Battery Yoyo

[phil4]

Ok, I've only had the car for 5 days now. But it's done over 750 miles in that time, and I've had a respectable 61-62mpg for two of my longer trips. However, one thing that has started me is the frequency that the Battery seems to drain down to 2-3 bars, and then get charged back up to 6-7. On a 20mile trip, I usually see it drop and charge at least twice if not 3 times.

So I wondered, I'd ask here, is this normal? After all, don't batteries have a certain number of charge cycles before they start to lose their ability to hold charge? Mobile phones seem to manage about 400. At that rate, on a 2 cycle per day, I'll be lucky if the car lasts a year.

I guess the rules might be different, but wondered whether what I was seeing above was normal?

[Grumpy Cabbie]

Ok, I've only had the car for 5 days now. But it's done over 750 miles in that time, and I've had a respectable 61-62mpg for two of my longer trips. However, one thing that has started me is the frequency that the battery seems to drain down to 2-3 bars, and then get charged back up to 6-7. On a 20mile trip, I usually see it drop and charge at least twice if not 3 times.

So I wondered, I'd ask here, is this normal? After all, don't batteries have a certain number of charge cycles before they start to lose their ability to hold charge? Mobile phones seem to manage about 400. At that rate, on a 2 cycle per day, I'll be lucky if the car lasts a year.

I guess the rules might be different, but wondered whether what I was seeing above was normal?

I'll try and keep this reply short and simple as I do have a tendancy to waffle .

Yes it is normal that the Battery cycles up and down like this. I use my Prius as a cab in town 10 hours a day and it is forever charging and discharging the Battery - even had it down to 1 bar the other day.

The traction Battery is the same stuff as a mobile or lap top battery but will last a lot longer due to the way the charging is managed. To put it simply, fully charging and fully discharging a battery is what wears it out. The computer on the Prius however, keeps the battery between 40% & 70% charged and this is the key to its longevity.

I'm sure others will elaborate and I hope this answers your concern.

[DrCez]

I guess the rules might be different, but wondered whether what I was seeing above was normal?

Hi, yes that sounds normal to me. I've read that the Prius keeps the Battery charge within a certain range: never over-charged and never fully discharged, and this prevents the Battery capacity from deteriorating, so it's not comparable with, say, a mobile phone Battery. I certainly see the charge level vary a lot on my car - I do a lot of town driving so it's switching to electric only quite frequently then running on petrol to charge back up again.

That's my anecdotal reply - someone else may be able to give a more authoritative answer!

[DrCez]

Thanks Grumpy Cabbie - you were quicker on the draw and posted (with a bit more detail as well) while I was writing my reply!

[timberwolf]

The HV Battery display on my Gen 2 doesn't seem to vary that much and it tends to stay somewhere in the blue or green bars region. I've only had it in the pink once and that was when I started the car when the interior was very hot and I then sat parked playing with the sat nav.

Maybe the Gen 2 and Gen 3 HV Battery representations are not programmed the same way when showing the SOC (State of Charge) changes? If you look at the pictures at the following site http://www.eaa-phev.org/wiki/Toyota_Prius_Battery_Specs you can see that the bars for a Gen 2 could mean a different percentage of SOC depending on whether the charge is increasing or decreasing.