Will headlights + charging house batteries overload alternator?

[Aaarrghh]

By way of background, when I installed solar, I bypassed the old inverter/converter, where the isolator probably is, so my house batteries have never been charged by the engine alternator since. Solar charging has worked fine, except for some stretches of cold dark days this winter, when I really wished the house batteries could be recharged while I was driving.
I've read a lot about different ways of isolating the starting battery from the house battery, and it seems that using a VSR (voltage sensitive relay) would be the best way to go. Now my concern is whether my alternator would suffer if my house batteries were really drained, and I was driving at night with all the lights on.
I can wire a normally-closed relay inline with the VSR, which would open when the headlights were on and cut off the charge current to the house batteries. Would this be a good idea, or just not necessary? I don't want to risk suffering an alternator failure, but maybe I shouldn't worry. What do you think?

[ClydesdaleKevin]

Almost every RV on the road is set up for the alternator to charge the house AND coach batteries while you are driving.  So what is your actual concern?  If you are worried about feedback destroying your alternator, simply switch your solar charge controller off (or disconnect it) while you are driving.  Easy peasy.  Here is what I do: 

With engine running:  Solar OFF.  Converter/charger OFF (unplugged).  Inverter OFF.

When parked with shore power:  Solar OFF.  Converter/Charger ON.  Inverter OFF.

When parked without shore power (boondocking):  Solar ON.  Converter/Charger OFF.  Inverter ON.

It really is that simple.  There is no reason to isolate your coach batteries from the alternator if you simply remember what to turn off, and what to turn on.  See above.

Kev

[Aaarrghh]

It really is that simple.  There is no reason to isolate your coach batteries from the alternator if you simply remember what to turn off, and what to turn on.  See above.

Kev

Thanks, Kev - but that sounds so complicated! I'm old and tend to forget stuff. It's got to be more simple, Y'heah?

[ClydesdaleKevin]

It can't get any simpler...lol!  Leave yourself a checklist on your steering wheel so you don't forget what to turn off or on when you are about to hit the road.   

Kev