Can't Jump Start 2011 Prius with Lithium Jump Starter

congrats!
could be, or maybe you didn't press 3 times the first time?

my patio heater came from tacklife, so it's unlikely they make anything, or have tech people.

 

Thanks for that link. I keep remembering very similar results that were posted on here years back, or maybe by hobbit, but never being able to find it when I want it.

As you saw this time for yourself, having the aux battery disconnected doesn't pose any problem by itself. The car doesn't care where its twelve volts are coming from. In dire circumstances, you might even want to disconnect the dead aux battery first. The reason: you only need 90 amp-seconds to get the car started, but the dead aux battery might slurp a lot more than that out of your jump pack before you even have a chance to slide behind the wheel and push the button. You can always hook the aux battery back up after the car is READY, and the DC/DC converter will take care of supplying its appetite.

One downside to doing that is the likelihood of a decent spark when you reconnect the aux battery. All the normal cautions about that from jumping traditional cars apply here too.

So far, I've never bothered disconnecting the aux battery first, and mostly haven't needed to. One time it did slurp everything out of the jump pack before I could start the car, and I had to go back indoors and recharge the jump pack, and had success on the next try.

I have been known to pull brake pump fuses or relays first, and replace those once the car is going.

I don't think the 30 second limit on the boost connection is much of a problem, unless for some reason it takes you longer than that to get behind the wheel and push the button.

Sometimes you do seem to have to try to go READY two or three times in a row, after the power has been out.

The one time I remember that 30 second limit was really a problem was when I was trying to talk an elder though jumping a Prius, over the phone. "You found the boost button? Good, press that. Now I need you to get right into the car. You're in the car now? Good. First you need to press the brake. The brake. Good. Now push the ... wait. Have to get back out of the car. Find the boost button?"

That was painful.

 

Your test method was REALLY BAD.
People tried to tell you that but you didn't listen.
You are lucky that you didn't "blow" some of the electronics.

Those small jumpers are designed to work with a weak battery in place; not for a battery that is missing or disconnected.
When you push the "boost" button, the voltage goes up and might damage circuits when you try to start .
You got lucky.
Others, maybe with a different brand of charger, might not be so lucky.

 

Hey Chapman, I really appreciate you writing up all this detail. I likely did post about this previously (as I have had username Hobbit, also) and have had a recent problem that made me research this specific issue here.

Really appreciate your posts and you can ignore the guy saying "You're lucky you didn't cause serious electrical damage..." (by unhooking your 12v and jumping with the "jump pack" Li-Ion jump starter). That's just ignorant ranting.

I had an Optimus Yellow top go completely dead recently. It was over 5 years old, so I figured it might have been the battery that was causing all the problems (nothing worked, doors wouldn't open, etc). Anyway, after hooking my jump pack (Audew brand which I've successfully used on other vehicles, including a pickup) directly to the battery leads (which were still connected to the battery), car wouldn't start. So I got another vehicle (Xterra) and tried jump starting with Xterra running at 3-4k rpm. Nothing. This baffled me, but I figured that maybe it was due to an AGM battery being totally dead vs a lead-acid, and maybe the jump-pack had to add some juice to the battery, and couldn't with the AGM. So I disconnected the battery leads and connected the jumper cables directly from the Xterra to the battery leads (Optimus battery completely removed from the vehicle). This did not work either. Crazy and really depressing. I checked all the ignition fuses, too. Car should be able to use an outside-source 12v supply without knowing the difference...particularly feeding that directly into the battery leads.


So I figured I had some weird electrical problem which was going to have to be worked out with Techstream at the dealership.

First though, knowing how weird our cars can behave electrically, I figured I'd feel pretty stupid if I took it for Techstream diagnosis, just to find out that it was the battery.

Put in a brand-new Optimus Yellow Top and voila! All the dash lights came on, doors worked, lights all worked, and all was SOLVED!
Except car wouldn't start. Holy #&*$&^% What the heck!?!?!
I don't remember exactly how I finally got it to start (I think it was just multiple tries with the new battery, much like you noted) and then it somehow started. Nevertheless, now it had no power steering, no ABS, all the warning lights on the dash were lit up (even check Hybrid system!), and I had no speedometer operation, either. So weird. At least I could now drive it to the dealership. It was running fine except for no power steering or power brakes.

Toyota Maintenance rep thought I likely had rats that chewed wires (very common in Tucson, AZ, where I am now...and I have to keep the car outside). I do keep a string of LED's under the car, but they are solar powered and get weak after a few hours and go basically dark after about 4 hrs. He highly suspected rat-chewn wires leading to a short.

Paid the diagnostics and luckily mechanic found no evidence of any chewed wires, and also found nothing wrong on Techstream, but the mechanic did find an ignition fuse that I had removed, lying in a recess near the fuse box. HAhahahaha!! CRAP! So all was working great and problems all were attributed to simply a dead 12v battery due to age of the battery.

And I forgot to put the damn FUSE back for the ingnition!! Dammit! Oh well. At least nothing seriously wrong.

All was resolved, until a few days ago (with new battery only about a month old), car did the same "playing dead" routine. Doors wouldn't unlock, car wouldn't power up. Nothing except a very small bit of amps to run the interior overhead light (very dim). Same as before. Tried jump-starting at the battery with my jump-pack (in tandem with low-power Optimus 12v connected). Nothing. Remembered about under-hood jump spot: No luck. Wouldn't start.

Started researching parasitic draws, while AGM charger hooked up to battery overnight. Battery only up to 6v. Recycled AGM charger numerous times (turning it off and resetting it to try again) and Optimus battery finally came back. I think my Duralast charger has an automatic shut-off that kept triggering for unknown reason. It would read "100%" and be at 6v. Not a charger setting issue, as the charger is set to 12v. Anyway, after almost 48 hours, I was getting over 13 volts and battery was back to health.

Car started and all looked good, but I needed to find out what was going on.
Tried again to disconnect 12v and see if I could jump start from under-hood terminals: Nothing. (fully charged Li-Ion jump pack)

Educated myself pretty thoroughly about parasitic draws and started testing, including voltage drops across all fuses etc. Couldn't find any parasitic draws.

Forward two days later and battery is still fine. Goes from 12.75v to 12.68v charge after sitting for 12hrs. That's probably normal drain over that time. Car is running well, no issues. Scanguage reads charging system is 14.1-14.2v while driving (normal). Apparently all is resolved, but I have no idea what caused this new battery to die after sitting for about 2.5 days. I'm continuing to watch battery voltage with a voltmeter and will see if it drops after sitting for another 12 hrs, but seems that 12.75 to 12.68v after 12hrs so far is likely normal.

I have no idea what's been going on. I didn't leave anything on to drain the battery, so the only thing I can think of is that maybe leaving the sunroof popped up for days when parked causes a small drain?? (doubtful). Even contacted Accessorides (remote start maker) to see if they've had parasitic drain issues, which they have not (research led me to many saying that aftermarket remote starters are a very common culprit). Accessorides has been very responsive and report no experience with parasitic drain, even when their units are several years old (mine is 3+ yrs old).



Regardless of whether or not I have a parasitic drain somewhere, I really do want to understand why in the heck I could not jump start my CT. I go camping in this thing in remote areas, and really want to be able to use my Li-Ion jump pack successfully if my battery were to go dead again. I may do some experimenting by disconnecting my 12v and seeing if mulitple tries will allow the Li-Ion pack to start the car. I really do need to be able to carry a jump-pack and be able to use it in the case of a dead battery. If it just takes cycling the car a few times, I'm fine with that. I really hope so! I'm going to do exactly what you did and disconnect my 12v battery when I try this. Need to simulate a totally dead 12v battery to be sure that I can jump start the car. Will use cables and another car, if there's no success with the Li-Ion pack. I've sent Accessorides a request to note if their starter system can possibly interfere with the under-hood jumper terminal system (I'll let the community know, but I doubt that's the issue....I probably just need to cycle the starting sequence a few times like you did, after the jump-pack is connected).

Sorry to be long-winded, but I really thrive on details and really want to be much more knowledgeable and thoroughly understand our jump-start system, so any and all input would be very much appreciated. Maybe there is just some circuit that needs to power up and be triggered a few times to get the relay to fire and connect the traction battery to start the motor?? Anyone knowledgeable please contribute details!! Thanks community!

 

The scheme is simple.
With a completely discharged 12V battery, remove the negative terminal from the battery.
Connect the starting device plus to the positive (red cover) in the fuse box.
The negative of the starting device to the body with good contact with the ground.
Press the start button in the car.

And of course the brake pedal))

 

The dead 12 volt battery being connected thwarts the jump starter?

 

A very weak 12v battery will suck all the energy out of the starting battery.

 

A 6v reading on your new yellow top is very bad and indicates it had a deep discharge. Often it is either the hatch not being 100% closed, a map light left on or your aftermarket accessories or bluetooth obd2 reader not shutting off. Rarely but not impossible is a factory component not shutting down completely or leaking current.

In many cases a 6v discharge will damage the battery such that it can eventually charge up but has low overall capacity. A load test at an auto supply is in order. Those yellow tops are not the greatest to begin with even though they were a Priuschat darling back in the day. You may need another one if it fails the load test.

Your detail did not mention if you did a series connected parasitic draw test. The mv fuse testing sounds good but fails with small but excessive parasitic draws. A normal standby current should be around 25 ma after ten minutes as the ecus go to a sleep mode. Obviously the hatch and doors must be shut. You do need to find out why your batteries are discharging. In unusual cases a excessive parasitic draw can be difficult to fix once a circuit is identified but that is rare. In those cases an expert might be needed.

Finally standard owners manual jump instructions require a 5 minute connected wait before trying to Ready to partially recharge the discharged battery. Then you go to On state and wait a few second to allow the ecus to boot before going to Ready.

 

I have a relatively small (38 watthour) jump pack, because it fits easily in the glove box and should normally be plenty to jump the car (or even somebody else's gasser).

But if the 560-ish watthour battery in the back is deeply discharged, the 38 watthours in the jump pack can disappear very quickly between connecting the clamps and ducking into the car to try to press the start button. Jump pack was at 100% and now you look and it's 0%. Inconvenient.

Last time I used it, I did disconnect the car's battery first, then reconnect it after successfully jumping to READY.

In a gen 3, it's easier to unplug the fat white cable in the underhood fuse box, which is what leads to the 12-volt battery. Connect the jump pack to the jump terminal and to body ground, jump the car, and after READY has lit up, plug the white cable back in (and stay READY a good long time to put some charge back in there).

One caveat: most of these jump packs these days have a feature to warn if you've connected them backwards. That feature can save you the headache of an expensive backwards Prius jump attempt. But if you have completely disconnected the car's 12-volt battery, the jump pack has no way to tell backwards from forwards. Usually that means you have to press an override button on the jump pack, and then you can jump. But you're on your own to be darn sure the cables aren't backwards when you press that button.

It comes from an older reality: cars with alternators and voltage regulators of the conventional type really did depend on the battery being in the circuit to keep the voltage under control. People who learned that and remember it are going to squirm at the idea of doing a jump with the battery unhooked in a Prius. It turns out not to be that kind of worry in a Prius, because the DC/DC converter regulates its output more the way computer power supplies do, instead of the way old alternator systems did. It produces a nice regulated output voltage on its own.