When the ICE cycles off and on, is it using the 12V battery to restart or the BatteryPack? It seems if you start/stop alot the battery is getting worked much harder than a conventional setup.
Im assuming there is no "starter" being used since its an instantaneous startup.... How does it work exactly?

 

The HV battery powers the motor/generator (MG1) as a starter to turn the crankshaft. When the engine speed reaches ~1,000rpm's, the PCM commands fuel injectors and spark to start the engine.

When the ICE cycles off, MG1 continues to turn the engine during fuel cut till all the unburned fuel in the intake manifold etc. is burned for emissions purposes.

The HV battery is designed to handle starting with MG1 with little effort as many times it takes for FE.

GaryG

 

Thanks Gary,
What about starting from a cold start (key turn). Does the 12v battery work alone here or is it also being assisted some way? Are the CCA the same as a conventional start?
john

 

The only thing the 12V battery has to do with starting the engine is to provide stable low voltage power to all the modules, brake pump, power steering, M/E coolant motor, fans etc.. Our 12V battery is rated at 500 Cold Cranking Amps (CCA), which is a minimum rating for a standard auto battery. The reason I think Ford choose this type of battery is it does not drain down much and will last like a standard auto battery would. In addition, the 12V battery is also designed to jump start the HV battery if its SoC falls below the starting limits.

GaryG

 

Got it. One last thing then I'll stop bothering you.
It seams that given the 12V battery is only being used for that purpose that it will last longer? or does the HV battery fall below its SoC limits often enough to put a drain on it? (what is the SoC exactly). please exuse my ignorance, 1st FEH.

 

The 12 v battery will last as long as most 12 v auto batteries. Its not the useage its the time since manufacture, though abuse will kill a battery sooner. I think the batteries in the 05s are reaching their useful life right now. If you didnt have the possible, though rare need to "jumpstart" the HV battery you could use a motorcycle battery.

 

It is very rare that the HV battery falls below the SoC (state of charge) limits required to start the ICE. Normal SoC range is 40-60% capacity which means the computers will try to keep the HV battery above 40% on the low side and 60% on the high side. This is what helps make the HV battery last over 150,000 miles which is its maximum warranty.

Your not bothering me, all of us were in your shoes and many people don't want to ask these questions. I want you to learn how to pay back big oil with good mileage. Learning how the FEH/MMH works will help.

GaryG

 

Gary, that was your 1000th post. Congratulations and thanks for all the good info.

Don

 

I still miss my friend Ray Martin who made all this possible.

GaryG

 

Over the years, I feel I've gotten better than average life from auto batteries by keeping them clean and, several times a year, giving them a long trickle charge to max them out. Is this of potential benefit on the FEH?