Auto Start Malfunction

[Dash]

, I have a 2021 Tellaro 20 LT. My AutoStart has never worked correctly. When you place the RV in monitor mode, the engine starts when the battery charge is above the trip point of 40%. It should only start the engine when the charge on the coach lithium batteries falls below 40%. It will even start the engine when the lithium batteries are charged 100%. Has anyone else experienced this problem? If so do you know what was done to fix the problem?

I’ve had the RV in the shop twice and worked directly with the component vendors (Mastervolt and Intermotive) and Thor and have not been able to get the problem resolved. The engine start seems to be triggering off of the voltage of the Dodge chasis battery - when that drops below 11.9 V. According to Thor Technical Support the system is not supposed to trigger off of the Dodge chassis battery but that seems to be what is happening on my RV. According to the technical support staff I have talked to, the most likely reason the AutoStart module is not working correctly is that it is either not configured correctly or not wired correctly.

[16ACE27]

Why is your chassis battery getting so low?

[Dash]

Good question - I asked the repair shop to look into why there is a draw down on the chassis battery. One thing I have noticed is that when I put the key in the ignition and press the button to place the RV in Monitor Mode there is a draw down on the battery. Normal voltage for the chassis battery is about 12.2V and the battery will draw down to as low as 11.7 when placing in Monitor Mode. This then seems to trigger the Auto-Start. I have also noticed the voltage dropping to about 11.8V overnight. So I drive the RV in the afternoon and park it - next morning chassis battery is low. No issues with the coach lithium batteries voltage.

Repair shop thought it could be because the Auto-Start module was wired incorrectly.

Regardless, my understanding is that Auto-Start is not supposed to be triggered off the chassis battery. What I don’t know is how Thor keeps that from happening because the Intermotive CWIN752 Auto Start module they use that works with the Mastervolt components does consider the voltage on the chassis battery.

[The Gritz Carlton]

Were the original batteries in the coach lithium? Could it be the two different type batteries don't know how to play together?

[Lt Keefer]

Originally Posted by Dash

What I don’t know is how Thor keeps that from happening because the Intermotive CWIN752 Auto Start module they use that works with the Mastervolt components does consider the voltage on the chassis battery.

Based on this line, it would seem your system is operating properly. Does the system draw it's power from the chassis battery? Is that draw within the specs of the components? Should the system draw from the coach batteries?

[Dash]

If you believe Thor Technical Support and the Thor Manual the system is not operating correctly. It is really tough to get someone at Thor Motor Coach who is knowledgeable about the AutoStart system. Half the time I have called in the person doesn’t even know what the feature is. If I get lucky and get someone who knows what the feature is, they say they don’t have access to technical information such as how the system should be configured. I called 12 service centers in the Denver area and none of them have experience working on AutoStart systems.

If you believe the Intermotive and Mastervolt documentation the system is operating correctly, with the exception that something is creating a draw down on the coach battery. Then this probably becomes a wiring problem.

[JCB]

2021 Tellaro 20AT reliable 800ah. I too would have our van start when batteries were well above the 30%. I learned from our dealership to remove the key as soon as the light goes red. If I leave the ignition key in and on, the van will start. As soon as I see the red light around the button, key is removed, light stays on and dash lights turn off 15 or so seconds later. Hope this works for you!!