Quote:
Originally Posted by gpsman1
Two things:
#1 The "jump start" button is not even "active" unless your HV battery is below some preset, very low level. Thus you can not warm a "normal" battery, only a nearly dead one.
#2 It sounds counter-intuitive, but in workshop manuals and wireing diagrams, no "step-up" voltage converter can be found anywhere. The DC/DC converter acts as an alternator would, and converts 330v to 14.2v to charge the 12v system. There's no mention that I can find that it works in reverse. However, there is explicit mention in the shop manuals that the "jump start" button warms the HV Battery. Anyone can try this: Put your cell phone battery in the freezer and it won't run your phone. Warm it up in your hands, and it will work again. Did your hands "charge" the cell phone battery? I think you'll agree not. I'm guessing here, but I 'think' the jump start button provided resistive heat to the HV battery pack. The manuals state that your 12v battery should have enough juice for two, 8 minute cycles, but will be nearly depleated after that. I've tried to recharge the HV battery via this route, and it doesn't work. I've never had my HV battery low enough for the button to even activate.
-John
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John, where is it stated in the workshop manuals that the 12V jump start button warms the HV battery? I'm sure that dumping the 12V battery charge into the HV battery in 8 min. would have some warming effect, but I couldn't find it in the manuals. Also, you must have overlooked the section that says there IS a low voltage charger that is used during the jump start proceedure. It is contained within the HVTB itself (page 414-03-2 of volume 2).
David, the reason the indicator light on the button went out when you returned to your vehicle after 10 min, is because after 8 minutes, the indicator starts to flash rapidly for two minutes and it then goes out. More than likely, your battery didn't need or could accept a rapid 8 min charge the way the system is designed. Again, a low battery can take a much faster charge. A cold charged battery takes a charge much slower. Anyone can test this out by checking your instant MPG with your econ reset or navi average reset from a low battery till it recharges. Simply reset with a low battery and watch the ICE increase MPG as the battery fills up. The small generator will slowly back off generating power and the ICE will get better mileage as the battery gets full.
Also, I've had first hand experience with a very low (below 40% SOC) battery when I ran out of gas with a low battery SOC and drove a distance further in EV on I-95. My FEH still had enough juice to start, but the small generator was pouring such a fast charge into the HV battery that regen could not add any more at the same time when I fake shifted. I'm sure the design of the Jump start button is only good for a jump start when you need one. Your not going to heat the battery with a 40% SOC or higher I would not think.
GaryG