Are there any issues jumpstarting another car from a 2014 ES300h?

 

Officially you are not supposed to do it. Regular system has an alternator and a battery
large enough to start the IC engine. Lexus/Toyota Hybrids have a smaller 12v DC battery
to stabilize the voltage for the radio/lights/wipers but the 288v DC traction battery actually
spins the MG, Motor Generator to start the IC engine. That MG produces 288v that gets
inverted to 12v to keep the smallish trunk mounted battery charged.

There is a 12v jump point under the hood in the fuse box to jump the ES if it needs it, but
that is very low amperage as it only needs to close a relay for the 288v system to start the
car. Highly unlikely the 288v hybrid battery would be discharged enough to not be able
to spin the engine.

If you were compelled to use the ES to jump start another car be sure to attach your cables
directly to the 12v terminals, pull the black cover off the battery on the right side of the trunk.
Do Not attach to the light duty fuse box connection and any body ground!
Follow all the usual guidelines, donor car running with major systems turned off, last connection
on the good battery to avoid sparking near weak battery fumes. If your dead battery is seriously
dead, frozen or has been flat a long time I would not use the hybrid. If it is a simple matter of
lights being left on overnight but the battery is capable of recovering a charge then...maybe.

 

Where is the under-hood fuse box connection? I have a 2016 ESh, and the manual shows only the method involving jumper cables attached to the 12v. battery and the fixed trunk latch. I had a Prius with the fuse box thing, but I don’t think it is on the 2016 model. Please correct me if I’m wrong!

 

Here is a couple of diagrams and procedures for jumping the ES...note it cautions Not to jump another car.

 

This procedure is for 7ES judging by the last picture.

 

I don't own an ES300, but my wife has a Prius V. I would never boost another car from the Prius. Way too much risk of damage in my opinion.

 

IMO these days with the lith ion battery jump starter power packs being so small and light this is a MUCH better and simpler more elegant solution. Get the most powerful one you can afford and I would hard wiring a charging cord into the fuse panel. Run it under the dash to somewhere you want it stored. glove box center console trunk underseat etc. This way its always full charged out of the way and not using one of the charging ports. '

They even make ones in weather shock sealed cases that you can mount in the engine bay and hard wire to your battery for both charging and jump starting.. If you have your battery go dead you just press a button and if will jump start you. If you need to jump another car either pull if out from in the car cab or plug in the jumpers to the port of the one mounted under the hood.

They also have enough storage to power a phone for a very long time or a laptop etc depending on the type. I have one in all our and my kids vehicles. Then I also have perm mounted trickle chargers in our vehicles as they sit from time to time and with all the electronics cpus etc they pull current and it ensures the batteries the longest life.

 

I would not jump start another car from a hybrid under any circumstances. Just tell 'em no, and offer to call a service for 'em, or offer a jump start battery. I have a one of these now

 

exactly!!!