Came out this morning and there's a thumping sound under the hood and key doesn't work. Manage to open door with physical key and the sound stopped but now completely dead. Presuming the 12v bat is flat but very difficult to get at .
yes, it sounds like it. do you need instructions to get to the battery? you can always jump under the hood.
Thanks for your reply Bisco. Managed to crawl inside, take all of the junk out of the back and the tyre bay etc and release the latch for the for the tail gate . . . . . what a pain in the arse that was! Charged the battery and seems ok now.
Learn how to jump from under the hood. I had this printed out in the car for my wife when she drove a gen2.
I know how to jump under the hood but unfortunately, nothing to jump with where I am. I've sent off for a jump starter now in case it ever happens again.
it might be a bit less efficient, but shouldn't be a problem. do the vids explain why? maybe i'm missing something.
I think some might not realize the 12v connection from the fuse box to the rear battery can easily handle well over 100 amps. The point is there is no need to do gymnastics in an attempt to reach a discharged 12v battery in the rear.
It seems pertinent to mention when choosing between making your charging connection up front or at the battery, the positive (+) connection in the front fuse box only has metal conductor on one side. So you have to be careful when attaching the clamp to put the jaw containing the cable on that side. This eliminates the various resistances that may be present through the pivot points or spring. I always charged at the battery in the back and disconnected the positive terminal to isolate the vehicle. My charger/maintainer would detect a battery in circuit and not perform the desulphation check or service.
yes, a precaution not heeded by many, with no ill effects. however, if there were a short somewhere that was discharging the battery, it would be a useful practice. otherwise, charging could be problematic
The manual is concerned with the possibility of hydrogen gas from the battery being ignited IF you create a spark when connecting a chatger in the back. They specifically say to hook up in the front when the battery is discharged WITH the battery hooked up. Further they specify to run the charger or boost device for 5 minutes to "recharge" the battery (eg bring the surface charge up) before attempting to start the car.
Any guesses as to what the thumping noise was? OP didn't say whether it was heard while attempting to make the Prius ready. Could be a failure to start cycle caused by an improperly initialized ECU somewhere caused by a flat 12V. Some creature under the bonnet (hood)?
Yes. Haven't a clue what it was. There was only 6v in the battery and even the doors wouldn't open with the remote key. All ok now after charge and no problems since.
Note that if a door is open or the hatch is up the car draws around 0.5A. The battery trickle charger I have only puts out 0.7A, so that is a significant current draw. I ended up putting the power cord through a window and had all doors and the hatch closed so that the battery could receive 0.7A and not 0.2A. In the end it didn't make much difference though, because that battery was toast.
