Discussion:
Toyota Highlander Hybrid (2006), battery power from 288 V to 12 V battery
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s***@battlefoundry.net
2007-01-04 22:56:38 UTC
Permalink
I purchased an used 2006 Toyota Highland Hybrid (HH). I
unintentionally discovered that when the standard 12 volt car like
battery is completely discharged, this hybrid would not start. This is
normal for most vehicles, but this is a hybrid; it has 288 volt
batteries underneath the rear passenger seat. From what I can
determine, there is no way to temporary charge up the 12 volt battery
from the 288 volt batteries.
I then wondered if there was anyway to "jump start" the 12 volt
battery, using the hybrid battery. I realize the hybrid battery is at
288 V.. A transformer would be needed to step down the voltage to 12
volts.
I ask as I live in a colder climate - Minnesota. Rarely, 12 volt car
batteries "die" when the outside temperature is -20 F or lower. With a
HH, I have the hybrid battery. This hybrid battery is also inside the
car. It may be slightly warmer, if the HH is parked out in sun on these
-20 F days (even 0 F is warmer).

Is there any way to temporarily get DC power from the 288V hybrid
battery to the 12V battery?
Looking at a HH that will not start at -20 F below would be an
unpleasant sight, at least for us fools who live in such climates. This
especially would be distressing as there is plenty of electric power
stored in the hybrid battery.

Getting AC current from the hybrid battery would also be nice. If the
above would work, ex. getting 12 V DC from the hybrid battery, this
could be converted into AC.
End
Andrew Stephenson
2007-01-04 23:16:21 UTC
Permalink
Post by s***@battlefoundry.net
I purchased an used 2006 Toyota Highland Hybrid (HH). I
unintentionally discovered that when the standard 12 volt car like
battery is completely discharged, this hybrid would not start. This is
normal for most vehicles, but this is a hybrid; it has 288 volt
batteries underneath the rear passenger seat. From what I can
determine, there is no way to temporary charge up the 12 volt battery
from the 288 volt batteries.
Have you Read The Fine Manual? If your HH is anything like the
Prius, there will be a point where you connect normal 12v jump-
start cables. A Prius keeps this in the engine compartment.
Post by s***@battlefoundry.net
Is there any way to temporarily get DC power from the 288V
hybrid battery to the 12V battery?
The car should take care of that, once you supply it with power
through the jump-start point. Again, RTFM.
Post by s***@battlefoundry.net
Getting AC current from the hybrid battery would also be nice.
If the above would work, ex. getting 12 V DC from the hybrid
battery, this could be converted into AC.
This topic came up a few days ago. At the time, everyone agreed
it probably could be done. Since then I have found a discussion
on the PriusChat.com web site, about connecting a full sine-wave
inverter rated up to 1250W to the 12v battery, letting the car's
system recharge the battery when needed. (You have to leave the
car turned on but can lock the driver's door with the mechanical
key stored in the fob. Obviously the car must be left in a well
ventilated place to disperse fumes when it runs the engine. And
there must be a fat fuse to guard the battery.)
--
Andrew Stephenson
Bruce L. Bergman
2007-01-04 23:54:57 UTC
Permalink
Post by s***@battlefoundry.net
I purchased an used 2006 Toyota Highland Hybrid (HH). I
unintentionally discovered that when the standard 12 volt car like
battery is completely discharged, this hybrid would not start. This is
normal for most vehicles, but this is a hybrid; it has 288 volt
batteries underneath the rear passenger seat. From what I can
determine, there is no way to temporary charge up the 12 volt battery
from the 288 volt batteries.
I then wondered if there was anyway to "jump start" the 12 volt
battery, using the hybrid battery. I realize the hybrid battery is at
288 V.. A transformer would be needed to step down the voltage to 12
volts.
I ask as I live in a colder climate - Minnesota. Rarely, 12 volt car
batteries "die" when the outside temperature is -20 F or lower. With a
HH, I have the hybrid battery. This hybrid battery is also inside the
car. It may be slightly warmer, if the HH is parked out in sun on these
-20 F days (even 0 F is warmer).
Is there any way to temporarily get DC power from the 288V hybrid
battery to the 12V battery?
Looking at a HH that will not start at -20 F below would be an
unpleasant sight, at least for us fools who live in such climates. This
especially would be distressing as there is plenty of electric power
stored in the hybrid battery.
Getting AC current from the hybrid battery would also be nice. If the
above would work, ex. getting 12 V DC from the hybrid battery, this
could be converted into AC.
They have an output relay for safety, you can't get any power out of
the 288V Hybrid Pack until after the computer boots up and deems it
safe. I seriously wouldn't try tapping into it unless you REALLY know
what you're doing.

Without Toyota's express blessing in advance, I wouldn't even try
tapping off the 288V feed after the safety contactor. The computer is
liable to see that added voltage drop/current load, freak out that
something's shorting out and shut down the car.

Besides, that's a Catch-22 - if you don't have 12V left you can't
boot the computer, so you can't close the contactor to get power past
it to run your 12V converter and jump the 12V battery...

The safest solution would be to get a bigger and better battery for
the 12V Accessory Battery, and then you don't have to worry about it.
If you have room in the 12V battery tray - or you can /make/ room -
I'd install either a deep-cycle wet battery $70-ish for Group 24, or
$80-ish for Group 27. No car starting, so deep cycle is perfect.

Or a Starved Electrolyte 'Optima" battery (Yellow-top Deep-cycle).
They will have enough excess capacity to get the car booted and
running till you get way down in the -50F range. And if you run
around in ultra cold climes regularly, battery heating blankets work
on them, too.

Or keep one of those "Jump Pack" batteries inside the house where
it's nice and warm - they don't care if they're starting up a Hybrid
or Regular car, just clip it on and get 12V out.

--<< Bruce >>--
Bill Tuthill
2007-01-05 01:35:29 UTC
Permalink
Post by Bruce L. Bergman
The safest solution would be to get a bigger and better battery for
the 12V Accessory Battery, and then you don't have to worry about it.
If you have room in the 12V battery tray - or you can /make/ room -
I'd install either a deep-cycle wet battery $70-ish for Group 24, or
$80-ish for Group 27. No car starting, so deep cycle is perfect.
The Toyota dealer did something like this for my mom's Prius, which
operates in upstate NY where temperatures are cold, although not as cold
as they become in North Dakota or the Yukon. I think they used a regular
lead-acid 12V battery with lots of cold cranking amps.

But I'm puzzled by your phrase "No car starting" above -- doesn't the
12V accessory battery have to start the gasoline engine using the hybrid
electric motor? I should think this takes more juice than the teensy
starter motor in a traditional engine.

Also what's the point of using a deep cycle battery in this application?
All that's needed is a battery with better cold-weather performance
than NiMH, and lead-acid qualifies. You don't need a battery than can
lose 80% of its capacity and still recharge without ill effects.
Bruce L. Bergman
2007-01-05 15:43:26 UTC
Permalink
Post by Bill Tuthill
Post by Bruce L. Bergman
The safest solution would be to get a bigger and better battery for
the 12V Accessory Battery, and then you don't have to worry about it.
If you have room in the 12V battery tray - or you can /make/ room -
I'd install either a deep-cycle wet battery $70-ish for Group 24, or
$80-ish for Group 27. No car starting, so deep cycle is perfect.
The Toyota dealer did something like this for my mom's Prius, which
operates in upstate NY where temperatures are cold, although not as cold
as they become in North Dakota or the Yukon. I think they used a regular
lead-acid 12V battery with lots of cold cranking amps.
But I'm puzzled by your phrase "No car starting" above -- doesn't the
12V accessory battery have to start the gasoline engine using the hybrid
electric motor? I should think this takes more juice than the teensy
starter motor in a traditional engine.
They 12V battery's main job is to run the dome lights and burglar
alarm, and to boot up the car computer. The computer closes the 288V
contactor, and the Hybrid System inverter spins the engine to start
with the 288V Alternator/Starter coupled to the engine.

The heavy lifting is all on the 288V side, the 12V battery doesn't
have to supply any cranking current.
Post by Bill Tuthill
Also what's the point of using a deep cycle battery in this application?
All that's needed is a battery with better cold-weather performance
than NiMH, and lead-acid qualifies. You don't need a battery than can
lose 80% of its capacity and still recharge without ill effects.
They should use Deep Cycle batteries more often - cars have 10ma to
50ma parasitic draws for the computer and radio memories and the
clock, and if you have a burglar alarm add another 50 to 100 ma for
the LED and the sensors. Don't drive the car for over a week, and
that little draw starts to add up fast.

--<< Bruce >>--
Bill Tuthill
2007-01-05 18:23:29 UTC
Permalink
Post by Bruce L. Bergman
They 12V battery's main job is to run the dome lights and burglar
alarm, and to boot up the car computer. The computer closes the 288V
contactor, and the Hybrid System inverter spins the engine to start
with the 288V Alternator/Starter coupled to the engine.
Aha, no wonder the charge on the 288V battery pack can't fall below 3/8.
Post by Bruce L. Bergman
Post by Bill Tuthill
Also what's the point of using a deep cycle battery in this application?
They should use Deep Cycle batteries more often - cars have 10ma to
50ma parasitic draws for the computer and radio memories and the
clock, and if you have a burglar alarm add another 50 to 100 ma for
the LED and the sensors. Don't drive the car for over a week, and
that little draw starts to add up fast.
I see what you mean! A hybrid-synergy vehicle could be parked
(e.g. airport long-term parking) a lot longer with a Deep Cycle battery
than otherwise. The only downside is that Deep Cycle lead-acid batteries
are heavier than regular lead-acid batteries, and much heavier than NiMH.
Bruce L. Bergman
2007-01-06 06:00:55 UTC
Permalink
Post by Bill Tuthill
Post by Bruce L. Bergman
They 12V battery's main job is to run the dome lights and burglar
alarm, and to boot up the car computer. The computer closes the 288V
contactor, and the Hybrid System inverter spins the engine to start
with the 288V Alternator/Starter coupled to the engine.
Aha, no wonder the charge on the 288V battery pack can't fall below 3/8.
Post by Bruce L. Bergman
Post by Bill Tuthill
Also what's the point of using a deep cycle battery in this application?
They should use Deep Cycle batteries more often - cars have 10ma to
50ma parasitic draws for the computer and radio memories and the
clock, and if you have a burglar alarm add another 50 to 100 ma for
the LED and the sensors. Don't drive the car for over a week, and
that little draw starts to add up fast.
I see what you mean! A hybrid-synergy vehicle could be parked
(e.g. airport long-term parking) a lot longer with a Deep Cycle battery
than otherwise. The only downside is that Deep Cycle lead-acid batteries
are heavier than regular lead-acid batteries, and much heavier than NiMH.
Yes, but you need that density in the plates to get the deep-cycling
ability without lead wool shedding on a conventional wet D-C battery.

And the heavier plate web sections on an Optima to deliver the
massive Cold Cranking Amps.

Toyota was shaving every excess ounce of weight off the car they
could find, to get every hundredth of a MPG they could across the
entire fleet - make a million cars, and every hundredth counts. Ergo,
they used that Garden Tractor sized U1 battery in the car.

Hell, my burglar alarm system has a bigger battery... ;-)

You, the end user, can easily sacrifice a few hundredths of a MPG on
your one car carrying a slightly larger and heavier battery, to get a
much more reliable battery system.

--<< Bruce >>--
t***@gmail.com
2019-05-20 12:42:57 UTC
Permalink
Your best bet is to get a drop in replacement lithium battery
It's available on ebay find the store selling it and contact them for your size.
Hachiroku ハチロク
2007-01-05 17:17:34 UTC
Permalink
Is there any way to temporarily get DC power from the 288V hybrid battery
to the 12V battery?
Looking at a HH that will not start at -20 F below would be an
unpleasant sight, at least for us fools who live in such climates. This
especially would be distressing as there is plenty of electric power
stored in the hybrid battery.
First, cover yourself with the kind of padding Bomb Squads wear, then buy
a fireproof suit, the kind the guys at the military airport Rescue teams
wear, you know, those siver things.

Get a good welder's helmet with 3 inch thick glass in the eyepiece. Gloves
are in order, Lineman's should suffice. Have your last Will and Testament
brought up to date. Lastly, move the car away from anything...anything at
all. Neighbor's fences, other cars, your garage. An abandoned airposrt
runway would be good.

The rest of us will be watching the evening news...or the Darwin Awards
page...



This system is NOT to be meesed with unless you are trained. The Toyota
techs go to a two week training session before they even start working on
these things. See the big orange connector? If you don't GOOD! DON'T go
looking for it.

If you do, RUN AWAY!!!! Disconnecting this thing out of sequence can kill
you and possibly start a fire that will engulf the car, and eventually
anuthing around it, since you'll at the least be knocked on your ass out
cold, and unable to respond.
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