Haven't come across anyone asking about this so here it goes: About 20 minutes ago I started up the car and the screen indicated the main battery was pretty much empty. And hour before I had pulled into my driveway and the battery had indicated maybe 70%+. The car was off, nothing like headlights or anything I know of was left on. This happened 3 weeks ago with almost the same scenario. Within a short period of time the main battery showed near complete discharge. Same as now, nothing was on (or the keys near) to drain the juice. After I drove around and parked, it sat for 7 days and when I came back the battery seemed to be holding steady at whatever I was able to drive/charge it up to beforehand. Any ideas on this?
The main traction battery is not used by anything when the car is off. So lights, doors, etc only deplete the 12V battery. I notice that once in a long while the battery ECU will initiate a deeper discharge/recharge cycle to recalibrate. It looks as though it suddenly empties, and then restabilizes at the normal level. But it really isn't empty, 1 purple bar is 40% or so. What are your temperatures, and mileage? If the battery is changing temp it can get the ECU confused initially at start up, but it sorts it out.
Thanks for the reply. I knew the basics of what is drawn from what battery and when since I've had the pleasure or replacing the 12V already, but since this appears to be happening when the car is off it does make me wonder. But... For these two instances the display read either one or two purple (so I was a bit off saying 'depleted'). I do know the system thinks the battery is low since I can hear/see the difference when driving. Right away mileage is only 15-19 in the city and even at stop signs/lights the car will idle to re-charge the main. I'll look at the display on my way back to the house in a few hours, but I drove 50 miles on the highway each way last night and mileage was up in the high 40's. Temps today are in the mid to slightly upper 80's. Temps from the incident 3 weeks ago was about 75. Considering a few weeks ago temps were at 98-104 and it didn't do anything, I would think this current temp range wouldn't make much difference. The other day I had to reset the tire sensor as it kept thinking a tire was down even after a tire check and fill. I do know that on occasion the sensor can be off after a sharp temp difference, but I would expect that in our normal WI winters, not a 15 degree difference in summer temps.
Getting close to 80k if I remember correctly. Will be needing it's oil changed in a couple hundred more miles.
I think it has done the same for me last week. Twice. I park it with all bars except one or two and when I drive it few hours later it had 2 bars and next time 3. I was planning to put a notepad in the Prius and start writing down how many bars when parking, but haven't implemented it yet. For the rest, the car works perfectly. Temperatures are 'high' here, but 25ºC (60F?) should be normal for many on this forum. Only thing I checked so far is to see if the vent for the HV-battery was blocked next to the rear-seats, haven't checked the boot-vents yet. I know the bars have a hysteresis and are temperature dependent, but can't imagine it could ever have this much effect in normal or even exceptional circumstances.
yeah the back seat vent was my first thought with possible temp issues but they were never blocked. Guess it is one of those things to just keep an eye on until it starts affecting the car's overall performance.
oh let's see. I had to leave the car sit in winter of 09 for 3 months and that nuked the battery so I installed a new yellow top. No issues since.
Keep in mind that the graph that you see doesn't correspond to 0 to 100% SoC. It's more like 40 to 80%. See Prius Palm Mileage Simulator.
Haven't checked the 12V voltage but since the battery is only a few years old I wasn't thinking it may be an issue so soon. For the actual graph, I know it's not a true rating, but as I mentioned before the car 'thinks/knows' the battery is low since it visually attempts to compensate to charge it back up.
Give us the under accessory load voltage of Optima battery. Push start button once without holding the brake down. Then push it again without holding the brake down. Your now in access mode. Measure voltage off jump points under hood. Unless you know the MFD trick. Make sure its in access mode second button push. Then measure again with headlights on. Post those 2 back here. Also how many times have you heard the back hybrid battery fan on? The one you checked and was not clogged or obstructed.
measured 11.8 w/o headlights 11.4 w/ For the battery fan, honestly couldn't tell you. The water pump around the left front wheel has always made the most noise so that is the only sound I really always here. That has been checked and replaced by toyota but since I locked on to that sound first I guess it's been a bit of tunnelvision against other sounds the car makes unless very obvious/out of place.
11.8 is not good to begin with and a 11.4 is very bad. Unhealthy battery. All bets are off on the battery health at that voltage. Inverter has to work extra hard to continually keep that Optima charged and that hamers nmileage. Although a great battery and I have a yellowtop too they are not immune to sulphation if you leave a light on or discharge pretty good and let it sit for a while. Its a tiny little battery. Time for a new Optima in your search for results or you could try a charger with anti-sulphation mode. See if it comes back. Watch its voltage carefully for a few days. Btw, if there was anything wrong with the Hybrid battery or BM ECU it would invoke a CEL. In fact numerous CEL's. And that hasn't happened right?
I know battery levels usually run as high as 13's but was thinking the measurement from the front panel might show a lower number since I wasn't testing right off the battery terminals (as in under the rear compartment. I can't remember the exact size of the battery but I do remember spending half a damn hour just trying to get it secured into place! Any recollectionof what the battery warranty is if I need to do that? I bought it somewhere in the timeframe of late march 2009. I thought most batteries should stretch out for at least 5 years so this seems rather surprising to me. This is either good or bad timing, but on Sunday I fly out to Camp Pendleton for 2 weeks, fly back then 2 weeks later fly to Bethesda for 2 weeks. Of course during those 2 times the car will be sitting unused. And to top this off I have pending orders to Afghanistan in Jan. Won't be back until this general time 2013. The posts I've seen about long term storage mention putting a battery tender on it (given that it is fully disconnected from the car right?) For indicators, none so far. And I just had it in the shop for an oil change. Not sure if it is standard procedure but one shop I used for a while would do a full hook up with the computer to see if anything interesting was going on. If this shop it was just in did hook up a computer, they never mentioned anything being wrong. But taking this back to the original question/problem, how does the lower 12V battery voltage link to the main battery showing (or at least registering) a decreased charge status?
No thats the correct and pretty accurate number on the mfd. The 13's you mention is when the car is on and you will then see charging voltage which in our cars is anywhere between 13.5 to 14.2 depending upon the charge level of the battery at the time of inspection but a moot point in our discussion. Your Optima got real low somewhere and is now sulphated. May be mild and repairable with anti-suphation charger. You should buy one as there very handy and useful and inexpensive. I cannot explain the exact reasoning you are seeing behind the state of charge of the Hybrid battery and its link to a poor 12 volt battery but I do know a sulphated battery is hard on mileage. I have a hunch why the mfd is reacting the way it does. But again it cannot be too bad a problem or the car would throw a CEL. It likes to do that.. Suffice to say we know your battery is struggling. Do you let the car sit for long periods of time? I think the Optima has a 3 year warranty. I have to get my receipt out. And you can put a float charger on the car when you go away by using the front jump points. By the way if you just had it in a shop for an oil change check the oil dipstick asap. Every shop especially the dealer really overfills the oil. Any level over the full line kills mileage.
It's been mentioned a few times about mileage but that hasn't been an issue. Well it has when I notice the front display indicating there are only 2 purple bars then the car runs gas only to try and charge it. I see one of the charger junior units on amazon and can get it here in a few days. Sounds like this is something I can leave plugged in/hooked up to the car for 2 weeks straight?
Well thats why it hammers mileage. The engine runs more to turn the mg which charges the Hybrid battery which powers the Inverter. And batery charger not sure which device your talking about. No link.
Oh sorry, I had ordered the battery tender jr. I see where you are going with the mileage, very true. Well I would think two weeks of this little gizmo attempting to revitalize my battery will indicate if a new one is needed or not.
