I'm pretty sure the jump start does charge the traction battery, albeit only up to about 30% SOC.

Gary, I personally would try to extract six more months out of the battery unless the voltage reading on the SG was consistently low. In the brutal heat here, batteries rarely last more than 2 years, and they die quickly when they go. I bought a new 1993 mustang many years ago, and the factory battery went out at 13 months. The battery warranty back then was only 12 months!

 

I would guage the current to charge the HV battery from the 12V battery by the size of the inverter. It is not large, so the current is not that great.

 

I would guess at least an amp, though. Otherwise 8 minutes wouldn't do much. FETs that can handle an amp are still pretty small. My guess is they only step the voltage up to 300V or less. A minor change to the boost converter could yield a realy nice plug-in charger - too bad it's inside the HV battery.

 

I think GPSman1 has even backed off the theory that the battery is being only heated during the jump start procedure and I think he posted that lately. It was him who came up with the theory in the first place and I recall disagreeing with him.

That's a great idea Carl about monitoring the SG voltage, but what are the lows and highs I should be seeing? Another idea was to go back to the Tech and the SA and tell them the HV battery should have started by the second jump start procedure, not taken a third with a battery booster.

I'm also with Mark on getting a little higher cold cranking amp (CCA) if that battery will fit properly in the holder. I'm thinking the fit into the holder will be the biggest issue, anyone find anything other than the OEM Motorcraft that fits? I'm very concerned about a lose battery in an accident and prefer a good fit with the mounting clamps.

BTW, this was my first disconnect of my 12V battery and KAM going back to the default Long Term Fuel Trim settings. My mileage has taken at least a 2mph hit. I go EV when I want, so the quicker EV programming in the TBCM doesn't help me as much as someone who doesn't work as hard at it.

GaryG

 

Next time you disconect the 12v battery rig up a 9v battery to the + and - terminals on the cables, this will keep your Keep Alive Memory (KAM) saved. I do this on most '98 and up cars as some of them are a pain in the **** to get the learned functions back( lots of driving around).

 

That's a good idea Mark, I was also thinking along the lines of using the new battery, but your way sounds much easier to handle and out of the way till you connect the new battery. Thanks

GaryG

 

Well, as a cell is going bad, the no load battery voltage will still be in the 12-12.5V range, but a load will drop it to 11V or less. If the SG voltage spends much time at all below 12V, the battery is definitely headed south. If it reads >13V most of the time, it's probably still good. Problem is, though, the 12V battery usually doesn't see much action to put it to the test. The jump start is the only thing that probably ever demands much out of the 12V battery.

 

...and that's when you are jumping someone else's car!

 

Gary, my recommendation would be to get a fully sealed battery of some variety. From past experience, any of the batteries that allow you to add water seem to eventually corrode the battery holder and surrounding area. This seems like an ideal application for a fully sealed battery.

Also, FWIW, the November '07 issue of Consumer Reports has a battery review starting on pg 55, called "Auto Batteries, High-tech models top test".

 

Thanks Don, but could you give me and others some of the top CR recommendation? I gave up on renewing my subscription over a year ago after some of the phony results they got caught on. I did enjoy most of their recommendations and results though.

GaryG