Like many here, I too have been monitoring my 12v battery & have noticed fluctuations that seem a bit off. I considered all my reasonable options like: 1) Go to dealer & waste my time. 2) Plugin my 12v Battery Tender daily. 3) Buy a new, possibility better 12v battery. After that, here's my simple solution to address this problem, I researched & purchased this flexable 12v / 10 Watt solar panel that's roughly the same size as a front licence plate. This particular 10 Watt panel puts out roughly a 1/2 amp under ideal conditions, but I figure the realistic output is closer to 1/3 of an amp per hour on any average partly sunny day. My total cost was about ~$19 dollars & it took roughly 2 weeks to take delivery. The panel was well packed, alligator clips are included & a blocking diode (important) is used inside the small black box on the back side of the panel. My first attempt at installation was to use the two license plate screws, but I didn't like the way it looked. On my second install I trimmed the panel smaller by cutting it with a pair of scissors & then I mounted it higher up on the chassis by using Velcro which is holding perfectly at any speed. The wiring easily gets fed through the grill & comes up through the hood latch, then the alligator clips conveniently attach to the battery terminals. I've only had this operational for about 1 week, but I'm optimistic about the ability of this solar panel to give a small positive edge in charging/helping the 12v starting battery. Ebay 12v / 10 Watt Solar Panel: www.ebay.com/itm/12V-10W-PolyCrystalline-Epoxy-Resin-Solar-Panel-With-Alligator-Clip-Wire-M2A5/352615881302?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649 Rob43
This strikes me as a good example of covering up a problem instead of actually fixing it. Unless maybe your car just sits unused for about 70% of it's life, there should be absolutely NO NEED for any such device. OH......and those "fluctuations that seem a bit off"......might not be a problem at all.
Thanks! Time will tell, it's been mediocre weather ever since I installed it. I of course hooked it up to my volt meter on a sunny afternoon and it does put out what it's suppose to. So for $19 bucks & an easy install, I see no down sides. Rob43 PS, On a side note: While at the mall, some guy ask me if the solar panel charges up the car, I said it sure does.
There is no way that panel is going to be very effective mounted vertically. You are losing about 70% of your potential solar input with that setup, and the protective plastic probably knocks off some more of the input. I'm not sure what problem is being solved - "fluctuations a bit off"? Was the battery discharging while the car was idle? Was the alternator putting out inconsistent voltage/current?
While it's always best to point any solar panel directly at the sun, solar panels still make reasonable* power when positioned at off peak angles. Realize this: Some 12v solar charge input is better than no solar charge input. Rob43 * What do you think happens on a cloudy day. (Rhetorical)
I don’t believe the Prime has an alternator. The 12 v battery is charged by the traction battery when the car is in ready mode.
honest question, if it doesnt have a alternator then what charges the traction battery when in hybrid mode, or driving in charge mode? I understand some charge will come from braking regen, but there has to be a alternator, or something doing that job. question for OP. That panel looks much larger than a license plate, is it covering up some of the air intake? I would have a concern about over heating. I do like the idea.
What circuitry prevents this from overcharging the car battery? Just the voltage level limit on the panel? What is the output voltage?
Interesting! Is the solar panel connected to 12v battery ALL THE TIMES or do you have to connect it when you park? What you need is one of those solar roof kit, I believe available for Japanese and EU models.
Same thing that charges the 12V battery when in EV mode: the DC/DC converter which is part of the inverter. It also runs instrument lights, dome lights, and anything else that runs off 12 volts.
Well done Jerry, Prof. Kelly once again answers all the questions in this thread very clearly and with data. Guess I won't be jump starting anyone anytime soon. Ready mode or not.
There is an electronic inverter/converter that runs off the HV battery and makes ~12 V for charging the small battery.
Alternator duties are covered by M/G 1(motor/generator). It also replaces the starter of a traditional car. As for overheating, the grills and radiators are designed for max engine load in a desert. They are oversized for the majority of users.
It's connected at all times, I refer to this as "set and forget"; remember it's just a trickle charge during daylight hours. Rob43