Avoiding 12v battery depletion

I have the VW charger, too. Their used when shipping and storing the cars, so if it works for them, it should work for the Prius. The main reason I'm asking is when I'm on lunch at work, I go out to my car and listen to the radio and I don't want to crap out the 12v battery.

 

^^^
I've heard of some negative effects of the VW solar charger on some cars where the 12 volt ends up being drained instead. The guess is that on those cars, the car gets confused and doesn't stay in some power saving mode, depleting the 12 volt.

As for your use case, how long are you doing this every workday? How long is this vs. your commute? If you're really concerned, I'd suggest you just properly power on the car instead (foot on brake + power).

 

I just picked the car up a couple days ago, so this'll be a bit of an experiment.

I've had the VW charger a few years. I bought it because when I had my Seville, it used to sit for weeks at a time and pull the battery down to a point where the car would just about start or I would have to charge the battery to get it to start. I never had that problem again after I started using the VW charger.

 

You cannot stop the battery from being discharged unless you actually disconnect it, either at the battery (negative terminal), or using a fuse pull (ask your dealer which one), or the positive lead at the boost terminal. You will loose any "options" you had the dealer program or that you programmed. You will have to reset the "auto window up" (which is easy) and the radio pre-sets. You may also have to press "on" two times when you reconnect the battery.
So that's one option.

You can get a solar charger. It should have a series diode to prevent reverse discharging of the Prius battery when there is no sun. Any solar panel you can fit on the dash will not overcharge the Prius battery. In fact, your problem will be to get one that actually puts out enough current to charge the Prius. You will need at least 30 mA, preferably 100 mA in the sun while -inside- the car. The car's windows DO reduce the charging!
So that's another option.

You can charge from the OBDII port. I would avoid that without knowing a lot more about what that may do regarding confusing the computers in the Prius. I don't see how it would confuse the computer, but without trying it I can't say for certain.

You CAN put a larger battery in parallel with the Prius one. It will lengthen the discharge time by a lot, depending on how much capacity it has. The problem is where to put it safely. It's heavy, and if there were an accident you DON'T want that thing flying forward toward your head! A 40 A-Hr would double the discharge time.

Finally, you can get a "Battery Tender" or a "Battery Minder". They come with "pig-tails" that can be installed in the car for quick connect/disconnect. They won't overcharge the battery, but you do need 115VAC, though it can be intermittent (on for, say a few hours a day only).
My battery tender sits on the garage wall where I installed a tiny shelf for it. I pop the hood and plug into the pig-tail that I installed on the fuse box booster terminal. There is enough room that the leads can be run out of the fuse box without compromising the water resistance of the fuse box. I will say I haven't used it until now (battery now 4+ years old). I plan on using it in the winter during very bad weather, when I'll be using the FJ and Pearl may sit for a week or two.

Those are the options I know of.

 

Good morning!

How do you do? I read a long time your forum priuschat.com and a category title It not meant it Everything takes longer than you think. All the best!

 

I don't know about later models, but on my 2005 if the smart key
disable button is not used when the car is not driven for a week to 10 days the chassis battery will fully discharge. Therefore, I
routinely shut it down when parking for the night. Being retired, I may not use the Prius for days. I posted this warning back when first joining PriusChat.

SIPNGAS

 

As was posted earlier, the SKS disable button/switch was removed from the Gen 3 (MY 2010 and later). I hope it comes back in the next gen or in the '12 refresh.

 

However, it is interesting to note that the SKS will automatically disable on both the Gen II and Gen III. It does this after several days of inactivity to help avoid draining the 12V battery. On the Gen III, the interval was shortened to help compensate for the removal of the disable button.

Tom

 

Here's the specs for the VW solar charger.
VW Solar Panel Specs | eHow.com

 

Anti-theft systems and even auto on/off headlight systems can drain the battery. I have a second car sitting in the garage with a disconnected battery; it can sit for months at a time with no problems (but don't forget the fuel stabilizer).

 

Due to being away on business for long periods of time, both my Prius and now my FJ (Only 300 miles since April) require the use of a VDC Battery Minder

BatteryMINDer® Plus 12 Volt 1.33 Amp Charger-Maintainer-Conditioner (Desulfator) | All | Battery Chargers by BatteryMINDers.com

Never a problem with the battery

My first winter with my '04 Prius, the combination of short winter days, very short 10 min commutes, -40, constant defrost and rear defog, the charging system could not keep up

The Battery Minder then became mandatory for me

 

I've had my battery die two times on my 2010 generation 3. The dealer replaced the battery the first time, but that did not resolve the problem. I purchased one of the small batteries that plug into the cigarette lighter to get the car started when if the 12 volt battery dies. Now that I realize that when this happens, I cannot access the accessory mode, so the cigarette lighter socket will not operate. Is this correct?

alan

 

If that's the case, cut off the plug-in adapter and add a couple of alligator clips.

 

Makes one wonder if a bigger battery that weighs a few extra pounds/is a few inches bigger wouldn't be such a bad idea.

 

It would be a wonderful idea but none is made that will fit. The Optima D51Yellow top will fit but is almost the same A-Hr capacity, though is more resistant to damage from full discharge. See my measurements here > http://priuschat.com/forums/gen-ii-...sion/96754-some-measurements-12v-battery.html . While this is for a GII I suspect the GIII is very similar.

Check very carefully all lights in the car. Some have three way switches and may not be visible from the outside if left on. For example, the hatch area light. Also make SURE -ALL- doors are fully closed when you leave the car. The two lower door lights can't be seen if left on (a door ajar will turn them on - including the hatch). While most other lights can be turned off with the switches those ones can't be.

 

Please ... tell us how long a 2010 Prius Model IV can be parked (and not used or started) before the 12v battery becomes of concern? We take 1-2 week vacations from time to time and I don't want any problems starting the car.

 

Two weeks is no problem if you have a good 12V battery.

Tom

 

Maybe giving the 12v battery a good charge with a regular charger before leaving will help.

 

. Agree with post 38 and 37, you can install a battery quick disconnect switch at the hatch area.

 

From another thread. I hope this works.
http://priuschat.com/forums/attachm...g-3rd-gen-tsbs-tsb-battery-during-storage.pdf