dead battery and awful mpg

Now that winter is here, how many miles per month are you driving the Prius, and how many days per month is the car in use?

It sounds like you may not be driving your car very much. That combined with the cold ambient temps can result in the 12V battery becoming discharged, and also negatively impact your mpg.

You may need to charge up the 12V battery by either using a battery charger or else leaving the car READY for several hours (don't need to actually drive the car, just leave it in P). Then to keep the battery charged up, use a battery tender if you plan to continue the pattern of occasional and gentle usage.

 

Welcome to the site. IMO a new battery shouldn't discharge that quickly. I suspect the hatch was not properly closed. Was the car locked? Check your tp. Mechanics are notorious for lowering pressure. At stock pressure (or lower) the car feels like it is rolling through glue. Last winter my lifetime average increased. This year with colder temps, more snow & less insulation I'll be happy to maintain the average. My recent worst tanks are in the high 40's.

 

I would say one problem is that you drive one-mile trips; how long does that take, 5-10 minutes at a time? That is not enough time to keep a battery charged.

It is possible that the new battery was not fully charged when installed and cold weather makes a big difference in terms of battery capacity.

Unless you find that a cabin light was left on, I think you need a battery tender to help keep the battery charged up on days that the car is not in use.

 

Skier98, you sound like one of the people I believe would be better of with something other than a Prius unless you do a weekly longer trip, say 50 miles or more.
20 days a month and 12 months a year at 2 miles a day, you are doing 480 miles a year or 2 tanks a year tops. If you had a 2.4 litre Camry you would spend an extra 30 or $40 a year, probably less as the poor Prius is always warming up anyway.

Can't you get a Zen, Zap Zebra or some other electric commuter car? What about an enclosed gofer?

 

As far as the dead battery thing is...no, never heard of this issue. On the mileage issue...yes. Noticed my milage (2008 Prius) drop from 47 in summer to 35 in winter. Called my dealer today and he said that is normal due to extra pull on the battery needed for heat. Said the milage should return to "normal" during mild weather. So I guess I have to wait and see. Oh...he also said to check the tire pressure weekly, that low pressure can dramatically effect the mileage. AND that the brand of gas does matter. He said stick to nationally trusted brands...exxon, shell, etc. I asked about costco ask, but he wasn't sure.
You a skier? Just got back from Steamboat springs, CO...awesome!

 

Hi JimM,
I see lots of your posts and you sound like you know what you're talking about. How do you get such great mileage? I have a 2008 Prius and during the summer I got around 45-47 mpg but this winter I'm getting around 35-37 mpg even in rather mild winter temps (35-50F). The best I ever did was a long highway trip with the ac on during mid summer (80+F)...not too many hills...got around 54 mpg.
Is there a trick to driving for better mileage? I've heard so many things like brake more ofter, coast more....what works?
thanks a zillion.
snowtoes

 

The trick for better mileage is to live farther from work. Short drives are the enemy of mileage. Your engine barely has time to warm up before you stop.

Your situation would be ideal for an electric car or bicycle.

Tom

 

newbie here. I just joined, on the advice of a Prius-owning friend to learn the scoop.

We are having to replace an older car that is rapidly dying. We only drive on weekends, but drive 150-200 miles at a time.

We live in an area that's very cold (PA) for part of the year, with no garage, so the car would have to sit for 5-6 days before being used again, with the occasional longer time when we're away.

Does this rule out the Prius for us, given all that's been said above?


The trick for better mileage is to live farther from work. Short drives are the enemy of mileage. Your engine barely has time to warm up before you stop.

Your situation would be ideal for an electric car or bicycle.

Tom[/quote]

 

1 mile!!!???

 

Never brake, that's the trick. Avoid if possible that big pedal in the middle of the foot-well. Try whenever you can to coast to a stop if you have to stop. If you live close to work, leave early and driver for a minimum of 45 minutes before arriving at work. Pulse and glide, search for it, you will have so much reading you wont drive for a week.

It is possible to get great mileage when you live a mile from work, but you have to drive there via a place 15 miles away. See, easy!

 

This is an OK usage pattern since you have nice, long weekend drives. When you are not driving the Prius for a couple of weeks or more, you should disconnect the 12V battery or else connect it to a battery tender.

 

I know someone out there will be able to enlighten me!

I have an '01 Prius with 140K miles. Just recently had the transaxel replaced by a shop, not the dealer. I asked them to install a new 12 volt battery, which I bought from a website that provides the Prius adapted "stuff". I had them do a tune up and asked them to service the inverter, also. The tech did not replace ANY coolant in the inverter reservoir. They test drove it for several miles, then returned it to me, saying that the trans worked great.

After I drove it about 10 minutes the triangle of death and all of the other lights came on. I called them from the side of the road, they said to drive back there, so they could "check it out".

They said my main battery was bad. They had codes P3001, P3006 and P3016.

My son went into the shop with me, to pick it up, so we could take it to the dealer. My son checked the fluids before driving it and found the dry inverter reservoir. They were shocked that it had never been refilled.

Rather than drive it with possible inverter damage, I had it towed to the dealer, who said that the inverter is just fine, determined by what, the service writer couldn't tell me. They only said my main battery is toast, determined by the codes. They said I could safely drive it the short distance back to the previous shop.

I picked it up from the dealer and drove it a couple of blocks to my workplace. It appeared to be charging and no "service" lights were present. I shut it off while I transferred my coat, gym bag, etc. from my '05 Prius to the dying '01 Prius. About 10 minutes later, when I turned the key to restart the '01, it was dead as a doornail. No interior lights, no radio, no remote access, no power at all.

My co-worker jumped it and the car fired up immediately. I was afraid to drive it and get stuck in between, so I left it at my work.

Now to my question: could it be that the inverter is indeed fried (due to being driven with zero coolant) and could this affect the recharging of the 12 volt battery and could the main battery codes be a result of the same event?

NO CODES OR LIGHTS OR SYMPTOMS OF MAIN BATTERY PROBLEMS WERE PRESENT PRIOR TO THE SHOP WORKING ON THE CAR AND DRIVING IT WITHOUT ANY INVERTER COOLANT.

What do you think? Thanks in advance for your help.

 

Why did you have the transaxle replaced? What were the driveability symptoms and DTC logged at that time?

What were you expecting to happen, when you asked for the inverter to be serviced? When the transaxle was replaced, the shop should have replaced the inverter coolant which also cools the transaxle. There's nothing else that needs service as far as the inverter is concerned.

Yes, the inverter could have failed due to lack of coolant. If so, then the 12V battery would not be charged. This is very easy to check. When the car is READY, measure voltage across the 12V battery. If ~13.8V, then the inverter is fine. If much lower, then the inverter is bad. Further if the inverter was bad, usually DTC P3125 will show up.

DTC P3001, P3006, and P3126 point to a bad traction battery (and also a bad battery ECU) and would not be caused by a failed inverter.

 

Hi Patrick,

The trans was replaced, as the car behaved like a regular car does when the clutch is bad. The dealer said the trans was bad, baised on the way it drove, they said there were no codes.

Actually, I don't know how to fix a lot on my cars. I can do a few small things but my husband usually had me hold the flashlight or he sent me out for parts, while he and our sons did the repairs. This being the case, I would appreciate it if you would define for me how I would know that my Prius is in the READY position. I assume this is when it shuts down to a resting mode after the initial start up. Is this correct?

By reading some of the other comments, I gather that I can jump the 12 volt to start it, then check the voltage across the battery. Would that be a true statement?

Do you think it is okay to drive it to the shop, or do you suggest I have it towed? I don't want to cause any additional damage, to any more parts.

Now that I am doing this on my own, your info is a GREAT help!

Thanks a million.

 

Welcome orgon. Here's my "Cliff's Notes" version to better FE. Inflate the tires. The harder the better. Stop when you don't like the ride/handling. I pump to 45psi on the compressor.

Block the grill. Tony started the definitive thread. I keep the top blocked all year. The bottom is mostly blocked most of the year.

Try to keep the instantaneous FE at half the speed when accelerating. Try to maintain a steady speed (on "level" ground) and coast instead of braking when possible. Not knowing your part of PA I'll defer to others regarding the terrain.

Plug a ScanGauge II into the OBDC connector to get a wealth of information. It's easier to drive when you can see what's happening.

Drive slower. If possible trade the interstate for state roads.

Unless I need to see, the Climate Control is off for the 1st 5 minutes, then set in the low 70's, low fan speed on manual.

I'd disable the SKS because of the time the car sits.

Experiment with gas but don't go by 1 tank. The Prius seems to run better on Shell but I don't see a difference in my Intrigue.

[/quote]

 

Usually when the transaxle has failed, one or more DTC will have been logged. So the statement that there were no DTC at that time is unusual - unless the failure was mechanical, like a bad bearing, a broken gear, etc.

Prius is READY when you see the READY light appear in the dashboard (under the gear selection indicator). This means that the vehicle can be driven.

Since you have a new battery installed, if you have access to a battery charger I suggest that you try to charge up the battery. If you leave it in a discharged state it may not be restorable to like-new capacity.

However, if it is necessary to jump the car to start it (carefully observing the correct battery polarity), then do so, note that you can see READY on the dashboard, then measure the voltage across the battery using a digital voltmeter.

If you find that the voltage is ~13.8V then that means the inverter is OK. Try driving the car around the block to see if it is driveable with the failed traction battery or not, then you can decide whether you can drive the car wherever it needs to go. Obviously, the shorter the trip, the greater is the likelihood that the car will get there under its own power.

If the voltage is much below 13.8V, then I suggest that you have the car towed. Given the failed traction battery, it is possible that the inverter may not be able to produce 13.8V even if it is functioning, so a low voltage does not guarantee that the inverter is bad.

 

Hello Patrick,

You know, I wonder if it really did need a trans, since they said that there were no codes.

THANKS SO MUCH for your advice. Armed with your info, I now understand more and I believe that I can do what needs done.

With my husband deployed, I need to take care of these minor problems without giving him reason to worry.

You are lifesaver!

I'll let you know how it turns out.

 

Hi Patrick and WC422,

There is a possible problem that could have happened, where the transaxle would need to be dismounted, to repair the problem, but not replaced. Between the transaxle and the transmission is a torque-limiter. It rarely happens, but sometimes it does, the torque limiter will begin to slip. Its built like a clutch, but because it slips only rarely in its intended function, it should not ware out.

This would have given the slipping like a standard car symptom, and no codes. So, you may have had a transmission swap, when you just needed a clutch pack ($150?) replaced (probably $500 labor though).