lolder Report post Posted September 8, 2009 The jump starting procedures are straightforward like in any vehicle. I believe the HV battery starts the engine via MG1. Is there a DC to DC converter from 12VDC to HV to charge the HV battery if it is discharged so the engine may be started? Quote Share this post Link to post Share on other sites
Oman Report post Posted September 8, 2009 Nope, only MG1 and MG2 will provide the high voltage needed to charge the HV battery. The computer will not let you completely discharge the HV battery. Pretty much the only way you can do it is to store the car with a low HV charge for months without disconnecting the 12v battery. The manual is pretty clear though that a completely discharged HV battery is a warranty buster, unless caused by a warranty covered defect. I believe the dealer can put a charge back in the HV pack but once the charge goes below a certain point it will not have the same capacity and life span. That's why they won't warranty it. If you are going to store the car for a long period: 1) Charge the HV battery. You can do this by starting the car and in park press the accelerator about 1/4 to 1/2 way. The ICE will start and will charge the HV battery.2) Disconnect the 12v battery. This disconnects the main HV connection relay. There must be some parasitic HV draw whenever this relay is engaged. This also keeps the 12v from discharging. I think the car is supposed to be good for a year or more this way. Jon The jump starting procedures are straightforward like in any vehicle. I believe the HV battery starts the engine via MG1. Is there a DC to DC converter from 12VDC to HV to charge the HV battery if it is discharged so the engine may be started? Quote Share this post Link to post Share on other sites
mastertape Report post Posted September 10, 2009 Nope, only MG1 and MG2 will provide the high voltage needed to charge the HV battery. The computer will not let you completely discharge the HV battery. Pretty much the only way you can do it is to store the car with a low HV charge for months without disconnecting the 12v battery. The manual is pretty clear though that a completely discharged HV battery is a warranty buster, unless caused by a warranty covered defect. I believe the dealer can put a charge back in the HV pack but once the charge goes below a certain point it will not have the same capacity and life span. That's why they won't warranty it. If you are going to store the car for a long period: 1) Charge the HV battery. You can do this by starting the car and in park press the accelerator about 1/4 to 1/2 way. The ICE will start and will charge the HV battery.2) Disconnect the 12v battery. This disconnects the main HV connection relay. There must be some parasitic HV draw whenever this relay is engaged. This also keeps the 12v from discharging. I think the car is supposed to be good for a year or more this way. Jon OK, so here's a scenario that I am curious about. It's January, -25 degrees, got some marginal gas. Go out to the car and attempt to start. Cranks for awhile then the computer gives up because the battery is too low, and throws a code. Ordinarily I would put the car into a heated garage to warm up, add a can of heet to the gas and top off the tankthen "CHARGE THE BATTERY" because it ran down too low out in the cold. Ordinarily this procedure would work fine for a normal car. For this car, I see the only option beingTie a tow rope to the front, pull it down the road, while somebody pushes the brake pedal to cause regen-brakingthen pull it back into the warm building, and try to start it. I guess the other option would be to have ittowed to a dealer, but I guess what would they do? I can hardly see this as a warranty issue. Anybody have any other ideas? I love this car, but I am wondering how its going to like Minnesota Winters. Quote Share this post Link to post Share on other sites