ToyoGuy Posted February 28, 2016 Share Posted February 28, 2016 Got a neighbor who has been using a dashboard-size (read $20+ here) solar battery maintainer for about a year now on his Landcruiser and swears by it. Since I store the RV outside here in $unny Ca, it seems like a simple, easy way to maintain charge without the extension cords I need for my current cheap-o plug-ins. It'd be one for each battery, I guess. Any experience, thoughts or warnings? BR, TG Quote Link to comment Share on other sites More sharing options...
zero Posted February 28, 2016 Share Posted February 28, 2016 1 hour ago, ToyoGuy said: Got a neighbor who has been using a dashboard-size (read $20+ here) solar battery maintainer for about a year now on his Landcruiser and swears by it. Since I store the RV outside here in $unny Ca, it seems like a simple, easy way to maintain charge without the extension cords I need for my current cheap-o plug-ins. It'd be one for each battery, I guess. Any experience, thoughts or warnings? BR, TG I don't know what you are calling "dashboard-size." I use solar maintainers on several pieces of farm and construction equipment. Main thing it this. The solar panel has to make more power then what your vehicle draws when parked. Otherwise it is useless. Something that can make 1/4 amp per hour, on average, for a 24 hour day is pretty much the minimum. Since there is only useful sun for 5-6 hours a day, that means a solar panel capable of at least 1 amp @ 14 volts. I.e. 14 watts or more. I use a fold-up 13 watt panel on some of my rigs. It fits nicely on a dashboard and folds up like a little suitcase when done. No controller needed for a panel that small. Harbor Freight sells them. Many people use tiny 1 or 2 watt so-called chargers and rave about them. Seems to be a placebo effect to me. A "1.5" charger likely puts out 1 watt for 5-6 hours a day. That comes to 7/100ths of an amp for 5-6 hours. That comes to 1/100th of an amp per hour for a 24 hour day. Quote Link to comment Share on other sites More sharing options...
ToyoGuy Posted February 29, 2016 Author Share Posted February 29, 2016 Thanks, and yeah, sure enough, he's got the 1.5 watt model. Sounds like anything else, if it looks too good to be true, it usually is. Will take a look at the 13 watt unit this week at Harvard freight. Quote Link to comment Share on other sites More sharing options...
zero Posted February 29, 2016 Share Posted February 29, 2016 A 1.5 watt solar panel in a sunny area might make just enough power to off-set the self-discharge rate of a smaller battery. All batteries lose power and go dead on their own even if hooked to nothing. 5%-10% a month. If your starting battery is 80 AH, that means it will lose a 1/4 amp-hour per day approx. A 1.5 watt solar panel makes just about that much power in one day if it's sunny all day. Note that I have never lived anywhere that has sun all day, every day. So if that is all it has to do - it helps. Newer vehicles have a lot of battery draw besides the self-discharge rate of the battery itself. With some - 200 milliamps is normal. So with newer vehicles - a 1.5 watt panel is pretty useless. On an old Toyota if it draws zero when parked , I can see where it can help a little. My 1988 doesn't draw zero but it's close. Uses around 20 milliamps when parked. I don't know if it's loss from the alternator, or memory for the radio, or the on-board computer, etc. Never cared much. My 2010 Suzuki and my 2002 Chevy Tracker both draw 200 milliamps when parked. My 2002 Dodge GrandCaravan about the same. That's why modern cars and trucks go dead when parked for two months without being started. At least with my Dodge - the owner's manuals states clearly - "must be started at least every 6 weeks to maintain battery." Quote Link to comment Share on other sites More sharing options...
Maineah Posted February 29, 2016 Share Posted February 29, 2016 We had low voltage automatic shut off controllers on several of the police cars more that any thing else they were for the huge collection of electronic devices that they forgot to turn off cell phone chargers, radar units flashlight chargers, two ways etc.. Saved the county a lot of jump starts. Quote Link to comment Share on other sites More sharing options...
linda s Posted February 29, 2016 Share Posted February 29, 2016 I've had a couple of these little ones that I got at Harbor Freight for free with a coupon. Worked great keeping my battery on my Nissan that's in storage topped off. Last visit it was gone and battery power was noticeably lower. Now I'm paying my granddaughter to go over every week and start and run it for a while. The free solar unit was cheaper Linda S Quote Link to comment Share on other sites More sharing options...
zero Posted February 29, 2016 Share Posted February 29, 2016 All depends on where you live and park the vehicle. There are areas in the USA with twice the usable sunlight then we have here in northern MI or NY. If you live where there is twice the sun, a solar panel acts twice as big. Anybody remember when Volkswagen was including little solar chargers in the mid-2000s? Plugged into the cigarette lighter and some had suction cups to stick on the windshield. I cannot remember how big they were. For a few years -there were tons of them for sale on Ebay. Now - I know VW and Audi use a 5 watt panel. IT plugs into the computer's OBDII port. 5 watts is not much but it is still a lot more then 1.5 watts. 5 watts means a max charge rate of 1/3 of one amp in max sunlight. I bet this guy's battery never goes dead. Quote Link to comment Share on other sites More sharing options...
Derek up North Posted February 29, 2016 Share Posted February 29, 2016 http://www.ebay.com/itm/Volkswagen-Solar-Panel/331781830855?_trksid=p2047675.c100011.m1850&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D35694%26meid%3D7c3afea4ffc04f65b514c2452db26e3e%26pid%3D100011%26rk%3D4%26rkt%3D4%26sd%3D150919527779 Quote Link to comment Share on other sites More sharing options...
zero Posted February 29, 2016 Share Posted February 29, 2016 By golly Derek, you found one. Price is pretty damn steep. The new ones VW use are also priced high. 5 watts now instead of 3.5 like the one on Ebay. And the new ones plug into the computer diagnostic port instead of a power port/cigarette lighter. Quote Link to comment Share on other sites More sharing options...
Derek up North Posted February 29, 2016 Share Posted February 29, 2016 Even the newer OBDII panels are 3.2w from VW. http://www.ebay.com/itm/VW-Volkswagen-12V-Solar-Panel-Battery-Maintainer-OBD-Plug-USED/272098039233?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D35694%26meid%3D90677a9894c5490c943e5d7ad4d36a2d%26pid%3D100005%26rk%3D1%26rkt%3D4%26sd%3D331781830855 Quote Link to comment Share on other sites More sharing options...
zero Posted February 29, 2016 Share Posted February 29, 2016 Different supplier maybe? Seems funny that the 5 watt panel - sold by German VW and Audi - in the USA - comes from a Canadian company and is made in China. Quote Link to comment Share on other sites More sharing options...
Derek up North Posted February 29, 2016 Share Posted February 29, 2016 Well, all I know is that the 2 I've posted say VW on them but yours doesn't. I've no idea if 'yours' is sold by dealers in the US as a Genuine VW Accessory. Quote Link to comment Share on other sites More sharing options...
Maineah Posted March 1, 2016 Share Posted March 1, 2016 A lot of the newer cars lighter sockets go off with the key the OBD does not. Quote Link to comment Share on other sites More sharing options...
zero Posted March 1, 2016 Share Posted March 1, 2016 14 hours ago, Derek up North said: Well, all I know is that the 2 I've posted say VW on them but yours doesn't. I've no idea if 'yours' is sold by dealers in the US as a Genuine VW Accessory. Maybe VW and Audi get 10 cents sent to them from each sale? Who the heck knows? Why were there Chrysler minivans made in Canada in Windsor and sold in the US as Volkswagen Routans? That makes about as much sense. $7000 added to the price-tag of a Grand Caravan or Town & Country Mopar to have the VW name stuck on at some plant in Canada? This name swapping stuff drives me nuts. I just bought a Suzuki XL7 SUV because I LOVE Suzukis. Found out later it is 100% GM. NO Suzuki in it. Just the name-tag. How ironic. So I have a 2002 Chevy Tracker made by Suzuki in Canada. And now a 2008 Suzuki XL7 made by GM in God-knows-where. Suzuki wants near $1000 for a fuel pump. Must be to rebox it? I can buy the same pump when listed for a GM for $200. Quote Link to comment Share on other sites More sharing options...
Maineah Posted March 1, 2016 Share Posted March 1, 2016 Why in the world do they want $125 for a 5 watt solar panel? Must be those expensive suction cups. Quote Link to comment Share on other sites More sharing options...
zero Posted March 1, 2016 Share Posted March 1, 2016 I guess for the same reason why some people pay $12,000 for a Toyota RV while others pay $1500. Note that 5 watts (or close) solar panels had price tags of near $200 back in the early 80s. That's $40 per watt. Now - many solar panels are 75 cents a watt. Quote Link to comment Share on other sites More sharing options...
Maineah Posted March 2, 2016 Share Posted March 2, 2016 True but they were today's prices maybe be like an OEM air filter. or tail light lens. Quote Link to comment Share on other sites More sharing options...
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