2-14.8V...
But... And that's a pretty important but... The MOSFET R/R tends to go towards middle voltage at just off idle RPM, and then towards lower voltage at high RPM, with only small peaks towards higher voltage usually when the RPM's change... Also the swings are slower, more controlled...
A SLA want's 13.8-14V or soo to charge, a GEL usually want's 14.1-14.2V to charge... Most SLA's "boil" and get reduced lifetime if the spend to much time above roughly 14.2V, same goes for GEL's at 14.5V... Drop to low and they simple stop charging... Just below optimal charging and you get "maintainance mode" as in most chargers...
This means that as long as the battery is in good condition it has no problems coping with a semi reliable R/R of either type... But a thyristor based R/R will age it sooner, and ages itself sooner... And then you get problems...
A MOSFET based R/R keeps the battery lasting longer, keeps the voltage more constant, which is good for the ECU/CDI, the electronics in the gauges, the fuses and also keeps the lightbulbs in your headlight happy since it likes just above 14V to make peak light output (provided you have decent wiring too it)...
Both types will make fireworks and smoke when the battery boils over if a diode in the rectifier decides to go wide open, and both will stop charging the battery if it fuses... But a MOSFET Regulator takes a very, very long time to go "bad" enough to create the heat needed for damaging the rectifier diodes... corroded connectors are obviously something that affects both equally in terms of resistance/heat...
Now for the LiFePo's... They like to be charged at 13.6-14.4V, and optimally at around 13.8V... They highly dislike going above 14.4V since that charges them very rapidly with no real way for them to dissapate the heat, and charging to much at lower than 13.4V will build up internal resistance which reduces lifetime...
So a thyristor based R/R in peak condition will work decently... but only in peak condition... A MOSFET one will work even in semi decent condition since it rarely peaks and if it does it's a short time... It might reduce lifetime, but it's unlikely to blow stuff up...
