Originally Posted by Happytrails3
We are into our second season with an '06 Tiffin Allegro Bus which has been good to us thus far. I did have some trouble early on with drained chassis batteries. They would be too weak to start the bus after a few days if not disconnected after shut down. The chassis must draw some current with the key off. The coach was always plugged into power when parked. Last fall I used jumper cables to connect the house and chassis batteries thinking that the chassis batteries may as well be charging with the house batteries. We've done two short trips this spring and I've mostly left the battery banks connected. The batteries are always right up when parked plugged in and plugging in is all that needs to be done after parking to keep them that way. Of course I realize that the jumper has to be disconnected when dry camping to keep from draining all the batteries. My question is am I doing something wrong? It seems to work so good. The only attention required is to take off the jumper when dry camping. Before I had to use the disconnect every time the coach was parked.
First off, we need to analyze a couple things here. One, If you own and, know how to use it, break out your "Volt-Ohm" meter and,
1. Check the house batteries voltage with the engine off.
2. Perform the same check, with the engine running.
3. Note any differences
4. Check the chassis batteries voltage with engine off.
5. Check them with the engine running.
6. Note any differences.
The above tests will reveal just what the alternator is putting into each set, while the engine is running.
Now, basically, perform the same tests with and without, the coach being plugged into shore power. And, note any differences between plugged in and not plugged in, for both sets.
Now, you say your chassis batteries were too weak to start the engine, after "a few days", correct? Well, how many is a few days? 2, 5, 10, what? And, your coach is an '06 and you're into your second season, correct? That basically means you bought it in around '13 or, maybe late '12 sometime and, that means, it was around, 6-7 years old at the time you purchased it, semi-correct?
Now, do you know if, those are the original chassis batteries? If so, you're running on borrowed time. They may be holding what's called a "Surface charge". That is, they may start the coach just fine, if, they're in full charge state. But, if they have had ANY load on them at all, when parked, they basically will not start the coach.
If the chassis batteries HAVE been changed, either before your taking possession of it, or after, you should be in good shape in the chassis battery department. But, you're experiencing what's called "Parasitic" drain on your chassis batteries. That could be multiple things. Engine ECM, Trans TCM, clocks, Radio memories, things charging off of the chassis batteries like GPS machines, small walkie-talkies (we in the Itasca/Winnebago world have those from the factory) and, a few other possible drains.
There's also a possibility of maybe a compartment light or, set of lights that are on but, those are normally powered up by the house or coach batteries.
Now, in your tests, you will reveal if your chassis batteries are being charged by Inverter/Charger. This is of course, presuming your coach is the Diesel version Tiffin Allegro. I think there's gas versions too but, not sure. If, yours is the diesel version, you should have an Inverter/charger on board. And, that inverter/charger normally provides a charge for the house/coach batteries.
Through various additional components, i.e. BIRD system charging, or, "Trik-L-Start" or, Amp-L-Start, the chassis batteries can also be charged with the same inverter/charger. Winne and Itasca started installing the "Trik-L-Start" in or around late '05 or, early '06. Before then, quite a few Winne and Itasca owners would realize the same issue of dead chassis batteries as you have, after even some short times in storage.
I have no idea if Tiffin or, any other brand of coach, has adapted the Trik-L-Start system or, any version of it, like Winne and Itasca has. But, what I and a few others have done to alleviate the dead chassis battery issue is/was, install/hard wire a three-stage battery charger, dedicated to the chassis batteries alone. This way, it's sole duty is those batteries and, if any thing goes wrong with your inverter/charger, you'll still be receiving a charge to your chassis batteries.
So, just some ideas here for you to ponder over. Good luck.