Hey guys, So I read one other thread already about having a "potentially" full battery. Well I am in the middle of my first long road trip in the Pri (from Texas to Virginia and then back again). Life was good until I got to the Appalachian mountains (more specifically interstates 77 and 64 in West Virginia as well as interstate 64 in Virginia). These extreme inclines and declines put me in a situation I had not yet faced in the Pri. The traffic was not light and simply driving 70mph (speed limit) on these grades kinda keeps you up on the wheel. So I was not watching the dash as much as normal. But when I finally did look down...the battery was full. And I mean full...even the terminal caps showed bars. I am not sure if this equates to eight or nine bars. I assume eight? Sorry as I was not trying to count at the moment. Well once I noticed it...I got concerned, but then also found myself where there was little I could do to undo the situation. Braking just charges more and I really could not speed up on the downhills due to the road conditions. I had not yet gotten familiar with the engine brake...perhaps this is what would have helped out some. Then the car did something I did not expect. It shut off the motor (at 70mph) and kept it off. Even when I hit the bottom of the grade and started up the next incline...I was giving it a good bit of throttle and the mpg meter was still showing 100mpg (motor off). I assume this is the fail safe mode the system goes into to put all attention on battery draining. Based upon what I have been reading, the hybrid system seems to not allow over charging...but I still remain concerned. Even once I got on back on an incline...it took a while to pull the battery charge back off of full. For those that know these roads....they are not a few hundred meters of downhill steep declines, we are talking miles. Just curious if any of you have ever seen the batter bar completely full including the terminal caps. I am heading back on Thursday via the same route (backwards). I will add the B mode since I have been tinkering with it since I got here will be interesting to see how it helps. Some of the inclines are so intense...not sure even that engine brake will be enough.
Don't be. You are overthinking the issue. Unlike many cheap consumer products, the car takes very good care of its battery without any user intervention. How tall are the Appalachians? I thought they were short compared to the Rockies and other ranges out west, where the Prius handles itself quite well on all Interstate highways, which are legally limited to a moderate slope. If you get off the Interstates to the really step roads, then start reading up here about mountain roads. And do go ahead with testing the B mode. Your brakes (not the battery) may thank you.
Not sure what your concern is. You're worried because the battery got full? Go down any hill for long enough time and the same thing will happen.
just wish for a bigger battery. at some point the car will spend the energy as fast as it gets it... (max electrical rotation to burn power... which includes spinning the ice)
It's not a fail-safe, it's just normal behavior. And the engine very well may have been on while you were getting >100 mpg. In fact, if you were over 46 mph, the engine was at least spinning, and probably doing a little bit of work. But yes, the car will mostly use energy from the battery. In general, when the state of charge is over 70% or so, the computer tries extra hard to use battery power. The battery is "full" at 80%, and the computer won't let it charge any further. The target level is 60% (6 bars); cruising on the highway at a constant speed will almost always leave you there. Even being 2-3% away from a 60% SoC is enough to make a small but measurable difference in the amount of energy drawn from or put into the battery while accelerating.
I get full battery indication on my trips down to LA too. As others have indicated once the battery is full, charging is stopped so you should not be concerned.
At any rate, the battery was NOT "full" or "fully charged". It was at 80% charge +or- a bit. The HSD will NOT allow it to overcharge or even -fully- charge. What it's showing you is you had full -allowable- charge. Again, nothing to worry about. In fact, it's a good indication your HSD is working properly. So enjoy, and watch the blinking lights. Well, the road first, then the blinking lights.
I topped out at 3252ft. Not sure where the highest peak in the range is...my guess I was not on it. I am sure it is nothing compared to the Rockies...but was the first time I had seen this scenerio. I do not have this in South Texas...it is flat as a board. The only reason why we have any hills is because of interstate overpasses
I would recommend getting a scangauge II. You can set it up to show the State of Charge and you'll always be aware of the charge % of the battery. You can also monitor the ICE RPM's, You'll always know if the engine is spinning or if its truly off. I've noticed in mine the engine will keep spinning around 990-1000 rpms even going downhill once I'm over a certain speed.
I can fill the battery around here without hills by driving at hwy speeds enough to fill it to 7/8ths and then heavy braking. Do it nearly everyday. Get real good mpgs for the short bit afterwards as it drains it off to back to 7/8ths. Next time you're in the hills you'll remember to shift to B. I bet you also forgot about hill assist too! Not much need for that either in south Texas.
Try running with the cruise on going down those mountains. Once you see your battery gauge hit the top you will start hearing the motor really wind up. The computers keep everything safe, but that motor is freakin screaming going down the mountains The first itme it happened to me I was like it's gonna hold me back or I'd be seeing motor parts scattered on the road behind me It stayed together of course and the car kept within 1 mph on the downgrade with the battery gauge showing to the top. Mike
