What I want to know is: Has anyone tried this? (Jump starting the 12 v battery from the 300 v battery by pressing that button and waiting 8 minutes. ) If it works I would rather do that than call the tow truck guy. I go to off road areas and it is tricky for tow guys to go there.

 

Have you done this? Leave the key in on position and let the 300v batt charge the 12v batt? I would not be able to jump my 12 v out in the boonies.

 

I would not be able to plug in a small battery charger out in the sticks. I barely get cell phone service in Maha`ulepu.

 

The 12v battery would be in worse shape after several months (especially with residual electronics operating) so you'll still be SOL if you do that. I'm pretty sure they tell you in the manual that you have to run it every so often so that it doesn't happen.

Also, there really isn't enough energy in the 12v battery to put much charge on the HV battery. It would be like trying to charge a 12v car battery with a D cell flashlight battery, yes it will charge, but not enough to make a difference.

I doubt Ford was trying to make it impervious to any and all situations, rather just trying to make the more common situation less of an annoyance.
see https://www.greenhybrid.com/discuss/...down.2833.html

If your 12v battery is dead, putting the key in the "on" position will do nothing because there's no 12v power available to energize the HV relay and the DC-DC converter. The high voltage cannot pass through the ignition switch, that would be totally unsafe, so a 12v relay is used to cut the HV battery off from the rest of the system when the vehicle is off. Bottom line is that you need some 12v to start the process of charging the battery, and that's what the jumpstart button is supposed to do.

If you still have a little bit of power left in the 12v battery, then yes it might work, but maybe not, depending on just how dead it is.

 

I'm afraid I have led us all down a garden path. My dealer directed me to page 237 of my manual, where it actually was talking about jump starting the big pac. He then led me through the instructions and I got that he was talking about charging the small battery from the big one. WRONG!! He may not have understood my question and so directed me there. I didn't read it thoroughly for myself until last night and realize we were talking about two different things. If my 12v dies again I guess I will have to call a tow truck or depend on someone else meandering out in the boonies. I'm a little leery about having just anyone jump start my vehicle.

 

If you are really concerned about the 12v croaking in the middle of nowhere, the best insurance you can have is one of those booster packs, they are relatively cheap (this one is $50 CAD) and very effective. You can also run things from them so you don't have to drain the car's battery too.

 

I was just about to suggest the same. They are also available with air compressors included, so you can even deal with a low tire.

 

This one's got it all! 150W 120vAC plug, 12vDC plug, air compressor, flashlight...

Very handy, even around the house.

 

The following explains the correct procedures to jump start the low voltage and high voltage battery in your Ford Escape (Hybrid) which is just one of over 24 hybrid vehicle jump start towing procedures outlined in the new hybrid vehicle jump start towing guide recently released by Hybrid Hazards Co. I hope this information helps you with your questions.



You can jump start the 12 volt low voltage battery, located under the hood.

• When jump starting make sure the Heater fan on both vehicles is on high.
• Connect the positive jumper cable to the positive terminal of the battery then connect the other end to the vehicle positive of the assisting vehicle.
• Connect the negative jumper cable to the assisting vehicle then connect the other end to an exposed metal part of your vehicle. DO NOT connect to fuel lines, engine rocker covers or the intake manifold.
• Start the engine of the assisting vehicle and run it at an increased but moderate speed. Start the engine of the disabled vehicle.
• After the engine has been started run both vehicles for three minutes before disconnecting the booster cables.
• Remove the jumper cables and allow the vehicle to run for several minutes so the engine computer can relearn its idle strategy. The vehicle may have to also be driven as much as ten miles for idle and fuel trim strategy to be relearned.
  If the low voltage battery is discharged or replaced the braking system must also be reset. This is done by slowly depressing the brake pedal one time.

Jump starting the High Voltage Battery
Engine cranks but does not start? Yellow service engine soon (wrench) light on?
If so, High Voltage battery may be discharged.
- Turn the ignition to off then open access panel on driver side foot well and depress jump start button momentarily.
- After pressing the button, wait 8 minutes before trying to start the engine.
- After 8 minutes the light on the button will start to flash rapidly.
- Now you may turn the ignition to run and try to start the vehicle.
- If the vehicle fails to start, you can repeat the same procedure after waiting 2 minutes.

Pat B / HybridHazards.info
Stay Safe!

 

I don't think I've ever heard of this step before. Can you explain the theory behind it? I'm interested...