Dashboard Alternator light
Hi all, The MPPT controller on my coach will deliver 14.6 volts in bulk mode which is fine. In fact it’s exactly what the specs on my GC2 house batteries call for. But when I turn on the engine and...
Forum Discussion
theoldwizard1 wrote:
I disagree !
As stated, the PCM controls the voltage. If it is not within the range of the desired voltage, the light come on. That range is very small.
Hold on. You and I are in agreement...mostly. It turns out that 14.6v is not necessarily "too high" but more like, "too high given the current conditions".
I did a bunch of reading last night and some this morning and I learned that the alternator will put out more than 14.6 volts when it's called for, like in the case of a severly depleted battery. In fact, 14.7 volts is the target of one of the tests used to determine if the alternator is good. But the PCM looks at things like battery voltage and engine RPM and if it determines that the alternator voltage is too high for the speed of the alternator and the condition of the battery, it will illuminate the charge light because it thinks the alternator or the voltage regulator is not doing its job. That's what I think my problem is. Given a fully charged battery and moderate RPMs, the PCM is concluding that 14.6 volts is out of range for the conditions at that specific time. It is mistaking solar output for alternator output.
That's my story and I'm sticking to it.
What I need to do is change the solar output voltage and see if I can turn off the light. If that works, I'll live with it. Less than ideal, but it'll be OK. What I'd like to be able to do is turn off the juice going forward to the chassis battery from the solar panels while I'm driving and only then, but that's above my pay grade.
To be continued...
