mechman 250amp alt and xs power d1400

[sexy 10+ year member]

^ Not quite true. Alot of cars have a threshhold in how much voltage they can handle through the ecu/bcm/ecm, etc... When an internal regulator goes bad on a stock alt your voltage can spike upwards of 18-19v in some cases. Car companies design their "computers" around this, knowing that this does happen, therefore saving the rest of the vehicles electronics when this happens. For instance, I have been running 16.5v setup in me Jeep Cherokee for 4 months now without 1 issue. I have seen about 5 other vehicles without an isolated electrical, all charging @ 16v-17v without any ecu related issues. Some things you stated are correct, such as more batteries, the more of the load on a alt. In the OP's case he has stated that he will be using a Mechman 250 alt therefore making your statement somewhat irrellavent in this case. Having (2) decent size batterys will not affect the alt as you may think it would. If it were a stock alt then it could possible be an issue for that alt to charge the batt's sufficiently

i agree that he may be ok with higher voltage but then again maybe not depends on what car he has and yes i should have said that. why would he be safer with the mechman 250 i dont know much about mechman alts.

 

[Millertime1028 10+ year member]

Not safer but more efficient considering the Mechman alt or any true high output alt, will sufficiently charge the 2 batteries without being affected by the "load" of the batts. Some stock alts can handle an extra batt or two. Some cannot and sooner or later your batteries reserve is drawn down from the current pull of the amplifiers, therefore putting a strain on the alt.