One 2008 FEH has dead HV battery. The 12V Jump start doesn't work.
Is it possible to connect the HV batteris then start the engine? If yes, where to locate the + and - terminals of the HV batteries?
Thanks!

 

Not realistically. It requires pulling the cover, and that essentially requires removing both batteries.

 

An FEH can be jump started with jumper cables if the 12V battery isn't completely dead like a normal vehicle. Once jump-started, the generator slowly charges the HV battery. If a regular jump start doesn't work, it probably isn't a DIY fix and needs to go to someone with a Ford computer/scanner to figure out what is wrong.

 

That is not correct, or it is at least misleading. Here's a clarification:

If an FEH 12V is dead and the HV battery is not dead, it can be jump started.

Regardless of 12V condition (crap or perfect), it is generally not possible to jump start an FEH with a dead HV battery per the poster's request. There are 3 exceptions:

1) for 2007 and older that have the HV jump start system installed.
2) for 2008 and newer - dealer can get a special ford charger that charges the HV battery - requires tow to dealer and may be EXTREMELY expensive with NO resolution.
3) for 2008 and newer - remove, partially disassemble and charge the HV battery with an electrophoresis power supply or high voltage LED power supply.

I have personally done #3, so I feel qualified to comment.

Steve

 

Do you mind detailing how you went about charging the HV battery using the electrophoresis or high voltage LED method?

 

You should be able to find the method under an older S Keith post.

 

This looks interesting if you can handle the cost

https://www.ebay.com/itm/HIGH-SPEED-...gAAOSw10VcTLcr

 

No. Horrible idea. 1.4A of charging with no means of driving the cooling fan? Well hello there cooked and ruined pack. Venice Hybrids has a history of this. Their initial offering didn't power the fan, and they claimed it wasn't necessary. Everyone else disagrees. Myself included. When a pack is full or near full, 100% of the input is turned into heat. I've seen 130°F pack temperatures in 35°F ambient with no cooling and pushing only 350mA.

Good news though... That charger will not fully charge the 250 cell FEH or any of the 240 cell hybrids like Highlander, GS450h or the GM 2 modes. 330V is too low, so heat will likely never be an issue.