Dead Prius 2005
 

OK I was sort of ready for this from my friends last trip - looks like someone left a door slightly ajar probably ran the battery down from the dome light a little faster - it had 2.4volts on the 12 volt battery - I figured her daughter would drive it a little but from the few times I went by it had not moved. I had to jump it with my flash light batteries (two 4.2volt lithium cells) until the voltage got high enough to get the 110 volt battery Vector Smart Charger to "see" the battery then I charged it slowly for a while (1.8amps) until it took enough charge to start the engine then took it for a 10 mile drive in the dark and rain - not fun with the headlights too high btw. The sloping windshield is so mich harder to see through than my nearly vertical xB windshield. Seems ok colder weather coming so best not to leave the battery dead. In case you don't know you can't get to the battery in the trunk with the battery dead - can't open the rear hatch without power so there is a jump connection under the hood in the relay panel where I charged it from. Hardest part was getting the relay cover off - all black plastic and dark. They put a jumper terminal under a little red plastic cover so it was easy to get to but not with the big battery clamps.

First, my hat's off to you for tenaciousness. What a PIA.

Second, it amazes me that someone would have a car that new and just let it start to kill itself. I hadn't ever considered the consequences of leaving a light on, on that type of vehicle.

I left the lights on, on my 89 Wagon and I blew the main fuse, trying to get it started in the middle of the night, in L.A. I was amazed at how much futzing around I had to do, just to get it started, so I could drive back home.

I would have thought that a Prius would have one of those "20 min kill all electrical drain" circuit to prevent things like this

Yeah well it has been sitting for 3 weeks and the Dome light is off just the door lights which you can't see and I guess the electronic key being inside the car keeps the ignition active too which draws more power. Plus the heat came on and the radio when it restarted so they were probably being used after it was shut down. It's a 2005 so not that new but it would be smart if it started up and charged the battery or at least took some energy from the high voltage battery to keep it charged up. They do warn you about this in the useer manual. I think there is a power down mode for long storage when you shut it off too.

Looks like a sealed Lead Acid battery in the trunk maybe rated at 40ah or so and they only recommend 4.2 amp charge rate although I started the engine and saw 14.06 volts on the terminals which is about 9 amps charge rate from what I can tell so I charged it a little harder up to 14.25volts before it started to reduce the current. Guess they do not want it overcharged too much. Man the car started to draw from that battery when I opened the door so I can see how it can be drained pretty quick. All sorts of relays clicking under the hood because of the proximity ignition key too. I charged it in the trunk for a few hours today to get the voltage up a bit before the single digit temps arrive in the next few nights.

I have heard of this as well. I think Darell figured out a way to pull power from the traction battery to charge the "appliance" or smaller 12v battery. Seems goofy to me that you can have a good sized battery pack sitting there and can't use it if the appliance battery is dead, there is probably some good reason, but heck if I know.

Unfortunately, no - I haven't created a HVB-to-Aux jumper. Should be included with the car, however! Hell, it should be automatic. Along with an "everything off' timer. What I have done, is put LED modules into every light fixture in the car. The modules are brighter than the factory bulbs, and draw about 1/5th the power - result is that you can leave the lights on 5x longer before you kill the battery. Hey, its a start.

Leaving the door open should take a LONG time to kill the Aux battery though. After half an hour, the dome lights automatically turn off. The only thing left on is the "door ajar" light. Eventually that'll kill the Aux, but it should take a good long time.

The EV1 was the only car I know of that could jump the Aux from the traction pack. EVERY electric-assist vehicle should have this feature. Silly to be sitting on enough energy to drive 100 miles, and not be able to start the car because the stupid Aux battery is dead. Technology is supposed to work FOR us - and this isn't rocket science!

Oh... and if you haven't already done so - get a new AUX battery. If you were reading under 3V, you'll not be able to trust that battery again. Certainly not in the cold!

I have a feeling the radio and heater was used a bit before the last shutdown which draned it and maybe the wireless keys were too close to the car all the time it was parked in the driveway. I did get the charge current down to 8.5 amps then opened the door and the charge current went up to 9.2 amps again for a while. Engine started put a steady 14.06 volts on the battery - looks like they regulate the voltage pretty tight so to not over voltage the Panasonic agm battery. It doesn't "start" the car so there are no big loads on it at least but its voltage drops pretty quick down to 12 volts when the charger turns off. Looks like it may be a 40-42 ah battery.

If the traction battery is in the 360 volts or less range then a switcher charger that can operate on 220 could be connected to it to make plenty of charging current as long as it didn't require 50/60hz AC to run/clock circuits. Usually the switchers convert 120 AC to +/- 180 DC volts and chops it down so feeding it DC should still work.

Maybe time to wire a 120 AC charger into the trunk battery that can be plugged in easily without opening the trunk.