DC Power Alternator

[JoeH]

I think my rig has the Surepower battery separator/isolator pec'd by SMB in the mid-2000s but I'm not certain if the relay closes at a specific voltage. Typically, the isolation process results in a small voltage drop as well. Never good to jam too much juice into a battery but got 9 years out of my Lifeline 4D house battery and I've now had the DCpower XP250 for 3.

It's above my pay grade but the main thing as I understand it is if the voltage drop is too large then the alternator can't charge to the capacity of the battery. So, it's continually working overtime which eventually kills the alternator. And that generates heat which doesn't help anything else under the hold like the FICM on a 6.0. Or, in my case one of the starting batteries was bad and I didn't know it and that eventually killed the stock alternator. In theory anyway.

[JoeyNick]

I did the 270 amp alternator upgrade, too.

Added 2/0 wire from the alternator to the battery, ground and fuse block. Fuse block upgraded, too.

While I was in there with half the front end pulled apart, I upgraded to an aluminum radiator, billet water pump, did a cooling system flush, added a coolant filter, put in fresh antifreeze and a new serpentine belt (I had over 150k when I did the upgrades.)

My Starcool A/C used to draw down the house batteries in the summertime, even when driving down the highway, to the point that when I parked, I would let the engine idle, with the A/C off, for ~20 minutes before I shut it down to ensure there was enough charge to restart the van. My remote start has that option so it's not like I needed to sit there and wait...

Now, it doesn't draw down at all and I'm never worried about low batteries.

[boywonder]

Originally Posted by JoeH

It's above my pay grade but the main thing as I understand it is if the voltage drop is too large then the alternator can't charge to the capacity of the battery. So, it's continually working overtime which eventually kills the alternator. In theory anyway.

I would imagine that even with an excessive voltage drop that eventually the battery would charge enough and get it's internal resistance high enough that the current would drop sufficiently to allow full voltage to the battery....

I notice on my battery monitor that when I plug into shore power and the batteries are above say 90% charged the current flowing is like 5 amps...

As mentioned above, if someone above my pay grade can explain why this isn't the case, please share your thoughts here. I suppose that if the voltage drop is really high the battery will never charge.....I'm thinking excessive voltage drops still have the voltage at the battery above say 13VDC or perhaps more, but less than the absorb charge voltage that the battery would like to see.

[TheWooginator]

UPDATE: So I've been running the 270xp for a little while now and shortly after I installed it, I started getting a current leak somewhere in the system that was draining the starter batts fairly quickly. I called up DC Power and had someone on the phone immediately (awesome customer service) and he helped me figure out what part of my problem was at least. In my adventure to get it installed I had to swap the harness plug to make things work and I had the wires in the plug backwards; the voltage sensing line was tied to the ignition line, so it basically always kept the field windings "ON", regardless of the ignition state. Oops. Note to self, double check that in the future. Got that fixed and still had trouble starting. Swapped to new batteries for the starter batts and that seems to have solved my problems for now. I also installed a two way separator so the shore power will charge the starter batts as well as the house batts.

1.21 GIGAWATTS!!