theoldwizard1 wrote:
Bert the Welder wrote:
Thanks. I'll look him up and try to find the vid's. It certainly seems like having something like the DC2DC is needed for the "new" type batt's.
First, I worked for Ford designing Powertrain Control Systems for over 30 years until 2007, so I DO KNOW what I am talking about. Yes, I am sure things have changed since then and different manufacturers do things a bit different.
Second, there are really two issues here. Is the alternator capable of putting out sufficient voltage and current to charge a RV "house battery bank" (1 or more batteries wired for 12V nominal) AND are voltages directly from the alternator "optimal" for recharging a house battery bank.
Almost all vehicles built after about 2000 have some type of "smart charging" system. Theses systems are designed to only replace the amount of energy used to start the vehicle and not let addition loads cause the starting battery to discharge. In simple terms, immediately after starting, the voltage at the starting battery will be about 14V. Within about 5-10 minutes, that voltage will drop done to about 13.2V at the starting battery. Even with the heaviest gauge wire you can install, you are not going to get more than about 13.2V at your house battery bank ! This is not sufficient to recharge a house bank that is below 80% SOC !!
Different battery chemistries require different voltages for optimal and complete charging. Flooded lead acid is different than AGM is different than LiFePO4.
A DC to DC charger, install close to your RV's battery bank, will BOOST the incoming voltage and apply the correct voltage to your battery bank !
Just a question, I understand how the smart alts in the new fords work, just had to diagnose my system to find a broen monitering wire , but just trying to wrap my head around this, if you have your charging system in tact and you have your camper pluged in and the batteries are down that would put a load on the trucks batteries and then the PCM would raise the voltage output from the altanator to charge the batteries untill that load is not detected any more, meaning the batteries are fully charged. the system doesnt say it takes 800 watts to start the truck so thats all I am putting back in. the new fords use a two wire feed back and command loop to controle the altanatore output depending on the Voltage read directly from the battery. so if you conect your batteries in the camper to the truck batteries then the overall voltage will be inbetween them and if thats the case then the system will ramp up the charge untill all the batteries are charged.
now if there is an isolater in there that could change things, and a DC_DC charger is starting to sound like it is a more efficient way to go but the responce from the altanatore should be the same either way , unless I am missing somthing like an isolator or somthing but that wouldmt make sence to have that thee when it is designed as a system to charge the camper batteries or such
Steve
