Does anyone out there feel like a 20A DC-DC charger would somehow be too much for the alternator with the other loads or is there nothing to worry about?
Right on, but to be fair your 170A alternator is rated for 55 more amps than mine... (your engine is also almost twice the size of my 4.6L too). There would be much less concern about whether you alternator could handle that extra load with the figures I've mentioned.
Please don't speak for me.
So you think it unwise to add a 20A DC-DC charger smoothJoey? When I took the readings, I had a hunch adding a 20A charger could be too much for the alternator, but I wanted to see what the forum had to say.
Yes.
Hold on, what was the time frame when this was measured? After the discharge during starting, it will take some time to recharge the starter battery so you might want to let the vehicle run for some time.
You spoke for you, it was your recommendation to me. ?
That's a good point, I was thinking about adding a switch. Then I can use it when I'm not putting all those other loads on the alternator.
That starter battery is only a couple months old.
I took more readings with different components on and off, idling and at 2000rpm:
Based on more knowledgeable member's recommendations to leave ~30% load buffer on the alternator's amperage rating, I perceive the data as an indication that I need to either:
I can't call it.
There are much better electrical minds than mine in this forum, but from what I have read, cooling is the big issue on high loads. At low RPM, the alternator does not see much air flow so there is a tendency to overheat.
Yes, I have since found an explanation. At high rpm, the alternator generates more heat due to it's ~50% efficiency. More heat means it needs more fans for cooling, adding more load to the alternator to power the fans.
