Not Started For 4 Weeks

[timberwolf]

My Prius 2008 has been sat idle for the last 4 weeks as I was admitted to hospital as an emergency with acute abdominal pain in the middle of December. I spent 3 and 1/2 weeks in Southampton General Hospital and having never been admitted to hospital before I was amazed that anything worked as you see so many different doctors and consultants (probably not helped because of all the bank holidays and the snow). By the way, I don't know if I was just on a good ward but the nurses were excellent always cheerful and friendly.

When I came out of hospital, I did wonder if my Prius 12V Battery was going to be dead, but the little amber flashing car symbol (alarm?) was still blinking away. The disc brake surfaces look pretty rusty, curse those alloy wheels. The car unlocked with the fob today, and I've hooked up a 12V trickle charger and put it on snowflake charge mode. I do wonder if the occasional trickle charge helped the 12V Battery survive the 4 weeks?

[Chris Dance]

Hope your soon recover Timberwolf. Good news about the Prius I expect the trickle charge helped the 12v Battery. I have left mine for two weeks with full anti theft devices on and the Battery was OK the car started first time.

[Jan&tone]

Get well soon pal, the car should be fine, just make sure the boot lightis switched off - just in case

[rodi]

get well soon, btw I left the interior/inside lights on by accident all night and next morning I though I may need to call for helo with Battery but, hey ho, the engine starts and I drove as usualy. Does anybody know how long you can play the car stereo till still allow you to start the engine?

Regards

[serendip]

Hi Timberwolf, best wishes for a full recovery, and it's good to hear favourable reports about the hospital ward and nurses.

I thought I would mention that, if we're talking about CTEK chargers and 'snowflake' charge, I tend to avoid this with the Prius Battery, unless you're charging out of the car, because of the slightly higher voltage in that mode.

Probably me just being over cautious, but could be of interest.

[acetip]

Get well soon pal, the car should be fine, just make sure the boot lightis switched off - just in case

i dont own a prius,as financse at the moment dictate otherwise.but i am interested in the tecnology.

ive seen several times on this forum of cases where owners have failed to close their boot/hatches properly and have drained their batteries.

many makes of cars have a delay of somesort that turns off the boot light after a certain time and protects against a Battery discharge.i am surprised at a car costing what a prius does that it does not have this protection fitted.

but it should be easy enough to fit an after market device to protect against this happening.

[Jan&tone]

Get well soon pal, the car should be fine, just make sure the boot lightis switched off - just in case

i dont own a prius,as financse at the moment dictate otherwise.but i am interested in the tecnology.

ive seen several times on this forum of cases where owners have failed to close their boot/hatches properly and have drained their batteries.

many makes of cars have a delay of somesort that turns off the boot light after a certain time and protects against a Battery discharge.i am surprised at a car costing what a prius does that it does not have this protection fitted.

but it should be easy enough to fit an after market device to protect against this happening.

Lol, there is a failsafe, it's called a switch!

The first thing I do when i pick up a new car is to turn off the boot light at the switch having been caught out many years ago with an Avensis!

[acetip]

Get well soon pal, the car should be fine, just make sure the boot lightis switched off - just in case

i dont own a prius,as financse at the moment dictate otherwise.but i am interested in the tecnology.

ive seen several times on this forum of cases where owners have failed to close their boot/hatches properly and have drained their batteries.

many makes of cars have a delay of somesort that turns off the boot light after a certain time and protects against a Battery discharge.i am surprised at a car costing what a prius does that it does not have this protection fitted.

but it should be easy enough to fit an after market device to protect against this happening.

Lol, there is a failsafe, it's called a switch!

The first thing I do when i pick up a new car is to turn off the boot light at the switch having been caught out many years ago with an Avensis!

poor excuse for lack of modern equipment i think.

[timberwolf]

Hi Timberwolf, best wishes for a full recovery, and it's good to hear favourable reports about the hospital ward and nurses.

I thought I would mention that, if we're talking about CTEK chargers and 'snowflake' charge, I tend to avoid this with the Prius battery, unless you're charging out of the car, because of the slightly higher voltage in that mode.

Probably me just being over cautious, but could be of interest.

Thanks everyone.

Yes it is a small CTEK charger. I only use snowflake mode when it is cold, there was a frost on the car, but I was probably being a bit optimistic in thinking it was close to freezing. I usually use the car mode of 14.4V/3.6A although I doubt the snowflake mode of 14.7V/3.6A is going to do any damage. When the Prius is doing the charging itself, the voltage only seems to rise to 13.8V according to the CAN Bus sensor diagnostic code, which I think is the reason that some have owners have concluded that the 12V Battery is normally not charged to full capacity.

[serendip]

Hi Timberwolf, best wishes for a full recovery, and it's good to hear favourable reports about the hospital ward and nurses.

I thought I would mention that, if we're talking about CTEK chargers and 'snowflake' charge, I tend to avoid this with the Prius battery, unless you're charging out of the car, because of the slightly higher voltage in that mode.

Probably me just being over cautious, but could be of interest.

Thanks everyone.

Yes it is a small CTEK charger. I only use snowflake mode when it is cold, there was a frost on the car, but I was probably being a bit optimistic in thinking it was close to freezing. I usually use the car mode of 14.4V/3.6A although I doubt the snowflake mode of 14.7V/3.6A is going to do any damage. When the Prius is doing the charging itself, the voltage only seems to rise to 13.8V according to the CAN Bus sensor diagnostic code, which I think is the reason that some have owners have concluded that the 12V Battery is normally not charged to full capacity.

Thanks for your response Timberwolf. I have read in other posts that the maximum charge voltage seems to be around 13.8v, and that is really what has led to my concern.

I think I'm right in saying that in a conventional car with an alternator, the electrical system will be running with the Battery 'floating', and achieving a good state of charge, at something like 14.2 to 14.4 volts. The lights and other accessories will be designed to operate efficiently and reliably at that voltage.

The Battery chargers that we are talking about also operate at 14.4 volts or thereabouts to provide a full charge. So if I connect my (CTEK) charger to the terminals under the Prius bonnet (without disconnecting the battery), might I expect to temporarily achieve a better charge for the lead acid battery, which in turn might help to reduce sulphation and prolong battery life? This would obviously be a plus.

BUT, and this is my question, what would the 14.4 (or 14.7) volts be doing to the computers, ECUs and other expensive electronic items in the circuit? I presume they are designed to operate efficiently at the maximum Prius charge rate of 13.8 volts. I suppose a jump start from another car would also produce a higher voltage if the engine were running at much more than tickover speed.

As I said before, perhaps I am just being over cautious.

[capnbirdseye]

I'm wondering why the Battery is so small, it's either because of weight or so that the charging system when on the move doesn't have to dedicate much of the charge to it so the majority goes to the main Battery. I would think the 12v Battery is on the same lines as a leisure battery such as in our camper van, this battery is not capable of starting a vehicle but is capable of running 3 12v interior strip lights for several hours without losing hardly any of the charge

[sjrainsford]

Simple, it's so small as it only needs to supply ancillary devices and not provide the huge starting current required to start an engine.

[capnbirdseye]

Simple, it's so small as it only needs to supply ancillary devices and not provide the huge starting current required to start an engine.

It's not really simply that though because reading all over the net it seems to be one of the Prius's common failings with reports of simply sitting in AUX mode listening to the radio etc. or leaving the boot light overnight can flatten it rather quickly to the point you can't start the car

[Jan&tone]

Simple, it's so small as it only needs to supply ancillary devices and not provide the huge starting current required to start an engine.

It's not really simply that though because reading all over the net it seems to be one of the Prius's common failings with reports of simply sitting in AUX mode listening to the radio etc. or leaving the boot light overnight can flatten it rather quickly to the point you can't start the car

The 12v Battery powers the computers that control the starting of the car.

If you notice when you first push the gogo button, apart from all the christmas tree lights coming on and a gentle hum from under the bonnet, nothing actually happens! On mine, the engine doesn't actually start until after I've got the car out of the garage, on very cold days it starts half way out, but normally I've just got out of the car to shut the garage door when the engine starts!

I suspect the 12v actually does bugg*r all apart from keeping the chips happy.

As for flattening the Battery overnight, I did that on an Avensis many years ago, left the tailgate on the first latch and came back next morning to find the whole thing dead... RAC man (it was the RAC did Club T in those days) said he knew what it was as soon as he got the call, his comment was that he only ever attended Toyotas with flat batterys, 'cos nothing else went wrong with them!!

[kithmo]

Thanks for your response Timberwolf. I have read in other posts that the maximum charge voltage seems to be around 13.8v, and that is really what has led to my concern....

With the NAV screen in diagnostics mode, the Voltage when the engine is running shows 14.2v on my Prius.

[Jan&tone]

Simple, it's so small as it only needs to supply ancillary devices and not provide the huge starting current required to start an engine.

It's not really simply that though because reading all over the net it seems to be one of the Prius's common failings with reports of simply sitting in AUX mode listening to the radio etc. or leaving the boot light overnight can flatten it rather quickly to the point you can't start the car

Just an afterthought for this one... I got stuck in a traffic jam on the M20 in my Gen2 last year for 2.5 hours 'cos some idiot that had overtaken me 5 minutes before decided to lose control and run up the embankment and back onto the carriageway upside down... we sat there listening to the cd's and every now and again the engine started, charged the HV Battery, and then switched itself off! seemed to be about an hour between charges as far as i can recall... the others in the jam around us were fascinated by the car and we spent an enjoyable time parked in lane 2 of the m20 explaining how the car actually behaved!

[Sagitar]

As I said before, perhaps I am just being over cautious.

Yes, I think you probably are. Pages 529 & 530 of my Owners Manual set out the procedure for getting a jump start from another vehicle. There is a clear instruction to raise the engine speed of the other vehicle and to maintain that higher engine speed while turning the Prius "Power" switch to the "On" mode and starting the hybrid system. There is no impression that Toyota are worried about the input voltage being too high.

If there is any part of the vehicle system that requires a tightly regulated voltage for its operation, it is most unlikely that the designers would leave that to the vagaries of the output voltage of an alternator on another vehicle.

[timberwolf]

Playing devils advocate, being a bit cautious doesn't hurt, especially when you consider the cost of the Prius compared with a 50 quid charger (for example, the liability if the charger was faulty would probably and usually be limited to just a new charger!). :!Removed!:

[Jan&tone]

Playing devils advocate, being a bit cautious doesn't hurt, especially when you consider the cost of the Prius compared with a 50 quid charger (for example, the liability if the charger was faulty would probably and usually be limited to just a new charger!). :!Removed!:

I'd be inclined to err on the side of caution as well. To the extent that frankly i wouldn't even think about taking the 12v out!!

Leave it to the professionals, then if they screw it up, you do have recourse!

[capnbirdseye]

Simple, it's so small as it only needs to supply ancillary devices and not provide the huge starting current required to start an engine.

It's not really simply that though because reading all over the net it seems to be one of the Prius's common failings with reports of simply sitting in AUX mode listening to the radio etc. or leaving the boot light overnight can flatten it rather quickly to the point you can't start the car

Just an afterthought for this one... I got stuck in a traffic jam on the M20 in my Gen2 last year for 2.5 hours 'cos some idiot that had overtaken me 5 minutes before decided to lose control and run up the embankment and back onto the carriageway upside down... we sat there listening to the cd's and every now and again the engine started, charged the HV Battery, and then switched itself off! seemed to be about an hour between charges as far as i can recall... the others in the jam around us were fascinated by the car and we spent an enjoyable time parked in lane 2 of the m20 explaining how the car actually behaved!

The difference there being that presumably you didn't put it in AUX mode which would have flattened your 12v Battery ?

[Jan&tone]

Simple, it's so small as it only needs to supply ancillary devices and not provide the huge starting current required to start an engine.

It's not really simply that though because reading all over the net it seems to be one of the Prius's common failings with reports of simply sitting in AUX mode listening to the radio etc. or leaving the boot light overnight can flatten it rather quickly to the point you can't start the car

Just an afterthought for this one... I got stuck in a traffic jam on the M20 in my Gen2 last year for 2.5 hours 'cos some idiot that had overtaken me 5 minutes before decided to lose control and run up the embankment and back onto the carriageway upside down... we sat there listening to the cd's and every now and again the engine started, charged the HV Battery, and then switched itself off! seemed to be about an hour between charges as far as i can recall... the others in the jam around us were fascinated by the car and we spent an enjoyable time parked in lane 2 of the m20 explaining how the car actually behaved!

The difference there being that presumably you didn't put it in AUX mode which would have flattened your 12v Battery ?

No, it was "ready"

[dawesy]

when i was working at toyota building the Auris HSV we went on a training course as some times repairs are needed that need the HV side de energising.

now de energising isnt too hard, pull the orange safety plug from the HV Battery,leave ten mins and check voltages at the inverter. it is however very dangerous as there is 201V DC there so any shock is going to be fatal!

the 12V Battery though, there is no problem with disconnecting it for charging off the car.

[Sagitar]

I'd be inclined to err on the side of caution as well. To the extent that frankly i wouldn't even think about taking the 12v out!!

Leave it to the professionals, then if they screw it up, you do have recourse!

Personally, I would have no concerns about taking out the 12v Battery. All the information I need is in the handbook. But of course, individuals must make up their own minds about their level of comfort and competence to do jobs of this kind. For me, it is well inside the owner-maintenance envelope.

[Doesn'tExist]

I've got one of those CTEK charger devices as well, absolutely brilliant has saved me lots of money when I had cars sitting on our land that otherwise needed a new Battery. Can bring back a Battery from dead pretty well.

And I used it on my boat throughout the winter period as well to keep them in good condition. Highly recommended. But I do take the batteries out of any type of vehicle when I do this and do it in the safety of a nice and dry environment and ensure nothing else is connected. Just in case.