Suggestions on Solar Float Charger for Windshield

The windshield on my 2006 Prius is not rechargeable. Perhaps this was a feature added for the later models.

Tom

 

I think he's planning some sort of aquatic voyage, he's looking for a float charger....

 

Sorry, I just had to add the above...

I bought one of these for my 4Runner since it sits idle for long periods of time nowadays... I tried all sorts of charging systems, and the absolute best one that I found was this one...
http://www.amazon.com/dp/product/B000FQBWCY?tag=priuschatcom-20
It actually WORKS GREAT!!! Keeps the battery topped off, monitors the battery and only comes on when needed, since I bought it over a year ago, my 4Runner starts like it has a brand new battery everytime now!!! Plus it does NOT overheat the battery!!!

 

Yes it does need 120VAC. I tried the Solar route, but unfortunatly it just does not put out enough charging current to really keep the battery topped off! To get a system that would really work as well as the Ctek, I would need the Solar unit with at least 2 large panels. It was just too big to fit in the car!!
I checked out the ones you have indicated, and the only one that might have a chance is this one..
12v Solar Battery Charger 15W

But its a bit larger than the 2 watt units....and to buy something too small is just going to disappoint you with pathetic results!

I know what your going through and feel your pain!
Good Luck

 

You will not be able to use a solar charger that plugs into the accy. plug as it is disconnected when the car is off (unless you modify it). You will have to connect to the 12V circuit.

A -small- solar panel won't overcharge the Prius 12V battery, but a medium sized one could. Most of these solar panel chargers don't include regulators so you will have no charge control. If the panel puts out a max. of 500 mA or less then you would probably be fine, as you would only get this max level for a few hours a day. The windshield does attenuate the sun quite a bit.
Do check that there is a diode in series with the panel. You would find it embarrassing (and expensive) if the panel discharged the battery overnight.

 

Go to Ebay and search for VW solar chargers. When they ship the cars over here they equip them with a solar panel that suctions to the front windshield and connects to the OBD II connector. You can always find a bunch on Ebay.

Wayne

 

Would something like this work?

http://http://www.harborfreight.com/15-watt-12-volt-solar-panel-96418.html

We have one of these, haven't ever used it in the Prius. It's pretty big, so I guess it would have to go in the trunk of the car.

 

Not by itself. As it says right on that page: "Use this solar panel to power an appliance, light, small motor, or battery, but you must use a voltage regulator (not included) between them to prevent overcharging the battery and consequent damage."

Why wait until you get stuck somewhere with a dead battery? Buy a new one now and be done with it.

 

I tried one once and it would not charge the solar panel through the tinted window. It was the front windshield and very slightly tinted.

 

Float charges are made for float glass:

[ame="http://en.wikipedia.org/wiki/Float_glass"]Float glass - Wikipedia, the free encyclopedia[/ame]




Tom

 

The following technical note was found in an article at some sort of wiki, Prius PHEV TechInfo:
------------------------
12 V system
Current draw from 12 V battery

When the 12 V battery is first connected, the car draws 1.5 A from it for about 30 seconds, then 0.62 A. That amount is enough to discharge the small 12 V battery in a matter of days.
[edit] Charging the 12 V battery

To charge a dead 12 V battery, without disconnecting it from the car, you can't use a trickle charger that provides just a few hundred milliamps. If you do, the car electronics will turn on, attempt to draw 1.5 A, swamping the trickle charger, and no current will get to the battery. Instead, you need a charger capable of more than 1.5 A (say, 2 A minimum), to handle the initial draw from the car electronics, and still have something left to charge the battery.

Alternatively, you can charge the 12 V battery by disconnecting it from the car.
[edit] Resetting after reconnecting the 12 V battery

After reconnecting the 12 V battery, you must calibrate the "Auto" function of the driver's window. If you don't do this, you can't open or close the window all the way with the Auto switch.

* Open window half-way
* Pull and hold window switch up until window is all the way up, and hold an additional 1 second or more
---------------------------
It was also noted elsewhere here that the 12v accessory outlets are disconnected by a relay when the car is off -- understandable when the car is so dependent on a charged 12v battery to run it's main controls; mustn't allow mistaken use of accessories with the car off to discharge that battery. The problem is this battery is not available aftermarket in auto stores, so replacing one accidentally damaged through excessive discharge is much more inconvenient.
(No one seems to remark that in the worse case, it would seem on the 2010 model with battery in the trunk, one could put a regular battery, only smaller size required, in the main trunk compartment of the 2010 models and run jumper cables to the battery connectors in the special battery bay under the back corner, when the regular battery doesn't fit in the designed spot, and drive away like that, at least until able to reach the dealer -- disconnect any existing battery damaged beyond charging ability.)

The above technical data is not entirely clear but indicates there are likely problems with any solar maintainer, even one connecting to the OBD II port as VW does -- if that even connects on the Prius at all in the first place, no one confirms that (though the standard OBD II specification indicates Pin 4 Chasis Ground, pin 16 (last) +12v -- but reports indicate variations in connectors and how pins are numbered in different models -- should be easy enough to isolate with a meter).
There are marketed general purpose connectors which attach on one end to the OBD socket and to cig lighter plugs on the other for power connections, such as the Clore "Solar ESA30 OBD II Memory Savor Connector" -- originally intended to provide power to OBD memory when the battery is disconnected, adaptable to maintaining the battery (so one is not limited to VW made chargers -- but note the need for proper over-charging controls on chargers, which even VW's might not have).

The part above about 1.5A loads when "first connected" is strange since a working battery is already connected and the car is not turned on when the maintainer is engaged -- unless this trickle triggers a turn on? It's all muddy. What if you just turn it off after it inadvertently turns on?
Enough to invoke Rodney Dangerfield.
[I think the point is they mentioned a dead battery, so any charger will be seen as an initiation of power, that's what switches on the engine computer drawing 1.5A. The trickle maintainer will probably not do this on a charged battery. I do not trust VW's charger to avoid over-charging, though -- they could rely just on the limited current supply, and the VW battery is much, much larger in capacity than the piddling 12v battery in a Prius, so harder to over-charge. I'd put in a Siicon Solar charge controller -- but they decline to comment an applicability to a Prius battery. Sunforce also offers panels and charging controllers, including interesting folding panels. You might get buy with the 6.5watt panel. Cost is going to be around $100. All these companies just want to sell solar cells for whatever customers find to do, but don't do any research on the applications themselves, lack of capital and markets. Very limited products, basically experimentation tools.]

 

The OBD II port always has a live 12V pin, so any maintainer connected to the port will be able to back charge to the 12V battery.

Wayne

 

I can't help but imagine someone trying to clamp a big jumper cable onto the OBD II port: "Okay, red to red ..."

Tom

 

Toyota options: on the 2010 at least, maybe the others, the dealer can program an option to default the Smartkey system to OFF. The manual also says it turns off anyway if not used in five days -- to save the 12v battery. You would have it defaulted off if the car is frequently left unused this length of time.
They also recommend just disconnecting the battery when the car is unused for long periods. If done infrequently, not clear this is more inconvenient than having to bother with solar battery maintainers, given how poorly developed they are for this car.
Another problem with such maintainers is they won't work if the car is outside in winter and gets snowed on, won't work inside a roofed garage at a business or airport etc. A simpler solution can be to just carry a portable jumpstart battery for the cases where it gets run down. The only real problem is over-depletion of the battery damaging it. There seems to be some protection against this in the Toyota electronics, turning off smartkey etc.

A subtle point made in the manual is don't store the smartkey fob within range of the radio transmitter in the car, they say six feet, as this activates power consumption. Maybe another reason to default the system to OFF by dealer programming. Inside a house on the other side of a wall of the garage could be in range.

 

I use a VW solar panel on my F250 PowerStroke, as it sits for long durations w/o use. It works similar to the Deltran Battery Tender in that it goes into "Maintenance Mode" once the batteries are topped off. However, remember to unplug the unit before you turn the car on.