- First Name
- Kendall
- Joined
- Feb 5, 2018
- Threads
- 8
- Messages
- 337
- Reaction score
- 526
- Location
- Santa Clarita, CA
- Vehicle(s)
- 2018 Rubicon
I've re-read this thread... and remain very troubled that a couple of you are having problems keeping the battery charged during long tows. This shouldn't be a problem - even with the twin battery system of the new JL's. It is admittedly perplexing to read paulrubin3's account of being able to walk away from the Jeep for ~40 minutes and then have it start. It is almost as if the two batteries are "normalizing" - but the question would be why aren't they "normalizing" all the time? In other words, what is triggering the "normalizing". That conundrum aside, let's review some basic facts/suggestions provided in the spirit that they may help us to get to the bottom of this!
1. For towing; transfer case in neutral; Ignition key/button in OFF position
2. Regardless what light harness solution you are using - ours (Cool Tech LLC), or another, the power for the lights comes from the tow vehicle.
3. Many (most?) of the aux braking systems WILL use the Jeep's on-board battery(s) to power the aux braking device.
4. If you are using one of these Aux Braking systems, you should have a provision to charge the Jeep's battery (e.g., RVi Toad Charger)
5. MAKE SURE the charging solution is working! At the connection to the Jeep's battery with the tow vehicle OFF, the voltage should be ~12.5-~12.8v. When you start the tow vehicle (Jeep remains off), the voltage at this connection should now show ~13.5-14.2V.
All of that said, I have an educated guess as to what is causing this problem for a few of you.
The new JL (and JT Gladiators) are designed to "go to sleep", ~2-4 minutes AFTER the ignition is off, and the last door is closed. To convince yourself, try this simple test. With the Jeep in the OFF position, depress the brake pedal and notice that the rear brake lights still function. Leave the Jeep's driver's side window down, get out and shut the door. Wait 3-4 minutes and then reach in through the window and use a broom handle to depress the brake pedal. The brake lights will NOT illuminate. The Jeep is in a SLEEP state and the battery should be fine for 3-4 WEEKS or more in this state (very minimal current draw). As soon as you open a door, the Jeep exits this SLEEP state and is in a READY state... where it is drawing a lot more power as it believes it will be called upon to start. (Shutting the door again and waiting 3-4 minutes will cause the Jeep to go back to SLEEP state... - you can verify with the broom handle.)
Onthego said something in a previous post that bothered me. He said that he has a (light) indicator on the dash that confirms the Jeep's brake pedal has been activated by the aux braking device. However, the Jeep SHOULD NOT be providing a 12v brake switch indication when it is in SLEEP state (remember our broom handle test).
My theory is that there's something in the way that the aux braking devices are being wired that is not allowing the Jeep to stay in SLEEP state and it is instead in a power consumptive READY state. In turn, this constant READY state is draining the battery. The theory is easy enough for any of you to test. Try the broom handle on the brake pedal test with the Jeep disconnected from the tow vehicle - just so you know how long to wait, etc. Now, with the Jeep connected and the tow vehicle running, once again perform the broom handle test. If the rear brake lights of the Jeep work, you have a problem.
Can one of you with this problem give this a try and see if my theory has got any legs?
1. For towing; transfer case in neutral; Ignition key/button in OFF position
2. Regardless what light harness solution you are using - ours (Cool Tech LLC), or another, the power for the lights comes from the tow vehicle.
3. Many (most?) of the aux braking systems WILL use the Jeep's on-board battery(s) to power the aux braking device.
4. If you are using one of these Aux Braking systems, you should have a provision to charge the Jeep's battery (e.g., RVi Toad Charger)
5. MAKE SURE the charging solution is working! At the connection to the Jeep's battery with the tow vehicle OFF, the voltage should be ~12.5-~12.8v. When you start the tow vehicle (Jeep remains off), the voltage at this connection should now show ~13.5-14.2V.
All of that said, I have an educated guess as to what is causing this problem for a few of you.
The new JL (and JT Gladiators) are designed to "go to sleep", ~2-4 minutes AFTER the ignition is off, and the last door is closed. To convince yourself, try this simple test. With the Jeep in the OFF position, depress the brake pedal and notice that the rear brake lights still function. Leave the Jeep's driver's side window down, get out and shut the door. Wait 3-4 minutes and then reach in through the window and use a broom handle to depress the brake pedal. The brake lights will NOT illuminate. The Jeep is in a SLEEP state and the battery should be fine for 3-4 WEEKS or more in this state (very minimal current draw). As soon as you open a door, the Jeep exits this SLEEP state and is in a READY state... where it is drawing a lot more power as it believes it will be called upon to start. (Shutting the door again and waiting 3-4 minutes will cause the Jeep to go back to SLEEP state... - you can verify with the broom handle.)
Onthego said something in a previous post that bothered me. He said that he has a (light) indicator on the dash that confirms the Jeep's brake pedal has been activated by the aux braking device. However, the Jeep SHOULD NOT be providing a 12v brake switch indication when it is in SLEEP state (remember our broom handle test).
My theory is that there's something in the way that the aux braking devices are being wired that is not allowing the Jeep to stay in SLEEP state and it is instead in a power consumptive READY state. In turn, this constant READY state is draining the battery. The theory is easy enough for any of you to test. Try the broom handle on the brake pedal test with the Jeep disconnected from the tow vehicle - just so you know how long to wait, etc. Now, with the Jeep connected and the tow vehicle running, once again perform the broom handle test. If the rear brake lights of the Jeep work, you have a problem.
Can one of you with this problem give this a try and see if my theory has got any legs?
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