Sign in to follow this  
GreenJuice

Low voltage (12V) battery failure Gen4 - some advice please?

Recommended Posts

First time I have experienced this, having previously owned a Gen2 and Gen3. This current Gen4 had a full service and its first MOT 2 months ago. I went on a 21 day holiday and left the car parked and locked in a garage. I have been away for up to 25 days before but usually leave the car unlocked.

This time, the car display came up with a 12V battery warning and wouldn't start. It was a chilly morning (about 5C). I tried again and the car started wildly flashing its headlights (any of you experienced this?) with another Battery warning and again refused to start. I had an old car trickle charger from my pre-hybrid days. Connected it up (following the instructions on page 157-158 of the User Guide manual); charging at around 4 Amps for 3 hours and the car is now back to normal.

I couldn't find anything that I had left on accidentally. The only difference was that I had locked the car this time, and I have heard that this may use up more charge as the car may be listening out for signals from the key fob (but, I might be wrong about this - any thoughts?).

This has dented my confidence in leaving the car for any period of time of around 3 weeks or more! Especially in an airport car park for example. 

Please, can I ask?:

1. How long have others left their Gen4 unused without experiencing a problem with the 12V Battery?
    1a. Is it possible that my low mileage (<5000 per year) and numerous short journeys in London may be reducing this Battery's life?

2. Do any of you keep a portable Battery jumpstarter? 
    I have looked around at various posts on Priuschat and it appears that the Prius only needs a peak current output of 35A to boot up its basic systems & pumps before handing over to the HV battery (which does mean it remains inadvisable to supply current via the cigarette lighter type sockets, as the fuse is rated at 15A). So most of the more expensive portable chargers on the market (rated at 600A or more) appear to be much more than needed for the Prius. I am wondering if any of you have thought this through before and could advise on how best to rebuild my confidence in the car, please?

Many thanks!

 

 

 

Share this post


Link to post
Share on other sites

I have a RAVPower 500A/12000mAh compact jump-starter (just search RAVPower in Amazon) in my car.  It comes in a neat case which holds the jump leads, a 12V charging cable and mains charger and fits nicely in the seat-back pocket so it's handy if I can't open the boot (vital if the 12V's flat!).

The 12V Battery died on my last Gen 4 Prius when the car was about 18 months old, which my dealer replaced under warranty without hesitation.  If you locked it with the remote, the Battery would be powering the alarm system as well as doorlock sensors etc.

I never left the Gen 4 more than about 10 days, so didn't have any other problems.  I was told not to drive for a month after a heart scare last year, but a couple of time I sat in it in READY mode for half an hour to top up the 12V Battery.  Obviously, you can't do that if you're away on holiday.

[REMAINDER IS JUST BACKGROUND IF INTERESTED]

Before that I had an old fashioned lead-acid jump starter, bought in 2004 for my Gen 1 Prius. It was quite large and heavy so had to live in the boot.  (Fortunately, the Gen 1 Prius was a saloon and the boot could be opened with the key or a cable release beside the driver's seat, alongside a fuel cap release lever.)

It was more frequently required as the Gen 1 had a higher current drain than later models, and a 35ah Battery.  Some members of another group used an ammeter to measure the drain, but we never fully understood why the drain was so high, given the car only had basic remote central locking and no key-less start.  In fact, just leaving the key in the ignition in the off position increased the drain quite a bit.  Leaving it in ACCesssory position would flatten it in  a few hours.

A Gen 1 with a perfect 12V Battery, fully charged, and with everything switched off, would be lucky to survive much more than 3 weeks in an airport car park, even when locked manually to ensure the alarm wasn't active.  Gen 2 & 3 did better, with 5 week periods being reported occasionally.

Since the Battery drain wasn't fully understood in the very early days, the 12V Battery was often already damaged by the time the car was sold, having been flattened during the voyage from Japan, and at least once at the dealer while waiting to be sold.  Only about 1,500 Gen 1s were sold in the UK from 2000-2004, only 60 dealers could handle them, and they were never actively marketed, so they sold very slowly, mostly to people (like me) with a keen interest in such technology.  Once the issue was known, I understand the 12V Battery was disconnected during the sea journey.

  • Like 3

Share this post


Link to post
Share on other sites

Many thanks for your helpful response. Hope you are better now after your scare.

  • Thanks 1

Share this post


Link to post
Share on other sites

Just this last Monday I posted my experience in the Auris club section to help someone......

I have a Suaoki U3 compact Battery with car leads, currently on Amazon for £39.99. Can be used directly across the Battery in the Auris boot (and Gen3 Prius) or across the Jump Start Point under the bonnet. Charges up using standard Android phone cable, has inbuilt torch that also flashes SOS, and can charge a mobile phone. Fits in trouser/jacket.

I keep it in the pouch behind drivers seat, handy there, accessible if 12v Battery is flat, use key to open driver door, reach over seat, open bonnet, access to jump start point. 
Interesting that Toyota have fitted the 12v Battery under the bonnet in Gen4 Prius.

  • Like 1

Share this post


Link to post
Share on other sites
1 hour ago, Catlover said:

...Interesting that Toyota have fitted the 12v battery under the bonnet in Gen4 Prius.

They've gradually been making the Hybrid components smaller, so finally found room to put it back in the front.

I think I read somewhere that Corollas with the 2 litre engine have it back in the boot, and certainly my RAV4 Hybrid (the engine is 2½ litre) has it back in the boot.

Share this post


Link to post
Share on other sites

Some things to consider:

  • Is your garage attached to your house, and were the keys left nearby? I've heard this can lead to increased Battery drain if the keys are left in proximity to the car - though I don't know how close this needs to be.
  • Turning off the intrusion sensor can reduce Battery drain, obviously with reduced security - not sure if it's an option with the gen 4 (or fitted in your example)

Share this post


Link to post
Share on other sites
2 minutes ago, QuantumFireball said:

...Turning off the intrusion sensor can reduce battery drain, obviously with reduced security - not sure if it's an option with the gen 4 (or fitted in your example)

The Gen 4 does have this, and pops a message on the dash every time you switch off with a yes/no choice to disable it.

At a further reduction of security, you can lock with the emergency key or by pressing the lock button on the driver's armrest and closing the door while holding the handle outwards. This will mean the alarm is fully off and the car is not deadlocked so may not be ideal.

  • Like 1

Share this post


Link to post
Share on other sites

If you have a window in the garage you could attach a solar charger. If you have power in the garage you could attache a trickle charger/battery conditioner like the Ctek which puts the Battery on a float charge once it's topped up.

  • Like 1

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this