Hi Steve

"In order to make emergency jumping safe, a special jump start switch and electronic module steps 12 volts up to 330 volts. Because the Escape Hybrid also has a conventional 12 volt battery to run lights and accessories, the emergency jump could come from itself."
http://www.gulfcoastnews.com/RT2005FordEscapeHybrid.htm

GaryG

 

I suggest that that article has actually got it wrong. As previously
mentioned here the "jump start button" actually warms the
battery not charge it. FWIW to design a circuit to take 12vdc to
330VDC, even at about 1AMP ( 330W ), would be quite a trick.

 

I have never read anything that the Jump Start Switch was used to heat the battery. In fact, my Hybrid Tech used the Jump start switch many times to charge my HV battery to start my '05 FEH in 90F degree weather when my relays went bad. The HV battery is most efficient at 78F degrees, so how would heating the battery up in ten minutes make it perform better in 90F degree weather?

When testing the Jump Start Switch according to the WS Manual, one connection test for 5 ohms and the other at 10,000 ohms, is this a heater switch? What kind of heater could heat the entire pack cells in ten minutes? Does this heater provide power to the internal battery fans?

I've used the Jump Start Switch in my '05 FEH to charge my battery after replacing my 12V battery when the relays were bad. I heard no battery fans!

Here is a good link comparing Hybrids and eCVT fluid change requirements Bill will enjoy.
http://opensiuc.lib.siu.edu/cgi/viewcontent.cgi?article=1016&context=auto_pres&sei-redir=1#search=%22Ford+Escape+Hybrid+HV+Battery+Ju mp+Start+Procedure%22

 

I guess it should be easy enough to check with a scan gauge set to measure
bat. temp and SOC. I ws assuming it warmed the HV bat. by drawing current
from it.

 

The SIU manual/link GaryG provide states the oil is to be changed every 5 thousand miles. The Ford owners manual states 10 thousand miles. Are there other errors in this link?

 

garyg: if you understood the chemistry of a battery you'd understand why warming it up increases capacity, even at 90ºF.

eCVT oil: just using the Ford tech note.

Subdewd: the warming circuit warms the traction battery with a separate warming circuit, not by drawing current from the traction battery.

 

A couple of photos to share:

 

Interesting because when I googled this Energizer's technical data shows that for NiMH batteries, the capacity decreases with temp for temps above 15C. It also shows a straight line decrease in capacity vs. temp below 15C down to -20C where the capacity is only 20% of maximum. That seems to be consistent with the terrible cold weather MPGs I got with my 2006 in Essex Junction.

http://data.energizer.com/PDFs/nicke...ide_appman.pdf

 

A review of basic chemistry would be useful. Electro-potential increases with temperature. That's it, even in your citation. ...And that's what Ford is trying to do by warming the battery with their gadget.

Don't confuse battery life versus temperature with a one time start attempt by warming the battery.

 

The first reference clearly shows battery capacity, not life, degrading with higher temps. Every other reference I've found says basically the same thing, that NiMH batteries suffer a loss in power delivery at temps above 25C or so.

In fact, this reference http://www.national.com/appinfo/power/files/f19.pdf says one of the advantages of Li-ion over NiMH is "The Li-Ion cell does not suffer a significant capacity loss at high temperatures, as the
discharge curves at 20°C and 60°C are virtually identical." and for NiMH, "At elevated temperatures, the cell experiences two undesirable effects:
a) The A-hr capacity of the cell reduces"

Also this reference http://www.hardingenergy.com/pdfs/3%...%20Hydride.pdf says the same thing, that actual capacity, not cycle life, decreases above 25C for NiMH batteries.

I really don't think warming the battery would help at all if the battery was at 20C or more already, and all the technical data says it would actually hurt.

However, I did two jump starts and saw the following:

SoC did not change at all. Battery temp did not change at all. HV Battery voltage changed, going from 328 to 338. 12V dropped from 12.7 to 11.7. Also my 10A Schumacher charger popped during the second jump start, I guess from too much current.