Originally Posted by mehitibel
Ford Escape jumpstart from 300 volt electric pac

Has anyone had experience with jumpstarting the small battery from the large one?

My regular battery died the other day. Tow guy said it would not recharge. Take it to Dealer, see if it is alternator problem. Also said that the red light showing in the battery means not fully charged.

Dealer messed around with it for about two hours. REd light still on. Dealer said not to worry. Their meter said it was OK.

I asked if anyone had hybrid training. Yes, Dave had. However, it was eight months ago and he can't remember much since he has not had much experience (I bought the first Ford Escape Hybrid on island.)

He did vaguely remember, and the General Manager of the shop looked it up in the users manual, that there is a way to jump start the small battery from the large one.

He pointed out a page in the manual which refers to a little door to the left of the driver's feet. You are supposed to open this door and stand on your head and push a button and wait for 8 minutes. I hope I don't have to try it, but I will if necessary. I go out to remote areas and would hate to have to wait for a tow truck and my cell phone might not work out there.

Has anyone had any experience with this procedure?

BTW, two of my housemates have Prius'. Such cool cars, great design, better mileage, but they won't go where I want to go with this 70 year old body.

aloha,
mehitibel

I did it once but I think the jump start is from the 12V to the 300V, not the other way. The way to charge the other way is to leave the key in the on position for a while and let the 300V batt charge the 12V batt (that is the way it does it when the engine is running).

Good luck

Chris

A small battery charger should be sufficient to get you started unless there's a short in the 12v battery or somewhere in the 12v system. All the 12v battery has to do is run the computers and energize the HV power relays.

Once you get it running it's important to keep it in the "run" position for at least 30 minutes to make sure the 12v battery has a chance to charge.

Of course you probably know the FEH doesn't have an alternator...

That's very interesting. No alternator. The tow guy said the Ford folks should check it and the Ford folks - no kidding now - said the alternator was just fine. What gives?

My problem was that the small battery was dead. Wouldn't jump start from tow guy's manuevers. I will go back to the manual and be sure of the directions. Obviously I have misinterpreted something and so have the Ford guys. 'course we're out here in never-neverland so who knows. I am really happy to have this web site to call on. Thanks to the creators (Jason?)

Confusion...

Your vehicle has two motors that act like alternators in various situations. They both charge or drain the high voltage battery, and the high voltage battery is monitored and maintained by the computer so that it never dips under ~40% charge and never gets charged more than ~80% so that it will last a long time. The small battery is charged by a DC to DC converter (some people mistakenly call this an inverter) that is capable of at least 100 amps of 12v current into the accessory system.

I think what Ford did is made some kind of "manual on" button for the DC-DC converter (or a second small "emergency" DC-DC converter) so that if your accessory battery (12v) dies you'll be able to charge it up manually from the big HV battery so that the computer (ECU) can turn on when you go to start the vehicle. The engine itself is spun up by the HV battery, so you don't need much charge on the 12v battery to get it started, but I think the manual (quoted by someone else) says to push the jumpstart button and then wait 8 minutes or so, then try to start it.

2001 Prius Photos       2005 Prius Photos
'97 Prius Simulation Prius inner workings

Yes, the "jump start" button allows you to use the 12v battery to minimally charge the HV battery. The charging circuit for this function appears to be enclosed in the HV battery pack, as it also provides the function of warming the HV battery to make a successful start more likely.

A fully charged 12v battery has enough capacity to run two jump-start cycles.

Do you have some info about this? I was under the impression that it was the other way around because the HV battery pack doesn't get consumed when the vehicle is off (or in accessory) and the computer maintains the charge above 40% at all times, so it should never need a jump start. The 12v battery on the other hand is the one that will die because it's in use when the key is in accessory and the HV battery is disconnected from the 12v battery.

2001 Prius Photos       2005 Prius Photos
'97 Prius Simulation Prius inner workings

Ah, but you can get a 12v battery jumped anywhere! Where can you get a 330v battery jumped?

There are conditions where it's possble for the HV battery to go flat (self discharge over several months, for example).