Hi Ed,
I've already tested where the generator gets its power, and unfortunately it is tied to the chassis batteries. I say unfortunately because I'd considered installing an Automatic Generator Start (AGS) but the idea was not that appealing to me for the very reason that my coach and your coach and everybody's SMC era coach's generators start off the chassis batteries unless you rewire them to the house system.
So I was disappointed to find this out, however, the reason to choose the chassis batteries is due to their relatively "light use" when compared to the 4-6 house batteries. In today's coaches with AGS, well, that point is moot, because the generator will sense low voltage from the house batteries because that's what its tied to and then it will start automatically BEFORE the batteries get too low - so that makes sense as well.
I understand SMC's choice (no AGS included in our coaches) therefore and its the logical one - you want to split the system and be able to start the generator if the house batteries get run down while dry camping.
What nags at me is all the forum talk about this "ECM parasitic charge" even when one turns off the battery using the "disconnect switches" whose design should be to do exactly that while in storage. I believe that switch does exactly what its designed to do just like the house battery disconnect switch. There is no "EMC parasitic draw" in my SMC era coach, so I am suggesting that there might be another issue your coaches have other than the "ECM Parasitic draw" (simply because we have such similar coaches - especially the engine).
The radio has been mentioned as well, but I've replaced mine, and when the battery disconnect is used, that radio is DEAD, so that's not an issue either. Besides that design has 2 leads to the radio, one for the radio (through the ignition switch) and one to keep the memory fresh (to the battery) while the ignition switch (and radio) is off. I installed my new radio with both leads tied to the battery so that I can play it while the ignition is off, but like I said, when the battery disconnect is OFF, my radio is dead, I lose all previous settings, so there's no parasitic draw there and again I don't believe my wiring is different from other SMC era coach wiring with respect to the radio.
We can disagree over whether 11.7 is a dead battery or not, but if it starts the generator after 6 full weeks in dry and covered storage, then it bridges the system so that you can start the coach after leaving it in storage for that long period of time rather than having to have an electrical connection (and you should be exercising the generator anyway). The difference between 12V and 11.7V might be the temperature outside, or, as I've been told before, the loss of voltage from the battery to the Silverleaf (yes, I've actually had people tell me that!) indicator.
Ed, now that you've eliminated the "ECM Parasitic Charge" with your wiring mod, which I assume you did because you experienced "dead batteries" after a week or so, even with batteries disconnected, have you left your coach for up to 6 weeks in dry (batteries turn off), covered (no direct sun solar assist) storage and is the chassis battery up to 12V after that time? That would convince me that SMC 2000 and later coaches have an ECM parasitic charge issue since that would be the "control" to the experiment. In my case, after 6 weeks, and without the mod I have certainly proved the opposite, that there is no draw of this nature on my '99 Marquis.
(Full disclaimer here, I haven't looked to see if either of the previous 2 owners made any sort of modification to my coach in this regard. I only say I doubt it, due to the fact that the hurricane system was maintained so poorly that I would wonder who would make this mod while at the same time allowing a critical system to decay.)
Let me state directly what I think. I think the "ECM parasitic draw" is a myth, and I've stated why I believe this to be so. I do agree that while batteries are connected, that my batteries will run down due to the ECM within a couple of days, and therefore I do use the battery disconnect for the chassis if I know I am going to be parked without power. That being said, I'd like to see if we can "mythbust" this claim that the battery disconnect doesn't prevent this draw by having someone who's "worked around" the issue, as you have, do the experiment as I have done WITHOUT doing anything in my case. I'd guess that you use your coach a bit more often than I do, so you're not going to be able to do the experiment, but I wish someone would. Here are old post references and I've read them, and I see no documentation provided -
http://beaveramb.org/forum/index.php/topic,1369.msg9210.html#msg9210http://beaveramb.org/forum/index.php/topic,955.msg5780.html#msg5780http://beaveramb.org/forum/index.php/topic,891.msg5961.html#msg5961It's funny now, but based on these posts, and later ones, when I first got my coach, I made sure I bought storage with an available electrical connection (cost me more) so that when my chassis batteries ran down as I was now sure they would from reading the forum, I could charge them up. I drove 60 miles round trip once a week to storage and back just to check on the batteries, then lengthened that to every two weeks, then slipped up and skipped 3 weeks (still without a problem), then went to once a month just to see how long they would last, and now sort of accidently (forgot when I'd last gone until my wife showed me) left it parked for 6 weeks. All without a problem. Based on my experience, and that I don't see why the design would change between 1998 and 1999 (the build years for 1999 and 2000 coaches) that something would have changed. Personally, I think the parasitic draw might be in the solar charging system. It is documented that the when solar panels are not producing current they are actually drawing on the connected batteries, and I believe the solar charging system is attached to both batteries - might be wrong. In my case, being in covered storage, I may be getting a slight charging during the day because there is light bouncing around even in under the storage, and at night there's the draw. If someone keeps their coach totally inside, in the dark, then there is a continual draw which might, over time, draw down the batteries even with disconnect switches off because I think the solar is still connected, right?
Thanks,
Mike
