bootenwagen
New Member
Greetings all, I'd like to share with you how I fixed a persistent chassis battery draining issue on my 2020 Freedom Elite 26HE. Perusing the forums, this seems to be an issue plaguing a lot of Thor RV owners. Obligatory disclaimer: perform work at your own risk, no implied warranties, yada yada yada 
.
The video I made for this can be found here, but I will also provide a text form step-by-step here in this forum.
Intro
Basically I noticed that despite being plugged into shore power, by the time I'm leaving the campsite, I'm having to use the emergency start button, which shunts power from the house battery. Eventually I started to unplug the battery every time I set up camp, but that was too little too late -- the battery couldn't hold a charge anymore and I had to replace it. Searching through google and forums yielded the usual suspect - the BIM. Additionally, some info seemed to indicate that being plugged into shore should be trickle charging the chassis battery, but it wasn't. I e-mailed Thor to get some clarification, and this was basically the exchange:
After this Sartrean comedic exchange, I decided to just dig into the problem myself. Started pulling fuses, measuring currents, mapped out the wiring for my RV, and read some spec sheets. Edit -- I kept calling what I have a BIM, but it is in fact an IRD - Isolator Relay Delay Here's the IRD schematic I created:
The IRD system had two parts -- a Trombetta contactor, and the Intellitec Isolator Relay Delay. Turns out, this particular model only works one way -- it charges the house battery off of the chassis battery when it senses a high enough voltage from the ignition wire. So much for the "trickle charge theory".
Thor Recall
I also wound up finding this NHSTA Recall that Thor issued in late 2019. The gist of this is that on certain 2020 Chateau, Daybreak, Four
Winds, Freedom Elite, Majestic, Outlaw, and Quantum models, there existed a potential loose BIM connection that was deemed a potential fire hazard. Originally, these models came with a Precision Circuits BIR 110, which does have the capability to charge both the chassis and house batteries. But in the recall, they chose to remove the BIR altogether, and replace it with the one way Intellitec IRD. Why, I don't know.
The first half of the solution
First, I wound up replacing the Intellitec with the Intellitec BIRD 00-00362-100. This unit works both ways - and will charge chassis off of house so long as it detects that house is being charged. Here is the updated schematic I made for it:
It's basically wired the same way as the old Intellitec, but does need an additional wire directly from the coach battery. First, disconnect both the house and chassis batteries.
1) Remove the coolant overflow reservoir, 3x 5/16" bolts to reveal the old BIM and Trombetta fastened near the wheel well. Don't remove any of the coolant hoses, just set the reservoir aside.
2) Cut the blue ignition wire and crimp a female spade connector on it
3) Remove the Intellitec's black ground wire off the Trombetta, 3/8" nut
4) Remove the Intellitec's red relay wire off the Trombetta, 3/8" nut
5) Cap the wires off. I kept the Intellitec where it was as a spare
6) Make the following:
-1x 24" 16AWG black ground wire with small ring terminal & female spade
-1x 24" 16AWG red voltage wire with 5/16" ring terminal & female spade & in line 10A fuse
-1x 24" 16AWG red relay wire with small ring terminal & female spade
7) Connect the new BIRD - voltage wire to house battery terminal on the Trombetta (1/2" nut), black ground wire to small ground lug on Trombetta, and red relay wire to relay lug on Trombetta. I Velcroed it down the wheel well, plenty of space. Ideally, I'd probably use plastic trim screws to fasten it so I don't risk shredding the tire.
8) Reconnect the batteries, and test. If you're on shore, after about 2.5 minutes, you should hear the Trombetta click, and your chassis battery should be charging off of the house battery.
Now, my RV's chassis battery was no longer discharging when plugged into shore power.
The second half of the equation
The BIRD gave me more peace of mind for sure, because I wasn't having to disconnect the chassis battery anymore, let alone performing an emergency start every time. But I wanted to figure out what was discharging it so much to begin with.
After coming up with no clues pulling fuses, I made an educated guess that the Axxera AVM80 audio head unit was the culprit - because even with the ignition off, I could still turn the radio on. I assume the intent was to allow the radio to be used when camping. Long story short -- the radio, even when off, uses 0.282A constantly. At this kind of discharge rate, the 4-5 days or so that it took for the battery to no longer have enough charge to crank the starter made perfect sense.
For this issue, I did two things. One, I moved the radio's power supply off of the chassis battery and to the house battery. In the worst case scenario, I'd rather the house battery gets discharged. Then, I spliced an on/off switch into the dash to cut power completely from the Axxera. I will be using this switch if I need to store/park the RV or go boondocking. It's pretty hairy, but here's how I did it:
1) Disconnect both batteries
2) Pried the dash off using my hands and left it loose, but didn't completely remove it. My RV is based on a Ford E-350.
3) Unplugged the cigarette outlet connectors for more dashboard wiggle room. I didn't unplug everything else because the HVAC seems to have vacuum lines, and I didn't want to mess with that
4) Pried the bezel off of the Axxera. Spoiler: not easy:nonono:
5) Broke the 4x 7mm bolts holding the Axxera loose, then used the jaw end of the wrench like a screwdriver to loosen them the rest of the way.
6) Slid out the Axxera diagonally, to get at the phillips screws holding the mounting brackets in place. Removed the mounting brackets. Slid the Axxera most of the way out.
7) The Axxera is powered by a red and yellow wire. The red is "ACC/Ignition", yellow is "battery/memory". Not sure what the red one is for, mine had a blown in-line fuse. Replacing it did nothing, and couldn't power the Axxera solely off of this wire.
8) Routed a 16AWG wire to the Chassis lug through the firewall on the Trombetta. Soldered an in-line 10A fuse on this wire, and attached a 5/16" ring lug. The video gives a much better visual of this, but basically I inserted the wire from the engine side into the same cable sheath (by the steering column) that goes to the emergency start button. Then I routed it to the radio.
9) I took the blank plug by the cigarette outlet, and carved space for the SPST switch. Made two wires for it.
10) Undid the splice on the yellow wire, and capped the wire coming off of the factory Ford harness. This wire has a constant 12V coming off of the chassis battery SOMEWHERE, so it needs to be well insulated so it doesn't inadvertently short out.
11) Joined the yellow wire going into the Axxera with 1 wire coming out my switch using a Wago 221, and did the same for the 16AWG I routed to the Trombetta
12) Tested the setup, made sure the Axxera powers on, and the switch does the job
13) Put everything back in
Conclusion
And presto. With the combination of the BIRD, a switch, and the Axxera being powered off of the house battery, the battery drain issue hasn't plagued me.
Hope this helps!
.The video I made for this can be found here, but I will also provide a text form step-by-step here in this forum.
Intro
Basically I noticed that despite being plugged into shore power, by the time I'm leaving the campsite, I'm having to use the emergency start button, which shunts power from the house battery. Eventually I started to unplug the battery every time I set up camp, but that was too little too late -- the battery couldn't hold a charge anymore and I had to replace it. Searching through google and forums yielded the usual suspect - the BIM. Additionally, some info seemed to indicate that being plugged into shore should be trickle charging the chassis battery, but it wasn't. I e-mailed Thor to get some clarification, and this was basically the exchange:
After this Sartrean comedic exchange, I decided to just dig into the problem myself. Started pulling fuses, measuring currents, mapped out the wiring for my RV, and read some spec sheets. Edit -- I kept calling what I have a BIM, but it is in fact an IRD - Isolator Relay Delay Here's the IRD schematic I created:
The IRD system had two parts -- a Trombetta contactor, and the Intellitec Isolator Relay Delay. Turns out, this particular model only works one way -- it charges the house battery off of the chassis battery when it senses a high enough voltage from the ignition wire. So much for the "trickle charge theory".
Thor Recall
I also wound up finding this NHSTA Recall that Thor issued in late 2019. The gist of this is that on certain 2020 Chateau, Daybreak, Four
Winds, Freedom Elite, Majestic, Outlaw, and Quantum models, there existed a potential loose BIM connection that was deemed a potential fire hazard. Originally, these models came with a Precision Circuits BIR 110, which does have the capability to charge both the chassis and house batteries. But in the recall, they chose to remove the BIR altogether, and replace it with the one way Intellitec IRD. Why, I don't know.
The first half of the solution
First, I wound up replacing the Intellitec with the Intellitec BIRD 00-00362-100. This unit works both ways - and will charge chassis off of house so long as it detects that house is being charged. Here is the updated schematic I made for it:
It's basically wired the same way as the old Intellitec, but does need an additional wire directly from the coach battery. First, disconnect both the house and chassis batteries.
1) Remove the coolant overflow reservoir, 3x 5/16" bolts to reveal the old BIM and Trombetta fastened near the wheel well. Don't remove any of the coolant hoses, just set the reservoir aside.
2) Cut the blue ignition wire and crimp a female spade connector on it
3) Remove the Intellitec's black ground wire off the Trombetta, 3/8" nut
4) Remove the Intellitec's red relay wire off the Trombetta, 3/8" nut
5) Cap the wires off. I kept the Intellitec where it was as a spare
6) Make the following:
-1x 24" 16AWG black ground wire with small ring terminal & female spade
-1x 24" 16AWG red voltage wire with 5/16" ring terminal & female spade & in line 10A fuse
-1x 24" 16AWG red relay wire with small ring terminal & female spade
7) Connect the new BIRD - voltage wire to house battery terminal on the Trombetta (1/2" nut), black ground wire to small ground lug on Trombetta, and red relay wire to relay lug on Trombetta. I Velcroed it down the wheel well, plenty of space. Ideally, I'd probably use plastic trim screws to fasten it so I don't risk shredding the tire.
8) Reconnect the batteries, and test. If you're on shore, after about 2.5 minutes, you should hear the Trombetta click, and your chassis battery should be charging off of the house battery.
Now, my RV's chassis battery was no longer discharging when plugged into shore power.
The second half of the equation
The BIRD gave me more peace of mind for sure, because I wasn't having to disconnect the chassis battery anymore, let alone performing an emergency start every time. But I wanted to figure out what was discharging it so much to begin with.
After coming up with no clues pulling fuses, I made an educated guess that the Axxera AVM80 audio head unit was the culprit - because even with the ignition off, I could still turn the radio on. I assume the intent was to allow the radio to be used when camping. Long story short -- the radio, even when off, uses 0.282A constantly. At this kind of discharge rate, the 4-5 days or so that it took for the battery to no longer have enough charge to crank the starter made perfect sense.
For this issue, I did two things. One, I moved the radio's power supply off of the chassis battery and to the house battery. In the worst case scenario, I'd rather the house battery gets discharged. Then, I spliced an on/off switch into the dash to cut power completely from the Axxera. I will be using this switch if I need to store/park the RV or go boondocking. It's pretty hairy, but here's how I did it:
1) Disconnect both batteries
2) Pried the dash off using my hands and left it loose, but didn't completely remove it. My RV is based on a Ford E-350.
3) Unplugged the cigarette outlet connectors for more dashboard wiggle room. I didn't unplug everything else because the HVAC seems to have vacuum lines, and I didn't want to mess with that
4) Pried the bezel off of the Axxera. Spoiler: not easy:nonono:
5) Broke the 4x 7mm bolts holding the Axxera loose, then used the jaw end of the wrench like a screwdriver to loosen them the rest of the way.
6) Slid out the Axxera diagonally, to get at the phillips screws holding the mounting brackets in place. Removed the mounting brackets. Slid the Axxera most of the way out.
7) The Axxera is powered by a red and yellow wire. The red is "ACC/Ignition", yellow is "battery/memory". Not sure what the red one is for, mine had a blown in-line fuse. Replacing it did nothing, and couldn't power the Axxera solely off of this wire.
8) Routed a 16AWG wire to the Chassis lug through the firewall on the Trombetta. Soldered an in-line 10A fuse on this wire, and attached a 5/16" ring lug. The video gives a much better visual of this, but basically I inserted the wire from the engine side into the same cable sheath (by the steering column) that goes to the emergency start button. Then I routed it to the radio.
9) I took the blank plug by the cigarette outlet, and carved space for the SPST switch. Made two wires for it.
10) Undid the splice on the yellow wire, and capped the wire coming off of the factory Ford harness. This wire has a constant 12V coming off of the chassis battery SOMEWHERE, so it needs to be well insulated so it doesn't inadvertently short out.
11) Joined the yellow wire going into the Axxera with 1 wire coming out my switch using a Wago 221, and did the same for the 16AWG I routed to the Trombetta
12) Tested the setup, made sure the Axxera powers on, and the switch does the job
13) Put everything back in
Conclusion
And presto. With the combination of the BIRD, a switch, and the Axxera being powered off of the house battery, the battery drain issue hasn't plagued me.
Hope this helps!
Last edited:
