External battery charger
Now and again I use an external three stage battery charger on my two 6 volts without disconnecting the batteries from the trailer. I have not had any issues so far but was recently told not a good id...
Forum Discussion
MEXICOWANDERER wrote:
# T900XHD - Extra Heavy Duty Voltage Regulator Brush Holder Assembly for 6G Series Alternators - I-D-A Connection, 14.8 Volt Set Point
Time to become knowledgeable about ALL systems that can affect your storage battery. This particular alternator is used on ALL NEWER FORD TRUCKS but it does have three variant voltage regulators. Do you know which one your newer Ford chassis has?
I'm not quite sure what "voltage regulation" has to do with my Ford's V10 alternator. I watch what it's output voltage is all the time with a voltmeter sitting right on the cab dash.
The alternator's voltage is all over the map - around 14.4 volts or so, briefly, when starting up cold, as low as 12.90-13.10 volts when going down the road in scorching hot weather, and everywhere in between - depending upon the outside air temperature at the time and depending upon the charging/maintaining load that the engine starting battery in parallel with the coach batteries are placing on it simultaneously. The alternator seems to "magically know" the float-voltage-versus-temperature table for our RV's coach batteries and applies the proper voltage accordingly. Somebody at Ford did their homework in specifying how our particular alternator model should and shouldn't act.
Kindof like the OP, I often use an external battery charger on the RV batteries ... but use it in parallel with the coach's stock converter that is also powered up and connected to the batteries at the same time. The resultant voltage winding up on the coach batteries is a mix (depending upon internal battery and charger impedances all in parallel with each other) of the higher voltage of the external charger and the lower voltage of the RV's stock converter. Due to the stock converter's nominal 13.6 volt output "dragging down" the external chargers output a bit, the internal 12 volt items in the RV never see over-voltage when both the converter and external charger are charging the coach batteries while the coach batteries are still switched into the RV's system.
