The MFD on my 2005 prius shows that every time the gas engine kicks in, it trys to charge the batt. even when it doesn't need to be charged. This has been happening for about 2 weeks, and not one time has the gas engine kicked in without showing the arrow going to the electric motor, even when the batt is completely full. I know it's not just a problem with the MFD because my MPG average has clearly gone down since this started.
What do you mean when you say the battery is completely full? Do you have full green bars all the way to the top? If so, under what conditions do you get full bars? Tom
I suspect it may be related to a demand for heat by the A/C system. Turn off "auto" A/C to see if the engine then shuts off. Anytime the engine is running the battery will be charged at least a bit. Unless it's in "waste power" mode because the battery is too full. I don't see a problem here.
+1, if it's original the ICE(internal combustion engine) is wasting gas topping off it's charge, look into the optima yellow top battery and installation kit, doing a quick search here on Prius chat will help find the optima, it's a deep cycle gel battery.
although you may have 8 green segments, that does not always mean you have a "fully" charged battery. also, when starting up, you should always be charging the 12 volt system as first priority during warm up anyway so a "bit" of charge i would think it to be normal. now on my Pri; i normally only have 8 segments on startup if it was very cold (not likely at this time of year) or had done several short trips that did not complete warmup cycle (also not likely since my Zenn is used for that kind of driving)
I take it you notice this while the driving so everything is already warmed up. Also you noticed it within the last 2 weeks. This was the same problem I somewhat saw before my battery pooped out completely. Do you notice a more rapid decay of the battery or is it seem ICE is kicking in more than it should, like coasting with battery almost charged and ICE kicking in. At least have the dealer check the battery. Fortunately mine was covered just before warranty expired. It was the battery and has been running fine for years now.
Yes, it is while the engine is when it is warming up and when it has warmed up. Like I said, every single time the ICE kicks in it sends charge to batt. There are no other circumstances, it does it every time. The batt does fill up all green bars often because I live in VT, and we have lots of down hill driving that alows it to coast until it fills up. I haven't noticed the batt drain any faster than it was. It fact it seems to be more charged than usual, I assume because the ICE keeps charging it.
It doesn't matter if the a/c is on or off, lights, heat, anything. The ICE trys to charge the batt no matter what is on or off.
I bought the car used a couple of months ago. I never bothered to ask (although I know I should have) if the everything is original or not. It's an 05, so I can only assume that everything in it is 5 years old.
From reading many posts on this forum I note that the 12v battery can cause all sorts of malfunctions when it starts to fail - usually about 4-5 years old. They're not that expensive to replace through the dealers and even less if you diy. Look at it another way - it's much cheaper to replace the 12v and find you have a dud HV battery, than to replace the HV battery and find you had a dud 12v!
