Odd Startup Routine

[Sagitar]

I'm no electrician so I may be spouting pure nonsense. As you may have read our 4 month old Prius was rendered useless over the Christmas period, despite all sorts of theories on how I have left open a door, a light etc it turned out to be a faulty earth cable leading from the 12v battery in the back which the dealer repaired. Upon pressing last Friday what really happened (well at least to the level still comprehendible to me) it seems to have been earth somewhere that was getting loose making the problem appear over a period of time and with the little to no journeys over christmas it just stopped.

As I said no idea whether that makes sense or not, but if you are looking might be worth a look.

Thanks. One of the first things that I looked at was the earth connection. It's a very simple check on the Gen3, there is a quite short earth strap from the Battery to a bolt into the chassis that is plainly visible once the boot floor etc is removed. In addition, I took the car to the dealer on Jan 10th and got them to check it over - they found nothing wrong. I have only done just over 8000 miles in the car in 17 months and I do a lot of short journeys in it. This morning e.g., because it is bucketing down, I took my wife to the local day centre where she helps with the old folk. The round trip was only three miles and I needed the lights, the wipers and the front screen heater, so I guess it didn't help the state of charge of the Battery.

The dealer recommended a particular trickle charger and I have that now, so I hope my problem is solved . . . . .

[Grumpy Cabbie]

Just seen this on PriusChat - does it help at all? Is it similar to your issue?

http://priuschat.com/forums/gen-iii-2010-prius-care-maintenance-troubleshooting/89002-new-prius-peculia-start-up-problem.html

[Cyker]

I'd lean more toward the Battery.

The problem is most Battery tests are just a voltage check which is useless unless the Battery is actually dead.

If a battery has lost capacity, it'll work okay until you put a high amperage load on it (Like starting a car! This won't apply to the Prius as IIRC it uses the HV battery for starting, but powering up the computers is still off the teeny 12v and that may be enough to tip it over the edge?), then it sags quite badly. Before then, it'll be fine under normal use.

I've had this with poor quality UPS batteries; They check out during self tests, and during power outages when the servers are not under any major loads, but then some horrid heavy database op or something gets sent through and the UPS voltage and capacity meters take a sharp drop from say 99% to 10% as the server suddenly pulls a crapload of amps from it.

Assuming that's what it is, replace the battery, preferably with one that has a higher amp-hour and max-amp draw rating as that should stave off the problem for longer.

[Sagitar]

Just seen this on PriusChat - does it help at all? Is it similar to your issue?

http://priuschat.com/forums/gen-iii-2010-prius-care-maintenance-troubleshooting/89002-new-prius-peculia-start-up-problem.html

Thank for the link.

There are certainly similarities. The key thing for me is that the "Ready" signal did not show when I pressed the start button.

I am now as certain as certain can be that this is associated with low Battery voltage. I have done a series of careful checks over a period of days and my pattern of use of the car results in a slow reduction of the Battery voltage until it reaches the point where the "Ready" light does not show when I first press the starter button.

If I top up the Battery with the trickle charger, the problem disappears.

I accept that this could be the result of a poor battery (though the dealer says that there is nothing wrong with it) but it could also just be caused by my pattern of limited use.

Bearing in mind that my present arrangements are working well and that a new (higher quality?) battery could cost a couple of hundred pounds with no guarantee of improvement, I shall stick with what I have got for the time being.

[Sagitar]

I'd lean more toward the battery.

The problem is most battery tests are just a voltage check which is useless unless the battery is actually dead.

If a battery has lost capacity, it'll work okay until you put a high amperage load on it (Like starting a car! This won't apply to the Prius as IIRC it uses the HV battery for starting, but powering up the computers is still off the teeny 12v and that may be enough to tip it over the edge?), then it sags quite badly. Before then, it'll be fine under normal use.

I've had this with poor quality UPS batteries; They check out during self tests, and during power outages when the servers are not under any major loads, but then some horrid heavy database op or something gets sent through and the UPS voltage and capacity meters take a sharp drop from say 99% to 10% as the server suddenly pulls a crapload of amps from it.

Assuming that's what it is, replace the battery, preferably with one that has a higher amp-hour and max-amp draw rating as that should stave off the problem for longer.

Thanks. You are probably right, but see my answer to Grumpy Cabbie above.

[Grumpy Cabbie]

One quick question - do you use your front fogs a lot?

Just a little theory of mine, but it'll be blown out the water if you don't.

[Sagitar]

One quick question - do you use your front fogs a lot?

Just a little theory of mine, but it'll be blown out the water if you don't.

Sorry, no . . . .

Apart from testing them when the car was delivered, I don't think they have ever been switched on.

[Chris Dance]

Only used them once in heavy fog and was pleased I had them.