Hello Everyone,

What happens when your traction control battery discharges? I've heard that the car cannot start period. If that is the case, and they (Toyota in their iGuide) claims there is no way of starting it, what do they expect you to do? Is there no way to get the car started if either the 12v battery (what I thought would start the ICE) or the T-battery discharge?

You would think, since there is an ICE, that if the hybrid drive wasn't working the ICE could take control so you would not be out of luck.

Thanks,
Mike

If your traction battery (HV) discharges too far, you have the car towed to a Toyota dealer.

The TCH does not have a 12V starter or alternator. The HSD (hybrid synergy drive) uses the HV battery to start the ICE, and recharges the HV battery. Once the TCH powers up the HSD, a 12V inverter provides up to 1KW of 12V power and recharges the 12V battery. The purpose of the 12V battery is to provide enough power to start up the computers, and power 12V accessories when the HSD is off. Only about 10 amps is needed to "jump" the 12V battery so the TCH computers power up.

I remember reading that if the TCH sits for two months, you are supposed to start the car and let it idle for at least 30 minutes to recharge the batteries. The dealer has special equipment to charge the 240V HV battery, should it be necessary. Oddly Ford's FEH has an emergency start proceedure that will "boost" the HV battery from the 12V battery so you can attempt to start the ICE if the HV battery SOC is too low. It does surprise me that Toyota doesn't have something similar.

If your 12V battery dies, jump it from another vehical and be on your way. Be aware the 12V battery is a AGM battery, and should only be charged at 2 amps. If you use a 10amp charger, you can easily overcharge the battery and shorten it's life.

Wow, I was very surprised to read that if the traction battery dies you are out of luck. To me, that could have actually swung my decision if I knew about it ahead of time. The last thing I need is for that battery to die and have to waste time and money towing to a dealer to spend more money to have then charge the battery. I stand by the "why would Toyota do that?" comment.

Is there a battery gauge anywhere for the 12v accessory battery? I'm installing a sub and amp and don't exactly want to kill my 12v battery. Is the 1kw of charge about the same as what an alternator would provide in a standard non-hybrid?

Does the main hybrid battery drive the lights and other operations after the car is started? I know you mentioned the charging of the 12v battery after power up.

Sorry for my lack of understanding in this area.

Thanks,
Mike

Mikey, buy one of these.
The Engel 240 volt Battery Charger is a two mode Boost and Float Type, and is designed to charge 240 volt lead acid batteries. This unit provides a safe method of charging Engel Battpaks and other discharged batteries, via Boost and Float Mode circuitry. Also available in a 3.5 amp model.

Product Details: Name: 240 Volt Battery Charger 6 Amp Model No: BC240/126 Category: Off Road Accessories Net Weight: 3.1 Kg Power: 240 Volt AC
http://www.engelaustralia.com.au/cgi...item=BC240/126
Recommended Retail Price: $115.00

TCH-43mpg
VW TDI--48
08 LS 600 HL-20
08 LX 470-16

mikieboyblue — There is an icon for the 12-V battery's state of charge in the dash display. It comes on when you put the car in ON (not READY) mode. You can trickle charge the 12-V battery as long as you keep the current low — the Owner's Manual says under 5 amperes. You cannot charge the high-voltage NiMH battery, and you shouldn't even try. (There are no accessible terminals that would let you do this anyway. The fused orange plug in the trunk is for disabling the battery. Its contacts cannot be used to charge it. First, the fuse is ~halfway along the series string of cells that make up the NiMH battery; and second, the battery floats relative to the chassis for safety. You don't have access to the actual battery terminals.) It would be very dangerous to attempt this.

Stan

It looks like this only charges the 12v battery not the traction battery right?



Is the traction battery separate from the high-voltage NiMH? I thought there were three batteries.

1. 12V accessory (just like a normal car battery)
2. Traction -- the one that goes dead and you are screwed that I'd like to charge
3. Main NiMH

Am I wrong about that?

Only two batteries, the 12 volt "house" battery, and the high voltage "traction" battery.

Ahhhh.....Ok. That makes sense then. So it is probably extremely unlikely that the traction battery would drain unless the car sat for a very long time.

mikieboyblue — You don't need to worry about the batteries during an absence of say 2-3 months provided all lights and accessories are left "off." The car sequentially powers down all its ECUs over a period of 2 weeks of disuse, so that it preserves its batteries' charge. The NiMH ("high-voltage" or "traction" battery) powers only the motor-generators (MGs) and the air-conditioning compressor, and can be charged only by the MGs, either from the ICE or through regenerative braking, and only if you are not in Neutral. The 12-volt battery powers everything else — lights, ECUs, gauges, sensors, door locks, power brakes, power steering, etc. It can be charged only by the NiMH battery, and only when the car is in READY mode. The ICE can be started only by MG1 from the NiMH battery. If the NiMH battery is too low to allow the ICE to be started by you, then Toyota can come round to your house with their Intelligent Tester. If it says that the NiMH battery still has enough charge to start the car without damaging itself, they can command it to do so, and you're on your way. The ICE will then recharge the NiMH battery, and thus also the 12-V battery. If the Intelligent Tester declares the NiMH battery too low for this over-ride, then the car has to be taken in for service. This should not normally ever occur. If the 12-V battery only is low (and the NiMH battery's charge is okay), you can jump start the vehicle as per the Owner's Manual. Just don't try charging the 12-V battery using anything other than a low-current (<5 amperes) trickle charger, or you may damage it, destroy it, or drastically reduce its life.

Stan

Thanks Stan....pretty darn complicated...!